When Good Printers Go Bad

 In 30 days of education

You know that feeling. You’ve spent hours designing and perfecting your model. You’ve leveled your build plate. You click print. And then you come back to check on it an hour later and your creation doesn’t even resemble what you modeled. Instead, it resembles spaghetti, bubble gum, your model having gone through a stair-stepper machine, or something else entirely. We’ve been there. There are a lot of things that can go wrong when 3D printing. Today we hope to highlight some of the most-common issues and how to minimize the likelihood of this happening to you.


Make sure your build plate is cleared!

It seems like a no-brainer, but if you’re using any sort of remote printing service like we offer at MyStemKits.com, it’s important to make sure you’re sending the print to the correct printer. Otherwise, you might run into a situation like in image “G” where the previous build still being there actually caused the entire build plate to get dislodged and pushed out of the way of the motor.

Make sure your printer is well-leveled.

This is by far the most-common issue with poor prints. Images C, I/K, and L were all caused by a poorly-level printer. If the build plate is too close to the printer, it may cause the printer to jam or scrape across the build plate until it gets to a level where it’s all the way off the build plate. It may then continue printing – leaving you none-the-wiser to the problem at the bottom until you remove it after it’s done printing. This is what happened with I/K. Also because the support that connected between the eyes didn’t get a solid grip on the build plate, it created a Mohawk effect where the printer was trying to build a support that didn’t exist and instead just extruded excess filament, which attached to the next printed part. As for the random gap in the jaw of the skull – that’s anyone’s guess. Most likely the printer got partially jammed back at the first couple layers and that’s a side effect of that. If your printer allows, this would be a good time to open it up and clean the stepper motor, as discussed below.
If the build plate is too far from the printer, you’ll likely end up with one of two results: bubble-gum stuck to the extruder or spaghetti all over the build plate. (Not actual food of course, but that type of filament construction.) This is because the filament isn’t close enough to get a good bond with the print bed and instead is either sticking to the extruder or just going where it will. You can see examples of build plates leveled too far from the extruder in images C and L. With C, the printer might have only been slightly unlevel, since it only messed up the first couple layers and then was able to successfully build on top of the messy layers. Follow your printer’s instructions for leveling. Most printers only need to be leveled every couple of weeks. Only level them if you’re noticing print issues or if you travel with them. Otherwise, if it’s not broke, don’t fix it. As a printer ages, the leveling screws will loosen and it will need to be leveled more often.
The best advice I have for this is watch the first layer print. Make sure it’s laying out a consistent-thickness of filament that’s been slightly pressed down by the extruder head. It should be binding to the build plate. Another way to help with this is to use build-plate surfaces such as painters tape or BuildTak for non-heated build plates and kapton tape for heated build plates.

Check the print speed.

Sometimes, all it takes is slowing the print down. Objects with high infill or that are tall and thin, or long and wide require slower print speeds to print successfully. This was the case with images A and H. In the case of image A, the object was printing with 100% infill and needed to be slowed down. Image H was such a large object that the print speed had to be slowed down. We also ended up redesigning that piece to prevent future print issues by breaking it into two halves. Sometimes, a redesign is the most-logical solution.

Check the gantry belts.

It depends on you type of printer, but often the belts will become lose, causing prints to stair-step to one side – sometimes drastically. You can see that in images B, D, and F. The print starts printing and then the whole thing moves over to one side. This can be caused by a kink in the filament that drags the motor over or by the gantry belts. See your specific printer’s how-to guides to figure out how to tighten and maintain those.

Clean the stepper motor.

As discussed when talking about images I/K under leveling above, a messy stepper motor can be the cause of irrationally placed gaps in models, as shown in the skull’s jaw. This can also account for air-printing, where a model just stops printing partway through. If your printer design allows for it, open it up and clean out the filament from around the stepper motor.

Unjam the printer.

Another common issue, printers that jam will result in air-printing. Unjam the model, clean out the stepper motor, level, and try again.

Now for those of you paying attention, I didn’t provide an explanation for either image E or J. Sometimes, the printers just decide to be difficult and there’s not a logical explanation for why. That’s why we provide the option to print each part individually and why each points-based subscription includes extra points for spare parts.

Have any great print failures to share or suggestions on how to avoid them? Share in the comments!

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