RP versus CNC

From: Prof P M Dickens (pdickens@dmu.ac.uk)
Date: Sun Feb 21 1999 - 13:18:24 EET

We did this work several years ago when I was at the University of
Nottingham. We CNC machined the North American Stereolithography User Group
Part for checking accuracy that was designed by Ed Garguilio.
I cannot lay my hands on the exact results but they are shown in one of
Paul Jacobs books.
The machined parts did not compare very well in terms of accuracy and this
was because they were finish machined with a long series, small diameter
cutter (the part has some sharp internal corners). During machining the
cutter deflected and this led to the innacuracies. If I remember correctly
we machined two in perspex (acrylic) plastic and two in aluminium.

It would be interesting to do this again but with a high speed machining
centre. Maybe Jan Willelm Gunnink at TNO in Holland might like to have a go!!!


-- [ From: Al Hastbacka * EMC.Ver #2.5.3 ] --

Several different RP systems have been used to make the standard user
part. Has anyone made this part with a CNC machine and measured the
results against the STL file to determine the accuracy of the NC machine
on on absolute basis and relative to several RP processes?

Would't this be an apples to apples comparison for a part that could be
made either way?

Al Hastbacka
Prof. Phill Dickens
Dept. of Mechanical & Manufacturing Engineering
De Montfort University
The Gateway
England LE1 9BH
Tel: +44 (0)116 257 7689
Fax: +44 (0)116 257 7689/7025
Mobile: +44 (0)468 827039
email: pdickens@dmu.ac.uk

For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/

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