Precision of Thermojet Parts

Date: Wed Mar 28 2001 - 18:02:24 EEST

Hi list, Hi 3D

We have recently installed a Thermojet Printer and made the startling
discovery that the parts are coming out differently depending on where
on the platform they are built. In short, a part that is built in the
front left corner of the platform will come out much larger than the
same part in the back right corner. A systematic investigation using a
calibration part has confirmed this scaring finding. The effect is most
pronounced in the x (= sweep) direction where the calibration part of 40
mm length varies (for the x coordinate) from 40.25 to 39.50 mm (i.e.
almost 2 % !) with the effect in the y - and z - coordinate being just
barely acceptable (0.3 mm = 0.75 %). We contacted 3D (Germany) about it
but they appear to be totally surprised and, apart from small effect in
the y direction supposedly due to the temperature distribution in the
process chamber, unaware of this. Since the effect is so large, that it
makes the machine of limited use for the production of investment
casting patterns, I wonder whether anyone has made similar observations.
I was already quite astonished that the installation of the TJ Printer
took only about 1 hour and no calibration or standard parts were built
(and measured) by 3D, but they told me that this is normal.

Thanks in advance for any response

P. Bernhard
Managing Director

For more information about the rp-ml, see

This archive was generated by hypermail 2.1.2 : Fri Jan 04 2002 - 09:57:01 EET