Completeness of a drawing
Completeness of a drawing
(OP)
Hello,
How complete does a drawing have to be and what is the general practice in the age of CAD? In many cases, I end up sending CAD files to the manufacturer and maybe just mark critical tolerances on the drawing with a general tolerance for unspecified dimensions. However, when this part comes in for inspection, the inspector might want to inspect even the dimensions left unspecified on the drawing - at least for the first time to qualify a new vendor for example.
Should I always strive to make the drawing complete to appease both sides and just highlight/mark critical dimensions? This might become unfeasible for complex parts. If I dont, the process of putting dimensions on the drawing becomes highly subjective - like one might want to put dimensions not not obviously critical on there to inspect to in the off chance that the vendor doesnt hit his general tolerance number.
How complete does a drawing have to be and what is the general practice in the age of CAD? In many cases, I end up sending CAD files to the manufacturer and maybe just mark critical tolerances on the drawing with a general tolerance for unspecified dimensions. However, when this part comes in for inspection, the inspector might want to inspect even the dimensions left unspecified on the drawing - at least for the first time to qualify a new vendor for example.
Should I always strive to make the drawing complete to appease both sides and just highlight/mark critical dimensions? This might become unfeasible for complex parts. If I dont, the process of putting dimensions on the drawing becomes highly subjective - like one might want to put dimensions not not obviously critical on there to inspect to in the off chance that the vendor doesnt hit his general tolerance number.





RE: Completeness of a drawing
Inspection is a job.
One of the things that a drawing must do is define how to perform an inspection.
RE: Completeness of a drawing
I also urge you to reconsider what you mean by 'critical dimensions' - again this has been discussed before with varying view points given.
Suggest you use the search button in the silver ribbon bar, not the google search.
thread1103-420134: Sending out RFQ 2D Drawings v 3D Models was a recent example.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Completeness of a drawing
Here is another interesting discussion: thread1103-322065: Critical Dimension.
I don't want to mark critical dimensions on my drawings. There are two conditions that require close attention from inspectors...
- The feature is critical for the functioning of the component.
- The feature is difficult to fabricate accurately enough. We expect production to fail frequently, and we need a lot of inspection, and we expect to scrap or re-work components.
The fun starts when both conditions are true.--
JHG
RE: Completeness of a drawing
Mike Halloran
Pembroke Pines, FL, USA
RE: Completeness of a drawing
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