Marshall
Answer 1
The first sketch is similar to the diagrams in 3D Systems ThermoJet sales
literature.
And yes they do show diagonal trusses.
And yes the top filaments are finer thus easier to clean up.
In the first sketch also I have shown differences in thickness and maybe
someone from 3D Systems will comment on the size between thick and thin
filaments.
By the way the Laser Cladding (Metal deposition) RP machine that PERA
developed here at Melton Mowbray built parts with angled overhangs without
any supporting material up to 30 degrees from vertical.
The second sketch just shows what could be possible if the automatic support
generation was made more intelligent. (Similar to gusset supports in SLA)
Answer 2
The thickest type of filament is stronger then 3D Systems fine support
structures so that when these contact the upfacing and some times vertical
faces of the model greater force thus care is needed to ensure a smooth
finish. (Not always possible)
The questions that arise from this that I hope 3D Systems will comment on
and improve their software is as follows:
Why fine support filaments are not the ONLY structures that come into
contact with the models?
What is the maximum angle from vertical that support filaments can be
produced?
Why when copy parts are built that similar support structures are not
produced thus providing identical cleanup strategies?
Jan Andrzejewski jan.rp@pera.com
RP Project Manager
PERA
Technology Centre
Nottingham Road
Melton Mowbray
Leicestershire
LE13 0PB
UK
Tel +44 (0) 1664 501501 Fax +44 (0) 1664 501556
-----Original Message-----
From: Marshall Burns [mailto:Marshall@Ennex.com]
Sent: Monday, July 24, 2000 7:02 AM
To: Jan Andrzejewski
Cc: "'rp-ml'"
Subject: Fw: Thermojet software
Jan,
I have two questions about your recent posting on ThermoJet software.
First, I don't understand what is illustrated in your attachment figure.
What is meant by the diagonal lines? My understanding is that the ThermoJet
deposits supports as strictly vertical filaments. Is the ThermoJet capable
of depositing diagonal filaments that can serve as connections between
vertical filaments, like triangle trusses? If that's what you're indicating,
then the supports shown holding up the downfacing surfaces would seem to be
analogous to castling in SLA supports. Is that correct?
My second question is why it is more of a problem to clean the stubble
of supports from upfacing than from downfacing surfaces and from the
vertical surface shown connecting to the support structure in your
right-hand drawing. Your illustration seems to show the vertical filaments
as thicker lines than the diagonal filaments. Is this indicative of a
characteristic that makes cleanup difficult?
Thank you if you can clear up my confusion on this.
Best regards,
Marshall Burns
President, Ennex Corporation
Marshall@Ennex.com
Los Angeles, USA, (310) 397-1314
http://www.Ennex.com
----- Original Message -----
From: "Andrzejewski, Jan" <jan.rp@pera.com>
To: "'3D Systems product suggestions'" <productsuggestions@3dsystems.com>
Cc: "'rp-ml'" <rp-ml@bart.lpt.fi>
Sent: Friday, July 21, 2000 4:36 AM
Subject: Thermojet software
> A very difficult problem is the amount of cleaning up from the supports on
> areas other than downfacing surfaces. These are easy to clean because of
the
> automatic software creating fine support structures.
>
> But the upfacing surfaces that come under the shadow of downfacing
features
> do not have this fine supporting structure and makes these surfaces prone
to
> problems when cleaning.
>
> When multiple parts of the same component are built then the supports are
> not the same and slight differences do tend to scar the component
especially
> when the thicker columns of supports are too close to vertical surfaces
that
> are part of the overhanging features.
>
> In this same region I had text that protruded out as an overhang feature
> from a vertical wall and these were impossible to clean up.
>
> It is very difficult to get clients to accept that we do not have any
> control over the support generation when you give them 6 parts and 1 out
of
> the five is excellent and the other five all show signs of support scaring
> and attempts to clean then up.
>
> It only needs to be a software upgrade then all existing users will
benefit.
>
> Jan Andrzejewski jan.rp@pera.com
> RP Project Manager
> PERA
> Technology Centre
> Nottingham Road
> Melton Mowbray
> Leicestershire
> LE13 0PB
> UK
> Tel +44 (0) 1664 501501 Fax +44 (0) 1664 501556
>
> <<supports.bmp>>
>
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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