Making Model parts through Rapid Prototyping


Jack Burgess <jack@...>
 

Charlie Vlk wrote:

There are four or more different processes for making RP parts and only two of them that we've used so far are satisfactory for
Z, N and HO sized parts.
Is the "printing" process being discussed one of them.....?

Jack Burgess
www.yosemitevalleyrr.com


Tom Madden <tgmadden@...>
 

--- In STMFC@..., Jack Burgess <jack@...> wrote:

Charlie Vlk wrote:

There are four or more different processes for making RP parts and
only two of them that we've used so far are satisfactory for
Z, N and HO sized parts.
Is the "printing" process being discussed one of them.....?

Jack Burgess
I haven't seen the FSM article, but the handout from my 2006 Rapid
Prototyping clinic at Naperville includes a discussion of the PolyJet
3D acrylic printing technology. The link to a pdf file of the handout
is:
http://home.att.net/~pullmanproject/RP2.pdf

Tom Madden


Charlie Vlk
 

Jack-

Yes.... but there are no "printing" processes that I have seen that are adequate for Rapid Prototyping of any parts
for us......
I hesitate to list all the processes that could be considered as the technology is changing rapidly (pun intended)...
The ones I am familiar with that give good results are:

"Prefactory" light hardened acrylic plastic
and the following from Wikopedia:
Prototyping Technologies Base Materials
Selective laser sintering (SLS) Thermoplastics, metals powders
Fused Deposition Modeling (FDM) Thermoplastics, Eutectic metals.
Stereolithography (SLA) photopolymer
Multi Jet Modeling (MJM) photopolymer
Laminated Object Manufacturing (LOM) Paper
Electron Beam Melting (EBM) Titanium alloys
3D Printing (3DP) Various materials
Objet PolyJet Modeling photopolymer


Prefactory gives superior results to anything I've seen. We've used PolyJet which is slightly lower
resolution than the Prefactory. It gives a similar finished part but the process involves a support
medium which must be flushed/scraped away from the finished part and the boundary between
the part and the support medium is not always sharp. It does give good enough results to cast
a GE44T body in N Scale that has detail down to the Flapper on the Exhaust Stacks. The Prefactory
process will yield Hex Nuts on the same part if they are there on the 3D drawing!

SLA and LOM have been used for model products but I don't think they give results that are close to
the two processes we've used so far. Again, the technology is changing and your results may vary.

The "printing" processes (sort of 3D inkjet printers) were not near to the resolution we require but they
may be the home units of the future for our use...

Charlie Vlk


jrwark <jrwark@...>
 

The Perfactory machine mentioned by Charlie is being used by Mark
Gasson of Mark 4 Design down under in New Zealand for direct
manufacturing of some Z and N scale rolling stock and other products
and HO scale detail parts. See some of their work online at:

mark4design.com

The level of detail that can be achieved - in Z scale - is quite
impressive using this process. I have been researching these
technologies and agree with Charlie that the Perfactory process is
currently the best for doing highly detailed small items like jewelry,
model parts, and the like.

These machines are still quite expensive and not the same technology
as people are currently designing into the lower cost desktop machines
being projected to come out at around a $10,000 price point from
people like Desktop Factory. Perfactory machines are made in Europe
and given the current strength of the dollar I am not sure how prices
have changed but these machines are in the $50,000 to $100,000 (or up)
price range I believe. The detail resolution on the low cost desktop
machines will likely not be good enough to handle the types of detail
that this group worries about, at least initially, but it is certainly
coming a few years down the road.

As someone has already noted, a service bureau with a Perfactory
machine would give a home modeler possessing 3D CAD skills with the
ability to create a design for some unavailable part and then create a
master for later resin casting at a manageable (but still pretty high)
price point. The biggest barrier is the learning curve for a 3D CAD
tool like Solidworks, AutoCAD Inventor, Rhino, etc.

John Wark

--- In STMFC@..., "Charlie Vlk" <cvlk@...> wrote:

Jack-

Yes.... but there are no "printing" processes that I have seen that
are adequate for Rapid Prototyping of any parts
for us......
I hesitate to list all the processes that could be considered as the
technology is changing rapidly (pun intended)...
The ones I am familiar with that give good results are:

"Prefactory" light
hardened acrylic plastic
and the following from Wikopedia:
Prototyping Technologies Base Materials
Selective laser sintering (SLS) Thermoplastics, metals powders
Fused Deposition Modeling (FDM) Thermoplastics, Eutectic metals.
Stereolithography (SLA) photopolymer
Multi Jet Modeling (MJM) photopolymer
Laminated Object Manufacturing (LOM) Paper
Electron Beam Melting (EBM) Titanium alloys
3D Printing (3DP) Various materials
Objet PolyJet Modeling photopolymer


Prefactory gives superior results to anything I've seen. We've used
PolyJet which is slightly lower
resolution than the Prefactory. It gives a similar finished part
but the process involves a support
medium which must be flushed/scraped away from the finished part and
the boundary between
the part and the support medium is not always sharp. It does give
good enough results to cast
a GE44T body in N Scale that has detail down to the Flapper on the
Exhaust Stacks. The Prefactory
process will yield Hex Nuts on the same part if they are there on
the 3D drawing!

SLA and LOM have been used for model products but I don't think they
give results that are close to
the two processes we've used so far. Again, the technology is
changing and your results may vary.

The "printing" processes (sort of 3D inkjet printers) were not near
to the resolution we require but they
may be the home units of the future for our use...

Charlie Vlk



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