Glyn,
Yes, that is an excellent description of the limitations of standard lasers
on SLA machines and other RP processes. What you are seeing is the effect
of the fact that the lasers image a line with a minimum width of .010" to
.017", depending on the system, power and tuning. And in the case of SLA
machines, 3D Systems knows that this limitation exists so in the Lightyear
software the slice algorithm actually leaves off any of these little
features during the slicing process. There is an option, called SFP (for
Small Feature Preservation) that you can select on Lightyear to cause it to
retain these little features, but since the laser's line width is fixed, the
features will not build accurately.
There is a better solution, however, if you regularly build parts with small
features or if you have embedded text that you would like to be crisp and
accurate. Small spot lasers are available for SLA machines (I don't know if
they are available for SLS) that reduce the line width to .003" to .004".
This allows much smaller features to be built accurately and provides parts
with crisp, sharp edges. At FineLine Prototyping we specialize in this very
type of SL part building, and it has proven very useful for medical device
manufacturers and electronics/consumer products makers.
If this interests you I would be happy to discuss it further.
Rob Connelly
FineLine Prototyping, Inc.
6300-130 Limousine DR
Raleigh, NC 27613
919-781-7702
----- Original Message -----
From: "Glyn Churchman" <glyn@protousa.com>
To: "RP Mailing List, RP " <rp-ml@bart.lpt.fi>; "RPML (E-mail)"
<rp-ml@bart.lpt.fi>
Sent: Thursday, April 19, 2001 11:50 AM
Subject: Re: a concise description of a buildable RP file
> To add to Tom's good advice, the most common problem I see in files, after
low resolution,
> is fine details that will not build or details so fine that they fill in,
or partially
> fill in from lack of adequate spacing. This is common to debossed
lettering and logos and
> to ends of clips or any sharp, pointy details on parts.
> I know this varies greatly, but what I see, in general, is that anything
below .015"
> width, may or may not be there in the final part. The same goes for
spaces that will or
> can fill in.
>
> Glyn
>
>
> For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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