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So, I'm having this problem where almost anything I print with a section(s) that is not directly connected to something below it breaks when I try to pull the small filaments meant to hold it up during printing off. For example, I 3D-printed a Rayquaza(this one) from Pokemon for my little brother, and as I was carefully pulling the filament from under the mouth, the whole head just snapped off. Does someone have a recommendation as to a way to get the small filament off without breaking the object? Would a solution just be to print it bigger and see if it holds up better, or is there something else I can do? Thanks.

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  • $\begingroup$ As an answer says: never pull off supports. Always cut or melt to minimize stress on the part. $\endgroup$ – Carl Witthoft Sep 22 '16 at 13:41
  • $\begingroup$ I don't think I could produce enough heat to melt them, and if i did it would probably melt more than i wanted it to. If I cut it, it might end up going wrong and cutting a piece I wanted off if I'm not careful. $\endgroup$ – TrojanByAccident Sep 22 '16 at 14:01
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The small filaments you remove that hold the parts up are called supports. The one model I located on Thingiverse clearly requires a number of supports, as the model is not easily designed for 3d printing with FDM printers. It would be better printed with SLS, but that's not the focus of your question.

You don't specify how large you printed the model, but certainly a scaled-up version will be stronger at the weak points. You will want to use sharp non-shearing cutters to clear away as much of the supports as possible, without torquing on the model.

Another option which also reduces the forces on the model body is to use a soldering iron to smooth and clear/cut the supports. If you are able to use cutters and not damage the model, the soldering iron can remove and flatten the remnants of those supports.

Please note that if your careful work has resulted in a model that snaps to pieces, your little brother will soon destroy the successfully cleaned up model just as easily.

If you have skill with 3d modeling software (Meshmixer and Blender come to mind for such organic models), you can add insignificant items to the model to provide functional support. Would the Rayquaza look fiercer if you 3d printed a cage as an integrated part of the model, using the bars of the cage to provide support?

I successfully printed a model that was created by an artist unfamiliar with 3d printing restrictions. The support material was wash-away PVA. I provided the model to the "owner" who washed away the support material and snapped the legs in two. It's sometimes impossible to solve poor designs. You have a good chance if you build a cage for this one.

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  • $\begingroup$ I'm actually not very advanced in this, I've been following 3D printing for a while but actually only started doing it myself a couple weeks ago. I don't have the model on-hand, but I know it was only a couple inches in length and width, and about 3-4 inches tall. Does the printer affect it? I used the M3D micro. $\endgroup$ – TrojanByAccident Sep 22 '16 at 1:26
  • $\begingroup$ Your description here means you probably used the Thingiverse model I saw. Your printer is FDM which means the layers of the small diameter portions of the model are the weak points. I'm not familiar with the slicer software for the M3D micro. You should look to see if there are adjustments for the supports to reduce the density. Even with easily removed supports, the youngster will likely break the model. $\endgroup$ – fred_dot_u Sep 22 '16 at 9:19
  • $\begingroup$ I actually used a model from MyMiniFactory, but it's quite similar. I edited my post to include the link. And you are probably right about him probably breaking it. Oh well. $\endgroup$ – TrojanByAccident Sep 22 '16 at 13:27
  • $\begingroup$ I examined the link you've provided and the designer of that model should have a refresher course in design. Perhaps his model would be useful in Blender animation, but not in 3d printing. Even a model printed with an SLS printer would have easily-snapped arms. The mouth appears weak as well. If you want a project to share with your brother that will keep him busy until adulthood, scale up the model and convert it to papercraft with Pepakura. I say this partly in jest, as some people have created amazing paper models with great effort. $\endgroup$ – fred_dot_u Sep 22 '16 at 15:20
  • $\begingroup$ Would the one on thingiverse( this one ) be better? $\endgroup$ – TrojanByAccident Sep 22 '16 at 18:30
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Depends how small your printing, if it's the one i see on thingiverse then it don't see why it would break unless:

  1. it's super small
  2. too many or strong support that's hard to pull off?
  3. Not calibrated for the filament - eg temperature too low or too much fan and the layer's aren't properly bonding.
  4. Too much moisture in the filament making it weak
  5. Needs more infill at the weak spots? (ex. if the neck is thin then infill other than 50-100 is a good idea if you can control that in your slicer).

i would start with the temps/adjusting settings. really hard to say without a reference photo.

However, i would try a stronger material for toys such as PETG either way. from experience they'll just break easily anyway from the abuse kids put them through. PETG has good layer bonding and easy to print, except it's terrible at bridging. Supports will most likely need to be cliped off with side cutters but it's not a huge deal.

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  • $\begingroup$ It was rather small, only a couple of inches wide. The support was also kind of strong and hard to pull off, there were parts where I got it halfway, then the rest stuck and wouldn't come off without considerable force. I used a brand new filament just out of the plastic wrap, and as far as I could tell, the calibration was fine. $\endgroup$ – TrojanByAccident Sep 22 '16 at 1:34
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To increase the strength of small parts I do:

  • Increase the nozzle size to layer height ratio. While 2 is the most popular choice (0.4 nozzle for 0.2 layer) the science behind the process really recommends around 4 (0.7 nozzle for 0.2 layer).
  • Increase the number of outer shells. I made dragons with great wings with 4 shells and no infill.
  • Typical things: raise temp, reduce speed.
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  • $\begingroup$ Well, it took 3 hours just to print how i described. $\endgroup$ – TrojanByAccident Sep 26 '16 at 13:31
  • $\begingroup$ +1 Your first bullet point is the real key here. The rest just ensures a successful print. I might add that increasing the extrusion temperature would go well with lower layer heights. This allows each layer to "weld" together easier. Some slicers like MakerWare reduce the flow of filament specifically for supports, so you shouldn't have to worry about the supports "welding" together as easy. This process ultimately leaves the part much stronger and the supports inherently weaker. Just a perk that the part looks better with lower layer height. $\endgroup$ – tbm0115 Sep 26 '16 at 20:37

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