Corners not sharp after switching to 2GT belts

I've recently rebuilt my Mendel90 and switched to genuine Gates Powergrip 2GT belts and an E3D V6 hot-end however I'm now experiencing rounded corners when printing the calibration cube. In the attached photo the cube on the left is the most recent print with 2GT belts printed at 40mm/s and on the right is using the original T2.5 belts printed at 50mm/s. As you can see, the corners are not sharp on the left cube.

Can this be resolved with acceleration/jerk or any other firmware settings and can anyone recommend good values to use with these belts?

I'm concerned that the 20 tooth pulleys have resulted in lower resolution, could this be an issue?

Cheers

Edited 3 time(s). Last edit at 03/11/2021 08:44AM by remondo.

DId you also get new *2GT* Pulleys, as from what I read 2GT tooth profiles are not the same as cheap gt2 pullies

Not sure what you mean by 20 tooth being lower resolution. 20 times 2 is 40mm, the same as 16 times 2.5 is 40mm. You shouldn't need to change any settings.

Your left hand cube has three outlines but the right only has two. If the inner outlines are done first I could imagine it would lead to more rounded corners. Other things that can affect it are the nozzle diameter, the plastic's viscosity, and the layer height.

If the belt profile does not match the pulleys I think the worst you would get is perhaps some backlash. I don't think you would get nicely rounded corners.

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[www.hydraraptor.blogspot.com]

Z

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Dust
DId you also get new *2GT* Pulleys, as from what I read 2GT tooth profiles are not the same as cheap gt2 pullies

Apologies for the lack of information. Yes I also replaced the pulleys with genuine Gates Powergrip pulleys, all purchased from E3D online so they should be compatible.

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nophead
Not sure what you mean by 20 tooth being lower resolution. 20 times 2 is 40mm, the same as 16 times 2.5 is 40mm. You shouldn't need to change any settings.

Your left hand cube has three outlines but the right only has two. If the inner outlines are done first I could imagine it would lead to more rounded corners. Other things that can affect it are the nozzle diameter, the plastic's viscosity, and the layer height.

If the belt profile does not match the pulleys I think the worst you would get is perhaps some backlash. I don't think you would get nicely rounded corners.

Good point about the resolution. This is why I had to retake maths at school!

Regarding the outlines, I have since tried with 2 outlines and the corners are much crisper. I always print perimeters inside-out, so the external perimeter is printed last. Nozzle is the standard 0.4mm for both cubes.

I think the issue I'm having is actually a lack of cooling. I foolishly printed a third-party fan duct that doesn't fit so I will need to print the 'official' one once I'm confident that the printer is calibrated correctly.

I've done another test print with the same settings as the the cube that was printed before the rebuild and with a rudimentary cooling fan pointing in one direction. In the attached photos the left-hand cube is using T2.5 belts (pre-rebuild) and the right-hand cube is the most recent print using 2GT belts (post-rebuild). Sorry I've since realised this is opposite to the original post, oops.

Maybe I'm being nit-picky but the corners still don't look quite as sharp in the right-hand cube when viewed from the top or bottom. Maybe if I didn't have anything to compare with I wouldn't even notice. You'll also notice that the X side is poor quality- this is the side that was facing away from the direction of the cooling fan so that will probably be solved with adequate cooling.

I am struggling to see much difference on the top but the bottom looks like the original was printed with the first layer a little bit further from the bed so getting slightly thinner extrusion.

The infill on the top layer is the opposite direction, so these are not from the same g-code and possibly not the same slicer. The acceleration would affect corner sharpness. I set that in firmware bit I think later slicers can override it in the g-code.

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[www.hydraraptor.blogspot.com]

You're right and I am just being nit-picky.

I came across your blog post in which you actually tested the fan duct I'm using, the one by Daniel Bull and it's pretty conclusive that the duct is not fit for purpose, and clearly illustrates why I'm getting poor quality results on the side furthest away from the fan. I'll print the 'official' duct and I'll stop questioning your thorough research!

Edited 1 time(s). Last edit at 03/24/2021 05:48PM by remondo.