Philips齿轮模具标准.docx

Philips齿轮模具标准Table of Contents1. Introduction32. Background2.1 Introduction2.2 Attainable tolerances and causes inaccuracies2.3 Influences on precision53. Hewlett-Packard3.1 Way of working3.2 HP process system3.3 Co-operation with Philips94. Rogue4.1 Specifications4.2 Development general4.3 Tolerance analysis4.4 Product Design4.5 Mould Design4.6 Material4.7 Process Design4.8 Design rules Rogue155. Carnegie5.1 Specifications5.2 Development Carnegie general5.3 Tolerance analysis5.4 Product Design5.5 Mould Design5.6 Material5.7 Process Design 5.8 Design rules Carnegie276. Design rules6.1 Process396.2 Material6.3 Mould6.4 Product7. Case study7.1 Specifications7.2 Product analysis7.3 Development7.4 Next generation478. Literature61AppendicesAppendix AStatistic Process Control (in Dutch)Appendix BInjection moulding and tolerances (in Dutch)Appendix C1Product documentation RogueAppendix C2Tolerance analysis RogueAppendix DAttainable tolerancesAppendix E1Product documentation Carnegie Appendix E2Tolerance Analysis Carnegie1. IntroductionThis project has been set up to fasten down the knowledge within the CCP about high precision injection moulding in relation to the Hewlett-Packard (HP) carriages. Two carriages for HP are developed for high precision injection moulding in co-operation with Philips Competence Centre Plastics. 〝Rogue〞 was a test case to develop a precision technology by injection moulding, fit for high precision in high volumes. In this case tolerances had to be attained, not by adjusting in the assembly line but by injection moulding. The results were the base for the development of the manufacturing process (part design, mould manufacturing, injection moulding process) for the 〝Carnegie〞 carriage.With the goal to help HP in the future developing products with similar aspects it is important to fasten down the obtained knowledge about this subject. This study will result in a general description of design rules for high precision injection moulding that can be used in the early stage of development. The earlier the co-operation with the customer can start the more efficient the product can be designed for high precision. Efficient in terms of shorter lead-times and more robust processing.The goal of the design rules is to share the knowledge within the BG-Plastics so people can use the experience in the future designs. This report starts with a general description about high precision injection moulding. Special attention needs to be paid to the process, the mould, the material and the product design.The product design is essential for high precision injection moulding. A poorly designed part, no matter how extraordinary the mould construction or process is, can destroy any chance of achieving the very tight tolerances of the precision part. The carriages of HP are the examples used to finally formulate the design rules for high precision injection moulding. One chapter has been spent on the development of the Rogue and one on the development of the Carnegie. This report ends with a test product to illustrate the design rules.2. Background2.1 IntroductionTalking about precision in plastics, is talking about micrometers and how to control micrometers within specification. It is about precision of plastic parts without any finishing treatment.Precision is influenced by:1. Material2. Process3. Mould4. Product designSo how can these aspects be handled to get the required precision? Before answering this question it is important to know what the inaccuracy sources can be and what the capable precision of plastics is.What are attainable tolerances and what causes inaccuracies in the product?2.2 Attainable tolerances and sources of inaccuraciesFour elements are related to high precision injection moulding. Each element has its own requirements in respect to material, process, mould and product design.1. Dimensional accuracyThe nominal values and their tolerances required for the product.2. Shape accuracyInaccuracy in the shape like warpage and sink marks.3. ReproducibilityStability of dimensions and shape in mass manufacturing, Cp- and Cpk-values (appendix A).4. Long term stability Long term stability of dimension and shape as function of time, inaccuracy caused by moisture absorption, ageing, creep etc.To deal accuracy of plastics in a good way, sources that can lead to inaccurate products have to be distinguished. Two types of variations influence the accuracy. The irreversible variations, like shrinkage, volume relaxation, 〝moulded in stress〞 relaxation and after shrinkage. The reversible variations like expansion through variations in temperature and humidity.Separately from these sources re。