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New heatbed...maybe?

Posted: Fri Apr 27, 2018 10:33 am
by InspGadgt
Hi Tom and everyone else,

Thanks Tom for your helpful videos...they have really been of great assistance though my 3d printing journey.

I bought an Anet A8 about a year ago and have been going about the process of learning the art of 3d printing mainly so I can 3d print RC aircraft. Early on in my journey I noticed my bed was warped so I started using a glass plate on the bed to level things out. It's important to have a perfectly flat surface otherwise fitting the pieces together is a pain to do. Things seemed great until I noticed that I was getting depressions in the wing prints...which as it turns out is due to the heat bed keeping the lower levels a bit soft and the weight of the piece as it gets higher begins to crush the lower layers. This is mostly single wall printing so the plastic is really thin. Most of the prints use 2 print processes. The first process lasts for about 5mm of printing and prints double wall. After that the 2nd process prints the rest of the part in single wall. So to avoid the crushing issue I started turning off the heat bed in the 2nd process. Sure enough the crushing problem went away...but I noticed the bottom part of the pieces is now not flat again like before I started using glass.

Ok so that's the issue/background. Tonight I was watching your 2014 video on heat beds and you mention a warping problem due to the bed cooling that caused your 2nd layer to separate from the first. I'm thinking on buying a new heat bed due to the problem but after seeing that video I'm starting to now think that my turning off the heat bed at 5mm is what is causing the non-flat bottom. Do you think that is likely or should I still be thinking about a new heat bed? If it's not the heat bed do you think reducing the heat but not shutting it off would prevent the warping and the crushing? FYI these are the planes from


Re: New heatbed...maybe?

Posted: Fri Apr 27, 2018 10:18 pm
by Stefan
Hi InspGadgt,

Welcome to the forum! I have two recommendations that you might try before investing in a new heatbed.
  • Remember that you can integrate break-away supports in your pieces that will help prevent them from sagging. This may allow you to keep the heat on and reduce warping.
  • Print your parts with a (bigger?) brim. A brim will increase the surface area of your first layer & allow it to stick to the bed better. It can then be cut off when the print is complete.
Additional information might be helpful: what type of plastic are you using & what are your print temps? Are you using anything to aid in the print adhesion (glue stick, abs slurry, painter's tape)?

Re: New heatbed...maybe?

Posted: Mon Apr 30, 2018 11:19 am
by InspGadgt
Supports are pretty much impossible with these prints and a brim isn't going to help with the crushing. I get plenty of stick without the brim already.