RE: sls scan speed

From: Brian Bauman (bbauman@proex.com)
Date: Fri Jul 25 1997 - 22:36:54 EEST


Actual scan speed on Sinterstations are arbitrary. Actual vector speed at a scan speed setting of 73 is 50 inches per second. However, no one is going to draw one single vector. When multiple vectors are drawn, there are delays in drawing subsequent vectors. These delays add up over the life of a build. Short vectors mean slower scan times and long vectors mean faster scan times.

Therefore, if you were trying to estimate scan time for a build, you must know the number of vectors and their lengths in order to accurately predict a build. However, I am a empirical kind of a guy and found an "average" for which I use to predict scan time. By using the following formula that my buddy Kamesh Tata created, I calculated scan times for many different builds and then took an average.

        Laser velocity(scan speed) = Distance scanned by laser for hatching
                                                Hatch draw time
where as,

        Hatch scan distance = 2 (total volume to be scanned)
                                (hatch spacing)(layer thickness)

You can obtain the total time scanned (hatch draw time) from a log file by typing gettimes at your Sinterstation. This log file will give you recoater times, warmup/cooldown times, etc.

After using the previous formula, I found that, on average, a scan speed setting of 73 = 26 inches / second and 146 = 40 inches / second. These numbers reflect all kinds of varying geometries. These numbers will definitely vary if you build large bulky parts or very detailed parts.

Hope this helps.

Brian Bauman
Plynetics Express Corporation
1425 Payne Rd.
Schaumburg, IL 60173
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bbauman@proex.com
ftp.proex.com (anonymous)
http://www.proex.com
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From: Rosemary Gault[SMTP:Gault@cardiff.ac.uk]
Sent: Friday, July 25, 1997 4:59 AM
To: rp-ml@ltk.hut.fi
Subject: sls scan speed

Hi all

Does anyone know how I can find the scan speed for the laser
in the sls machine? Is it material dependent? Is this value
specified in the software, or must I stand by the machine and measure
it?

Thanks

Rosemary Gault
*********************************
Rosemary Gault
PO Box 688
University of Wales Cardiff
Newport Road
Cardiff CF2 3TE
UK
email: gault@cf.ac.uk
*********************************



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