3D Printing SLA resin printed object characteristics

[Winston]

I've been looking for an excuse to buy a resin printer and have previously been deterred by general, vague statements online about poor mechanical strength. Not any more. Also, about temperature weakening, common resin has a rough analog for plastic temperature (heat deflection temperature) of 85 °C (185 °F) and that is not considered a high temperature resin. By comparison, ABS has a 105 °C (221 °F) plastic temperature.

I still haven't found good data on any dimensional change after curing or due to ambient environment after curing, so if anyone has that please post it:

Comparing strength of SLA Resin objects with FDM printed objects



Curing under UV at 60 °C (140 °F) instead of at room temperature can increase tensile strength 40%.

Effect of Post Cure Temperature on Resin Prints



The Science of Post-Curing

https://formlabs.com/blog/introduction-post-curing-sla-3d-prints/

Post Curing Guide

https://www.dynamism.com/download/2016/Post-Cure-Guide-by-Resin.pdf

 

[Wallace]

Looks like a gooey mess to me. I personally don't want anything to do with it.

 

[Wallace]

That's not from zero experience either. I bought a UV cured glue kit to "fix" my favorite pair of glasses, hope to never experience that crap again.

 

[manixFan]

My son bought a $250 SLA printer and I've been very impressed with the quality of the prints. The detail is amazing for such an inexpensive printer. The first models he tried turned out pretty well (posted in another thread about SLA printers.) It's very different from using a filament based printer and does require a fair amount of pre and post processing. But you can make parts that would be nearly impossible otherwise.

One of the biggest learning curves was learning how to position the models and adding supports. But there are several excellent Youtube videos that saved him a lot of trial and error. The biggest issue is the resin stinks. He prints in a spare bathroom with the fan running and that helps a lot.

For a scale modeler, being able to create small, highly detailed parts is a boon. And there is a huge repository of models freely available on the web.


Tony

 

[Wallace]

I'm holding out for the non-sintered metal printers. Doubt I'll live long enough for them to become affordable though..

 

[Wallace]

Pre and post processing is not something I'd look foward to..

 

[Winston]

Looks like a gooey mess to me. I personally don't want anything to do with it.

If you don't want extremely detailed, smooth-surfaced prints you shouldn't need to have anything to do with it.

 

[Winston]

That's not from zero experience either. I bought a UV cured glue kit to "fix" my favorite pair of glasses, hope to never experience that crap again.

Not exactly the same thing...

 

[Wallace]

Exactly, it being on a much larger scale makes it much worse. Y'all gimme a 6 month report and we'll see how you feel about it then...

 

[AG0D]

OK...here's a couple of years report. I have never had a "gooey mess" even with failed prints using SLA. The resin maintains a liquid state and is easily rinsed with the appropriate agent. The details are cleaned with a soft bristle brush or agitation or a directed stream. Post hardening is done in a inexpensive (about $150.00), temperature controlled UV oven. Fidelity and detail is within acceptable standards for the piece being printed. That varies on the piece and the print parameters are chosen to optimize print time to layer thickness requirements. These requirements have a direct impact to the quality of the detail. There has never been complaints of the "aroma" of the resin or other agents due to proper systems engineering of the printer and post processing enclosures in the basement. There are way more offensive odors when I paint rockets, fiberglass parts or change the brake pads on my vehicles in the garage.

 

[Wallace]

Appropriate agent? Wtf???

 

[AG0D]

Since you have such a wide breadth of experience in the procedures and materials used it shouldn't be difficult for you to ascertain which cleaning agent would be most appropriate to employ for the resin of choice. But then again it is just a "gooey mess" and you won't have anything to do with the process, other than bad mouth it from the sidelines. You can learn from others or from experience or not at all, your choices. Have a good day, that is all!!

 

[Wallace]

All I "know" about it is what I've seen on YouTube (and that's as close as I plan on getting to it btw.) they were using gallons of IPA, Lysol, Simple Green and some other crazy "agents". Personally I get upset if I have to get out my deburring tool, post processing in my mind defeats the purpose of printing a "finished" part.

 

[AG0D]

I have never used gallons of any cleaning agent for a part I have printed. I can look through the pile of invoices and verify this but I can safely say that a gallon of IPA would last through the most of six months and several hundreds of parts. Again, if you set up the cleaning area with the proper ventilation, lighting and tools it really isn't burdensome. Having said that it does require post processing at the right temperatures, using the right cleaners and the right wavelength of light to achieve a high quality product. With FDM I have temperature controlled enclosures to ensure that the prints don't delaminate at inconvenient places due to room temp fluctuations, it is just part of the system engineering that is required to produce high quality parts. Even with FDM there is a level of post processing that is required to remove support structures and then smoothing for some parts. I don't know of any manufacturing process that just gives you a finished part.

 

[evvo]

Appropriate agent? Wtf???

Usually isopropyl alcohol. Depending on the specific resin you can usually use Simple Green, also. Nothing fancy.

 

[OverTheTop]

Personally I get upset if I have to get out my deburring tool, post processing in my mind defeats the purpose of printing a "finished" part.

A lot of people don't get that about most forms of 3D printing. There are nearly always some extra steps involved, but the number of steps saved, or some other payoff, make the effort worthwhile.

Our SLA printer at work uses IPA to clean the parts.

Mechanically the parts can be stronger than those off our high-end ABS printer, if you choose the right resin. Some of the more flexible resins are mongrels for dimensional tolerances, and others ("rigid" for example) are absolutely spot-on.

Here are some measurements of strength I did on some parts.
https://forum.ausrocketry.com/viewtopic.php?f=56&t=5324&start=43

 

[jpatton]

A lot of people don't get that about most forms of 3D printing. There are nearly always some extra steps involved, but the number of steps saved, or some other payoff, make the effort worthwhile.

Our SLA printer at work uses IPA to clean the parts.

Mechanically the parts can be stronger than those off our high-end ABS printer, if you choose the right resin. Some of the more flexible resins are mongrels for dimensional tolerances, and others ("rigid" for example) are absolutely spot-on.

Here are some measurements of strength I did on some parts.
https://forum.ausrocketry.com/viewtopic.php?f=56&t=5324&start=43

Very interesting comparison between these resins and FDM. Did you happen to look at anything along the lines of the nylons with embedded CF or glass. I have honestly been thinking about doing some comparisons between my FDM and SLA printers using some of these higher end filaments. I love the SLA for resolution and consistency of prints, I just wish I had a larger plate size than I currently do.

 

[OverTheTop]

Very interesting comparison between these resins and FDM. Did you happen to look at anything along the lines of the nylons with embedded CF or glass. I have honestly been thinking about doing some comparisons between my FDM and SLA printers using some of these higher end filaments. I love the SLA for resolution and consistency of prints, I just wish I had a larger plate size than I currently do.

We have some newer resins that I have not used for parts yet. There is a rigid resin that has glass-fibers in it which would be interesting to test. It is seriously rigid and strong. I should get a test sample printed and get the numbers for comparison...