The detail drawing will usually contain the most technical information since it tells how to build the part from scratch using raw materials. It is important to know all the correct (and up to date) processes and call outs listed on the bill of materials (BOM) or parts list. I have seen many detail parts get held up in the quality assurance (QA) inspection because information was not current leaving the inspector to hold up approval of the detail part. Also clear and complete drawings will alleviate any misinterpretation by the machinists or those who will fabricate the part.
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| A typical engineering drawing (courtesy of www.keywordpictures.com) |
The assembly drawing will bring two or more details together. Again clear drawings help immensely as well as keeping up to date on processes. These drawings will show many detail parts so it is essential that all detail part numbers are correct on this drawing. QA will stop an assembly from moving if the incorrect part numbers are listed on the BOM. Also special consideration must be given to how parts are mechanically attached to each other and if necessary put precautionary notes on the BOM.
The installation drawing will show how an assembly is located into a final product. Installation drawings are used in the aircraft and automobile industries due to the enormous number of parts required to build the product. Again clear and complete definition is essential for installation drawings. In addition, the topic of tolerance analysis must be addressed. Many times the tolerance stack up will be too far in one direction and the assembly will not properly install in the installation drawing. This is usually discovered in the factory and requires immediate attention to fix the current unit and others behind it in the factory queue.
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| An engineering drawing has many downstream users (courtesy of www.gocollege.com) |
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