Re: sls scan speed

From: Alexandre L. PAPADATOS (
Date: Fri Jul 25 1997 - 16:39:26 EEST

Dear Rosemary,
At 09:59 AM 07/25/97 GMT, you wrote:
>Hi all
>Does anyone know how I can find the scan speed for the laser
>in the sls machine?

Here are (I hope) some information that will help you out. I am a research
assistant in Clemson University working on the SLS process and these are
the information I found concerning your questions.

I guess you are using a Sinterstation 2000. The scanners of these machines
are probably galvanometers, manufactured by General Scanning Inc. They have
a fast axis range of D degrees (depends on each machine, but D is probably
around 40 degrees) that is divided into 65535 increments by the digital
The Beam Speed, BS, refers to the linear velocity of the laser beam across
the powder surface. This is an adjustable, machine specific, parameter that
is essentially the product of the scan radius, SR (the distance from the
scanner mirror to the powder bed surface, in centimeters), the angular rate
of rotation and geometry. A parameter, 0 > SS <65536, the Step Size,
defines the number of increments that the mirror turns between steps.
Another parameter, SP, the Scan Period, defines the duration of each step
when multiplied by 1E-05 seconds. The Beam Velocity is then given by the
following formula :

BV=2*tan(D/2)*SR*(SS/65535)*(1E05/SP) [cm/s]

> Is it material dependent?

The speed of the laser beam itself is not material depend. The rate the
powder sinters after the laser has passed is material depend.

> Is this value specified in the software,

Which value is that and what software are you using ?

>or must I stand by the machine and measure it?
This is a just good way to validate the values given by the above formula.


 Alexandre L. PAPADATOS
 Research Assistant
 Clemson University
 Office 124
 Fluor Daniel Building
 Clemson, SC 29634-0921
 phone : (864) 656 7174
 email :
 web :

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