huangyhg

drawing format
i'm pretty consistent on drawing layouts (i.e. format: note callout, hole callout, dimensioning to the best
features and between views). one thing i never got a handle on was using typ, 3 places, as oppose to 2x or 4x.
lets say a square part has a dim. that is 2.00 long. i use 2x, 2.00 as oppose to placing two dimensions on the drawing view. i have seen some prints regarding the same intent but specifies 2.00, typ. and what about 2 places? if i had a hole callout that said this thru hole is .20, 2 places. i would use 2x. are there different discipline between using 2 places, and typ with regards to using 2x? or is this a drafters preference
also how does one get his feet wet to become a tool and die designer. is that something you fall into or
something you have to pick up on your own? how do you get your tool and die design break? what would one do
instead of waiting around to be one?
do a search in this forum.
also, it is important to know which drawing standards govern your drawings.
per asme y14.5m-1994, use 2x, not typ or 2 places, etc. you can also put quantities and location dimensions in a table for convenience. for the square feature, providing that it is visibly square on the drawing, you could theoretically get away with dimensioning one side, without a quantity ... it relates to visible symmetry. typ is a lazy practice and can be risky when there are minimal visual differences between similar features on the drawing.
re becoming a tool & die designer, there are three basic ways. first, you can go to any of a number of colleges to study it. second, if you have a basic mechanical engineering background already, you can get a regular design job with a tool & die or mold shop and learn from them. third, get in touch with an instructor from a college and find out what reference texts they suggest, then study your butt off. this last method will get you a good understanding of the basic theory, but the finer details will need to come from someone with experience.
jim sykes, p.eng, gdtp-s
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cad-documentation-gd&t-product development
tool design is an esoteric trade that is run by tribal knowledge. not to say it cannot be taught, but it is a hands on learned discipline. you will need to understand the designed part you want to manufacture and the fabricating processes.
most tool designers i know can, and do work as design engineers. but i can't imagine a design engineer coming over and doing a tool design. i guess my point is you need to know both the designed part and how to make it.
try landing a direct position in a corporation that has a tool design group and work to get in that group.
cheers
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