<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type"
content="text/html; charset=ISO-8859-1">
<meta name="Generator" content="Microsoft Exchange Server">
<!-- converted from rtf -->
<style><!-- .EmailQuote { margin-left: 1pt; padding-left: 4pt; border-left: #800000 2px solid; } --></style>
</head>
<body bgcolor="#ffffff" text="#000000">
<br>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<meta name="Generator" content="Microsoft Exchange Server">
<!-- converted from rtf -->
<style><!-- .EmailQuote { margin-left: 1pt; padding-left: 4pt; border-left: #800000 2px solid; } --></style><font
face="Arial, sans-serif" size="2">
<div>Hi Martin, </div>
<div> </div>
<div>Here is my stab at a scenario for the Boeing/Renton demo in
October. </div>
<div> </div>
<div>Goal: demonstrate the integration of portable-arm metrology with
machining for validation of in-process features and final part
machining using STEP-NC. </div>
<div> </div>
<div>This demo picks up where the NIST Boxy demo left off. The NIST
demo showed how STEP-NC can be used to represent the information needed
to sequence through multiple setups. Each setup produces some
in-process geometry that has the potential to be validated
with an external measurement system with better accuracy than the
machine tool. This external system can drive go/no-go decisions for
validation, and also help with part registration between setups.
However, it is recognized that part registration is not a
primary function of portable-arm metrology given the mature state of
on-machine probing systems for this purpose such as those from
Renishaw. </div>
<div> </div>
<div>1. The blank boxy stock is fixtured at the nominal first setup
position, and the three orthogonal datum surfaces are machined as in
the NIST demo. The part is flipped to its second setup using the
machine stops and vise for registration. </div>
<div> </div>
<div>2. The features at the second setup are machined. The Faro arm
operator will asked to conduct two manual inspection operations, one
for the flatness of the top surface and another for the pocket. STEP-NC
integration here means that the Faro arm software
has imported the AP-238 file, recognized the measurement steps, built a
list of these steps, and can guide or follow the operator as he
sequences through the measurement operations. For example, the operator
could indicate that he is measuring the flatness
of Datum B, picks some number of points, signals that he is done, the
Faro software determines the flatness and a go/no-go decision can be
made. Likewise for the pocket measurement. </div>
<div> </div>
<div>3. The operator flips the part into setup 3. Here we have three
choices on how to proceed. One choice is to rely on machine stops and
vise geometry to ensure that the datum surfaces from setups 1 and 2 are
positioned properly, as was done in the NIST demo.
A second choice is to use these stops, but get a better registration
through the use of on-machine probing with the Renishaw system. A third
choice is to use the Faro arm to get the registration. The third choice
does the most flexing of STEP-NC data exchange:
the measurement operation needs to be recognized by the Faro software,
and its results (full 6-DOF transform) need to be fed back into STEP-NC
machine or the CNC's TRAORI table. </div>
<div> </div>
<div>4. Machining continues at the third setup. The Faro does the same
feature validations as in (2) for this setup. </div>
<div> </div>
<div>5. Part flipping continues through all the remaining setups, with
pre-machining registration via any of the three choices described
above, and post-machining validation via the Faro. We could try all
three choices to show the range of functionality supported
by STEP-NC. </div>
<div> </div>
<div>6. At the seventh setup, the Faro can be used to measure the top
and two sides of the part, if reachable, for a final validation. </div>
<div> </div>
<div>Faro Inc. would need to develop STEP-NC import to the extent that
they can sift out the measurement working steps, present them to the
operator and generate measurement results that can be fed back into
STEP-NC machine via an export facility. </div>
<div> </div>
<div>Can you send this out to the group and see what they think? </div>
<div> </div>
<div>--Fred</div>
<div> </div>
<div><font face="Arial, sans-serif">Frederick M. Proctor</font></div>
<div><font face="Arial, sans-serif">Group Leader, Control Systems Group</font></div>
<div><font face="Arial, sans-serif">National Institute of Standards and
Technology</font></div>
<div><font face="Arial, sans-serif">100 Bureau Drive, Stop 8230</font></div>
<div><font face="Arial, sans-serif">Gaithersburg, MD 20899-8230</font></div>
<div><font face="Arial, sans-serif">301-975-3425 (voice)</font></div>
<div><font face="Arial, sans-serif">301-990-9688 (fax)</font></div>
<div>240-479-6043 (mobile)</div>
<div><font face="Arial, sans-serif"><a class="moz-txt-link-abbreviated" href="mailto:frederick.proctor@nist.gov">frederick.proctor@nist.gov</a> (email)</font></div>
<div><font face="Arial, sans-serif"> </font></div>
</font>
</body>
</html>