# Mathematical Model for RP Acquisition

From: Peter S. Rourke (rourke@wit.edu)
Date: Thu Sep 25 1997 - 03:20:52 EEST

I am a grad student in the Manufacturing Engineering Program at WPI,
working on my thesis. I am studying the capacity decisions service
bureaus must make based on market demand and the technological
capabilities of various RP systems. Wohlers most recent report
highlights how critical these decisions are now with the trend toward
increased capability and competition for service bureaus.

I need some additional data about service bureaus to develop the model
and would greatly appreciate your response to the short questionnaire
that follows. The thesis will be completed January 1, 1998, and I will
be pleased to share the finalized model with all correspondents. Some of
the information requested may be regarded by some as sensitive and
directly related to competitive advantage, so confidentiality will be
strictly protected, and only aggregate data reported.

If you can indeed help, please keep in mind that only approximate data
is required for this initial study. Also, if you feel there are
interested in opening a dialog with those concerned with or curious

Questionnaire:
Part One: Demand
1) Present capacity: How many and what type of machines are you
presently using?

2) Using Wohlers model breakdown, what are the approximate percentages
for the end use of your applications:
a) Visual aids for engineering
b) Visual aids for toolmakers
c) Functional models
d) Fit/Assembly
e) Ergonomic Studies
f) Quoting
g) Proposals
h) Patterns for prototype tooling
i) Patterns for cast metals
j) Direct tooling inserts

3) Part Size: Within each of the above categories what is the
breakdown of part size on a percentage basis, defined by the bounding
box volume with small<2 cube inch, medium between 2 and 6 cubic inch,
and large above 6 cubic inch.
Small Medium
Large
a) Visual aids for engineering
b) Visual aids for toolmakers
c) Functional models
d) Fit/Assembly
e) Ergonomic Studies
f) Quoting
g) Proposals
h) Patterns for prototype tooling
i) Patterns for cast metals
j) Direct tooling inserts

4) Run Time: for each of the above categories what is the approximate
(RP machine run time) / (total project time) ratio.
a) Visual aids for engineering
b) Visual aids for toolmakers
c) Functional models
d) Fit/Assembly
e) Ergonomic Studies
f) Quoting
g) Proposals
h) Patterns for prototype tooling
i) Patterns for cast metals
j) Direct tooling inserts

Part Two: People Skills

5) What percentage of parts require the following processing abilities:

a) CAD file repair prior to modeling (convert from 2 to 3
dimensions)
b) 3-D design model repair
c) Post process model finishing
1) support removal
2) surface improvement

6) Staffing: Total number of employees directly involved with the RP
process:

7) What percentage of the above employees work day is involved with:
a) preprocessing
b) running RP equipment
c) post processing

8) What are the skills you feel are important for people to have in
order to contribute in the RP department. Has this changed?

Part Three: Customer requirements

9) What is the normal delivery time required in order to "get the
job?" Does this depend on end use category. Please elaborate.

10) How sensitive to price is your present market. Wohlers uses \$35 to
\$100 / hour for machine. Do you feel this is reasonable, and do you
fall somewhere in between?

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