Best material for printing structural MK4 parts? (ABS versus PETG)
 
Notifications
Clear all

Best material for printing structural MK4 parts? (ABS versus PETG)  

  RSS
Line Arc Line
(@line-arc-line)
Active Member
Best material for printing structural MK4 parts? (ABS versus PETG)

Hey folks!

If I had the option to print the MK4 parts in either PETG or ABS/ASA, which would be the more functional option for the long-term performance of the MK4? (Regardless of price and printing difficulty)

I hear from some places that ABS has better rigidity and a higher glass point. The Voron prints all require ABS because of their enclosed nature. PETG doesn't withstand as much heat, but has higher elasticity and impact durability.

  • Which will perform better over time?- Does the design of the MK4 rely on the elasticity of PETG that prevents other materials?
  • Could ABS/ASA provide a structural advantage for parts of the gantry or frame?
  • Would some parts function worse when printed in ABS/ASA instead of the standard PETG?
  • Was PETG chosen because of its material properties, or for its availability and low print difficulty?

I'm aware the fan shroud needs to be ABS/ASA, and some parts are not structural. Could different materials for different parts be beneficial? 

The reason I ask, is I have just as much ABS/ASA as I do PETG (and some carbon-fiber petg!), and I can print both well. I'm sure the PETG is a fine choice, and I've already seen a few MK4's with the standard PETG that work great. However, if there is even a slight long-term benefit and low repercussions, then now is the best time for me to act on that. I've searched around for this comparison, and most conversations were around PLA/PETG, so I hope somebody can shed some light on this variant of that question.

Posted : 19/08/2023 9:32 am
Artur5
(@artur5)
Reputable Member
RE: Best material for printing structural MK4 parts? (ABS versus PETG)

In a nutshell:   ASA/ABS over PETg, no doubt.

Elaborating a bit:

If you’re not printing inside an enclosure high temp. filaments like PC/ABS/Nylon and room temperature never exceeds 30C, then PETg is fine too, except for the fan shroud and maybe other parts near heat sources, like the heatbed cable covers and the parts surrounding the hotend.  I can’t  think of any 3D printed part where the slightly superior elasticity of PETG over ASA/ABS would be of special advantage. Instead, speaking of the MK3S, there’re some of them that would benefit from the superior strength of ABS (i.e. those flimsy Y-rod holders and other small parts ).

My guess is that Prusa recommends PETG because it’s ‘good enough’ and, as you say, easier to print without an enclosure, which many Prusa users don’t have.

Posted : 20/08/2023 4:20 pm
Line Arc Line
(@line-arc-line)
Active Member
Topic starter answered:
RE: Best material for printing structural MK4 parts? (ABS versus PETG)

Thank you for responding, this is exactly what I was looking for. I'll start printing in ASA once my order ships, and if I run into any trouble with that decision, I'll update here.

Posted : 23/08/2023 10:17 pm
Line Arc Line
(@line-arc-line)
Active Member
Topic starter answered:
RE: Best material for printing structural MK4 parts? (ABS versus PETG)

Well, I ran into a problem with my ASA prints. It seems that ABS and ASA have some natural shrinking when printing with it.
This caused the rods to not fit in the Z-parts. When printing with PETG, they fit nicely. I think I will play around with scaling the parts to account for this shrinkage.

Don't be a rube like me and print all the parts without testing their fit, especially with the smooth rods.

Posted : 28/09/2023 1:27 pm
Antimix liked
konfuzed
(@konfuzed)
Member
RE: Best material for printing structural MK4 parts? (ABS versus PETG)

 

Posted by: @line-arc-line

Well, I ran into a problem with my ASA prints. It seems that ABS and ASA have some natural shrinking when printing with it.
This caused the rods to not fit in the Z-parts. When printing with PETG, they fit nicely. I think I will play around with scaling the parts to account for this shrinkage.

Don't be a rube like me and print all the parts without testing their fit, especially with the smooth rods.

Thanks for this tidbit. I’ve been printing all my upgrade parts after much delay thanks to holidays and family schedules, and dry fitting all the ASA parts I have should have been a no brainer for me but I hadn’t thought of the rods until your post. I was worried more about inserting nuts and such. 

Posted : 13/02/2024 2:37 am
frebys
(@frebys)
Trusted Member
RE: Best material for printing structural MK4 parts? (ABS versus PETG)

 

Posted by: @line-arc-line

Well, I ran into a problem with my ASA prints. It seems that ABS and ASA have some natural shrinking when printing with it.
This caused the rods to not fit in the Z-parts. When printing with PETG, they fit nicely. I think I will play around with scaling the parts to account for this shrinkage.

Don't be a rube like me and print all the parts without testing their fit, especially with the smooth rods.

This might not be shrinkage, this might be the filament simply expanding after it leaves the nozzle. According to the Prusa course (Design principles for 3D printed parts), the extrusion width is roughly 110% of the nozzle diameter. I.e. all holes are a bit smaller IRL than in the CAD files. 

This can be remedied (maybe) with the Prusa slicer setting "XY compensation" which compensates for this. 

Posted : 16/02/2024 10:58 pm
Share: