Are technical drawings necessary?

I work in the lighting industry- pedestrian scale light fixtures- and
the majority of our manufactured parts are die and sand cast. Before I
came to this company the process was to design the parts in 3d CAD,
create a technical drawing with only critical fit and function
dimensions (mostly for inspection purposes) and only qualify vendors
who would make the part from the model. The main reason for this is
each part will only have maybe 10-15 critical dimensions, but a
considerable amount of cosmetic surfaces that are difficult and timely
to dimension.
Now, however, because of quality issues, we are starting to go back to
full dimensioning so that we have back-up when the vendor produces a
sub-par part. I think that having a written clause in the purchase
order and well as a note on the drawing stating "Part must meet
critical dimensions and match 3d model within acceptable tolerances"
should be enough.
Question: How does your company deal with this process? Are there any
good solutions you have come up with? Do we really just have to go
back to the days of full dimensioning?
thank-you!
** If there's a better place to post this question let me know, I love
solidworks so i'm posting here =)
Reply to
nora.onofrio
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We do it like you have been. Critical or inspection dimensions are on the drawing and there is a note that all other surfaces must lie within .xx of the 3D CAD model as inspected by CMM. .xx varies depending on the process (roto-mold, sand cast, injection molded, etc). This covers us when a part comes in with somehting very wrong that has no explicit dimension. If the vendor won't work to this, they don't make our parts. Same for tooling. If they can't tool with CNC equipment from 3D models, we don't consider them for the work.
This is very different from what we were doing 5 years ago (drafting board, traditional pattern making, and MANY section views) and we've been very successful with it.
If your parts are being tooled and made overseas (China), you may want to consider the completely defined route as being the necessary evil. They WILL misinterpret you if you're not EXPLICITLY clear with every detail.
MHill
snipped-for-privacy@gmail.com wrote in news:1179932025.462017.37410 @w5g2000hsg.googlegroups.com:
Reply to
MHill
In addition to my comments on eng-tips to this same question, I'll simply add "You get what you pay for." :-p
Matt
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Reply to
fcsuper
In addition to my comments on eng-tips to this same question, I'll simply add "You get what you pay for." :-p
Matt
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Reply to
fcsuper
In addition to my comments on eng-tips to this same question, I'll simply add "You get what you pay for." :-p
Matt
formatting link
Reply to
fcsuper
In addition to my comments on eng-tips to this same question, I'll simply add "You get what you pay for." :-p
Matt
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Reply to
fcsuper
In addition to my comments on eng-tips to this same question, I'll simply add "You get what you pay for." :-p
Matt
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Reply to
fcsuper
In addition to my comment on eng-tip.com, I'll add here that "You get what you pay for." :)
Matt
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Reply to
fcsuper
LOL These repeated message is from trying to enter the same message, but getting errors instead. Apparently they took anyway. Anyways, I think the point was made. hehehe. Best of luck on your project.
Matt
Reply to
fcsuper

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