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Re: What you could do...

Posted by Andy on Wed Jan 23, 2002 03:11:00 PM

In reply top Re: What you could do... posted by bdk on Wed Jan 23, 2002 12:15:50 PM

A few thoughts from a Draffie with 20ys experience (14 of them in the CAD world)

CNC produced parts can get very economical to produce as the component quantities involved increase significantly. The up front design hours, material, machine set-up costs etc are diluted amongst the eventual batch numbers produced.

Producing Solid CAD models can be an expensive business if you have to foot the bill, budget on ~?22-28 per hour for a 3d design draffie?s time, let alone the engineering manhours (?????). Having said that if you are just copying a good paper drawing of a component, a good draffie can achieve a lot in an hour.

I don?t think it would necessarily be any cheaper to produce one off's or very limited run components via a CNC lathe, mill etc. Really depends on the complexity of the part. Unless you know a poor man with an under utilised CNC shop and you can supply him with a nice ACIS CAD model which his CNC software can readily interpret tool paths for from your files.

Reproducing drawings in CAD format if the old ones are knackered can be economical for example if there are quite a few similar component drawings where one file can be copied multiple times and modified readily. CAD is a fantastic tool for sorting out geometry problems quickly and accurately. A four hour manual drawing board, slide rule/calculator backed up geometry calc, from days gone by may take sec?s to solve by simply drawing a few lines in a CAD program.

On the whole lots of swings and roundabouts, though CAD/CAM is the king of quantity, quality and repeatability. Having said all this, there may be some parts, which in the absence of the original weird one off old machines used, may be prohibitively expensive or impossible to reproduce manually.

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