huangyhg

ansi standard for electronic d
i'd like to know if there's a consesus on whether or not it's necessary to fully dimension electronic drawings. we design small rf electro-mechanical assemblies. since our machined parts are created directly from the cad data, as a design department we've decided that fully dimensioned detail drawings are counter-productive. we are limiting ourselves to giving dimensions for precise or closely toleranced features, for the machinist and the inspection department. so far it has been very well received by our vendors, but unfortunately some in our engineering department are resistant to this approach and still prefer to see fully dimensioned drawings.
what is the forum's view on this? how many of you still fully dimension drawings? are there guidelines for industry standards? what are the requirements for military jobs? generally, what are the pros and cons?
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i don't see how your vendors can produce parts to your requirements if those requirements are not defined. m however, if you vendors are giving you acceptable parts, and they are passing your instection, more power to you.
i can understand not fully dimensioning a drawing for parts that would be created in-house. however you would run into problems if for some reason you had to purchase your parts outside, and didn't provide enough information for a vendor to manufacture your parts.
ray reynolds
"there is no reason anyone would want a computer in their home."
ken olson, president, chairman and founder of digital equipment corp., 1977
all parts should be documented with dims for history and inspection needs them. without dwgs, how do you know your parts are machined properly? inpection needs to verify for you. all military programs i have worked on require controlled dwgs that they must approve before the job can be started. some still require micro-fish cards! ugh! but will be going away, if it hasn't already. so, from my experience, stay with creating dwgs and also save them as pdf in a folder somewhere on a server and keep everything updated. if they are not used anymore, store them away from active dwgs as "obsolete" if for some reason you need them again in the future. fyi: asme y14.5 1994 and asme y14.41 2003. i hope this helps.
as said, critical dimensions and tolerances are given on our drawings, as are material and finish requirements. the electronic drawing file is exact. why fully dimension a part when no one will be reading those dimensions (data goes directly to cam) and if a dimension does need checked it can be measured. qc checks the critical dimensions given and can also measure other questionable features.
have you checked out the new standard, asme y14.41-2003 digital product definition data practices? it will probably be a few years before it is fully accepted by industry, but it does address doing away with dimensioned drawings.
asme y14.41-2003 is nice, but i agree, it will be a while before alot of shops will fully accept it.

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