UM2 print head scratching up wall at Home position

[gonazar 0]

Hello,

I've had my printer for about a month or two, but more recently I've noticed a scratching sound at the beginning and end of printing. While working on a print I checked the home position and noticed the wall is being scratched by the fan of the print head. Due to this, one of the fans is being warped upwards.

 

Any idea what caused this, how to fix it and what I can do to prevent it in the future?

I'm wondering if the firmware update caused this, as I haven't touched or modified any of the hardware. If it's not that, then I think it might be accumulating error from the stepper motors.

But there should be an encoder to fix that should there?

Also why didn't the limit switch trigger?

 

[gr5 2,167]

Yes, bend back the fan. Also after bending it back listen for the limit switch and make sure when it clicks there is still a gap between the fan and the wall. If not the limit switch may have moved or it may be broken. If the limit switch is broken it is obvious because homing the X axis would be incredibly loud. It does the "death rattle" when the limit switch isn't working.

Still the switch may have moved and you might want to bend it back by .5mm or so after you bend the fan duct back.

 

[gonazar 0]

Thanks!

I ended up just sticking a piece of PLA in between so the limit switch would trigger earlier.

Does this offset the dimensions of the build area though? (Not that I would print all the way out to the edge anyways)

How would the printer know when it hits the opposite edge? I don't see any limit switches for that side. Is that software based in the printer settings of how big the build area is?

 

[gr5 2,167]

The printer has "software end stops" enabled. So, yes, it's a software thing. I forget the XY dimensions but I think 225 and 235mm. You can command the printer to go to various positions (220,225,230,235) and see if it hits the other side. You won't break anything. The printer is tough that way - many times I've moved X or Y axis farther than it's supposed to go. It makes a loud scary noise but nothing is damaged.

You can hook up the printer do your computer with USB, go to print window in Cura and configure it for "pronterface" mode and then send gcodes:

G0 X10

moves X axis to 10mm from home position.