Modern 52' Gondola with fiberglass cover

Stephane Savard Jan 12, 2021

  1. Stephane Savard

    Stephane Savard TrainBoard Member

    I see that people are mostly posting finished products to the 3D printing forum, but this will be more of a work in progress. It actually started a good while back now when I got my first 3D printer, and was recently revived on receiving my new Anycubic Mono X printer.

    So what is it?

    (picture links to - the best picture of this type of gondola I could find!)

    I see these on the rails close to home in Montreal, and while the one above is used to carry copper concentrate, I believe they are also used to carry zinc concentrate to the refinery in Salaberry-de-Valleyfield, (near Montreal).

    So yes, when I first bought a 3D printer, I used Tinkercad and printed a simple model...


    It's okay, but has several problems...


    The edge of the fiberglass cover never printed quite right (it is removable), and while I didn't print flat, the gondola still has a nasty layer line at the floor level (visible as a lighter line running across the bottom of the car).

    So fast forward to now, and I do want to step up my 3D printing quality and get a better print! I've since learned how to use Fusion 360, so I've redrawn and upgraded my old model...


    So now, that's my starting point! On the original model I used some micro-train trucks with 33" plastic wheels - it was the only roller bearing trucks I could find at the time, and honestly, I didn't know much about 33" vs 36" wheels. Not that I know that much more now! :D

    I want about nine or ten of these railcars for my layout since I'm planning to add a Zinc mine to it. But sometime ago, I bought a dozen intermountain CN coal-porters. I've got no interest in them anymore, so they all sit in their jewel cases unused (and one set is still shrink wrapped). Well, they have micro-train compatible trucks with 36" metal wheels, so perfect. I'm going to borrow those.


    Okay, so far I've run two prints on my new model. But I'm having a bit of a problem. The first time around I made the walls too thin, which warped. I also printed in two parts, the floor and the walls which were then glued together. I figured this would prevent the suction issues I had on my Tinkercad model. Okay, the model was a failure, but it was a necessary experiment. The trucks didn't fit well (wheels rubbed on the underside, not enough clearance for the coupler, etc).

    I corrected the problems, and launched a second print. This time in one piece, and oriented exactly 45 degrees to the build plate.


    Much better print! But again, more problems. First, is this curious deformation, looking at the end of the car, we see a curvature...


    So either the ends lifted, or the middle drooped. I'm not quite sure what happened there.

    We can see some of this same deformation from the side...


    See that the upper lip curves downwards right at the end? This was the end closest to the build plate. Honestly, in all my time printing with either printer, I've found this to be a problem with printing long rectangular shapes at an angle, and I have yet to really find how to correct this.

    Of course, predictably, the other end got a divot due to suction. I had a feeling this would happen, but I went with it to see what would happen and how bad it would look.


    So again, not a successful print, but I learned some more! First, this time the trucks fit better. I had a locomotive pull this car around the layout mostly successfully. It still needs a bit more clearance to let the trucks pivot a tiny bit more - on a particularly nasty curve, it did derail once, though the car is very very lightweight right now.

    So that's it for now. I hope to continue showing my progress, and showing what works, what doesn't, warts and all. We see a lot of amazing stuff from others (you know, the gods of 3D printing), and I always wonder about the journey to that final model, how they oriented the model, how some problems were resolved, etc. So this is going to be a sort of build log from a mere mortal of modelling :D

    Oh, and yes, the print is dirty with "white" residue, should be much deeper black. This is my first time using a new water-washable resin, and the first time post-curing the print in water. Yeah, so I did a poor job of cleaning off the resin. Next time I think I'll add a few drops of dish detergent to help clean the print.

    Hope you enjoy!
  2. Sumner

    Sumner TrainBoard Member

    Great work and all of those problem areas would of passed my eye test and I'd be on to the next project :),

  3. HemiAdda2d

    HemiAdda2d Staff Member

    I have read a few reasons the white residue occurs. Some folks say it's curing while wet, others say overcuring or not washing well enough before curing. I had the same problem before I dialed in my cure time.

    I would estimate the warpage is due to suction. I would print supported flat on the plate like this:

    I also added 2ea 5mm holes to drain the resin and prevent suction issues. You could place those holes in between the floor support ribs. If you intend to model with the cover on all the time, you can omit filling the holes after printing. If not, you can fill them with styrene rod and weather the interior to suit the service the model represents. Suction can occur in places large masses of printed material are being layered at once. For that reason, angle the model, like you had tried, but the layer lines can be a problem. Another good fix for suction is slowing your lift speed. Your default lift speed might be too fast, so slow it down incrementally, until you find the sweet spot.

    Take my advice with a HUGE grain of salt, as I'm a complete nOOb win the world of 3D printing, and while I have a Photon, my model count is not high, and I haven't encountered the issues you have. I do follow a Facebook group for Photon owners, and they post suction issues ALL THE TIME. Most of these guys are printing wargaming miniatures and comic book characters, but suction affects them all one way or another.

    I did print (successfully) 25 of the model above, but learned after printing a liter bottle worth of resin that the rib count was wrong for my prototype...:eek:

    4200 revised.jpg 4200 revised 3.jpg 4200 revised 2.jpg

    I'd also print the lid flat on the plate, supported, just as above. You might need to invert it so the top is facing the vat, but supported properly, you might be able to avoid suction issues and you won't see any marks form the supports being removed.

    I only post the post print photos as it illustrates how your gon can turn out, printed flat on the plate. My Photon is old school, but your new Mono X should do so much better.
    BNSF FAN likes this.
  4. Metro Red Line

    Metro Red Line TrainBoard Member

    Don't the edges of gondola cars get banged up due to the loading/unloading process over time anyway?
  5. SLSF Freak

    SLSF Freak Staff Member TrainBoard Supporter

    Looking real good - and you're going thru the same stuff we all go through with the trial and error. You'd think eventually you'd hit on the secret formula but every model is different and new "issues" pop up it seems. The most frustrating thing for me still is dealing with shrinkage that causes deformations and flaws. I haven't had as much of that when I got my Mono printer, I think due to the improved LED matrix providing a more even cure across the build area. I look forward to seeing your progress!

  6. Stephane Savard

    Stephane Savard TrainBoard Member

    Oh wow, thanks everyone! This is what I was hoping to generate, lots of discussion regarding printing structural models. I really like all the youtube channels like 3dPrintingPro that talk about supports and orientation, etc. They've helped me a lot, but the one thing I find frustrating is looking at their models. How can anyone tell if their goblin or troll knights ends up slightly deformed or skewed? :D As for facebook, yes, I'm part of the original Photon group, though haven't been there in a while... have they stopped posting pictures of Baby Yoda models yet? :ROFLMAO:

    Yeah, in my case, I wouldn't be surprised by it being all three. Honestly, not sure why I bothered with water curing, I've always cured dry under a lamp and a little turntable and it's worked well for me. The biggest thing is the Phrozen water washable rapid black resin I started using. I got sick of using IPA and wanted to try water washable for a change. It's different when washing. I just need to rework my cleaning workflow and it'll be good again.

    In the Tinkercad model I did have some drainage holes, they happened to be the bolster holes :D But I think they ended up being too small, and I have none in this current model. I've debated a long time on whether to make the cover permanent or not. Honestly, I don't think I'll be removing it and putting back on much, if at all. Maybe I should make my life easier and just glue them on. If I want some with no covers, just print more later one I guess.

    The only suction issue I know I got was at the top of the supported model structure, but as I've mentioned in the original post, I expected it really. But the bottom warping, that one still confuses me. There would not have been any closed sections to create suction. As for lift speeds, I'm not in a hurry, I use a 1 mm/s (60 mm/m) lift rate with a 3 mm/s (180 mm/m) retract setting. This still results in amazingly fast prints versus the old photon.

    I do agree on the printing flat however. I've seen in skipgear's thread how he supported his awesome caboose, and now your own rail car you posted above. Printing flat seems to be the way to go. If I print in one piece, I will need drainage holes however. If I print like skipgear and print the floor separately, I won't need the drainage holes. hmmm!

    That doesn't bother me as much really. I couldn't find any information on the MCWX gondola, but I found a whole datasheet with side and end view of a Greenbrier (GBRX) mill gondola that looked almost identical

    So I based myself on that datasheet and photos of various MCWX gons to make the model. Though I suspect the MCXW gondola might not have the same height. But I'm not looking for perfect accuracy. Just see the ladders - they end up pretty much molded into the side, and quite a bit thicker than realistic. Same with the stirrups, which I need to beef up some more, too easy to break off. The Phrozen resin is much more delicate than the Siraya Tech Fast! Even the decals I put onto my first model was rather invented. I just ordered some Mill Gondola decals and did what I could to make it looks real enough for me.

    So yeah Sumner and Metro Line Red... I don't mind inaccuracies on the models. To me they just have to be "good enough", but I know the machine can do better and I want the flaws due to my inexperience with the machine to be fixed :)

    Hemi, what thickness did you make your walls in that model? I suspect I may be trying to keep too close to "scale" in terms of the wall width. In my case they are currently at 0.75mm for anything above the floor. The skirting at the bottom of the car is 0.5mm.

    Thank you Mike! Your cabin in the other thread is really amazing! And yeah, warping is really what gets to me too. When looked at real close on my old photon printed gondola, it's possible to see that the ribs gets more skewed towards the ends from most likely the old photon's single UV lamp. I was amazed at how the Mono X prints so much better now!
    SLSF Freak likes this.
  7. HemiAdda2d

    HemiAdda2d Staff Member

    I bought the model from the designer--I'm not sure how thick the gon's walls are. I have Fusion360, but I don't know how to check the STL file.
  8. Stephane Savard

    Stephane Savard TrainBoard Member

    I've learned to use Meshmixer to edit STL files, early on when I got my first 3D printer I found that there are dozens upon dozens vehicles models on 3D warehouse. These are all built using Sketchup, and are absolutely terrible for 3D printing (non-manifold models, inverted faces, etc). I had some fun evenings of taking models of construction vehicles and "meshmixing" them into a printable form. This is one of my favourites...


    So where am I going with this? well, aside from editing meshes, it has some really nice analysis tools, including one for measuring, including thickness of parts.

    Anyhow, it's alright, I was just curious.

    Okay, so I ran out of time editing my model this afternoon after work, so I didn't have the time to add supports and send it to printing.


    I'm going to print both items flat, but the floor will be "upside down" with the ribs printing last. I decided to separate them like this because as one piece, I figure every single rib void between the ribs would end up a suction nightmare, pulling at the skirt. Last time I tried this, I printed the bottom piece flat on the build plate. But sanding the elephant's foot caused me some problems. The first time around the gondola's walls were also only 0.5mm thick. This time they've been beefed up to 0.80mm

    Other changes include beefing up the stirrups and adding more clearance for the trucks and coupler.

    Anyway, it's Family Time now, so time to set this aside, and tomorrow I'll send this off to the printer! :D
  9. Stephane Savard

    Stephane Savard TrainBoard Member

    Just starting printing.. machine reports it will take 2h 22m...


    Really, with this attempt, I'm trying to reproduce what skipgear did with his caboose. Worked out well for him, so why not try it here!

    I'm curious to see how the floor prints, it's the first time I print a large cross section flat like this. The biggest thing I struggle with is usually trying to figure out how many supports and how far to space them apart. I also made sure to raise the body itself a little higher than the floor section, trying to prevent suction layer lines from appearing across the walls.

    I was going to add tiny supports to the bottom of the upper wall lip, but decided now to. Lets see how it turns out first, and adjust as necessary.

    Don't think I'll have time to clean and photograph the resulting print tonight, but should have time tomorrow after work. See you then!
    BNSF FAN and gmorider like this.
  10. SLSF Freak

    SLSF Freak Staff Member TrainBoard Supporter

    Just realized you appear to be using Chitubox...are you using the beta version that has support for the Anycubic "Mono" printers? Also - if you're doing a "draft" just to see how things fit you can print .075 layers and it's pretty speedy. On my SE I use 1.95s exposure for .075 layers (as opposed to 1.5s for .050) but that will vary from printer to printer depending on various factors. The "X" may be just a hair more but I bet you could print that thing in under an hour!(y)

    Cheers -Mike
    Stephane Savard likes this.
  11. Stephane Savard

    Stephane Savard TrainBoard Member

    Yes! Though this is actually the first time I ever use the screenshot feature. :D I've long been a fan of Chitubox, and before getting the Mono X I was still on version 1.6. I really like the manual supports tools they added to 1.7+ and just upgraded this past week to beta 1.8 for the Mono X slicing. However, before then I would simply save the supported model as STL and slice it in Photon Workshop. Today was the first time I actually sliced a project for the Mono X in Chitubox itself.

    That trick for a faster print is pretty cool! Should of thought of that on the original photon back when I was using that - would have saved quite a lot of time! Another trick is to increase the lift/retract speed. 3DPrintingPro made a video on this new "technique" lately. I printed at a lift/retract speed of 60 mm/s and 240 mm/s for a total print time of 2h 20m. If I made the lift speed 240mm/s, the slicer reports that it would instead take 1h 29m.

    But honestly, the faster prints wouldn't help for me. My issue is that I work all day, and have only a few hours of time before dinner and family time. I'm used to printing something, and leaving it on the build plate until the next day. Like right now.. I just turned off the printer. I can see on the build plate that the print was successful (no failures), but I'll only take a closer look tomorrow :D
  12. Stephane Savard

    Stephane Savard TrainBoard Member

    Well. That was disappointing.


    Cleaned the prints today after work. Water washable is not quite water-washable, at least not in the case of Phrozen rapid black. It's rather sticky, and two warm water baths (with a small amount of Mean Green), then a trip through the ultra sonic cleaner didn't get everything off.

    So it looks fairly good in the above picture, but lets get to some closeups shall we?

    First, lets get the floor section out of the way. The underside printed beautifully, that was to be expected. But side with supports?


    Yeah, a bulbous mess. I knew to expect this, but I wanted to try it out anyhow. The edges are not square either, too much suction off the FEP. Not looking great so far. If I wanted to print this part flat, the best bet would be directly on the build plate, and simply sand off the elephant's foot.

    However, what really surprised me was the main body.


    The entire thing warped badly. See how the bottom of the ladder isn't square? the walls basically sagged towards the middle of the rail car. The next photo shows how clearly the whole thing went banana!


    Could it be the type of resin? The very first version I printed of this gondola (which I have not pictured here) I had done much like this. The floor section was also detached, but was printed right on the build plate. The walls of the main body were much thinner as well. But that was printed with Siraya Tech Fast Grey. In that one, that was supported in a similar manner, there is some warping, but barely perceptible. So, either it's the resin, the thicker walls (0.8mm vs 0.5mm), or maybe the supports themselves. Hmm, I do remember using MORE supports along the sides.

    To make matters worse, the walls curled!


    We can see how the bottom of the gondola's walls are curling outwards.

    So right, what now?

    I can either try this again with a greater density of supports, or switch tactics entirely.

    Also, I'm wondering if the length of time I'm washing these prints might be causing some warping. Next time I print, I'll really look for warps before any cleaning of the parts.
    BNSF FAN and Sumner like this.
  13. SLSF Freak

    SLSF Freak Staff Member TrainBoard Supporter

    There are so many factors it's hard to pin down which is the culprit for banana prints. You can "waterlog" a print by soaking it for extended periods of time. I wouldn't have believed it until I forgot a print while it was soaking and noticed the really thin wall areas were bubbly and deformed when I pulled it out. I let it dry and those areas straightened out. That however is probably not your issue here. I suspect either the resin has a higher shrink rate or something I've been experimenting with in the last couple weeks is the orientation of your print while it's curing. If you want to join me in this experiment, on your next gon when you cure it, flip it upside down so the base/bottom is up in the air getting the brunt of the UV cure. The idea being that the exposed parts on top will get extra curing and curl up as the resin shrinks. My results are inconclusive but lean positive. The other experiment I've been trying lately is to hold the banana print under really hot water, gently bending it to shape, then after I feel like the model is sufficiently hot all the way thru I hold its shape and run it under cold water to lock it into place. Easier to do on a thinner piece like the bottom of your gon. Those are just two ideas coming to mind.

    By the way I tried the 240mm/s lift/retract but it didn't change the actual print time for me. Downloaded beta 1.8 of Chitubox for that experiment (PWS wouldn't let me put in a number that high, maxes out at 99?) The beta software also was making my machine run hot - processors were going crazy and I was having trouble saving the sliced file. Finally got it to work to complete the speed test!
    Stephane Savard and BNSF FAN like this.
  14. Stephane Savard

    Stephane Savard TrainBoard Member

    Do you remove the supports before or after post UV curing? I've always done it before, mostly because it's easier to remove the supports without causing any damage. I do like this idea, and I will be trying it. However in my case, I think the banana effect was already there before the post UV cure. You can already see it in the pictures of the gon with the supports still in place - those were taken before post curing in the UV light.

    This morning I will try another print in the same orientation. After much thinking, the gon side walls might be sagging during print itself. I will increase the amount of supports along the bottom edge of the wall, and increase the thickness of those supports (the supports at each end of the gon are mediums, and the entire row of supports under the skirting and stirrups are lights).

    I will also definitely take a photo of the gon's side while still attached to the build plate, after cleaning, and after uv curing. And why not, I have the space, I'll print two and one will be cured before removing supports, the other after removing supports :)

    About the lift speeds between Chitubox and PWS - Chitubox uses millimeters per minute, while PWS uses millimeters per second. Divide or multiply by 60 for the equivalence (240 mm/m is 4 mm/s). I don't have any problems with processing, but then again, I have i7-6700 processor with 16 GB RAM, which tends to help with lots of processing.

    Here is one of the videos on increasing lift speed. I thought it was 3DprintingPro, but he only mentioned in a recent video that he will soon be making his own video on the subject. The Video was from UncleJesse..

    Edit: I just rewatched the video, note that I haven't changed any gcode on the Mono X, don't know if it even needs it.
    Last edited: Jan 16, 2021
    SLSF Freak likes this.
  15. mah2219

    mah2219 New Member

    Just for comparison, I've got some example prints. I print mainly HO scale using an EPAX X10. I use Siraya Tech fast grey resin. One thing I've found with my printer is a consistent layer shift at about 10mm in height. IMG_0298.jpg

    I tried multiple settings to resolve and finally increased my support height to fix the issue. I know it's not best practice, but I like to print as much as I can vertical/horizontal to the build plate. The taller support solution added print time but at least I got good results. I use Fusion360 and started drawing my supports so I could make minor adjustments easier.

    I also print car bottoms flat on the plate without supports. This image is HO scale with 4 bottom layers. The foot on the bottom is minimal and I get flat floors this way. Your gondola bottom should print fine the same way. IMG_8126.jpg
    One thing I would try with your gondola is to flip it so the flat top is on the plate. Hope this helps with troubleshooting. There are so many variables with printers/resin/models it's tough to get to the best result.
    SLSF Freak and Stephane Savard like this.
  16. Stephane Savard

    Stephane Savard TrainBoard Member

    Just finished post processing a new print...

    Serious increase in supports, and why not, one upside down version as well, as suggested by mah2219!


    This new test leads me to believe the problem with the banana was with the supports. Here it is right off the build plate.


    Overall it's not showing any banana shape, however the bottom edges still "lifted". You can see it when comparing the bottom two rungs of the ladder, which are not parallel to each other.


    Here is the other side, where I printed the gondola upside down. It's fairly straight, except again, the very ends are curing upwards. Interestingly, look at the supports. The further they get from the center of the build plate, the more slanted they are being printed. Could this be the shrinkage effect you mentioned?


    Again, just showing that there's very little to no banana shape. This leads me to believe the problem was really in the lack of supports in the first place. How about after washing?


    Washing did not introduce anymore distortion, though this time I did not use the ultrasonic cleaner. And in the end I did a much better job of cleaning We can clearly see the bottom end is curling up. I got some nasty lines in the print, but this I'm fairly sure was due to uneven pull forces from having one upside down and one right side up.


    Above is the upside down print. Shrinkage much? Look at the slant on those supports! I'm not sure why I got some nasty scars on the side of the walls here, but it might be floating debris. I didn't support some of the ladders on one end correctly (my mistake, just rushed the supports a bit too much).


    And the final image for now. Printing upside down gave the best results overall, except for those ends. So really, how do I stop this from happening? I've always had problems with distortions on the ends or rectangular prints. This is something that's been plaguing me ever since I got into 3D printing, even had the same problem with the photon. There's something I'm doing wrong, I'm sure, but what is it??
    gmorider likes this.
  17. mah2219

    mah2219 New Member

    Hi Stephane. A couple more suggestions you might try.

    How is the tension on the FEP in the vat? If it's not tight, it could cause some pulling on the resin since it will flex more as it pulls away from the build plate. Even if it's the factory installed film it might be worth checking.

    Also wondering if you can orient the gondola on the same axis you had the car floor? Not sure if you have enough room this way but it seems the warping always happens on the car ends.

    Finally, just thinking about some of the layering you see in the car sides. I saw you had some discussion earlier about increasing lift speed. When I was chasing my layering issue, I read a recommendation to reduce lift speed to solve suction issues. I think this article was on the Chitubox website. They reduced lift speed as much as 90% to reduce suction forces.

    Just don't change too many variables at the same time. I know it gets frustrating trying to improve prints. I've had plenty print failures myself.

  18. Stephane Savard

    Stephane Savard TrainBoard Member

    Thank you for the suggestions Mike! Always appreciated!

    On the old photon I used to "tune" the fep using a mobile app for tuning guitars, basically, tighten until it drums at 300 Hz. I haven't seen anyone mention the ideal tention for the mono x though. But yeah, I think I may tighten it a bit.

    As for lift speed, I'm not in a hurry, I keep them at 1 mm/s and retraction at 3 mm/s.

    I did think to reorient 90 degrees, but moved away from that when I saw how tight it fits on the build plate.

    Right now I'm printing another variation on the upright gondola with improved supports at the ends. I still expect it to warp, but it is in preparation for the next print... I'll switch back to Siraya Tech fast grey. And make the identical print. That way will see if the problem is resin shrinkage.
  19. Stephane Savard

    Stephane Savard TrainBoard Member

    Right, my latest plan was to print the same model twice, ultra-supported, in both the Phrozen Water Washable Rapid Black, and the Siraya Tech Fast Grey.

    Just for completeness, this was the model I sent to the printer...

    (why two brake wheels? they're really fragile, and easily damaged just washing them :D)

    As expected, the phrozen print distorted the ends slightly. On the other hand the siraya tech resin faired better. Although there is a slight warp at the very ends, I think I'd be happy with such a print.


    I accidentally broke the stirrups off when removing the supports. I had some supports going to the skirt just above the stirrups on the back side of the wall, and when the supports broke off, they took those stirrups along with them. oops. Anyway, even without those, we can see that the Siraya Tech Grey has less distortion - at least the bottom two rungs of the ladder are pretty much parallel.


    Here, just comparing the ends. Again, looking at the bottom, we can see that on the black gon, the extreme ends are pulling upwards, while on the grey, the entire bottom is much straighter across.

    So yeah, remember when I mentioned that I felt that shrinkage might be the cause of the end warps? Look at this last picture....


    Clamped together so that the right side is exactly equal, the Siraya Tech print is clearly longer than the Phrozen print. I mean not even close!

    I loaded the STL I sliced into Meshmixer and measured the model. From end to end, the model measures 101.7mm. Then I measured the prints using a digital micrometer....

    The Phrozen print is 100.95mm
    The Siraya Tech print is 101.56mm

    So there it is, I think that's the big problem!

    Now there are some caveats here. First, I think I overcooked the Siraya Tech resin. I gave it 2.4 seconds per layer, based on a R_E_R_F print, but looking at the print, it does look bloated a bit, especially compared to the Phrozen. However, I have never been 100% happy with the Siraya Tech Fast resin because of the bloating that occurs on the model facing the build plate. On the one side, Siraya Tech is really durable, and less prone to breaking than many other resins I've tried (including the Phrozen), but yeah, it doesn't hold the details of other transparent resins (in my experience)

    So the take away here for me is to keep the Phrozen for prints for high detail smaller prints, or maybe when I start making buildings for the layout.

    Next, two things. First, I want to try dialing in the correct exposure for the Siraya tech. I also want to try a second water washable resin I bought at the same time at the Phrozen. This other one is Eryone Water Washable in blue (opaque). I couldn't make up my mind and decided to buy both :D

    Oh, a little tidbit of information... When I switched resins I took the opportunity to tighten the FEP... or rather I tried. Turns out the screws holding the fep in place are as tight as they can be right out of the factory, unlike my old photon.
    Dogwood likes this.
  20. SLSF Freak

    SLSF Freak Staff Member TrainBoard Supporter

    Wow, that's a lot of shrinkage. I had an Anycubic white resin that was pretty bad, too. In fact it was so bad at one point I thought the slicer specs on my large printer (Epax X10) were wrong which would cause the slicer to create smaller models. If someone hasn't already done a shrinkage chart for UV resins, maybe we can start one. I've actually been thinking about this for awhile. For organic models this probably isn't that big of a deal but obviously for what we're doing it makes all the difference. .14mm off a 100+mm object ain't bad at all. I wonder if a 5x5x100 bar printed flat would be a good standard to gauge a shrinkage rate. Should probably include a pre and post cure measurement as well. Will have to think on that. Anyway great job sticking with the investigation!


Share This Page