Small Parts - Solidworks and RP

First let me say, though not entirely new to 3D CAD, I am new to
Solidworks and Rapid Prototyping (3D Printing). I read with great
interest a post, a few days back, titled "3D Printing - which
process?" I'm somewhat in the same boat with some small differences.
I produce 1/48 scale model kits. To date mostly structures. Wood parts
are cut on a Universal laser. I'm branching out into other areas,
that's were Solidworks comes in. What I'm looking for is a service
bureau that will do small detail parts without having to pay an arm and
a leg. A good example would be a chimney. Keep in mind 1/48" scale. A
chimney might be only 1/2" square and 2" tall. What process would you
recommend so the bricks and mortar will show good detail? What I would
like to have is a good master prototyped from my file that I can make
silicon molds from and then cast the parts in resin. I have sent this
file out for quotes and received prices from $150 to $275. To my way of
think, that is way too much for what I'm after. Then again I had the
feeling that the people I asked for quotes, really didn't want to be
bothered with something so small. So, hope you all understand what I'm
after and can lead me in the right direction. Either the process I
should look for or better yet a lead to someone who will do this type
of work



Thanks for any help,
Roger Malinowski
Stoney Creek Designs

 

Try Metropolis Design. http://www.metropolisdesign.com/
I have had them make silicone molds and polyurethane molds with very good
results, from both SLA and Objet prototypes. Pretty cheap too. Call and ask
for Randall Wardle (801-298-0406).
They are great to work with.

 

errr.. to my thinking $150 is way cheap for the casting. THe machine
time or size is not whats killing you- its the manual labor involved in
making the cast and pouring the resin. Especially as this is a one-off.
Say they charge $40 hourly which again is very reasonable, then thats a
half day of work at least to make a mold and THEN pour into it.

Maybe I am not seeing the big picture here

If you are doing chimneys and orthogonal objects have you considered
paper models from drawing files?

 

parel wrote:
errr.. to my thinking $150 is way cheap for the casting. THe machine
time or size is not whats killing you- its the manual labor involved in
making the cast and pouring the resin. Especially as this is a
one-off. Say they charge $40 hourly which again is very reasonable,
then thats a half day of work at least to make a mold and THEN pour
into it.

Maybe I am not seeing the big picture here

If you are doing chimneys and orthogonal objects have you considered
paper models from drawing files?

Parel,
Maybe I didn't explain myself sufficiently. The cost was for one RP
master. I am, then pouring the mold and doing the casting. The chimney
was but a small example. The paper wouldn't work in most other cases.
I'm trying to find what is the appropriate method (slr, sla Objet,
whatever) and a service bureau that, perhaps, deals with small
companies producing small parts.

 

Sorry Roger - the $150 price looks about right for that sort of size
part in either an SLS or SLA model. I don't think your going to get
it for $40 or there abouts.

The old starch RP models were cheap but I don't think they get made
anymore. The last one I had done was about 8 years ago. Your will
have to search around and maybe someone still has a mchine knocking
around that they can run off a model on, but you will spend time
cleaning it up..

For a change - size makes not difference in this instance ;-) . If it
was small they could even have made it alongside another job.

http://www.autofieldguide.com/articles/090101.html


3DP Starch can be cheap but would need finishing


Either the process I

 

Most RP machines aren't going to work very well for you. Fine detail is not
their strong point. The Objet machines claim the best resolution and might
work out OK. I don't have any experience with them and don't know who to
send you to.

Jerry Steiger
Tripod Data Systems
"take the garbage out, dear"

 

I would look into who might have a Solidscape T612 Benchtop or T66
Benchtop (or earlier) machines.

If you are concerned in paying $275 for a smallish DETAILED part, then
I suspect you will be disappointed whether you do the model by hand or
by any other method, as they are generally going to be time intensive
to get fine detail, no matter how you do it.

You wind up paying for the machine hours and then the clean up, which
gets done on any RP part. The clean-up is necessary, and indeed if you
are going to require a fine surface finish, you may need to put in many
hours yourself to get it to your tight specs. I have had to do this
many times with my parts when I needed either very tight control of
size for difficult functionality issues or finish to get it to look
like a finish molded part.

http://www.solid-scape.com/

Bo

 

Maybe I'm not expressing myself properly. I'm not necessarily looking
for the "finest detail" and certainly not the "tightest specs". In my
example it's a 1/48 scale brick chimney. All I need is something that
looks like a brick chimney. It can't look like a blob. I'd need to
be able to see the mortar joints, etc... I have loads of leeway. There
seems to be quite a few different methods and I also notice that some
are considerable more expensive. Earlier one of the responses pointed
me towards a sight that explained in detail SLR, etc..which I have
looked at and printed and will read when I get a chance. I guess I was
hoping someone would come along and say, "Oh small architectural parts,
you need to use XXX, try contacting XYZ". No what I mean. What I was
trying not to do is send a part to a number of different service
places, get a different process at each, then judge the results for
myself.

Bo wrote:
I would look into who might have a Solidscape T612 Benchtop or T66
Benchtop (or earlier) machines.

If you are concerned in paying $275 for a smallish DETAILED part, then
I suspect you will be disappointed whether you do the model by hand or
by any other method, as they are generally going to be time intensive
to get fine detail, no matter how you do it.

You wind up paying for the machine hours and then the clean up, which
gets done on any RP part. The clean-up is necessary, and indeed if you
are going to require a fine surface finish, you may need to put in many
hours yourself to get it to your tight specs. I have had to do this
many times with my parts when I needed either very tight control of
size for difficult functionality issues or finish to get it to look
like a finish molded part.

http://www.solid-scape.com/
Bo

 

So, a brick is maybe 3 inches tall. That makes it 1/16 of an inch at 1/48
scale. The mortar is maybe 1/2 inch, so it is only .010". Our FDM machine
lays down a bead that is supposed to be .010" thick, but you can't count on
details that are less than about .030" or even .040" to show up looking
correct. It wouldn't work very well at all for what you want to do. A lot of
the machines claim to have higher resolution than they actually seem to
build. The Objet machines have the highest claimed resolution and really do
seem to make very fine details, like you are looking for. You would be
disappointed with most SLA or SLS parts.

Jerry Steiger
Tripod Data Systems
"take the garbage out, dear"

 

Stratasys runs a service called RedeyeRPM (www.redeyerpm.com) and they will
make parts using both their FDM systems and the Objet systems. The Objet
systems can make highly detailed parts with better resolution than SLA
machines and I believe they cost less to make due to the fact there is less
work involved with cleaning them up and there is no post curing needed.
I've never used the service, but Stratasys is a real quality outfit.

Ken

 

Objet claims a vertical resolution of 16 Microns thick and I believe 300 DPI
x 600 DPI in the X and Y.
RedEyeRPM can make the parts for you.

Ken

 

I generally agree with Jerry on trying to duplicate what amounts to a
scratch mark on an RP part; it is difficult to do right.

The SolidScape machines at one time would allow layers to be built at
..0005" layer thickness, however, you can easily take 10 times as long
to build the model, and walah, 10 times the price for the model.

Now you understand why some RP guys didn't sound too interested in
quoting.

Bo

 

In addition to everything else, the look of an RP horizontal surface
during the build, will be different from the same pattern on a vertical
surface on the model.

Making them look the same will require a good amount of old-fashioned
hand work.

Bo

 

Roger,

The model we had made was a SLA type process and it produced a very detailed
model for our purposes.
The model has a reasonable amount of extruded text varying from 4 down to
1.75mm also with a logo. Most of this text was 2mm Arial font and it
detailed fine in all but 2 places - funnily enough both these areas were
text, the capital letter M where the angled strokes on M were missing
We were advised that the standard export settings of "fine' should be
changed to custom and drag the slider up a bit for better detail in this
area.
A few things have been changed, so I am awaiting the next "print" with
interest.
Alot of the finish and detail level, depends on the operator and how they
orient the model within the resin tank, at the time of build.
That is why you should use someone who is well experienced and preferably
has a background in plastic molding as well.

 

Can you build the chimney flat?
I'm imagining 4 "brick" sides with 45 degree miters (similar to a
plywood box)

If you can build in sheets, build time will be minimal and surface will
be best.

RP print machines build slowly in z-direction (vertical).
Objet machines have great resolution with glossy surface on Top build
surface.
I would expect "brick and morter" resolution.

Does anyone have advice on an RP company with a lowest minimum price.
To me, it seems that Service Bureaus have a minimum per part price of
~$80 to just start the machines.

-Blair

 

Perhaps you could save some time and money by RPing a mold directly
from Solidworks

 

Most molds I know of use silicone to cast plastic into them & use
silicone rubbers elasticity to help get the parts out of the mold, &
you can't laser cure silicone.

The trick on getting a SLA direct set of parts to work as a mold would
be in getting the cast part out of the SLA mold parts. Idon't have a
clue if you could devise some moldrelease which would work for you.

mold surface finish is always a primay key in getting the parts to
release along with mold release sprays.

Bo