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Plug materials influence on final part quality in Thermoforming process

Final Report Summary - PLUGIN (Plug materials influence on final part quality in Thermoforming process)

The thermoforming process is something of a black art; when a new product is being developed, the process parameters and plug properties are determined through a mixture of trial and error and experience. These methods are highly inefficient, stifle innovation and reduce the overall competitiveness of thermoforming companies.

The technical data generated as a result of the literature searches and experimental programmes conducted in the work packages were gathered together and have been presented as databases within the expert system program. General information on the PLUGIN project, the consortium members and the major outcomes from the various work packages have also been included in the database.

As well as the 'Plug selector' expert system, the final package contains a suite of databases covering the basic properties of available sheet and plug materials, detailed technical information on plug contact phenomena and testing techniques and practical advice on thermoforming. This task was completed throughout year 2 of the project and it largely involved the gathering together of the most important results from the work. The work package was lead by QUB with support by all members of the project team. Visits were made to CIFRA in France to discuss the plug selection guide from work package 1 and consultations were held in Belfast with staff from CGP on the main results from the experimental programmes. A detailed study was undertaken of the software available for presentation of the PLUGIN results. Demo versions of several software packages were obtained and evaluated and after detailed consultation with the consortium members it was decided to select the package Adobe Authorware 7, because of its ease of use and ability to provide a user friendly interface. Time was then spent learning to program with the software and a series of prototype programs were developed and made available to the consortium members for evaluation. Through feedback and testing the range and complexity of the program was gradually expanded.

The accumulated reservoir of knowledge from work packages 1-6 and the simulation trials will be sorted and evaluated to form rules regarding the selection and operation of plug materials for thermoforming. Through an iterative process of consultation and feedback with all of the SME partners, the rule base was refined to form the final expert system. Virtual trials of the experiments completed in work package 6 were completed using the T-Sim package by Accuform. The results showed good correlation with the experimental measurements and demonstrated the improved predictive capability of the software as a result of the project. For a number of cases the software provided new optimised tool geometries which were then implemented in production trials by the thermoforming companies (Jacob and Holfeld). These trials were carried out in the final few weeks of the project and have shown real improvements in production. The validated simulation software developed under work package 6 will be used to carry out virtual production trials, examining a much wider range of plug / sheet combinations and process settings than would be feasible in the companies given the available timescale. Each of the industrial thermoformers (Holfeld and Jacob) are able to access the T-Sim simulation package for this work and Accuform will provide technical support. Where possible the results have been compared to actual thermoforming tests, which were carried out by each of the industrial partners in tandem with the simulation work.

The final expert system is implemented within a user-friendly web-based interface, which is password protected and accessible only by the partners. It includes links to all of the partners' websites and it will promote horizontal and vertical integration of their activities. The system is transparent and will genuinely enable each of the partners to equally share the results of the programme. In this task, feedback from the consortium members on the prototype expert systems was used to create a final working program. Particular attention was given to making the software as simple and easy to use as possible. Using the user friendly features of the Authorware package the expert system has been provided on a bootable and standalone CD. This has readily enabled its wide dissemination amongst the consortium members and it gives the consortium the option of making the software more widely available in the future. The same software has also been uploaded to the project web page and it is assessable to registered users through a password.

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