WO2007091283A1

WO2007091283A1 - A method for tracking the manufacturing of a complex product by means of rfid technology

Info

Publication number: WO2007091283A1
Application number: PCT/IT2006/000065
Authority: WO
Inventors: Giuseppe De Rosa; Gianfranco Giordano
Original assignee: Alenia Aeronautica S.P.A.
Priority date: 2006-02-09
Filing date: 2006-02-09
Publication date: 2007-08-16

Abstract

A method for tracking the manufacture of a complex product from a plurality of components is described. The complex product and the component materials are sensitive to one or more monitoring parameters. The method comprises the steps of : associating a radio frequency identification device with each of the components, the identification device storing updatable data on the accumulated life which are dependent on the monitoring parameters, and which indicate the ageing of the component; reading the identification devices in a contactless way by means of radio frequency so as to retrieve the accumulated life data of the components; combining the component materials according to a predetermined manufacturing procedure so as to obtain the complex product; associating a radio frequency identification device with the complex product, the device being capable of storing updatable accumulated life data which are dependent on the monitoring parameters, and which indicate the ageing of the complex product; comparing with each other the accumulated life data retrieved for the corresponding components according to a programmed algorithm', so as to make a selection among the accumulated life data of the components; and writing the selected accumulated life data in a contactless way, by means of radio frequency, to the identification device associated with the product. The selected accumulated life data are stored as the initial accumulated life data of the complex product .

Description

A method for tracking the manufacturing of a complex product by means of RFID technology

The present invention relates to a method for tracking the manufacture of a complex product from a plurality of component materials, said complex product and said component materials being sensitive to one or more monitoring parameters .

As is known, radiofrequency identification devices (RFID) have been used for several years in many payment and security systems. In industry, particularly in logistical applications, conventional identification systems such as bar codes are increasingly being replaced by RFID.

The radio frequency of the RFID procedure is based on resonant circuits tuned to a specified resonant frequency. For communication, RFID devices use the principles of magnetic fields and electromagnetic waves. The communication range depends on the frequency and type of RFID devices (active or passive tag(s) or transponder (s) ). Furthermore, this technology is a contactless method which has a higher identification speed than conventional automatic identification technologies and does not require the exact positioning of the object which is necessary with these technologies. RFID systems can also include the use of memory in the transponder and the simultaneous reading of a plurality of tags. The information can thus be -processed and stored directly on the object.

RFID technology has proved to be particularly effective in the tracking of perishable goods or materials. Indeed, some systems have been developed for checking the preservation status of these goods or materials, by monitoring specific monitoring parameters such as the air humidity and temperature . This characteristic is of particular interest to the aeronautical industry, among others . This is because some limited-life materials are used for manufacturing aircraft components such as fuselage barrels. An example of these materials is carbon-resin. As is known, this material has a limited life both in terms of time and in respect of its permanence at temperatures exceeding the maximum acceptable storage temperature (e.g. -18°C) . Although the life of some materials can be extended in terms of time by means of re- approval tests, it is not possible to perform this re- approval in respect of exposure to heat, and the material has to be rejected if the maximum units of exposure permitted by the corresponding technical specification have been reached.

To the best of the knowledge of the inventors of the present invention, RFID has hitherto been investigated in relation to the management of the distribution and storage of materials.

However, the recording of the passages of materials through different steps of a manufacturing process is nowadays generally not automated. This is a critical factor, particularly for limited-life materials such as carbon-resin. If, as a result of an error in the recording and/or determination of the units of exposure, the material is used for production, even if only partially, the end product will have to be irreparably rejected owing to evidence of starvation (lack of diffused resin) and/or delamination of the fibers and/or lack of compaction of the same and/or diffused voids or porosity between fibers, etc., detectable downstream of the production process in the course of steps of precise inspection of the product.

Furthermore, the cost of the materials is frequently high, and thus it is also necessary to avoid errors of evaluation leading to a rejection of a quantity of material which would be shown by more precise and detailed inspection to have a reserve of units of exposure which enable it to be used safely.

The present invention therefore proposes a method for tracking the manufacture of a complex product starting from a plurality of component materials, said complex product and said component materials being sensitive to one or more monitoring parameters, in which the method has the characteristics defined in claim 1.

Preferred embodiments of the invention are defined in the dependent claims.

A preferred, but not restrictive, embodiment of the invention will now be described, with reference to the attached drawings, in which:

Figure 1 is a diagram representing a production plant with which a tracking system is associated,

Figure 2 shows schematically the monitoring and tracking system associated with the plant of Figure 1,

Figure 3 shows the operation of the tracking system during steps of transfer of materials, and

Figure 4 shows the operation according to the invention of . the tracking system during a step of manufacture of a complex product .

The invention will now be described with reference to an application in the field of the aeronautical industry, and particularly with reference to the manufacture of fuselage barrels for an aircraft. However, as will be made clear by the following description, the invention is not limited to this application.

Figure 1 shows in a schematic way a plant F for the manufacture of such fuselage barrels. For information, fuselage barrels can have dimensions of about ten meters in length and several meters in diameter. Conventionally, fuselage barrels are multilayer structures formed by deposition of a plurality of layers of material on a suitable mandrel (shown on Fig. 4) . In the present example, specific reference will be made to carbon-resin, in other words resin reinforced with carbon fibers. As is known, this material is supplied in rolls and is a limited-life material both in terms of time and in respect of its permanence at temperatures exceeding the permitted temperature. Typically, each material has three separate life limits: a storage life (measured in calendar days/months) , a handling life (measured in units of exposure) characterizing the undeposited material, and a mechanical life (also measured in units of exposure) characterizing the material when it has been deposited on the mandrel. The storage life is the maximum age limit of the material, even in optimal storage conditions. The handling life is the maximum number of units of exposure that can be accumulated when the material is exposed to temperatures other than the storage temperature (normally - 18⁰C) . The units of exposure increase in different ways according to the temperature. For example, in the case of exposure to temperatures ranging from -18°C to 26°C, the number of units of exposure is equal to the number of hours for which the material has been exposed to these temperatures. However, for exposure to temperatures ranging from 26⁰C to 32°C, the number of units of exposure is equal to twice the number of hours for which the material has been exposed to these temperatures. On the other hand, for exposure to temperatures above 38⁰C, the number of units of exposure is equal to 4.5 times the number of hours for which the material has been exposed to these temperatures. The limit accumulation of units of exposure for the handling life relates only to the period before the material has been deposited on the layering mandrel .

When the material is deposited on the layering mandrel, it is the mechanical life that is considered. This is because the mechanical life is the maximum limit of accumulation of units of exposure (including the units of exposure consumed during handling) which are accumulated when the material is exposed to temperatures other than the storage temperature (normally -18°C) and is deposited on the layering mandrel. The units of exposure for the mechanical life increase in a different way according to the temperature, similarly to the units of exposure for the handling life.

The plant F conventionally comprises a clean room 10, an autoclave 20, and one or more other departments or installations if necessary, such as a department for removing vacuum bags (debagging) , a profiling/drilling department, an inspection department and a packaging and dispatch department (not shown) . Each of these processing departments or installations has one or more entrance and/or exit gates, indicated schematically by 70 in Figure 1.

According to the invention, the plant F is associated with a material tracking system 80, shown schematically in Fig. 2. This system 80 uses a radio frequency identification (RFID) technology. It therefore comprises a plurality of tags or transponders 81, 81', 81'', a plurality of reading and/or writing devices 82 which communicate at radio frequency with the tags 81, 81', 81' ', and a management system 83 connected to the reading and/or writing devices 82, for collecting and processing the data captured by these devices 82. The symbol ". . ." used in Fig. 2 indicates that each reading/writing device 82 interacts with a large number of tags 81, 81' , 81' ' .

There are generally two types of radio frequency tags, passive and active. Passive tags are powered by externally energizing their antennae. On the other hand, active tags have their own batteries or power supply devices. Conventionally, like all RFID tags, each tag 81, 81', 81'' of the tracking system comprises at least memory means for storing data and transmission/reception means connected to the memory means via processing means for transmitting/receiving the aforesaid data to or from the reading and/or writing devices 82. The transmission/reception means comprise a miniaturized antenna.

As shown in Fig^'. 1, the reading and/or writing devices 82 are positioned at the entry and/or exit gates 70 of the processing departments and installations of the plant F.

The tags 81, 81", 81' ' are prompted to transmit and/or receive information when they pass through the magnetic field generated by the reading and/or writing devices 82. In this way a radio call is established, in which the tag 81, 81' , 81'' returns the information contained in it.

This information is transferred from/to the RFID management system 83 for data collection and/or processing. In turn, this RFID system 83 is interfaced with central company management systems 84 (shown in Figs. 3 and 4) by means of specified interface protocols.

A pair of RFID tags 81, 81' , active and passive respectively, is placed on each roll of carbon-resin. The passive tag 81' is used to store identification/tracking data for the roll and other information such as identification codes of the material or of the batch, the roll number, the date of manufacture, references to a certificate of conformity, list of defects, etc. The active tag 81 comprises, in addition to the aforementioned components, a temperature sensor and a clock programmed to detect and record the temperature at predetermined intervals. The memory of the active tag 81 thus stores accumulated life data, which in the present example consist of age data and data on the accumulated units of exposure, which substantially represent the different forms of ageing of the material, in other words that of the calendar type (storage life) and that relating to the handling and use in manufacture (handling life) . These accumulated life data depend on one or more monitoring parameters, which of course consist of time and temperature in the present example.

In order to obtain all the information relating to each roll, the tags 81, 81' are applied by the supplier, and the recording of. the time and temperature parameters must start as soon as the material leaves the supplier's store (not shown) .

During the transport of the rolls of carbon-resin from the supplier to the user's plant F, the corresponding active tags 81 record the temperature readings of the corresponding temperature sensors at predetermined intervals. This is because the transport phase is the first step in which the roll can be exposed to temperatures other than the long-term storage temperature, even though refrigerated containers and/or trucks are normally used.

On receipt at the plant F (shown in Fig. 3) , the container C therefore passes through an appropriately equipped gate 70 which carries out multiple readings on the rolls R, detecting the stored records and sending everything to the management system 83 for calculation of the corresponding cumulated units of exposure (for the purposes of the handling life) . In this phase, the transport temperature/time records in the memory of the active tag 81 are erased, and the tag can be switched to stand-by (to save battery life) on entry into the plant's cold store M, monitored by calibrated sensors S, while maintaining the possibility of reading on interrogation. This operating procedure is activated by means of the management system 83. This makes it possible to check the correctness of the operation of the active RFID tag 81 both in terms of efficiency and in terms of calibration, to validate its use in the subsequent phases after removal from the cold store. The management system 83 is programmed to reveal any anomalies and signal them by suitable alarms to the store management, for the appropriate corrective action.

During the period in the cold store, the temperature is read by means of the sensors S of the cold store M at predetermined times and the value of the units of exposure for each roll R is calculated and then retained in the management system 83 for subsequent transfer to the active tag 81 of the rool R when it is collected for use in manufacture, as it passes through the exit gate of the store (not shown) . In this phase, the active tag 81 is reactivated and/or reprogrammed to read the temperature at regular intervals .

On collection for sending to the processing area in the plant F (as shown in Fig. 4 and indicated by the arrow Fl in Fig. 1) , each roll R therefore has a correct registration according to the specified tracking criteria, and carries the information on the units of exposure accumulated up to the time of collection.

In the example in question, the first phase of manufacture of the fuselage barrels takes place in a clearly delimited area, namely the clean room 10, where the material collected from the cold store is used for the initial deposition of layers of carbon-resin on an appropriate mandrel T for the part to be produced, so as to produce a complex semi-finished article, in other words a complex unfinished product P. This phase of manufacture of the end product can be carried out either manually or by numerically controlled machines for the layering of the material .

The clean room 10 is a temperature- and humidity-controlled environment. However, the temperature is very different from the long-term storage temperature and ranges from 23 to 25°C. The management system 83 therefore counts the periods of permanence in the clean room 10 and the exposure temperatures of each roll R in order to calculate the units of exposure up to the moment of the deposition on the layering mandrel T, storing the identifying registration data and the cumulated units for each roll and/or part of a roll R used for the manufacture of the component. For this purpose, temperature sensors S2 for reading the temperature at predetermined times are present in the clean room 10.

The management system 83 is also designed to manage information on the status of the rolls (or of the parts of rolls not yet used) for event/alarm management, supplying a prompt indication of the presence of ^* rolls whose life has expired (in terms of calendar time and/or exposure for handling life) in the cold store and clean room areas, so that the specified corrective action can be taken (for example by re-approving material for time expiry and/or by rejecting it because the handling life limit has been exceeded) . This can be done, for example, by means of display screens in the clean room and/or alarm signals to the materials and/or stores managers .

As mentioned above, fuselage barrels are conventionally manufactured by using suitable mandrels T, on which successive layers of material are deposited by a predetermined manufacturing process. Each of these mandrels T is associated with an active RFID tag 81' ' having the same functionality as the RFID tag 81 which was associated with each roll R. of starting material for managing the parameters of the semi-finished product.

The RFID tag 81' ' associated with the mandrel T is initialized by the management system 83 with registration data identifying the complex semi-finished product P and with an initial accumulated life, calculated according to an algorithm which compares the data on the cumulated units for all the rolls and/or parts of rolls R used for the manufacture of the component deposited on the mandrel T. In fact, the management system 83 receives the values of units of exposure consumed by the individual rolls and/or parts of them used for the manufacture of the product, and defines the most critical value by selection, for the management of alarms/events related to the units of exposure (for example, if all the materials used have the same threshold levels, the one most exposed at the time of deposition is selected as the reference, while if the threshold levels are different the material closest to the exposure threshold is selected as the reference) . The value of the units of exposure for the semifinished product P is transferred to the active tag 81' ' of the mandrel T at the time when the mandrel with the layered semi-finished product P leaves the clean room 10.

Thus, at least some of the data relating to the individual rolls of material used for the production of the complex semi-finished product in the manufacturing process become, from the moment of deposition on the mandrel, distinctive characteristics of this product (which in turn is provided with active RFID tag 81'') and are therefore subject to monitoring and recording similar to those for the individual component materials but with different thresholds and/or permitted limits (mechanical life) .

The exposure parameters are managed (in terms of alarms) by calculations performed by the management system 83 during the whole layering process (which may be manual or automated) up to the physical and chemical stabilization of the component materials of the product, which begins with the entry into the autoclave 20.

The whole history, in terms of identification and exposure, of the individual rolls and of the group of rolls during layering is recorded by the management system 83 on the job record (electronic and/or hard copy) according to the specifications of the method and the quality requirements for traceability for certification of the product.

The RFID system 80 is therefore designed to monitor the life expiry not only of individual component materials, but also of the complex semi-finished product P consisting of a set of quantities of various materials (each having its own chemical and physical characteristics and permitted exposure times) which are sensitive to heat and to exposure times and which have variable permitted exposure times according to the state of progress of each material in the production cycle.

The operations in the clean room 10 are completed with the production of the vacuum bag in preparation for entry into the autoclave 20. After this operation, both the layered part P and the mandrel T leave the clean room 10 and are conveyed into the autoclave 20. The departure from the clean room 10 and the entry into the autoclave 20 (both indicated by the arrow F2 in Fig. 1) are recorded by means of the corresponding reading devices 82. When the mandrel leaves the clean room, the temperature/time reading functionality of the tag 81' ' associated with the mandrel T is reactivated for the reading of the data transmitted to the management system for the calculation of the units of exposure up to the point when the semi-finished product is inserted into the autoclave.

The tag relating to the product being transformed is disabled and removed when the product is. inserted into the autoclave 20, both because of problems of heat resistance and, principally, to prevent the recording of irrelevant additional exposure (the mechanical life limit relates to the product being transformed, and not when the chemical and physical conversion is commenced by curing in the autoclave) . This tag will be disabled and recovered for maintenance checks (on batteries, damage due to movement, and calibration if applicable) , so that it can be re-used for another product . All the data on the product collected and processed by means of the RFID management system are archived and available in the company systems 84 for analysis and evaluation for the purposes of certification of the product.

By using radio frequency tags provided with memories and temperature/time sensors with radio transceiver equipment, it is therefore possible to monitor and record, during the critical phases of the manufacturing process in which the semi-finished product is sensitive to heat and time, the temperature variations which this semi-finished product undergoes, and, by means of the calculation algorithms input into the RFID management system 83, to duly determine the units of exposure accumulated.

Sensors S, S2 are provided in the monitored areas, such as cold stores M, other stores and, in particular, the clean room 10, to transmit radio frequency signals to the RFID system 30 according to predetermined timed scans. The RFID tags 81, 81'' provided with sensors will thus be required only in the passage through areas which are not monitored. Most of the monitoring and recording activity in the clean room 10 is therefore carried out by the management system 83 which, after calculation, transmits the number of cumulated units of exposure to the tag 81' ' associated with the layering mandrel T on request and/or according to programmed timed scans .

In this process it is provided that, when a roll of material has been consumed, the corresponding tag 81 is disabled and recovered for maintenance checks (relating to batteries, damage due to movement, and calibration where applicable) so that it can be re-used for other rolls. The tag 81'' is also to be disabled in this way if the roll is rejected because the life of the material has expired. All the disabled tags 81, 81'' are re-usable when they have been combined with new rolls and/or products, and are therefore checked in terms of functionality and calibration before they are re-used.

Claims

1. A method for tracking the manufacture of a complex product (P) from a plurality of components (R) , said complex product and said components being sensitive to one or more monitoring parameters, characterized in that it comprises the following phases: associating a radio frequency identification device (81, 81') with each of said components, said identification device storing in a memory data on the accumulated life representing the ageing of the component, said data being updatable and dependent on said one or more monitoring parameters, reading said identification devices in a contactless way by means of radio frequency according to a predetermined procedure so as to retrieve said data on the accumulated life of the components, combining said plurality of components according to a predetermined manufacturing procedure, so as to obtain said complex product, associating a radio frequency identification device (81'') with said complex product, said identification device being capable of storing in a memory data on the accumulated life representing the ageing of the complex product, said ageing data being updatable and dependent on said one or more monitoring parameters, comparing with each other the accumulated life data retrieved for the corresponding components, by means of a predetermined algorithm, in order to make a selection among said data on the accumulated life of the components, and writing said selected accumulated life data, in a contactless way by means of radio frequency, to said identification device associated with the complex product, said selected accumulated life data being stored as initial accumulated life data of the complex product.

2. The method as claimed in claim 1, comprising a phase of updating said accumulated life data, according to the following phases: measuring said one or more monitoring parameters at a predetermined rate, so as to obtain one or more sequences of measurement values, processing said one or more sequences of measurement values so as to generate said accumulated life data, and writing said generated accumulated life data to at least one of said identification devices in a contactless way by means of radio frequency.

3. The method as claimed in claim 2 , in which said updating phase additionally comprises, after the measurement phase, storing said one or more sequences of measurement values in the memory of at least one of said identification devices, and reading said at least one of said identification devices in a contactless way by means of radio frequency according to a predetermined procedure so as to retrieve said one or more sequences of measurement values.

4. The method as claimed in any one of the preceding claims , in which said monitoring parameters comprise time.

5. The method as claimed in any one of the preceding claims , in which said accumulated life data comprise data on the age of said components and of said complex product.

6. The method as claimed in claim 4 or 5, in which said monitoring parameters comprise temperature .

7. The method as claimed in claim 6, in which said accumulated life data comprise sums of quantities of accumulated units of exposure, each of said quantities of accumulated units of exposure depending on the length of time for which said components or said complex product are exposed to a predetermined temperature above a storage temperature.