Introduction

The Ratrig VCore3 and VCore4 come with excellent guides and documentation. However, based on what I understand of the theory and practice, a few things might need to be revisited. What I have found is that

• It is good to understand what causes the difference in belt tension with corexy
• The belts cannot be adjusted independently
• There could be a better way to square the gantry and tune the belts.
• The MEASURE_COREXY_BELT_TENSION macro should not be used for measuring the belt tension
• The belts do not have to be of equal length to the tooth

That is quite a list, and since there are several successful vcore4/3 setups there, you might argue that the list does not matter. If you follow the current guides, you will end up with a fine printer. However, I feel it might be interesting to look at these issues from a different angle, and see whether it would make sense to do things differently.

I am still a bit confused as to why things are the way they are, and of course slightly worried that I might be missing something, or that I have made an error. Thus feedback is welcome, especially the constructive kind. mazas#3738 at discord

Tuning the Belts

Belt tuning in corexy means adjusting the tension and/or the length of the belts for desired outcomes. In vcore4 the tuning is done by moving the front pulleys (tensioners), in vcore3 tuning is done by moving the belt grabber position at the toolhead. Both work pretty much the same from belt tuning perspective.

Why tune belts

Belt tuning is needed for:

• making it easier to build with slack belts that can later be tightened
• squaring the gantry
• providing the desired tension on the belts
  • positional accuracy, wear, noise, stress to other parts

After tuning, we would need to see the results. Here I am using the Input Shaper graphs as the result, which hopefully somehow correlates with real printing perfomance.