tailieunhanh - Ebook Mechanical engineers data handbook: Part 2

(BQ) Part 2 book "Mechanical engineers data handbook" has contents: Manufacturing technology, engineering materials, engineering measurements, general data, general information on metal cutting, limits and fits, british standard specification of steels, miscellaneous metals. | Manufacturing technology ~ Metal processes Metals can be processed in a variety of ways. These can be classifiedroughly into casting, forming and machining. The following table gives characteristics of different processes for metals, although some may also apply to non-metallic materials such as plastics and composites. General characteristics of metal processes Economic quantity Materials (typical) Optimum size Minimum section Holes (mm) possible Inserts possible Sand casting Die casting, gravity Die casting, pressure Centrifugal casting Investment casting Closed die forging Hot extrusion Smallbarge Large 1400 kg 1-50 kg 3 3 Yes Yes Yes Yes 50g to 5 kg 1 Yes Yes Large No limit AI, Cu, Mg, Z alloys n AI, Cu, Mg, Z alloys n No limit 3 Yes Yes Smallbarge No limit 30mm to l m diameter 50g to 5Okg 1 Yes No Large No limit 3000 cm3 3 Yes No Large No limit 500mm diameter 1 - No Hot rolling Cold rolling Drawing Large Large Smallbarge - No No Yes Spinning One-off, large Large No limit No limit AI, Cu,Zn, mild steel Al, Cu,Zn, mild steel AI, Pb, Zn, Mg, Sn Fe, W,bronze No limit Process Impact extrusion Sintering Machining Large Large One-off, large - 3 mm/6 m diameter 6mm/ diameter 6-l00mm diameter 80g to 4kg No No No No Yes - No - - Yes Yes Yes Yes - 173 MANUFACTURING TECHNOLOGY ~~ . I Turning Single point metal cutting In metal cutting, a wedge-shaped tool is used to remove material from the workpiece in the form of a ‘chip’. Two motions are required: the ‘primary motion’, . the rotation of the workpiece in a lathe; and the ‘secondary motion’,. the feed ofa lathe tool. Single-point tools are used for turning, shaping, planing, etc., and multi-point tools are used for milling, etc. It is necessary to understand the forces acting on the tool and their d e c t s on power requirement, tool life and production cost. In the following tables of tool forces and .