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2015年8月22日 星期六

Laser Cutting Basics

With very little set up time, no tooling and the advent of CAD to CAM production, lasers are often utilized in prototyping and production parts. Well suited for intricate details and irregular contours, additional economies can be obtained through the nesting of parts when laser cutting.


Press Brake forming Basics



Press brake forming is the process of forming sheet metal along a straight axis using punch and die sets.  Typical punch and die combinations include “V” shapes, “U” shapes and in some cases channel shapes. 

Sheet Metal Design Hand Book

http://www.qualitytool.com/resources/Design-Handbook-Rev3.pdf

2015年8月11日 星期二

Aluminum alloy 5052 / 6061




3003 is the most formable of the alloys mentioned. it's used lots for sheet metal interiors, tanks etc. min bend radii of 1t and (in the UK) cheaper than 5052. 5052 has better mechanical properties but is not quite as formable- more suitable for light duty brackets but can be used just as 3003

normal tempers are 3003-H14 and 5052-H32. if you need to do any complex forming (say, hammerforming compound curves) either can be annealed by coating the area (to be shaped) with soot from an acetylene flame and then heating until the soot burns off. after shaping you'll be back to about half hard (H14) condition.

FWIW 6061 can be bent successfully provided a suitably large radius is used- aim for 3t.

321 is the best stainless alloy to use for exhaust headers, it's less prone to cracking at high temperatures than 304. having said that 304 seems to hold up OK in normally aspirated applications. i've heard some comments that 304 is not up the job (and seen/repaired some cracked 304 headers) but personally i think it's down to poor fabrication techniques