maintaining the edge answers

From: Elaine Persall (
Date: Tue May 21 1996 - 16:36:14 EEST

My questions seems simple enough but everyone seems to approach it
differently. Is there a perfect solution to:

1) Calibration or tuning RP systems for accuracy and repeatibility?

        "NO! I have recalibrated the SLA-500 several times since
it's installation and each time I have run into trouble and different

"Calibration or tuning RP systems for accuracy and repeatibility? All
precision equiment requires calibration at some defined periodic interval.
The manufacturer or user sets the standards usually. Even a scale needs to
verified if it to be used for acceptance measurments. Time required to
tweak a RP system and how often?
8 hours minimum. Once a month." "Time required to tweak a RP system and
how often? If the machine had some kind of self calibration it would still
be unavailable for usage for at least a day or two. The only way at present
for a user to verify their machine accuracy is to build a standard part and
measure the output. In the case of an SLA any time you remelt or tune the
laser your correction factors may change.

2) Operator skill required to produce a model?

"(A good model?) Basic class in the RP specific equipment and 6 months
worth of trial and error or practical use."

        "Operator skill required to produce a model? Lets hope so. As T.
Wohlers announced the 1500th rp machine being produced I am sure the 1500th
wizard necessary to make that machine perform anywhere near claimed
specifications is still just a gleam in someones eye. "

3) Training on the job or vendor class?


        "It takes experience and common sense to fine tune one of these
processes, neither of which can be learned in a week. "

4) Which area guarentees great models: the RP operator , CAD designer, and
post postprocessing?

        "All of the above and I have found that communication between all
three of the above departments is also required. "

        "All three. Some designs will never be producible regardless of the
method. Even CNC requires some post processing to correct for inadiquacies
of the machine responsible."

5) As the need for accuracy increases due to the requirements for tooling
andcastings.....the need for perfect machine operation rises. If a RP
machine requires fine tuning each week.....does this hurt or help the

        "I don't think that it would hurt the industry at all. Most of the
equipment is calibrated or tuned on a weekly basis. "

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