CA2180314A1 - Method and apparatus for monitoring and controlling the dispensing of materials onto a substrate - Google Patents
Method and apparatus for monitoring and controlling the dispensing of materials onto a substrateInfo
- Publication number
- CA2180314A1 CA2180314A1 CA002180314A CA2180314A CA2180314A1 CA 2180314 A1 CA2180314 A1 CA 2180314A1 CA 002180314 A CA002180314 A CA 002180314A CA 2180314 A CA2180314 A CA 2180314A CA 2180314 A1 CA2180314 A1 CA 2180314A1
- Authority
- CA
- Canada
- Prior art keywords
- bead
- signal
- height
- substrate
- value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
- B05C5/02—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
- B05C5/0208—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work for applying liquid or other fluent material to separate articles
- B05C5/0212—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work for applying liquid or other fluent material to separate articles only at particular parts of the articles
- B05C5/0216—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work for applying liquid or other fluent material to separate articles only at particular parts of the articles by relative movement of article and outlet according to a predetermined path
Abstract
A dispensing system includes a robot that controls the positional location of a dispenser that dispenses a bead of material, such an adhesive, onto a substrate and wherein a sensor monitors the geometric configuration of the material dispensed. The dispensing system also includes a control circuit which receives information from the sensor so as to monitor geometric characteristics such as height, width and cross sectional area in such a manner that statistical process data can be gathered and also to provide alarm indications whenever the height or width of the bead do not comply with predetermined characteristics.
The control circuit also provides a closed loop feedback system so that the supply of material and the nozzle can be controlled in such a manner to modify the flow of bead material whenever a discrepancy or error is detected by the control circuit.
The control circuit also provides a closed loop feedback system so that the supply of material and the nozzle can be controlled in such a manner to modify the flow of bead material whenever a discrepancy or error is detected by the control circuit.
Description
-A METHOD AND APPARATUS FOR MONITORING AND
CONTROILING THE DISPENSING OF MATERIALS
ONTO A SUBSTRATE
S TECHNICAL FIELD
The invention herein resides in the art of material dispensing systems which monitor and control the ~h~r~rt~ricfinc of the bead of material being dispensed.More p~l Li~u~ y~ the present invention relates to a sensor which transmits and receives sound waves to determine the height and width of material that has beendispensed. Specifically, the present invention relates to a dispensmg system wjth a closed loop feedback control for adjusting the dispensing flow of the materjalbased upon bead llcl~u l~ Li~ monitored by a sensor.
BACKGROUND OF THE INVE~ON
1~ This invention relates generally to the dispensing of fluid materials onto substrates. More particularly, the mvention relates to the detection and/or l",-"lll"i"o of a bead of material which has been deposited onto a substrate.
Specifically, this invention is app]icable to the detection of the presence of ""li",.ili~.caSSociatedwjthadepositedbeadofmaterial,suchas,forexample, ~0 a bead of an adhesive, sealant, or caulk, as well as ~l~t~rtnininc other qualities of the deposited bead, such as its height, cross-section, or the amount of materialthat has been dispensed. This invention is especially useful in the ll"",;~ of a bead of material dispensed onto the periphery of window glass, such as a windshield in preparation for adhesively bonding the glass to the body flange of2~i a vehicle.
The presence of an air bubble passing through a nozzle of a dispensin~
system or a reduction in the material supply pressure may cause a disruption in the flow rate of material being dispensed so as to produce a ~ y or d~rtn~ti~n m the bead deposited upon the substrate. If the air bubble o} the reduction in the material supply pressure or flow rate is small, the effect on the resulting bead may be minima~. However, if the air bubble is large or the material supply pressure is inc~l~firjPnt, the effect may produce a significant ~ ' 2l8o3l4 y in the bead, or a bead having an insufficient height or cross-section.
In some dU~ dLiulls, ~ , ",lli""ili~ in the bead may not be critical, however, in otherstheymaybe. Forexample,,li~,lllllilll,ili~inabeadoftheadhesive/sealant applied to a windshield may not only affect its ability to act as a moisture barrier, S but it also may affect the strength of the bond of the windshield rn the vehicle.
Attempts have been made to detect gaps in dispensed beads ~1-tr~m~ti~ ly as opposed to an operator's visual inspection. This has mcluded monitoring pressure fluctuation within the system as set forth irl United States Patents 4,662,540 and 5,182,938, as well as monitoring the vibration of the dispenser, such as set forth in United States Patent 5,086,640. These patents attempt to detect a ~ ,llli"",ly in the bead before the bead is actually deposited onto the substrate. They only infer that a ,li~..",li,l";ly has occurred, as opposed to verifying that a ,li~ l;ly has actually occurred m the deposited bead.
Although not in the assembly of automobile glass, sensors have been used to monitor energy radiating from the deposited bead by utilizing an infrared sensor, such as shown in United States Patent 5,026,989. However, this device must be used with a heated adhesive, such as a hot melt adhesive. It therefore would not be useful with room ~ dLu~ adhesives commonly used in the automotive industry.
German Utllity Patent G 91 10 924.8 and United States Patent 4,376,244 generally teach directing a beam of light onto a substrate before the adhesive is applied and directing the beam of light onto the substrate after the drop of adhes*e has been applied. This device monitors only the presence or absence of adhesive on the substrate and does not provide a rlrlr, l"i",,li"" if sufficient~5 material, such as evident by its height and/or width, has been deposited.
Fu~Lllel~uvlr, this device requires a reflective substrate, such as metal or veneer, and may not be suitable for all substrates, such as glass.
Beads that are continuous, but not of a sufficient height or width, may also be lmr~ because the ability o~ the bead to act as a moisture barrier and/or .
~=
the strength of the bond of the window glass to the vehicle may be affected. In like mamner, beads exceeding a certain height or width may also be undesirable.
Therefore, it is desirable to be able to determine not only .~ ;",l;~ in the bead, but also to detect the quality, such as the height, width, etc. of the deposited S bead.
S~MMARY OF TED~ INVEN~ON
It is, therefore, among the aspects of this mvention to provide for the detection of gaps or (li~".lli",li~ in a dispensed bead on a substrate.
It is also an aspect of one f .I,l,,~.li-~,, ,,L of this invention to provide for the monitoring of a bead dispensed upon a substrate to detect beads not having a desirable bead height and/or cross-section.
It is also an aspect of this invention, according to one ~ bodiLl~llL~ to provide for the ",."lill";"e of a dispensed bead and to adjust the amount of 15 material dispensed from a dispenser as a result of said l~ k The foregoing and other aspects of the invention, which shall become apparent as the detailed description proceeds, are achieved by a dispensing system for ml~nitorin~ the characteristics of material dispensed onto a substrate, ~,Ulll~liaillg. a supply o~ material; a noz~le for receiving said material from said 20 supply of material and dispensing a bead of said material onto the substrate; and `a sensor for 1llllll;llll;ll~ the bead of dispensed material, wherein said sensor transmits and receives sound waves around an area of the dispensed material to determine if prf (lf tf rminPd . lldla~L~,IiaLi~a of the bead have been met.
Other aspects of the invention which will be become apparent herein are 25 achieved by a dispensing system which controls the flow of material onto a substrate, .",1,~ ;l"~. a nozzle for dispensing a bead of material onto the substrate; a non-contacting sensor that monitors at least one ~ lillf~
a~L~ liaLi~ of said bead of material; and a control circuit connected to said non-contacting sensor for regulating the flow of material based upon said at least one 3û pre~lf.tf rminf d characteristic.
.
Still other aspects of the invention are attained by a dispensing system, u~u~ g. a control circuit; a nozle for dispensing a supply of material onto a substrate in the form of a bead, wherein the flow and shape of said bead is ~iPtPrminPrl by said control circuit; and a sensor connected to said control circuit S for providmg ~ of said bead to said control circuit for analysis DESCRIPIION OF THE DRAWINGS
The following is a brief description of the drawings in which like parts may bear like reference numerals and in which:
Fig. 1 is a schematic view of the application of a bead of sealant onto the marginal edge of a windshield of a vehicle in a~ dll~ ~ with one embodiment of the invention used in ~ulljUII~ Li~ with an industrial robot;
hg. 2 is an enlarged rld~lllCllLdly portion of Fig. 1;
Fig. 3 is an enlarged cross-sectional vie~v of the dispensed bead illustrating the transmitted and received waves from a sensor;
Figs. 4A and 4B illustrate the Lldllallliaa;~ll and reception of an ultrasonic (4A) and of a shock wave Lldlla~ (4B);
Fig. 5 is a schematic of a portion of a control circuit according to one PmhnrlimPn~ of the invention; and Flg. 6 is a schematic of another portion of the control circuit for adjusting the material dispensed.
DEIAILED DESCRIPrION OF TH~ INVENTION
With reference to Figs. 1 and 2, there is illuatrated a dispensing system, shown generally as reference numeral 10, used in conjunction with an industrial robot 12, such as, for example, the type employed in the assembly of ~lltom(7hilPc or other vehicles. The dispensing system includes a dispenser 14 which is coupled via hose 16 to a supply of fluid material 18. The dispenser 14 includes a nozle 20 for dispensing a bead of material 22 onto a substrate 24. The bead of material 18 may be, for example, an adhesive, a sealant, or a caulk. In one particular d~lk ~Lioll, the substrate 24 may be glass, such as a windshield for use in vehicles.
Furthermore, the bead æ may be an adhesive, such as illustrated in EP 379 908, assi~,ned to Essex Specialty Products, Inc., which is used in the assembly of duLuluubilc window glass.
Preferably, a sensor 26 for llf~,,lill,,i,,~ the dispensed bead 22 on the substrate, is carried by the dispenser 14. For example, the sensor 26 may be mounted to the no771e 20 of the dispenser 14 by a clamping 1~ ";~," 28 or other suitable mounting means. The sensor 26 is coupled via cable 30 to electrical control circuitry, shown generally as reference numeral 32.
As seen in Fig. 3, the senso} 26 is a transducer for L~ uiLLillg and receiving ultrasonic waves or focused shock waves. The sensor 26 is useful for measuring the distance between the sensor and an object, by generating a pressure waYe and then receiving an echo as a return pressure wave after the created wave is reflected back to the sensor 26. The time interval between L~ ;"~ a pressure wave and receiving an echo or a reflected wave by the sensor 26 is a function of the distance of the bead 22 from the sensor. The timeinterval between the tr~n~ nittt f', wave 34 and the return echo 36 can be electrically processed to produce a voltage signal indicative of distance of theobject from the sensor 26.
An ultrasonic pulse or shock wave 34, shown generally as a plurality of parallel rays 38, is tr~n~ nitt~ri orthogonally toward the substrate 24. The individual rays or wavelets will strike either the bead 22 or the substrate 24 and, depending upon the angle of incidence, will either be reflected back toward the sensor 26 as depicted by rays 40 or will be deflected beyond the sensor's receiving range, such as illustrated by rays 42. For beads 22 having a triangular cross-section, the rays which strike an apex 44 of the bead 22 will be ref~ected back and received by the sensor 26 before the rays that have been reflected from the substrate 24. Furthermore, the rays 42 which strike sides 46 of the bead 22 willnot be received by the sensor due to their angular orientation relative to the sensor 26. This results in two separate echoes being received by the sensor 26, one corresponding to the top or apex 44 of the bead whi~e the other ~;Ull~ JUllda to the substrate 24. As such, the height (h) of bead 22 can be .1. . .'11.1;11. d by the following equation:
h = ~ ~txc (l) ~here ~t is the time interval between receipt of the first echo from the apex 44and the second echo from the substrate 24, and where c is the speed of sound.
The ~ factor is employed to account for the lJlu~d~aliul~ time of the ~ rll rays 38 and the reflected rays 40.
This is further lln~r~trlo-l with reference to Figs. 4A and 4B, wherein the sensor 26 is ~ Liv~ly employed to generate either an ultrasonic ~
48a of a certain duration as associated with an ultrasonic transducer or a pulse48b of a certain duration as associated with a shock wave transducer. The time interval between the Lldllalllia~iull signals 48a and 48b, and ~ull~a~ulldillg return echoes 50a and 50b from the bead is noted at time tl. The return echoes 50a, lS 50b have an amplitude 51 of the bead echo (ABE). The time rnterval between the Llcllallliaaiull signals 48a, 48b and ~ ull~:al~ulldillg return echoes 52a, 52b from the substrate is noted at t2. Likewise, the return echoes 52a, 52b have an amplitude 53 of the substrate echo (ASE). As such, the difference between t2 and tl equals ~t.
To determine the base or width of a bead 22, the amplitude of the bead echo signal 50 and substrate echo signal 52 are employed. In particular, the amplitude 53 of the substrate echoes (AS~) 52a, 52b, that is the echo reflected from the substrate, is related ,~JIU~JOI Liullally to the area of the substrate exposed to the incident l l A l l~ ;l ll l or pulse 48a, 48b. The area of the substrate exposed to this 11;111~ l)11 is inversely related to the width or base of the bead of material. In other words, less of the substrate is exposed to the ~ `;' ll l pulse if more of the substrate is covered with the bead 22. Therefore, the amplitude 53 of the substrate echoes (ASE) 52a, 52b is inversely related to the base of the bead. As a result, the amplitude 53 of the substrate echoes (ASE) 52a, 52b is greater with beads having a narrower base and is smaller with beads having a -wider base.
Where the bead 22 has a triangular ~ UII~UldLiUII, the cross-sectional area of the bead may be ~iPfprminp~l The following equation provides a value for the area:
S A = 3~ (base x height) (2) Where the value for the base is ~irtprmin~d by the amplitude 53 of the substrateecho 52a, 52b, and where the height is determined by equation (1) above. Based upon the foregoing, the quality of the dispensed bead may be ~iPtPrminPd from its height, width, or cross-sectional area by repetitively lldllsll.iLLillg a signal 48a or 48b and ~ the corresponding retum signals of the bead echo signals 50a or 50b and the .UII~UII;lillg substrate echo signals 52a or 52b on a dispensed bead along its length.
Furthermore, by knowing the cross-sectional area of the bead L~IIUU~1lUUL
its length, the volumetric output of material dispensed during a dispensing cycle, such as applying the bead 22 about the periphery of the windshield 24, may be Ptprminp~i and corrections made to rnmrPn~t~ for dispensmg more or less than the desired amount of material during the dispensing cycle.
Utilizing the bead height and bead base in conjunctiorl with a feedback control loop, the flow rate of material dispensing from the nozzle 20 may be adjusted to keep the bead within the targeted constraints. If however, the bead height, width, etc., falls below or above certain prt~-lPtPrrninPfl levels, alarms may be activated to indicate a defective bead.
In particular, Fig. S iLustrates a Ill~ ".il.~ portion of the dispensing system 10 and in particular control circuit 32. The sensor 26 is preferably a '~ type ele~ LIu~dLi~ transducer, such as m~nllf~rtllred by Cleveland Machine Controls, Inc. of Cleveland, Ohio, which provides reflected signals or echoes from the dispensed bead 22 and the substrate 24 which are then passed through signal processing circuitry 60 such as described generally in U.S. Patents 4,887,248 and 4,459,526, the disclosure of each being ill~o~uldL~d herein by reference. The signal processing circuitry 60 dPtPrminP~ and generates signals Cu~ ulldillg to the amplitude of the bead and the substrate eehoes ABE, A'iE, as well as ~t.
It can be seen that the sensor 26 is UlU~IdLivcly conneeted to the eontrol eireuit 3æ Generally, the eontrol cireuit 32 ineludes the signal proeessing eircuit 5 60, a bead measuring system 62 which includes a bead height processing circuit64 and a bead width processing circuit 66, a sensor alarm circuit 68 and a statistical proeess eontrol eireuit 70. This portion of the eontrol eircuit 32 functions to process the i r lI~A~ generated by the sensor 26 and determines whether the bead height and bead width of the dispensing bead 22 eomply with 10 pr~ ttr7ninf~ dlc~ i~.Additionally,eontroleireuit32~ t~rminPcwhether the dispensed bead æ2 eonforms to a desired shape while eolleetmg data regardingthe dispensing proeess for sllh~e~ nt analysis.
In particular, the signal proeessmg circuit 60 receives data from sensor 26 and, as discussed previously, generates a bead echo amplitude signal 51, a 15 substrate eeho amplitude signal 53 and the ~ullc~ull.:lillg time interval signal ~t which is generally represented by the numeral 71.
The time interva] signal 71 is received by the bead height processing eireuit 64. The bead height proeessing eircuit 64 includes a multiplier 72 whieh, as diseussed before, multiplies the time interval 71 by a factor of the speed of sound 20 divided by two so as to generate an analog height signal 73. The bead height processing circuit 64 then ~t~r7ninPc whether the height signal 73 is within lrd upper and lower limits and, if not, an alarm signal is generated.
In operation, the height signal 73 is received by an upper limit ~.UIII~dldlUI 74 so as to generate a difference signal that is received by a timing circuit 76. The æs timing circuit 76 in turn generates a signal that is received by a timing ~UIll~dldlUl 78. The timing circuit 76 determines for what period of time the bead height exceeds the upper limit defined by ~;UIll,Udld~UI 74. ~s such, II~UlllCillLdly or non-critical excesses in bead height will not generate the alarm signal. Therefore, if the ~ AIAIIll 78 rl~t~rmin~c that the prerll~t~rminl~l upper limit has been 30 exceeded for a time greater than a predetermined period of time, an alarm 80 is .
g activated.
In a similar fashion, the height signal 73 is received by a lower ]imit ' ""'l'H'rl"' 82- The lower limit ~ H~Al~ 82 generates a signal that js }eceivedby a timing circuit 84 which generates a timing signal that is received by a timing 5 ~UIII~)dld~UI 86. As before, if the height signal 73 falls below a ,ulrri. l. ~ ",il,fd lower ]imit for a time greater than a predetermined period of time, an alarm 88 is activated accordingly. Those skilled irl the art will also appreciate that the height signal 73 is passed on by the bead height processirlg circuit 64 to the sensor alarm circuit 68 and to the statistical process control system 70.
The bead width processing circuit 66 receives the substrate echo amplitude signal 53 to determine whether the width of the bead material 22 is within pre~Pt~nninPd upper and lower limits and, if not, an alarm signal is generated.
In particular, the substrate echo amplitude signal 53 is received by a bead width multiplier/converter 90 which generates an analog base signal 92. The base signal 15 92 is received by a, ulll,uald~ul 94 to check the bead width against a prPfiPtPnninp~ upper limit. The :ul~ d~ul 94 then generates an ~,UIu~ulidl~
signal that is received by a timing circuit 96 which provides a timing signal to a timing ~ULLI~JdldLUI 98. If the timing ;UllllUdld~Ul 98 ~iPtP.nninP~ that the bead base exceeds a prP-iPtPnninPd upper limit for a time greater than a pre~lPtPnninPd 20 period of time, an alarm 100 is activated.
In a similar manner, the base analog signal 92 is received by a lower limit ~Ulll,ua~d~ul 102. As before, the lower limit ~Ulll~JdldLUl 102 generates a signal that is received by a timing circuit 104 which generates an d~J~)lU~)lid~ signal that is received by a timing ~:u~ udldLul 106. E this signal is less than a ~
25 width foratime greaterthana~ul~lrll l ",i"r~1 periodoftime, the (UIII~dlGLUI 106 generates an d~lù~,iaL~: signal to activate an alarm 108. The bead width processirlg circuit 66 also passes through the analog base signal 92 to the statistical process corltrol circuit 70.
The sensor alarm circuit 68 is employed to perform a sensor check to ensure that the sensor 26 is functional and free from ~ H I ~ . In operation, the sensor 26 is placed over a reference bead-substrate pair of fixed and known .li,,,. ,~i..,,c In response to a sensor check command, circuit 68 compares incoming ABE 51, ASE 53, and bead height analog signal 73, with pre-f'lf ff rmin~ d reference values for the bead-substrate pair. If the incoming AE',E 51, AC,E 53,5 and bead height analog signal 73, match the pr~tf-rminf-d reference values forthe bead-substrate pair then the sensor 26 is deemed functional and free from ...,.,li~,,,;.,i1linn If not, then a sensor alarm 116 is activated indicating a sensor m~lfi~nftinn or ~
As mentioned previously, the statistical process control circuit 70 receives the analog height sigmal 73, the analog base signal 92 and, additionally, an external sampling signal 118. It also receives all previously mentioned alarms indicated collectively as 119. Those skilled in the art will appreciate that the statistical process control circuit 70 employs the signals 73, 92,118 and 119 to generate and store the necessary data i"r."",~lif.,. for analysis by quality control personnel ~ ullal~lc for the operation of the dispensing system 10.
Referring now to Fig. 6, it will be d~ idL~d that the control circuit 32 also utilizes the data generated by the bead measuring system 62 within a closedloop feedback system for the dispenser system 10. In particular, this portion ofthe control circuit 32 includes the bead measuring system 62 and a variable flowrate controller 120. It will be appreciated then that the control circuit 32, which is connected to the sensor 26 and the material supply 18, monitors the amplitudeof the sound waves reflected from the dispensed material, the amplitude of the sound waves reflected from the substrate, and a time difference between when thes~mplitllf',f~c of the reflected sound waves are received by the sensor so as tocontrol the flow of the material onto the substrate.
In particular, the sensor 26, .,,l,l,.ll.,;. ,l~ ~ with the bead measuring system 63 which, as discussed previously, generates an analog base signal 92 and an analog height signal 73. A multiplier 122 receives both the base signal 92 and height signal 73 and multiplies them so as to generate an area signal 124. The area signal 124 is then received by a cross sectional area ~ fJ~ dldlul 126 which :
~ t~.rminl~c the difference between a desired target cross sectional area and the actual value of the bead material cross sectional area and generates a correction signal 128 that is rece*ed by the variable flow rate controller 120. In a similar manner, the analog base signal 92 is received by a bead base target ~iulu~alaLul13Q The ~ 130 generates a base correction signal 132 which provides the difference between the measured base signal and the desired target value of the base signal to the variable flow rate controller 120. Fmally, the analog height signal 73 is received by a bead height target ~U~ dldLul 134. Based upon the difference between the measured height sigmal 73 and the desired height target, the ~Ulll~ala~ul 134 generates a height correction signal 136 that is also received by the variable flow rate controller 120.
Based upon the correction signals 128, 132 and 136 received by the variable flow rate controller 120, ~ull~."uul~ lg correction signals are sent to either the material supply 18 or to the dispenser 14 so as to adjust the shape and ~u~lfi~;ulaLiull of the material bead 22. Those skilled in the art will appreciate that the dispenser 14 could be a variable orifice gun which controls the manner in which the material is dispensed from the dispenser 14 so as to control the shapeof the bead or that the variable flow rate controller 120 could control a variable speed gear pump l.lllllllllllli. ~liv~ with the material supply 18 so as to control the amount of material flow onto the substrate.
Based upon the foregoing discussion of the structure and operation of the dispensing system 10, it should be apparent that the dispensing system provides numerous advantages over the prior art. In particular, the present invention provides the advantage of an on-line bead lu~a~ul~luC.IL and control system using a sensor that does not come in contact with the measured material. This invention allows the dispensing system 10 to s~llfl~m~tir~lly correct any malfunctions within the dispensing system so as to ensure the smooth operation of the assembly line. Additionally, the bead Ill~a>ul~ and control system employed allows for an alarm system that indicates when the dispensed bead does 30 not conform to the l~.luil. ll.~ of the assembly process. This further allows the ; ~
2l8o3l4 "..,.,",.r,..l";..g bead to be easily identified and reworked so as to minimize machine down time and ms~n-lf~tllrine costs. Yet another advantage of the alarm system is that if the upper or lower bead height and base limits are only exceeded for less than a pr~1Pt~rmin~l period of time, the alarms are not activated. As such, the dispensing system disclosed is sensitive enough to disregard minor in the shape of the bead material. It will be dLJ~lCl.id~t d that the pr~ t~-rmin~d periods of time can be adjusted as required by particular dispensing ~ I;cd~io~
A further advantage of the present dispensing system is that real time 10 U~ Ul~ iU~lL~ can be taken of the bead height and bead base .li",~ :. ",~ so as to provide statistical process control infi-rm~ltitln to the d,u~JIu~ulial~ persommel in the m~nllf:~tllrjn~ facility. This allows ",,.""r," ll" i"~ engineers to deterrnine the characteristics of various materials, substrates, sensors, and dispensing devices used in the mslnllf~tllrin~ operation.
Thus, it can be seen that the objects of the invention have been satisfied by the structure presented above. It should be apparent to those skilled in the art that the objects of the present invention could be practiced with a wide variety of materials and substrates as required.
While only the best mode and preferred embodiment of the invention has 20 been presented and described in detail, it will be understood that the invention is not limited thereto or thereby. Accordingly, for an ùlululc~ Liull of the true scope and breadth of the invention, reference should be made to the following claims.
CONTROILING THE DISPENSING OF MATERIALS
ONTO A SUBSTRATE
S TECHNICAL FIELD
The invention herein resides in the art of material dispensing systems which monitor and control the ~h~r~rt~ricfinc of the bead of material being dispensed.More p~l Li~u~ y~ the present invention relates to a sensor which transmits and receives sound waves to determine the height and width of material that has beendispensed. Specifically, the present invention relates to a dispensmg system wjth a closed loop feedback control for adjusting the dispensing flow of the materjalbased upon bead llcl~u l~ Li~ monitored by a sensor.
BACKGROUND OF THE INVE~ON
1~ This invention relates generally to the dispensing of fluid materials onto substrates. More particularly, the mvention relates to the detection and/or l",-"lll"i"o of a bead of material which has been deposited onto a substrate.
Specifically, this invention is app]icable to the detection of the presence of ""li",.ili~.caSSociatedwjthadepositedbeadofmaterial,suchas,forexample, ~0 a bead of an adhesive, sealant, or caulk, as well as ~l~t~rtnininc other qualities of the deposited bead, such as its height, cross-section, or the amount of materialthat has been dispensed. This invention is especially useful in the ll"",;~ of a bead of material dispensed onto the periphery of window glass, such as a windshield in preparation for adhesively bonding the glass to the body flange of2~i a vehicle.
The presence of an air bubble passing through a nozzle of a dispensin~
system or a reduction in the material supply pressure may cause a disruption in the flow rate of material being dispensed so as to produce a ~ y or d~rtn~ti~n m the bead deposited upon the substrate. If the air bubble o} the reduction in the material supply pressure or flow rate is small, the effect on the resulting bead may be minima~. However, if the air bubble is large or the material supply pressure is inc~l~firjPnt, the effect may produce a significant ~ ' 2l8o3l4 y in the bead, or a bead having an insufficient height or cross-section.
In some dU~ dLiulls, ~ , ",lli""ili~ in the bead may not be critical, however, in otherstheymaybe. Forexample,,li~,lllllilll,ili~inabeadoftheadhesive/sealant applied to a windshield may not only affect its ability to act as a moisture barrier, S but it also may affect the strength of the bond of the windshield rn the vehicle.
Attempts have been made to detect gaps in dispensed beads ~1-tr~m~ti~ ly as opposed to an operator's visual inspection. This has mcluded monitoring pressure fluctuation within the system as set forth irl United States Patents 4,662,540 and 5,182,938, as well as monitoring the vibration of the dispenser, such as set forth in United States Patent 5,086,640. These patents attempt to detect a ~ ,llli"",ly in the bead before the bead is actually deposited onto the substrate. They only infer that a ,li~..",li,l";ly has occurred, as opposed to verifying that a ,li~ l;ly has actually occurred m the deposited bead.
Although not in the assembly of automobile glass, sensors have been used to monitor energy radiating from the deposited bead by utilizing an infrared sensor, such as shown in United States Patent 5,026,989. However, this device must be used with a heated adhesive, such as a hot melt adhesive. It therefore would not be useful with room ~ dLu~ adhesives commonly used in the automotive industry.
German Utllity Patent G 91 10 924.8 and United States Patent 4,376,244 generally teach directing a beam of light onto a substrate before the adhesive is applied and directing the beam of light onto the substrate after the drop of adhes*e has been applied. This device monitors only the presence or absence of adhesive on the substrate and does not provide a rlrlr, l"i",,li"" if sufficient~5 material, such as evident by its height and/or width, has been deposited.
Fu~Lllel~uvlr, this device requires a reflective substrate, such as metal or veneer, and may not be suitable for all substrates, such as glass.
Beads that are continuous, but not of a sufficient height or width, may also be lmr~ because the ability o~ the bead to act as a moisture barrier and/or .
~=
the strength of the bond of the window glass to the vehicle may be affected. In like mamner, beads exceeding a certain height or width may also be undesirable.
Therefore, it is desirable to be able to determine not only .~ ;",l;~ in the bead, but also to detect the quality, such as the height, width, etc. of the deposited S bead.
S~MMARY OF TED~ INVEN~ON
It is, therefore, among the aspects of this mvention to provide for the detection of gaps or (li~".lli",li~ in a dispensed bead on a substrate.
It is also an aspect of one f .I,l,,~.li-~,, ,,L of this invention to provide for the monitoring of a bead dispensed upon a substrate to detect beads not having a desirable bead height and/or cross-section.
It is also an aspect of this invention, according to one ~ bodiLl~llL~ to provide for the ",."lill";"e of a dispensed bead and to adjust the amount of 15 material dispensed from a dispenser as a result of said l~ k The foregoing and other aspects of the invention, which shall become apparent as the detailed description proceeds, are achieved by a dispensing system for ml~nitorin~ the characteristics of material dispensed onto a substrate, ~,Ulll~liaillg. a supply o~ material; a noz~le for receiving said material from said 20 supply of material and dispensing a bead of said material onto the substrate; and `a sensor for 1llllll;llll;ll~ the bead of dispensed material, wherein said sensor transmits and receives sound waves around an area of the dispensed material to determine if prf (lf tf rminPd . lldla~L~,IiaLi~a of the bead have been met.
Other aspects of the invention which will be become apparent herein are 25 achieved by a dispensing system which controls the flow of material onto a substrate, .",1,~ ;l"~. a nozzle for dispensing a bead of material onto the substrate; a non-contacting sensor that monitors at least one ~ lillf~
a~L~ liaLi~ of said bead of material; and a control circuit connected to said non-contacting sensor for regulating the flow of material based upon said at least one 3û pre~lf.tf rminf d characteristic.
.
Still other aspects of the invention are attained by a dispensing system, u~u~ g. a control circuit; a nozle for dispensing a supply of material onto a substrate in the form of a bead, wherein the flow and shape of said bead is ~iPtPrminPrl by said control circuit; and a sensor connected to said control circuit S for providmg ~ of said bead to said control circuit for analysis DESCRIPIION OF THE DRAWINGS
The following is a brief description of the drawings in which like parts may bear like reference numerals and in which:
Fig. 1 is a schematic view of the application of a bead of sealant onto the marginal edge of a windshield of a vehicle in a~ dll~ ~ with one embodiment of the invention used in ~ulljUII~ Li~ with an industrial robot;
hg. 2 is an enlarged rld~lllCllLdly portion of Fig. 1;
Fig. 3 is an enlarged cross-sectional vie~v of the dispensed bead illustrating the transmitted and received waves from a sensor;
Figs. 4A and 4B illustrate the Lldllallliaa;~ll and reception of an ultrasonic (4A) and of a shock wave Lldlla~ (4B);
Fig. 5 is a schematic of a portion of a control circuit according to one PmhnrlimPn~ of the invention; and Flg. 6 is a schematic of another portion of the control circuit for adjusting the material dispensed.
DEIAILED DESCRIPrION OF TH~ INVENTION
With reference to Figs. 1 and 2, there is illuatrated a dispensing system, shown generally as reference numeral 10, used in conjunction with an industrial robot 12, such as, for example, the type employed in the assembly of ~lltom(7hilPc or other vehicles. The dispensing system includes a dispenser 14 which is coupled via hose 16 to a supply of fluid material 18. The dispenser 14 includes a nozle 20 for dispensing a bead of material 22 onto a substrate 24. The bead of material 18 may be, for example, an adhesive, a sealant, or a caulk. In one particular d~lk ~Lioll, the substrate 24 may be glass, such as a windshield for use in vehicles.
Furthermore, the bead æ may be an adhesive, such as illustrated in EP 379 908, assi~,ned to Essex Specialty Products, Inc., which is used in the assembly of duLuluubilc window glass.
Preferably, a sensor 26 for llf~,,lill,,i,,~ the dispensed bead 22 on the substrate, is carried by the dispenser 14. For example, the sensor 26 may be mounted to the no771e 20 of the dispenser 14 by a clamping 1~ ";~," 28 or other suitable mounting means. The sensor 26 is coupled via cable 30 to electrical control circuitry, shown generally as reference numeral 32.
As seen in Fig. 3, the senso} 26 is a transducer for L~ uiLLillg and receiving ultrasonic waves or focused shock waves. The sensor 26 is useful for measuring the distance between the sensor and an object, by generating a pressure waYe and then receiving an echo as a return pressure wave after the created wave is reflected back to the sensor 26. The time interval between L~ ;"~ a pressure wave and receiving an echo or a reflected wave by the sensor 26 is a function of the distance of the bead 22 from the sensor. The timeinterval between the tr~n~ nittt f', wave 34 and the return echo 36 can be electrically processed to produce a voltage signal indicative of distance of theobject from the sensor 26.
An ultrasonic pulse or shock wave 34, shown generally as a plurality of parallel rays 38, is tr~n~ nitt~ri orthogonally toward the substrate 24. The individual rays or wavelets will strike either the bead 22 or the substrate 24 and, depending upon the angle of incidence, will either be reflected back toward the sensor 26 as depicted by rays 40 or will be deflected beyond the sensor's receiving range, such as illustrated by rays 42. For beads 22 having a triangular cross-section, the rays which strike an apex 44 of the bead 22 will be ref~ected back and received by the sensor 26 before the rays that have been reflected from the substrate 24. Furthermore, the rays 42 which strike sides 46 of the bead 22 willnot be received by the sensor due to their angular orientation relative to the sensor 26. This results in two separate echoes being received by the sensor 26, one corresponding to the top or apex 44 of the bead whi~e the other ~;Ull~ JUllda to the substrate 24. As such, the height (h) of bead 22 can be .1. . .'11.1;11. d by the following equation:
h = ~ ~txc (l) ~here ~t is the time interval between receipt of the first echo from the apex 44and the second echo from the substrate 24, and where c is the speed of sound.
The ~ factor is employed to account for the lJlu~d~aliul~ time of the ~ rll rays 38 and the reflected rays 40.
This is further lln~r~trlo-l with reference to Figs. 4A and 4B, wherein the sensor 26 is ~ Liv~ly employed to generate either an ultrasonic ~
48a of a certain duration as associated with an ultrasonic transducer or a pulse48b of a certain duration as associated with a shock wave transducer. The time interval between the Lldllalllia~iull signals 48a and 48b, and ~ull~a~ulldillg return echoes 50a and 50b from the bead is noted at time tl. The return echoes 50a, lS 50b have an amplitude 51 of the bead echo (ABE). The time rnterval between the Llcllallliaaiull signals 48a, 48b and ~ ull~:al~ulldillg return echoes 52a, 52b from the substrate is noted at t2. Likewise, the return echoes 52a, 52b have an amplitude 53 of the substrate echo (ASE). As such, the difference between t2 and tl equals ~t.
To determine the base or width of a bead 22, the amplitude of the bead echo signal 50 and substrate echo signal 52 are employed. In particular, the amplitude 53 of the substrate echoes (AS~) 52a, 52b, that is the echo reflected from the substrate, is related ,~JIU~JOI Liullally to the area of the substrate exposed to the incident l l A l l~ ;l ll l or pulse 48a, 48b. The area of the substrate exposed to this 11;111~ l)11 is inversely related to the width or base of the bead of material. In other words, less of the substrate is exposed to the ~ `;' ll l pulse if more of the substrate is covered with the bead 22. Therefore, the amplitude 53 of the substrate echoes (ASE) 52a, 52b is inversely related to the base of the bead. As a result, the amplitude 53 of the substrate echoes (ASE) 52a, 52b is greater with beads having a narrower base and is smaller with beads having a -wider base.
Where the bead 22 has a triangular ~ UII~UldLiUII, the cross-sectional area of the bead may be ~iPfprminp~l The following equation provides a value for the area:
S A = 3~ (base x height) (2) Where the value for the base is ~irtprmin~d by the amplitude 53 of the substrateecho 52a, 52b, and where the height is determined by equation (1) above. Based upon the foregoing, the quality of the dispensed bead may be ~iPtPrminPd from its height, width, or cross-sectional area by repetitively lldllsll.iLLillg a signal 48a or 48b and ~ the corresponding retum signals of the bead echo signals 50a or 50b and the .UII~UII;lillg substrate echo signals 52a or 52b on a dispensed bead along its length.
Furthermore, by knowing the cross-sectional area of the bead L~IIUU~1lUUL
its length, the volumetric output of material dispensed during a dispensing cycle, such as applying the bead 22 about the periphery of the windshield 24, may be Ptprminp~i and corrections made to rnmrPn~t~ for dispensmg more or less than the desired amount of material during the dispensing cycle.
Utilizing the bead height and bead base in conjunctiorl with a feedback control loop, the flow rate of material dispensing from the nozzle 20 may be adjusted to keep the bead within the targeted constraints. If however, the bead height, width, etc., falls below or above certain prt~-lPtPrrninPfl levels, alarms may be activated to indicate a defective bead.
In particular, Fig. S iLustrates a Ill~ ".il.~ portion of the dispensing system 10 and in particular control circuit 32. The sensor 26 is preferably a '~ type ele~ LIu~dLi~ transducer, such as m~nllf~rtllred by Cleveland Machine Controls, Inc. of Cleveland, Ohio, which provides reflected signals or echoes from the dispensed bead 22 and the substrate 24 which are then passed through signal processing circuitry 60 such as described generally in U.S. Patents 4,887,248 and 4,459,526, the disclosure of each being ill~o~uldL~d herein by reference. The signal processing circuitry 60 dPtPrminP~ and generates signals Cu~ ulldillg to the amplitude of the bead and the substrate eehoes ABE, A'iE, as well as ~t.
It can be seen that the sensor 26 is UlU~IdLivcly conneeted to the eontrol eireuit 3æ Generally, the eontrol cireuit 32 ineludes the signal proeessing eircuit 5 60, a bead measuring system 62 which includes a bead height processing circuit64 and a bead width processing circuit 66, a sensor alarm circuit 68 and a statistical proeess eontrol eireuit 70. This portion of the eontrol eircuit 32 functions to process the i r lI~A~ generated by the sensor 26 and determines whether the bead height and bead width of the dispensing bead 22 eomply with 10 pr~ ttr7ninf~ dlc~ i~.Additionally,eontroleireuit32~ t~rminPcwhether the dispensed bead æ2 eonforms to a desired shape while eolleetmg data regardingthe dispensing proeess for sllh~e~ nt analysis.
In particular, the signal proeessmg circuit 60 receives data from sensor 26 and, as discussed previously, generates a bead echo amplitude signal 51, a 15 substrate eeho amplitude signal 53 and the ~ullc~ull.:lillg time interval signal ~t which is generally represented by the numeral 71.
The time interva] signal 71 is received by the bead height processing eireuit 64. The bead height proeessing eircuit 64 includes a multiplier 72 whieh, as diseussed before, multiplies the time interval 71 by a factor of the speed of sound 20 divided by two so as to generate an analog height signal 73. The bead height processing circuit 64 then ~t~r7ninPc whether the height signal 73 is within lrd upper and lower limits and, if not, an alarm signal is generated.
In operation, the height signal 73 is received by an upper limit ~.UIII~dldlUI 74 so as to generate a difference signal that is received by a timing circuit 76. The æs timing circuit 76 in turn generates a signal that is received by a timing ~UIll~dldlUl 78. The timing circuit 76 determines for what period of time the bead height exceeds the upper limit defined by ~;UIll,Udld~UI 74. ~s such, II~UlllCillLdly or non-critical excesses in bead height will not generate the alarm signal. Therefore, if the ~ AIAIIll 78 rl~t~rmin~c that the prerll~t~rminl~l upper limit has been 30 exceeded for a time greater than a predetermined period of time, an alarm 80 is .
g activated.
In a similar fashion, the height signal 73 is received by a lower ]imit ' ""'l'H'rl"' 82- The lower limit ~ H~Al~ 82 generates a signal that js }eceivedby a timing circuit 84 which generates a timing signal that is received by a timing 5 ~UIII~)dld~UI 86. As before, if the height signal 73 falls below a ,ulrri. l. ~ ",il,fd lower ]imit for a time greater than a predetermined period of time, an alarm 88 is activated accordingly. Those skilled irl the art will also appreciate that the height signal 73 is passed on by the bead height processirlg circuit 64 to the sensor alarm circuit 68 and to the statistical process control system 70.
The bead width processing circuit 66 receives the substrate echo amplitude signal 53 to determine whether the width of the bead material 22 is within pre~Pt~nninPd upper and lower limits and, if not, an alarm signal is generated.
In particular, the substrate echo amplitude signal 53 is received by a bead width multiplier/converter 90 which generates an analog base signal 92. The base signal 15 92 is received by a, ulll,uald~ul 94 to check the bead width against a prPfiPtPnninp~ upper limit. The :ul~ d~ul 94 then generates an ~,UIu~ulidl~
signal that is received by a timing circuit 96 which provides a timing signal to a timing ~ULLI~JdldLUI 98. If the timing ;UllllUdld~Ul 98 ~iPtP.nninP~ that the bead base exceeds a prP-iPtPnninPd upper limit for a time greater than a pre~lPtPnninPd 20 period of time, an alarm 100 is activated.
In a similar manner, the base analog signal 92 is received by a lower limit ~Ulll,ua~d~ul 102. As before, the lower limit ~Ulll~JdldLUl 102 generates a signal that is received by a timing circuit 104 which generates an d~J~)lU~)lid~ signal that is received by a timing ~:u~ udldLul 106. E this signal is less than a ~
25 width foratime greaterthana~ul~lrll l ",i"r~1 periodoftime, the (UIII~dlGLUI 106 generates an d~lù~,iaL~: signal to activate an alarm 108. The bead width processirlg circuit 66 also passes through the analog base signal 92 to the statistical process corltrol circuit 70.
The sensor alarm circuit 68 is employed to perform a sensor check to ensure that the sensor 26 is functional and free from ~ H I ~ . In operation, the sensor 26 is placed over a reference bead-substrate pair of fixed and known .li,,,. ,~i..,,c In response to a sensor check command, circuit 68 compares incoming ABE 51, ASE 53, and bead height analog signal 73, with pre-f'lf ff rmin~ d reference values for the bead-substrate pair. If the incoming AE',E 51, AC,E 53,5 and bead height analog signal 73, match the pr~tf-rminf-d reference values forthe bead-substrate pair then the sensor 26 is deemed functional and free from ...,.,li~,,,;.,i1linn If not, then a sensor alarm 116 is activated indicating a sensor m~lfi~nftinn or ~
As mentioned previously, the statistical process control circuit 70 receives the analog height sigmal 73, the analog base signal 92 and, additionally, an external sampling signal 118. It also receives all previously mentioned alarms indicated collectively as 119. Those skilled in the art will appreciate that the statistical process control circuit 70 employs the signals 73, 92,118 and 119 to generate and store the necessary data i"r."",~lif.,. for analysis by quality control personnel ~ ullal~lc for the operation of the dispensing system 10.
Referring now to Fig. 6, it will be d~ idL~d that the control circuit 32 also utilizes the data generated by the bead measuring system 62 within a closedloop feedback system for the dispenser system 10. In particular, this portion ofthe control circuit 32 includes the bead measuring system 62 and a variable flowrate controller 120. It will be appreciated then that the control circuit 32, which is connected to the sensor 26 and the material supply 18, monitors the amplitudeof the sound waves reflected from the dispensed material, the amplitude of the sound waves reflected from the substrate, and a time difference between when thes~mplitllf',f~c of the reflected sound waves are received by the sensor so as tocontrol the flow of the material onto the substrate.
In particular, the sensor 26, .,,l,l,.ll.,;. ,l~ ~ with the bead measuring system 63 which, as discussed previously, generates an analog base signal 92 and an analog height signal 73. A multiplier 122 receives both the base signal 92 and height signal 73 and multiplies them so as to generate an area signal 124. The area signal 124 is then received by a cross sectional area ~ fJ~ dldlul 126 which :
~ t~.rminl~c the difference between a desired target cross sectional area and the actual value of the bead material cross sectional area and generates a correction signal 128 that is rece*ed by the variable flow rate controller 120. In a similar manner, the analog base signal 92 is received by a bead base target ~iulu~alaLul13Q The ~ 130 generates a base correction signal 132 which provides the difference between the measured base signal and the desired target value of the base signal to the variable flow rate controller 120. Fmally, the analog height signal 73 is received by a bead height target ~U~ dldLul 134. Based upon the difference between the measured height sigmal 73 and the desired height target, the ~Ulll~ala~ul 134 generates a height correction signal 136 that is also received by the variable flow rate controller 120.
Based upon the correction signals 128, 132 and 136 received by the variable flow rate controller 120, ~ull~."uul~ lg correction signals are sent to either the material supply 18 or to the dispenser 14 so as to adjust the shape and ~u~lfi~;ulaLiull of the material bead 22. Those skilled in the art will appreciate that the dispenser 14 could be a variable orifice gun which controls the manner in which the material is dispensed from the dispenser 14 so as to control the shapeof the bead or that the variable flow rate controller 120 could control a variable speed gear pump l.lllllllllllli. ~liv~ with the material supply 18 so as to control the amount of material flow onto the substrate.
Based upon the foregoing discussion of the structure and operation of the dispensing system 10, it should be apparent that the dispensing system provides numerous advantages over the prior art. In particular, the present invention provides the advantage of an on-line bead lu~a~ul~luC.IL and control system using a sensor that does not come in contact with the measured material. This invention allows the dispensing system 10 to s~llfl~m~tir~lly correct any malfunctions within the dispensing system so as to ensure the smooth operation of the assembly line. Additionally, the bead Ill~a>ul~ and control system employed allows for an alarm system that indicates when the dispensed bead does 30 not conform to the l~.luil. ll.~ of the assembly process. This further allows the ; ~
2l8o3l4 "..,.,",.r,..l";..g bead to be easily identified and reworked so as to minimize machine down time and ms~n-lf~tllrine costs. Yet another advantage of the alarm system is that if the upper or lower bead height and base limits are only exceeded for less than a pr~1Pt~rmin~l period of time, the alarms are not activated. As such, the dispensing system disclosed is sensitive enough to disregard minor in the shape of the bead material. It will be dLJ~lCl.id~t d that the pr~ t~-rmin~d periods of time can be adjusted as required by particular dispensing ~ I;cd~io~
A further advantage of the present dispensing system is that real time 10 U~ Ul~ iU~lL~ can be taken of the bead height and bead base .li",~ :. ",~ so as to provide statistical process control infi-rm~ltitln to the d,u~JIu~ulial~ persommel in the m~nllf:~tllrjn~ facility. This allows ",,.""r," ll" i"~ engineers to deterrnine the characteristics of various materials, substrates, sensors, and dispensing devices used in the mslnllf~tllrin~ operation.
Thus, it can be seen that the objects of the invention have been satisfied by the structure presented above. It should be apparent to those skilled in the art that the objects of the present invention could be practiced with a wide variety of materials and substrates as required.
While only the best mode and preferred embodiment of the invention has 20 been presented and described in detail, it will be understood that the invention is not limited thereto or thereby. Accordingly, for an ùlululc~ Liull of the true scope and breadth of the invention, reference should be made to the following claims.
Claims (18)
1. A dispensing system for monitoring the characteristics of a bead of material dispensed onto a substrate, comprising:
a supply of material;
a nozzle for receiving said material from said supply of material and dispensing a bead of said material onto the substrate; and a sensor for monitoring the bead of dispensed material, wherein said sensor transmits and receives sound waves around an area of the dispensed bead of material to determine if predetermined characteristics of the bead have been met.
a supply of material;
a nozzle for receiving said material from said supply of material and dispensing a bead of said material onto the substrate; and a sensor for monitoring the bead of dispensed material, wherein said sensor transmits and receives sound waves around an area of the dispensed bead of material to determine if predetermined characteristics of the bead have been met.
2. The dispensing system according to claim 1, further comprising a control circuit connected to said sensor, wherein said control circuit monitors an amplitude of the sound waves reflected from the bead of dispensed material and the substrate and determines a time difference between when the amplitude of respective reflected sound waves are received by said sensor and accordingly controls the flow of said material onto the substrate.
3. The dispensing system according to claim 2, wherein said control circuit comprises:
a signal processing circuit connected to said sensor for generating said time difference and a substrate echo amplitude signal; and a bead height and width processing circuit for comparing said time difference and said substrate echo amplitude signal to corresponding predetermined ranges and activating an appropriate alarm if one of said time difference and said substrate echo signals are not within said predetermined ranges.
a signal processing circuit connected to said sensor for generating said time difference and a substrate echo amplitude signal; and a bead height and width processing circuit for comparing said time difference and said substrate echo amplitude signal to corresponding predetermined ranges and activating an appropriate alarm if one of said time difference and said substrate echo signals are not within said predetermined ranges.
4. The dispensing system according to claim 3, wherein said signal processing circuit generates a bead echo amplitude signal, and wherein an echo amplitude processing circuit receives both said substrate echo amplitude signal and said bead echo amplitude signal to ensure that said sensor is functional and free from contamination.
5. The dispensing system according to claim 4, wherein said bead height and width processing circuit generates a height value and a base value for the dispensed material which are received by a statistical process control circuit for data storage and analysis.
6. The dispensing system according to claim 5, wherein said control circuit further comprises:
a multiplier for receiving said height value and said base value for calculating an area value, and wherein said height value, said base value and said area value are compared against respective target values so as to generate respective correction signals; and a variable flow rate controller to control the dispensing of said material.
a multiplier for receiving said height value and said base value for calculating an area value, and wherein said height value, said base value and said area value are compared against respective target values so as to generate respective correction signals; and a variable flow rate controller to control the dispensing of said material.
7. A dispensing system which controls the flow of material onto a substrate, comprising:
a nozzle for dispensing a bead of material onto the substrate;
a non-contacting sensor that monitors at least one predetermined characteristic of said bead of material; and a control circuit connected to said non-contacting sensor for regulating the flow of material based upon said at least one predetermined characteristic.
a nozzle for dispensing a bead of material onto the substrate;
a non-contacting sensor that monitors at least one predetermined characteristic of said bead of material; and a control circuit connected to said non-contacting sensor for regulating the flow of material based upon said at least one predetermined characteristic.
8. The dispensing system according to claim 7, wherein said non-contacting sensor is carried by said nozzle in such a manner than said control circuit generates and monitors a height value, a base value, and a corresponding area value wherein said control circuit is employed to control the height and base ofsaid bead of material depending upon said base, height and area signals.
9. The dispensing system according to claim 7, further comprising:
a height comparator for comparing said height value to a desired height value and generating a corresponding height correction signal;
a base comparator for comparing said base value to a desired base value and generating a corresponding base correction signal;
an area comparator for comparing said area value to a desired area value and generating a corresponding area correction signal; and a variable flow rate controller for receiving said height correction signal, said base correction signal and said area correction signal, wherein said variable flow rate controller adjusts the shape of said bead of material based upon any one of said height, base and area correction signals.
a height comparator for comparing said height value to a desired height value and generating a corresponding height correction signal;
a base comparator for comparing said base value to a desired base value and generating a corresponding base correction signal;
an area comparator for comparing said area value to a desired area value and generating a corresponding area correction signal; and a variable flow rate controller for receiving said height correction signal, said base correction signal and said area correction signal, wherein said variable flow rate controller adjusts the shape of said bead of material based upon any one of said height, base and area correction signals.
10. The dispensing system according to claim 7 wherein said non-contacting sensor transmits a pulse wave onto the substrate with said dispensing material and wherein said non-contacting sensor receives a reflection of said pulse wave in the form of a bead echo amplitude signal and a substrate echo amplitude signal.
11. The dispensing system according to claim 10 wherein the height of said bead of material is determined by measuring the time difference between when said bead echo amplitude signal and said substrate echo amplitude signal are received by said non-contacting sensor, and multiplying this time difference by an appropriate factor.
12. The dispensing system according to claim 10, wherein the width of said bead of material is determined by measuring the amplitude of one of said bead echo amplitude signal and said substrate echo amplitude signal and multiplying by an appropriate factor.
13. A dispensing system, comprising:
a control circuit;
a nozzle for dispensing a supply of material onto a substrate in the form of a bead, wherein the flow and shape of said bead is determined by said control circuit; and a sensor connected to said control circuit for providing indicia of characteristics of said bead to said control circuit for analysis.
a control circuit;
a nozzle for dispensing a supply of material onto a substrate in the form of a bead, wherein the flow and shape of said bead is determined by said control circuit; and a sensor connected to said control circuit for providing indicia of characteristics of said bead to said control circuit for analysis.
14. The dispensing system according to claim 13, wherein said sensor transmits pulses onto said bead and said substrate and receives reflected pulses in return.
15. The dispensing system according to claim 14, wherein said control circuit comprises:
a signal processing circuit for receiving said reflected pulses and generating a bead echo amplitude signal, a substrate echo amplitude signal and a time difference signal corresponding to the time period between when said bead echo amplitude signal and said substrate echo amplitude signal are generated;
a bead measuring system for receiving said substrate echo amplitude signal and said time difference signal and generating a corresponding bead height signal and a corresponding bead width signal; and an echo amplitude circuit for receiving said bead echo amplitude signal and said substrate echo amplitude signal to ensure that said sensor is functional and free from contamination,
a signal processing circuit for receiving said reflected pulses and generating a bead echo amplitude signal, a substrate echo amplitude signal and a time difference signal corresponding to the time period between when said bead echo amplitude signal and said substrate echo amplitude signal are generated;
a bead measuring system for receiving said substrate echo amplitude signal and said time difference signal and generating a corresponding bead height signal and a corresponding bead width signal; and an echo amplitude circuit for receiving said bead echo amplitude signal and said substrate echo amplitude signal to ensure that said sensor is functional and free from contamination,
16. The dispensing system according to claim 15, wherein said bead measuring system activates an alarm whenever one of said bead height signal an said bead width signal exceeds corresponding predetermined ranges for corresponding predetermined periods of time.
17. The dispensing system according to claim 16, wherein said control circuit further comprises:
a multiplier for multiplying said bead height value by said bead width value to generate an area value;
a height comparator for comparing said height value to a desired height value and generating a corresponding height correction signal;
a bead width comparator for comparing said bead width value to a desired bead width value and generating a corresponding bead width correction signal;
an area comparator for comparing said area value to a desired area value and generating a corresponding area correction signal; and a variable correction signal, said bead width correction signal and said area correction signal, wherein said variable flow rate controller adjusts the shape of said bead of material based upon any one of said height correction signal, bead width correction signal and said area correction signal.
a multiplier for multiplying said bead height value by said bead width value to generate an area value;
a height comparator for comparing said height value to a desired height value and generating a corresponding height correction signal;
a bead width comparator for comparing said bead width value to a desired bead width value and generating a corresponding bead width correction signal;
an area comparator for comparing said area value to a desired area value and generating a corresponding area correction signal; and a variable correction signal, said bead width correction signal and said area correction signal, wherein said variable flow rate controller adjusts the shape of said bead of material based upon any one of said height correction signal, bead width correction signal and said area correction signal.
18. The dispensing system according to claim 16, wherein said control circuit further comprises:
a statistical process control circuit which receives said bead width value, said height value and an external sampling signal for analysis.
a statistical process control circuit which receives said bead width value, said height value and an external sampling signal for analysis.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/509,132 | 1995-07-31 | ||
| US08/509,132 US5666325A (en) | 1995-07-31 | 1995-07-31 | Method and apparatus for monitoring and controlling the dispensing of materials onto a substrate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2180314A1 true CA2180314A1 (en) | 1997-02-01 |
Family
ID=24025408
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002180314A Abandoned CA2180314A1 (en) | 1995-07-31 | 1996-07-02 | Method and apparatus for monitoring and controlling the dispensing of materials onto a substrate |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5666325A (en) |
| EP (1) | EP0757232A3 (en) |
| CA (1) | CA2180314A1 (en) |
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| FR2838824B1 (en) * | 2002-04-19 | 2005-02-04 | Sogem Fl | METHOD AND DEVICE FOR AUTOMATICALLY CONTROLLING A QUANTITY OF PRODUCT REPETITIVELY DEPOSITED BY A REMOVAL ACTUATOR, AND THE REMOVAL INSTALLATION EQUIPPED WITH SUCH A DEVICE |
| US6991825B2 (en) * | 2002-05-10 | 2006-01-31 | Asm Assembly Automation Ltd. | Dispensation of controlled quantities of material onto a substrate |
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| ATE481887T1 (en) * | 2004-02-27 | 2010-10-15 | Hauni Maschinenbau Ag | GLUE GENERATING DETERMINATION |
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| US20060099334A1 (en) * | 2004-11-08 | 2006-05-11 | O'brien Joseph | Apparatus and method for applying a coating to a windshield |
| US7749553B2 (en) * | 2005-01-31 | 2010-07-06 | Boston Scientific Scimed, Inc. | Method and system for coating a medical device using optical drop volume verification |
| FR2907350B1 (en) * | 2006-10-18 | 2009-04-03 | Peugeot Citroen Automobiles Sa | DEVICE FOR STICKING A SUPPORT BY EXTRUSION AND USE OF THE SLEEPING DEVICE |
| TWI323189B (en) * | 2006-12-29 | 2010-04-11 | Ind Tech Res Inst | Real-time dispenser fault detection and classification method |
| ATE502986T1 (en) * | 2007-04-27 | 2011-04-15 | Purbond Ag | METHOD FOR CONNECTING (WOODEN) COMPONENTS |
| WO2009070568A1 (en) * | 2007-11-29 | 2009-06-04 | Nordson Corporation | Method of dispensing a viscous material |
| TWI482664B (en) * | 2009-03-19 | 2015-05-01 | Tazmo Co Ltd | Coating apparatus for substrates |
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| US10471543B2 (en) * | 2015-12-15 | 2019-11-12 | Lawrence Livermore National Security, Llc | Laser-assisted additive manufacturing |
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| JP2597778B2 (en) * | 1991-01-03 | 1997-04-09 | ストラタシイス，インコーポレイテッド | Three-dimensional object assembling system and assembling method |
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| US5150334A (en) * | 1991-09-16 | 1992-09-22 | Bindicator Company | System and method for ultrasonic measurement of material level |
| ES2117085T3 (en) * | 1992-11-20 | 1998-08-01 | Nordson Corp | A PROCEDURE FOR MONITORING AND / OR DISPENSING MATERIALS ON A SUBSTRATE. |
| US5319974A (en) * | 1993-08-30 | 1994-06-14 | Isco, Inc. | Ultrasonic level measuring system |
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-
1995
- 1995-07-31 US US08/509,132 patent/US5666325A/en not_active Expired - Fee Related
-
1996
- 1996-07-02 CA CA002180314A patent/CA2180314A1/en not_active Abandoned
- 1996-07-04 EP EP96110809A patent/EP0757232A3/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| EP0757232A2 (en) | 1997-02-05 |
| EP0757232A3 (en) | 1998-05-13 |
| US5666325A (en) | 1997-09-09 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Discontinued |
Effective date: 20030702 |