Sheet P Elastomer and composite moulding processes Injection moulding ± Elastomers Compression moulding ± Composites Hand/spray lay-up ± Composites Sheet Q Non-traditional machining processes Electrical discharge machining Electrochemical milling Electron beam machining Laser beam machining Ultrasonic machining Sheet R Chemical milling ± Steel Chemical milling ± Aluminium alloys Photochemical blanking ± Steel Photochemical blanking ± Copper Key to maps 1. To determine the risk value `A', look along the horizontal axis until the characteristic dimension is found, and at the same time, locate the adjusted tolerance on the vertical axis. Read o the `A' value in the zone at which these lines intersect on the map by interpolating as required between the zone bands, A  1toA  9. 2. A  1 corresponds to a tolerance that is easily achieved by the manufacturing process. 3. The intermediate values of `A'(A  1:1, A  1:3, A  1:7) correspond to increas- ing technical diculty/cost to achieve the tolerance. 4. A  3toA  9 correspond to a tolerance that is technically unattainable using the manufacturing process. A secondary (and possibly a tertiary) process may be required to achieve the tolerance. 5. The two bold lines at A  1 and A  1:7 represent the normal range of tolerance capability for the process under ideal material and component geometry conditions. This information can be used as knowledge in the redesign process if required. 6. All tolerances are plus or minus unless stated otherwise. 7. All dimensions and tolerances are in millimetres and both axis have log scales. Note: The process capability maps for casting processes (excluding investment cast- ing), closed die forging/stamping and plastic/rubber/composite moulding processes are for tolerances in one half of the die/mould only. Additional allowances will need to be added for tolerances that are across the die/mould parting line when the process capability maps are used in the redesign process as a knowledge base (see Swift and Booker (1997) for approximate parting line allowances). The map for machining centre positional tolerances gives C pk values directly, and no other analysis is required. Appendix IV 315 Material key for plastic moulding processes Abbreviation Name ABS Acrylonitrile butadiene styrene CA Cellulose acetate CP Cellulose propionate PF Phenolic PA Polyamide PBTP Polybutylene terephthalate PC Polycarbonate PCTFE Polychlorotri¯uoroethylene PE Polyethylene PESU Polyethersulphone PETP Polyethyleneterephthalate PMMA Polymethylmethacrylate POM Polyoxymethylene PPS Polyphenylene sulphide PP Polypropylene PS Polystyrene PSU Polysulphone PVC-U Polyvinylchloride ± unplasticized SAN Styrene acrylonitrile UP Polyester Note: The injection/compression moulding process capability maps 1, 2 and 3 are used for large parts with a major dimension greater than 50 mm typically and/or for large production volumes. Map 4 is for injection moulded parts that have a major dimension less than 150 mm and which are produced in small volumes. 316 Appendix IV Sheet A Casting processes Appendix IV 317 Sheet B Casting processes (cont'd) 318 Appendix IV Sheet C Casting processes (cont'd) Appendix IV 319 Sheet D Hot forging processes 320 Appendix IV Sheet E Cold forming processes Appendix IV 321 Sheet F Cold drawing and rolling processes 322 Appendix IV Sheet G Extrusion processes Appendix IV 323 Sheet H Sheet metalworking processes 324 Appendix IV [...]... processes Appendix IV Sheet L Machining processes (cont'd) 327 328 Appendix IV Sheet M Powder metallurgy processes Appendix IV Sheet N Plastic moulding processes See material key and notes 329 330 Appendix IV Sheet P Elastomer and composite moulding processes Appendix IV Sheet Q Non-traditional machining processes These processes are not strictly dimensional dependent 331 332 Appendix IV Sheet R Non-traditional... CH1878-1018 mp ˆ 1:3  1:5 ˆ 1:95 Material Alloy steel gp ˆ 1  1:1  1  1  1  1 ˆ 1:1 Manufacturing process Turning/boring Characteristic description Internal core length Characteristic dimension 122 .09 (mm) Design tolerance Æ0.05 (mm) Surface roughness 0.6 (mm Ra) Adjusted tolerance ˆ ˆ Design tolerance mp  gp Æ0:05 ˆ Æ0:023 1:95  1:1 tp ˆ 1:4  1 ˆ 1:4 sp ˆ 1  1 ˆ 1 qm ˆ tp  sp ˆ 1:4  1... of qm Drawing number ERC4215 mp ˆ 1  1:7 ˆ 1:7 Material Bronze gp ˆ 1:7  1:1  1  1  1  1 ˆ 1:87 Manufacturing process Sintering/sizing Characteristic description Length Characteristic dimension 12. 7 (mm) Design tolerance Æ0.076 (mm) Surface roughness ± (mm Ra) Adjusted tolerance ˆ ˆ Design tolerance mp  gp Æ0:076 ˆ Æ0:024 1:7  1:87 tp ˆ 1:25  1:1 ˆ 1:4 sp ˆ 1  1 ˆ 1 qm ˆ tp  sp ˆ 1:4  1 . dimensions and tolerances are in millimetres and both axis have log scales. Note: The process capability maps for casting processes (excluding investment cast- ing), closed die forging/stamping and. using the manufacturing process. A secondary (and possibly a tertiary) process may be required to achieve the tolerance. 5. The two bold lines at A  1 and A  1:7 represent the normal range of tolerance capability. Sheet P Elastomer and composite moulding processes Injection moulding ± Elastomers Compression moulding ± Composites Hand/spray lay-up ± Composites Sheet Q Non-traditional