Author Topic: core-xy  (Read 1722 times)

ggallant571

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core-xy
« on: July 31, 2017, 07:49:20 AM »
Based on the posts by pawpawpaw69 and others I have started a core-xy build. Have frame and first pass belt done. Has anyone determined the necessary belt tension?
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ggallant571

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Re: core-xy
« Reply #1 on: October 25, 2017, 11:59:03 AM »
Machine is operational with a few oddities. Number 1 is speed. I etched a drawing and cut a frame around it. Dimensions of the cut are good. Speed was much slower than expected. The frame was 260 mm at a cutting speed of 600 mm/min. I think it should take 26 seconds. Instead it takes 37 seconds. This is approximately square root of 2 times longer. Is this because a horizontal or vertical line is a 45 to the motor? Why doesn't the firmware compensate?
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ThothLoki

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Re: core-xy
« Reply #2 on: October 25, 2017, 02:00:41 PM »
Ggallant. I cannot speak to any of your questions because I am just starting my corexy setup. I am converting my old broken A5 to a corexy system. I will try to catch up. I am very interested in how it turns out and what answers you find.

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« Last Edit: October 25, 2017, 02:01:31 PM by ThothLoki »
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Zax

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Re: core-xy
« Reply #3 on: October 25, 2017, 02:05:06 PM »
The only reference I have is the EleksDraw and it is slower than the calculations compared to the Cartesian laser but I just figured it was their Mana firmware (Grbl 0.9 and their settings). It does seem odd that Grbl wouldn't calculate the correct feed rate but CoreXY isn't very common.

ggallant571

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Re: core-xy
« Reply #4 on: October 25, 2017, 02:06:44 PM »
Does grbl calculate the "true" feed rate for 45 degree cartesian moves?
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Lob0426

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Re: core-xy
« Reply #5 on: October 26, 2017, 12:28:49 AM »
There is a couple of settings in the grbl firmware for CoreXY did you set everything to CoreXY?
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ggallant571

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Re: core-xy
« Reply #6 on: October 26, 2017, 06:36:15 AM »
I think so. The x/y distances are good.
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Pawpawpaw85

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Re: core-xy
« Reply #7 on: March 07, 2019, 09:22:20 PM »
How is it going with the core-xy design? Happy to see someone more working on this too!

From the post made in the other thread, I have two suggestions that may be of help:
1) Do not use the steel springs to tighten the belt; It's much better to skip them and then tighten the belt without any springs in them as it'll help stiffen up the motion.
2) Adding support both under and over the bearings; This will over time support the bearings to be vertical for longer time, reducing risk of belt slipping off the bearing.
3) Center belt separator may not be needed; As bearings are ~500mm apart, the force pushing the belts together is very small so wear should not be an issue without it, as long as it's the smooth back of the belts rubbing together (you dont want tooth against tooth)

Hope some of the suggestions may be of use and good luck with your build!

Really miss to have the time to build on the laser instead of the forced new hobby :) (newly house owner)

ggallant571

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Re: core-xy
« Reply #8 on: March 08, 2019, 05:06:49 AM »
Welcome back and thanks for posting about the CORE-XY. I have built three and have hundreds of hours on them. They seem to be very tolerant of belt tension. I have the non-burning traverse speed set at about 3000 mm/min for most etching operations.
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ThothLoki

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Re: core-xy
« Reply #9 on: April 01, 2019, 03:13:52 PM »
Pawpaw. Are you still having issues with speed?
Laser: A5 2000mw with L7 Board / A3 2500mw PWM with Mana SE -- All using T2Laser
3D Printer: Monoprice Maker Select v2.1
Image Resizer Applications (All OS): http://benboxlaser.us/index.php/topic,1434.msg17297.html#msg17297