I want to print the following model on my Kobra Max using ABS.
I have uploaded it here.
I have tried it 3 times now, it always results in this:
As you can see, one part managed to break free from the support and warped upwards. At this point, I had to stop the print process.
The element which broke free really has a strong will to bend.
What could I do in this case?
These are my print settings; bed temperature is 80 °C, and nozzle temperature is 195 °C.
What is this called
This is called warping.
Warping of prints occurs frequently when you use a filament that shrinks. If the model would shrink uniformly, it will become smaller, like in a scaled version (unfortunately, the print is attached somewhere, which causes stresses in the first layers). But, if (due to the geometry of the print) some part of the model shrinks more, the model warps. It could then bend upwards from the build plate, deform at higher layers or sometimes even crack (e.g. in between layers).
and how do I avoid it?
ABS is a challenging material to print because it warps. It warps because it shrinks as it cools. The top layers are cooler than the bottom layers on a heated bed, so they become slightly smaller, and flat things turn happy face shape.
The real way to print big flat parts in ABS is with an insulated enclosure, that keeps the temperature up and the top layers don’t shrink enough to peel the model off the build plate. Recommended bed temperature is 100 °C, which many printers struggle with.
I have only been able to get ABS to stick to the bed with “ABS juice”, a mixture of acetone and scrap ABS filament. Wear gloves and mop some onto the bed with a paper towel or brush. Check that your print surface is compatible with acetone, otherwise you’ll have to use something milder, like gluestick.
As well as using ABS juice/glue on the print surface, use a brim. It is an extra, sacrificial layer of plastic around the model on the first layer that can help big flat parts stay stuck down. It is relatively easy to peel off by hand or shave off with a utility knife.
A brim of 10 mm is a good starting point. Nuclear option: if a print or material is really problematic you can pause the print after 3 layers or so and tape the brim down to the bed with wide blue painter’s tape.
If it is cold in your shop, a heat lamp or 100 Watt incandescent bulb near the print can keep the temperature up, if you don’t want to build an enclosure.
This is definitely warping caused by subpar adhesion to the bed, you can try glue or making the bed hotter as this answer suggests.
Another way of really making sure is to take off the square corner. They seem to be really prone to warping. When I have a persistent issue that is beating the glue stick and bed heat I will add a bit to the design itself to have a rounded edge at the corner. Basically just a flat circle that goes a bit further out where the sharp corner is and just for the first few layers (frequently called mouse ears). Then during post processing I cut it off.
You are getting warping. It's unusual in this case, as your overall model is relatively low profile. It's the taller stuff that likes to warp.
Consider to edit your post to include the layer heights and also the filament type and filament and bed temperatures. My first instinct is that your bed temperature is too low. There's little harm to be had by raising the temperature by ten degrees or so. Also if your slicer arbitrarily reduces the bed temperature after the first layers, disable that feature. There's no sense to set a good adhesion temperature on a print and later reduce it, yet I've seen slicer results that do just that.
Too cold filament by a substantial amount can also reduce the adhesion in combination with a too low bed temperature.
If you still run into adhesion problems, the Elmer's Purple Glue Stick works wonders.
With the new information comes new responses:
For ABS, 80 °C is on the low end for the bed, but may work. The extruder temp is really low for ABS. I run 250 °C for ABS. Also ensure some form of enclosure, even a cardboard box will help. I've accidentally fed ABS into a PLA profile. The results were surprisingly good, although warping was prevalent and some underextrusion was evident.
If you have a glass bed, you will very much want to use glue stick, as a release agent, not as an adhesive. ABS sticks really well to clean glass, well enough that it will pull fragments of glass from the surface!
