prototyping technologies

Getting your 3D files into 3D parts:

I wanted to share some experience and knowledge with those interested in printing their work. I think the prices have come down enough in recent years that they are certainly more affordable to both companies and individuals.

To prototype a project you need to get your file into an .STL extension one way or another. Once there you have some options and here’s a run down of some RP technologies out there ideal for printing:

SLA: Stereolithography is the most common additive RP tech in the field. It’s basically a vat of liquid resin with a metal platform just beneath the surface. A laser draws on surface, where the laser hits the resin becomes a solid and sticks to the metal platform. Then the platform drops down .006 of an inch and another layer is made. And so on. The advantages are you get a detailed model that has some strength to it.

Standard Tolerances that you can expect on SLA models are:
In X/Y: +/- 0.005" for the first inch, +/- 0.01" for the each inch thereafter.
In Z: +/- 0.01" for the first inch, +/- 0.002" on every inch thereafter.

Here’s the manufacture’s website for more info:

Below is a female model in SLA by Gerard Price at Ban Qiao Express. She is sporting a standard finish, where we have sanded all the build lines off and sand blasted to give a solid look. This is an industry standard because the steps on SLAs are very noticable. So to sum up, SLA would do well for people on a budget.

Objet PolyJet: Objet PolyJet is an inkjet technology that works by jetting layers of photopolymer onto a build tray, layer by layer, until the part is completed. Each layer is cured by UV light immediately after it is jetted.

PolyJet models offer outstanding surface features and fine details. Their horizontal layers of 16 microns (0.0006") are the highest resolution available in the RP industry. That’s 10 times the resolution of an SLA though you will still see a slight stepping of the laters, depending on the geometry of the plan. But its easily removed with some light sand paper and priming. Objet parts are generally more expensive than SLA’s due to the higher resolution and material.

Here’s their website for more info:

Here’s Teeter by Joe Ledbetter (built on objet, painted by the artist:

Then there are other means that like FDM and Z-Corp for example. These are more choose if you are on more limited budget and can sacrifice accuracy.

This project below was a mix of SLAs and CNC’ed renshape. Done for for Crayola.

For more examples, check out this gallery:

I hope this helps people get an idea of the range and potential of RP. If you have questions, please ask away.

Hello Straka,

Thanks for the great info. Do you know if there is a service bureau offering polyjet parts in Ontario Canada?

No prob. I’m not aware of any Objet’s in Canada.

We ship to Canada at least once a week, often objets to a few artists that do jewelery work, and the customs isn’t very expensive if that’s your concern.