減速器箱體加工工藝及夾具設(shè)計(jì)（全套含CAD圖紙）

G. Seliger et al. (eds.), Advances in Sustainable Manufacturing: Proceedings of the 8th Global Conference 149on Sustainable Manufacturing, DOI 10.1007/978-3-642-20183-7_22, Springer-Verlag Berlin Heidelberg 2011Methodology for High Accuracy Installation of Sustainable Jigs and FixturesJ. Jamshidi, P.G. MaropoulosDepartment of Mechanical Engineering, University of Bath, UKAbstractThe ability to accurately measure the components of jigs and fixtures during their installation determines thestate of their precision, especially for large size products and applications. This matter is crucial in masscustomisation where small batches of products and components with high variety in design are manufactured.Product quality should be in harmony with rapid changeover philosophy as compromising quality for speed isnot forgivable for sensitive components and assemblies such as those seen in the aerospace industry. It isnecessary for the installation of the jigs and fixtures to be highly accurate in order to minimise the use oftolerance budget due to variations in jigs and fixture positioning. Major overhead costs for jigs and fixturesparticularly in the aerospace industry led to the development of the concept of flexible and reconfigurable jigsand fixtures. Reusability of reconfigurable jigs and fixtures makes them attractive for sustainable solutions astheir components can be reused for several variant of a product or assembly. The main drawbacks of this typeof jigs and fixtures have been their poor accuracy and reliability. In this paper accurate positioning of the keycomponents of sustainable jigs and fixtures is investigated. The factors affecting the performance of the jigsand fixtures are reviewed from the installation stage. The paper introduces a methodology for minimisinguncertainties in positioning of the holds and clamps for flexible jigs and fixtures.Keywords:Sustainable Jig, Jig installation, Calibration Uncertainty, Jig Monitoring, Metrology, Reusable Jig1 INTRODUCTIONFactors such as quality and reliability have long converted toimplicit characteristics of the new products. Recent markettrends have forced manufacturing industries to move towardsmass customisation in their products and service range.Increased variation in the design of new products is followedby a second wave of variation with higher amplitude atsubassemblies and component level.State of the art manufacturing systems and technologieshave provided more flexibility, enabling designers to thinkmore freely. For instance new large volume measurementsystems, developed in the past few years, are capable ofmeasuring several decametre distances. Such technologiesfacilitate the verification of large size components that used tobe manufactured from several assembled components.The manufacturing of large size products requires specialistjigs and fixtures in order for their components to be held in thedesired orientation during build and assembly. This requiresmajor overhead cost that can only be justified by massproduction in some cases or otherwise the cost of finishedproducts can be very high. This issue contradicts with themarket trends where customers are constantly looking forhigher value for their money. In a typical product the variationin the product creates a more sustainable business as it canfulfil the needs of a relatively larger market.Flexible and reconfigurable jigs and fixture that can be formedin different shapes to support different variation of products isa key solution for the above challenges. The concept offlexible jig existed for several years in the research domain1. However, they are not fully utilised to a great extent inreal production facilities especially for large size productmanufacturers, such as aerospace. This is due to thechallenges related to their initial installation, poor calibration,and repeatability that often exceed the tolerance requirement.The manufacturing of these jigs and fixtures from high qualitykey components as well as their integration with large volumemetrology systems can reduce the above limitations.This paper covers metrology issues related to the installationand calibration of flexible jigs and fixtures as well as theirmonitoring during service.2 RELATED WORK2.1 Manufacturing and assembly of large scale partsTypically prior to precision manufacturing of mechanical partsit is essential to move the raw material to the machine bench,proceed with rough cutting then fine alignment and clamping.At this stage the part is ready for machining of its highprecision key features. However, this is not always possiblefor large size and/or heavy components. Large scale productsrefer to those with components that are not economicallypossible to handle or move around in the factory forfabrication and assembly purposes 2. The manufacturingand assembly processes of these parts encompassmovement of the machines and systems to the desiredlocation and orientation with respect to these parts. Suchparts are normally held in their positions using large size jigsand fixtures. If these parts are produced in small batch sizesthat is the case for aerospace industries, high overhead costper product will occur. There have been many attempts todesign and manufacture jigs and fixtures so that they canhold a number of variants of components 3, 4. However, thisapproach is not feasible for parts with sensitive or keyfeatures due to their high accuracy requirements.