3D Printing FormLabs resin choices

[JohnCoker]

For those who are printing structural parts in SLA, particularly with the FormLabs printers, which resin did you choose? It looks to me like the "Rigid 10K" would be the best option, also the "Tough 2000" and "Gray Pro" look good. I'm curious what others have settled on.
https://formlabs.com/materials/engineering/#compare

 

[rocketlabdelta]

I am curious about this too.

I got a test part printed in Ridgid 10K and it’s remarkably light, stiff, and tough. It seems like a good choice for hobby rocketry applications.

That being said, don’t yet know how it holds up to repeated flight stresses nor can I speak to how it compares to their other resins.

 

[rlhatcher]

I've been using the AnyCubic plant based white resin, which is super tough, but somewhat brittle. Different curing approaches makes quite a difference.

 

[RCBrust]

John,

Do you have any feedback on your resin printed parts yet? Strength, dimensional accuracy, etc. Are you happy with what you're getting out of it?

Randy

 

[JohnCoker]

Do you have any feedback on your resin printed parts yet? Strength, dimensional accuracy, etc. Are you happy with what you're getting out of it?

No, I haven't tried resin printing yet. I guess most of us are still using FFF printing as there hasn't been much response to my question.

 

[watheyak]

I have been using Siraya Blu Tough and E-Sun Hard Tough resins for structural parts. Mostly av-bays with structural bulkheads. They work great, but have mostly been used in single use rockets. The one that has flown a few times has held up well.

I don’t have a Formlabs printer and dmhavent used their resins, so I didn’t think it was relevant, but thought I’d throw that out there.

 

[RCBrust]

Scott,

How do you feel about the accuracy and straightness of the parts you've made? YouTube is basically useless WRT resin printing. All the "parts" are toy figurines and stuff like that.

Randy

 

[watheyak]

Scott,

How do you feel about the accuracy and straightness of the parts you've made? YouTube is basically useless WRT resin printing. All the "parts" are toy figurines and stuff like that.

Randy

Round is difficult and orientation has a big influence on just how round. Higher end printers are allegedly better. I just can’t figure out some of the round-ness accuracy issues and I’ve done quite a bit of research and asking around. If anyone has a solution I’d love to hear it!

But when it comes to mounting holes and the like, the accuracy has been pretty good. I either print the holes undersize then drill and tap, or use machine screws meant for plastic. The latter has worked best.

To deal with the round-ness issue I have been printing undersize and using O-rings to fill the gap. The inner diameter of the O-ring groove prints accurately, the outer diameter not so much.

Here’s an example-

 

[RCBrust]

Thanks Scott.

Randy

 

[Sandy H.]

I have a Form2 and only used the standard gray that came with it. A nosecone for LPR rockets seemed fine with that material, but there could be more optimal solutions.

I quickly learned that I wasn't as enamored with 3D printing as I expected to be. My results seemed to be less than optimal compared to what you see posted on forums and the slicing aspect and supports seemed to be more of an art than science and I'm not very artistic. . .

I think the machine itself was as represented, but the process from going from a 3D model to a functional piece just seemed to fiddly for my taste/patience.

Anyway, from my limited experience, the standard gray seemed nice, but since I quit using the machine, I didn't use other options and they have probably added more since I bought the machine 4 years ago.

Sandy.

 

[BDB]

I use a Phrozen Sonic printer, and I print mostly with Siraya Tech Blu. I often mix in ~30% Siraya Tech Tenacious to make the parts a little more flexible/tough.

I did some crude strength testing by printing rectangular pieces with various resins and then having my kids stand on them. Blu/Tenacious was very strong, though impact resistance is still more problematic with resin-printed parts.

 

[OverTheTop]

I have had a number of things printed in a variety of resins. Pro Grey is nice, but I think Rigid is stronger and stiffer, although I found it to be a bit more brittle. Regular Grey I would stay clear of as it is way too brittle. I seem to remember Tough is quite reasonable too. All of these resins hold their dimensions quite well. My current favourites are Pro Grey and Rigid.

Their flex resin was all over the place dimensionally from the parts I had printed in it.

 

[watheyak]

I use a Phrozen Sonic printer, and I print mostly with Siraya Tech Blu. I often mix in ~30% Siraya Tech Tenacious to make the parts a little more flexible/tough.

I did some crude strength testing by printing rectangular pieces with various resins and then having my kids stand on them. Blu/Tenacious was very strong, though impact resistance is still more problematic with resin-printed parts.

I’m definitely going to have to try that. Thanks for the info.

 

[JohnCoker]

It's interesting; there was a lot of initial excitement when the resin printers dropped into the hobbyist price range, but it appears that they are still lacking for structural parts. I'm pretty happy with FFF printing, but I will give resin printing a try at some point. (Probably once I get a testing machine.)

 

[jpatton]

I have been tossing around the idea of picking up elegoos' newer saturn specifically to play with siraya blue and liqcreate strong-x/tough-x on a larger build area and see how they hold up for a variety of more functional parts. It would be nice to see more work done with this on youtube or just out there but for the most part its still mini figures etc with the sla.

 

[OverTheTop]

I did some strength measurements of FDM and some resins a while back. I am more than happy enough with the strength of the resin parts compared to the FDM.
https://forum.ausrocketry.com/viewtopic.php?f=56&t=5324&start=43
I have recently had another set of fins printed, a bit smaller and also much finer than the earlier version, in Rigid glass-filled resin.

 

[tjkopena]

I have been using Elegoo's ABS-Like resin for LPR nosecones with great success. Mostly for MMX micro-rockets, so the forces are on the very small end of the spectrum, but the dimensional tolerances required can be fairly tight. It took a good amount of calibration of the printer and refinement of the post-processing workflow to get the dimensional accuracy both consistent and spot-on. A few prominent manufacturers like Semroc and ASP also use resin printed nosecones in micro-rockets. New Way Space Models does have several micro-rocket kits that are almost entirely 3D printed, I believe out of resin but I could be mistaken.

I've been a little hesitant to use resin for other parts and rockets for a couple reasons---

• Fins: Resins I've used tend to be heavier than equivalent FDM parts. E.g., a nosecone that's 1g in FDM ABS might be 1.5g in ABS-Like resin. This is problematic for micro-rockets where the entire rocket might only be 3--5g. Having a little extra weight in the nose can be a good thing, but putting it on the tail via fins or other parts could reduce stability and/or constrain the space of stable designs.
  
  Another consideration for parts that might be subject to shock or torqued against the ground is that resins can be (much) more brittle than FDM parts. This is a function of both the specific resin used, print exposure settings, and post-print curing times. There's a tradeoff between accuracy of the resin and brittleness. The resins used for miniature figures and so on are more brittle than the "tough" resins, but the latter don't capture fine details as well. However, this concern is probably not applicable for the vast majority of rocketry projects where the shapes are relatively coarse. But resin prints also generally aren't as hard as FDM (lower shoreness), which might come into play for parts subject to impacts.

• Motor mounts, fin canisters, and heat-exposed parts: In addition to being worried about weighting the tail, I believe most resins have lower heat tolerance than ABS and PETG. Probably not actually an issue for small rockets, but it's an important consideration. Until recently high temperature resins were a good bit more expensive. Now I think Siraya and others have some in the same price range as standard resins but I have not yet experimented with them (it's on my to-do list).

• Mechanical and interacting parts, e.g. conformal or otherwise shaped launch lugs: Dimensional accuracy on resin parts is harder to achieve than on FDM. In particular, I've found it very hard to reliably get crisp, accurate, small concave shapes, namely holes. E.g., the launch lug for a typical micro-rocket is ~2mm. In my experience, at that diameter the resin doesn't drain properly or easily out of the interior while printing or post-processing. It's also somewhat difficult to maintain dimensional accuracy with pieces that have elements of different thickness. E.g., you might want a fin canister with an integral launch lug to have 1mm walls for the body but 0.5mm walls for the lug. Those probably need different durations of post-print UV curing or they will expand at somewhat different rates, which is problematic and difficult to work around.

All that said, I am planning to begin incorporating resin prints into other components. I'm very curious to hear others' thoughts and experiences around these points. That's a great writeup on strength comparison, @OverTheTop.

 

[JohnCoker]

The multiple comments about lack of part dimensional accuracy are very interesting. That's not what I would have expected and good to know.

 

[BDB]

I can address the heat resistance of resin printed parts. I have tested resin printed nozzles for research purposes. This is Siraya ABS-like Fast resin in a Loki H160. It definitely eroded, but I was pretty happy with how it held up.



I have also done some simple testing by putting 3D printed parts in boiling water. PLA parts are remarkably flexible after 1 minute, while resin-printed materials are still quite stiff.

 

[BDB]

The multiple comments about lack of part dimensional accuracy are very interesting. That's not what I would have expected and good to know.

IMHO this is the real challenge with resin printing. I have successfully printed threaded parts in resin, but it takes way more trial and error than FDM.

 

[OverTheTop]

I have found a lot of the resins are dimensionally good. Some of them are all over the place but useful for other properties. Features can be much finer and there is no z-axis weakness in my experience. Surface finish is superior.

I would print in resin preferably to FDM any time. Build volume is the limiting factor for me currently.

 

[tjkopena]

New Way Space Models does have several micro-rocket kits that are almost entirely 3D printed, I believe out of resin but I could be mistaken.

An order coincidentally including one of these arrived today and I correct myself: They're FDM printed, in PLA. The body tubes in particular are printed very smoothly at a small layer height with a small nozzle so in the low-res pictures I've seen in online catalogs you can't tell. In person though they're visibly FDM. There's also a note in the instructions that it's PLA and advising you not to leave it in a hot car.

 

[SolarYellow]

I did some strength measurements of FDM and some resins a while back. I am more than happy enough with the strength of the resin parts compared to the FDM.
https://forum.ausrocketry.com/viewtopic.php?f=56&t=5324&start=43
I have recently had another set of fins printed, a bit smaller and also much finer than the earlier version, in Rigid glass-filled resin.

In your writeup, you refer to "Pro Grey." Is this the product you used? https://formlabs.com/store/grey-pro-resin/

And I'm jumping to the conclusion that this is the glass-filled resin you used? https://formlabs.com/store/rigid-resin/

Any updates in your opinions or experience since two summers (winters for y'all) ago?

 

[cwbullet]

I have been using Siraya Blu Tough and E-Sun Hard Tough resins for structural parts. Mostly av-bays with structural bulkheads. They work great, but have mostly been used in single use rockets. The one that has flown a few times has held up well.

I don’t have a Formlabs printer and dmhavent used their resins, so I didn’t think it was relevant, but thought I’d throw that out there.

Blu tough is very tough. I am trying to get the perfect Unistrut button printed with it. Having some issues with warping.

 

[OverTheTop]

In your writeup, you refer to "Pro Grey." Is this the product you used? https://formlabs.com/store/grey-pro-resin/

And I'm jumping to the conclusion that this is the glass-filled resin you used? https://formlabs.com/store/rigid-resin/

Any updates in your opinions or experience since two summers (winters for y'all) ago?

You are correct with the linked web pages. The rigid 4000 is good for a lot of things. I have since tried the Rigid 10K which seems to be even better. Both are dimensionally good and not brittle. The Pro Grey is good, but brittle somewhat. I have shattered a part (display stand) that dropped and hit the floor.

FYI the canards I have flown on my Vertical Trajectory system were in Pro Grey and survived landing intact.

I am still very impressed by the smooth finish and performance of these resin prints. Sometimes I just wish we had a printer with a bigger build volume.

 

[SolarYellow]

Blu tough is very tough. I am trying to get the perfect Unistrut button printed with it. Having some issues with warping.

Any updates on that project? I just ordered my first bottle of the stuff. Blue, not nylon black.