A technique to avoid warping on large 3D prints

[Jamie Mantzel] figured out his own way of 3D printing large objects without fear of warping. First a bit of background information. When using a 3D extrusion printer like the RepRap or Makerbot, prints that span a large area tend to warp. That’s because these printers lay down one thin layer of plastic at a time. If the first layer cools too much, it will shrink a bit before the next layer is laid down. As that second layer cools it pulls the part toward the center, eventually bowing the part which causes it to hit the extruder head.

After having several prints encounter this issue [Jamie] decided to alter his design so that it wouldn’t cause these stresses. The first thing that he did was to add alternating voids to a layer between the raft and the actual part. You can see these as notches on the bottom the piece pictured above. This takes care of the initial stresses from the first layer. Next, he adds holes wherever he can in the main body of the part. This is especially important on the edges of the piece where the warping forces will be the greatest.

He also moved the starting position of the bed closer to the extruder head. His hope is that this will help the raft bond better, and resist pulling away from the bed during printing.

See his video explanation of his adventure after the break.

[Thanks Ziddan]

Comments

  1. Brad says:

    I’ve got no experience with 3d printing (for now), but isn’t that what the heated build platforms are intended to help combat? This is by no means a troll. I understand that heated platforms raise the monetary barrier to entry of a 3d printer, and I appreciate this guy’s ingenuity in coming up with a hack to solve his problem. Just wondering is all.

    • Alex says:

      Whoops, you beat me to it.

    • Daid says:

      HBP (as it’s called) helps. Printing with PLA also helps (ABS warps more)

      I have an ultimaker with PLA. And I have seen some warping, but nothing as bad as I’ve seen with RepRaps with ABS.
      As you can see on this photo:

      The corner of the top one is a bit warped.

      To my experience, tight corners don’t stick to the bed very well. Which causes corner warping. (But that might be my calibration)

      • nrp says:

        A combination of using PLA and a heated glass bed has eliminated warping entirely for my RepRap. No matter how large the print is, nothing warps, not even the corners. PLA on hot glass is magical like that. At 70C, PLA will stick to hot glass well enough that you’ll need a hammer to knock it off, but as soon as it cools to 40C, the piece will pop off by itself.

      • Daid says:

        That sounds perfect! But glass is quite hard to work with.

        I was thinking about a software solution myself. If I press the head down at the corners a bit then the filament will stick better to the bed at those corners. It might make the corners a bit ugly, but it will make it flat (I hope)

    • HackTheGibson says:

      Yes a heated bed would help.

      I couldn’t make the monetary leap yet, and have added a heat gun (originally designed to strip paint) to blow on my prints until complete. Doesnt melt them, but keeps them warm until done.

  2. Alex says:

    Those are nice looking parts.

    Commercial fused deposition modelers use a heated work envelope. Would that help alleviate this issue without having to modify the part geometry?

  3. Josef Prusa says:

    Thats clever solution.

    What would help a lot is heatbed, of course.

    Lowering the nozzle to stick better might work for few layers, but thing is, then then you get layer delamination. Since the warping forces are still there and instead of lifting it at the base, it cracks the object along the layers. That happens even with heatbed. The holes in object solves that tho :-)

  4. Taylor Alexander says:

    Interesting. I wonder if this is better than the traditional methods, which are:
    Use a heated build platform when printing with ABS, which prevents warping from the plastic cooling too much.
    or:
    Print with PLA, which is more dimensionally stable with temperature changes. With PLA, you can just blast it with a fan to cool it as quickly as possible and it won’t warp (I’ve heard), which helps it solidify quickly for rapid printing. Since ABS has to stay warm to avoid warping, you can’t use a powerful fan to cool the layers. Without a powerful fan cooling it, you have to run the print slowly, to make sure one layer has cooled before the next layer is deposited on top (or else it will get hosed). That seems to put speed limits on ABS that PLA doesn’t seem to have.

    I think thats why the Ultimaker guys prefer PLA. The machine is super fast, but the speed would be wasted on ABS if you have to wait 30 seconds per layer for cooling!

    My Ultimaker is shipping tomorrow!!! :)

    -Taylor

    • sneakypoo says:

      May I ask when you ordered yours? I’m still anxiously waiting for my machine that I ordered on the 19th of November to ship.

      • Taylor Alexander says:

        I ordered mine Sept 28th.

        You ordered yours in the future? ;)

        -Taylor

        • sneakypoo says:

          Whoops! I’m gonna go with blaming that little slip up on it being late ;) And damn, I guess that means I have a couple of more weeks to wait since they apparently ship them out in batches twice a month.

          [whiny kid voice]But mooOOom, I want it NooOOOoooOW![/whiny kid voice]

      • Taylor Alexander says:

        Yeah, unfortunately its a long wait, and one made to feel longer by the complete lack of information provided by the ultimaker guys. I hear they’re very busy and I know how that feels, but a simple system that would let us know where we were in the queue would be really handy.

        To top it off, I wanted some soft PLA with my order. It was in stock 6 weeks ago when I ordered, but now that its shipping time, its out of stock. It would have been really nice if they just set the stuff aside when I ordered it. :-/

        Anyone know of a good source of soft/flexible PLA in the US?
        -Taylor

      • Cynyr says:

        may I ask what software you use to design the models? I come from the mechanical engineering world, and just can’t seem to find anything I can afford that is as fast to use as solidworks. Also it would be nice if it worked on linux.

        • sneakypoo says:

          Well it would be mostly SW but I’ve also tried Autodesk 123d which is free (at least so far) and is shaping up to be a pretty nice little program. And of course Sketchup for quick simple sketches.

      • Daid says:

        The people behind Ultimaker are doing so many things at once with only a few people. So they are quite busy.

        I emailed them 4 weeks after placing my order, to ask about the status (which was still “payment received” at that point). They told me exactly when it would ship.

        You’ll also get a DHL tracking number when it ships. Just be patient, they got a lot of attention (quite a few people have told me: “I’ve seen that thing on TV!”) so they got lots of orders to fill I guess.

        • sneakypoo says:

          I’m not worried at all, just itching to get my hands on it :) And I’m sure they’re busy, and that’s a really really good thing. I’m loving how much attention 3d printing has gotten lately, it seems we are very close to a real leap with these things as I’m sure the big companies out there are keeping a close eye on this emerging market.

  5. Bernhard says:

    3 letter solution: PLA

    • Cynar says:

      PLA’s not always an option. I know I’ve had issues with it’s low softening point, as well as it’s brittleness

      PLA and ABS are useful for different things.

      • sneakypoo says:

        How brittle is “brittle”? I’ve been wondering about this as it’ll be my primary medium on the UM. Can it be used for anything structural at all or is it mostly for models and such? Can’t seem to find much info about that on the net.

      • Cynar says:

        PLA is stronger than ABS, it does not flex to the same level.

        ABS tends to bend and warp under stress.
        PLA holds a lot better until it fractures.

        Personally, I’ve not had any issues with PLA. The amount of force needed to make it fail would severely warp ABS anyhow. It’s more a case of how it fails than where. (Think the difference between a glass ‘glass’ and a plastic ‘glass’, though not quite so extreme)

        The biggest issue with PLA is it’s low softening point. It will soften under v.hot water, which can cause issues in some ideas. ABS is fine with those sorts of temperatures.

    • Trav says:

      I know, I should probably go Google this answer, but has anyone ever tried modeling wax? I just wondered about printing in wax and then using that to cast in aluminum.

  6. xtremegamer says:

    and if you dont want holes why not fill the most outerlayer ? , sure it will pull but that’s only one single string against many more so.

  7. Bubba Gump says:

    We have a dimension printer at work and the work environment has to be 70C before the print job will start. The way they get the work environment to 70C? Well the print head heats up way past that but it would obviously take forever to get the work area up to temp. It is accomplished with two halogen MR-16 lamps. Those things get uber hot, and we only wait a few minutes from turning that machine on to being able to build. I think the same method could be translated to these machines to help with warp.

    • Abbott says:

      It’s actually a set of heating elements near the circulating fan. It’s a convention oven pretty much. The Dimension printers are nice and all, but they way overcharge for them.

    • macegr says:

      The reason you don’t see many people building heated enclosures for RepRaps is because a lot of the parts are made of the same material that is being printed. The temperatures you need to eliminate internal stress could cause the printed structural components of the machine to shift and sag. While the actual melting point of ABS is much higher, it begins to deform under strain at much lower temperatures.

  8. Lee says:

    What about using a heating pad element to heat the base. It heats to various temps. With a little hacking, you could figure a way to make it heat to a specific temp. They aren’t too expensive and you might be able to pick up a cheap one at a garage sale.

  9. Girrrrrrr2 says:

    Anyone who hasn’t subscribed to him on youtube, you should do it now.

  10. Andrew Diehl says:

    The problem is, somehow Stratasys got the heated chamber patented (seems extremely obvious to me) and that is one of the things preventing additional development in that area.

  11. mario says:

    you failed to remind readers to check out his giant robot builds, and his very irregular lifestyle in general. Following him on youtube is definitely better than any sort of movie or television series.

  12. Max says:

    So excited to see jme on hackaday. He needs more cred.

  13. Sean says:

    JME: “Hey, guys, I just found a cool way to combat warping without using a heated bed!”
    Hackaday Commenters: “Yeah, we use a heated bed for that!”
    Me: *epic facepalm*

  14. Alan says:

    My solution to the 3D print warping problem. Heating and cooling of plastic causes it to expand when heated, and contract when cooled. This causes the print to warp. I tried Kapton tape on a glass heated bed. Works a little but still lifts up. Tried hair spray and glue sticks and they also worked somewhat, but the problem persisted. Tried different heated build platform temperatures and problem persisted. So I’m thinking, I have to find a way of attaching the print to the bed where it will not separate, yet can be removed without destroying it.
    I cut out a piece of 3/16 inch aluminum the same size as the glass print bed that came with the printer. I took my belt sander with a very course sanding belt on it and roughed up the surface leaving scratch marks all over the surface. I put this in place of the glass and fired up the heater for the bed, about 110 degrees Celsius. When It got hot, I took a hot melt glue stick and rubbed it around the surface leaving hot melt spread across the surface. I then used a putty knife to smooth out the hot melt leaving a flat surface, then turned off the heat. Now I loaded up my stl and sliced it. By this time the bed had cooled to where the hot melt was stiff. I started my print. The first layer adhered very well to the hot melt, after all they are cousins. As the four inch tall by 4 inch wide coffee mug printed, the bed cooled and the hot melt got hard. The entire cup printed without any warping at all. You could hit it with a hammer and it would not come off. So how did I get it off the hot melt? Well hot melt melts at a much lower temperature than plastic, so I removed it the same way I put it on. Remove the bed plate, with the print still attached, sit it on the range in the kitchen and turn on the burner. ( Make sure the wife don’t catch you, this could be hazardous to your health.) As the plate heats up, the hot melt melts and you can remove the print by turning it while pulling up and holding down the plate with a fork of something. This is a good time to apply more hot melt for your next print. This way you don’t need to use the heated bed at all. The hot extruded filament melts the hot melt easily enough. First cup, I turned over and used a heat gun to melt the hot melt glue that had stuck to the bottom, and scraped it off with the putty knife. Second cup, after heating it with the heat gun, it smoothed out and I decided it would make a good bottom for this cup, so I left it there. This heat gun also works great for the light areas where your support material was removed. Just hit that with hot air and the light color vanishes. The reason for roughing up the bed surface is so the hot melt has something to really adhere to. This crazy idea works for me and I hope it is food for thought for you. I use this on large prints. For small prints the glass bed with blue painters tape works great. You-all have a great day and NEVER GIVE UP.

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