CoreXYL(aser) setup

Hey guys, so I'm nearing the finish with my CoreXY build.

Teaser pic: (click for way bigger picture)


It will first be a laser cutter, because it was an easy design to 'box': (click for way bigger picture)


The laser is a 2W 445NM laser diode known as the 'L-Cheapo' laser.

But, as I am running towards the finish line, I just want to make sure I'm setting up the firmware and Ramps correctly. The laser I'm using will just use the hotend's output to turn on and cut. So the firmware doesn't need any changes when talking about the laser. All I did was enable CoreXY in Marlin, it will work right. However, there are some things I couldn't find.

Question one:
How do I know which motor is the X-motor and which motor is the Y-motor? I tried finding images that explain but couldn't find any in google.

Question two:
Does anyone have advice for setting up CoreXY?

Question three:
I am experienced in setting up standard 3D-printers, but since my laser cutter doesn't need a thermistor, is there a way to turn it off? I have disabled 'prevent dangerous extrusion'.

Tomorrow I will run the first tests with the machine after I finish all the optical endstops, right now theres only one actually working, I am afraid to try out the machines Z-axis without the endstop as the X- and Y-axis belts can be disconnected, but the Z-bed can't. So if I make a mistake with it going the wrong way, it will go on until it runs itself into the bottom of the machine

I will update with some new pictures tomorrow. The machine is not completely finished yet. I have iterated the X-carriage around 5 times already, and am nearing the final stage. The belt-tensioning works well/flawlessly, but it's very inconvenient to use right now.

Edited 2 time(s). Last edit at 01/15/2015 09:12AM by Ohmarinus.

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http://www.marinusdebeer.nl/

Your motors aren't necessarily designated X and Y because if only 1 motor turns, the carriage should move diagonally. What you need to do is jog the carriage and make sure it moves in the appropriate direction. If it doesn't, you can try flipping one stepper connection in either the firmware or on the board. You might have to test a few configurations out to get it right.

For disabling the thermistor, you should be able to set it to "0" in the firmware and it will be like there is no thermistor.

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Could you give a few details on your belt tensioning, Ohmarinus? Maybe some pictures? I am having difficulties coming up with a tensioner for my design that has similar belt path characteristics to your CoreXY system.

Hey, I hope this clarifies a little:






However, instead of aiming the tensioners to the inside, I want them to be aiming outside from the middle, because the way I did it now is self-limiting and not effcient. Also hard to reach with a hex screwdriver hehehe.

I'll update it soon.

Edit:
I have set mintemp for the extruder to zero. Now the machine doesn't give an error anymore when it's turned on. Didn't want to make a useless thermistor so I figured just disabling it in the firmware was a better idea. The endstops are almost all finished now, after connecting them I will start troubleshooting the machine if necessary.

Edited 1 time(s). Last edit at 01/15/2015 08:06AM by Ohmarinus.

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http://www.marinusdebeer.nl/

Okay, everything works, except for the endstop/axis directions...

When homing, it does home to the correct endstops, but then when I say move +10mm it does the exact opposite and tries to crash into the endstop.

I tried:
switching stepper cables for X and Y axis
turning around stepper cables for X and Y axis (flipping them 180º)
inverting endstops in firmware
inverting axis in firmware

No combination I've tried works.

One thing, I am only using an Y-max endstop. Because I wanted the endstop to be on the backside of the machine. Not sure if this could cause a problem? It seems no config will be able to make it work normally.

I have discovered that inverting the 'X' direction doesn't truly invert the X-direction, it inverts the movement of one of the motors, which ruins the complete setup. Marlin has errors, maybe I'm using an older firmware version...?


Edit:
I have managed to get it to work, BUT, the machine is now 90º rotated inside. So the printing direction is turned a quarter of a circle.

This means that when you sit in front of the machine, you are looking at the left side. The left side of the print bed is considered to be the bottom
Hope one day I find out how to change this, but there seems to be no solution for this at the time.

Edited 2 time(s). Last edit at 01/15/2015 05:28PM by Ohmarinus.

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http://www.marinusdebeer.nl/

I had a similar problem with a friend's machine. We kept inverting a direction and or swapping motor leads to no avail. What did work was to swap both the motor lead and endstop on the y axis for the x-axis! He was using all Min endstops. Also double check the endstop on your board corresponds to the set endstop in your firmware. Are you using max or min endstops?

Send M119 command and check that the y-endstop is triggering on y-axis and same for x and z. I use repetier firmware and repetier host so I have the logic setup to trigger H signal when endstop triggered.

Edited 3 time(s). Last edit at 01/19/2015 03:59PM by runninfarmer.