Small Parts - Solidworks and RP

Try Metropolis Design.

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?

ms wrote:

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.

3DP Starch can be cheap but would need finishing

Either the process I

Regards

Jonathan

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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.

Bo

RogerMal wrote:

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.

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

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.

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.

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

Jerry Steiger wrote:

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

Bo wrote:

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

parel wrote: