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blackomega

UM2 Print Head Homing

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Noticed when my UM2 homes the print head it moves the head to the back left corner but when it does this it slams into the side of the case. This causes an ever increasing groove to develop in the inside of the left side wall.

I've only noticed this since upgrading to the latest release of the firmware.

Is there any way to reset what the "home" position is?

 

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Just a thought, have you checked to make sure that the end stop(s) haven't moved? Maybe a screw shook loose during shipping?

 

Forgive my ignorance but where are the end stops? Nothing appears to be missing and besides I'm pretty sure (although I can't be 100% certain) that it didn't do this before the firmware update.

 

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See picture below. Try moving the head manually (if the motors are engaged turn your printer off so you can move it) to the home position. You will hear a soft click when the end stops engage, check to make sure that you hear that click before the print head hits the side of the case.

endstops

 

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I see that now. Both microswitches are there and both do get engaged however the back one (righthand one in the picture) is too far left in my opinion as the leading edge of the lefthand head fan makes contact with the side wall of the casing at the point when the microswitch is engaged. It really needs moved right by 5mm. I see there are already some adjustment available however I have mine as far right as the holes allow.

 

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What exactly is it hitting?

1) The side plastic panel?

2) The side aluminum (dibond) panel?

3) The rear metal stepper cover?

If #3 then you might need to raise your fans by 1mm or so. Maybe you could take a photo with the machine off at the position where the head hits the "side of the case".

The 2 side fans should be symmetrical - same height and same distance sideways. The folded metal part that holds the side fans has been a problem for the early UM2's and yours might not be bent properly (not the right shape). Or your fans might be loose - not only has the metal been in the wrong shape, the screws that hold the fans on keep getting loose and sometimes fall out. Some people have added a rubber band to hold it together better (so it is quieter). UM is experimenting with different types of screws and rivets.

 

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What exactly is it hitting?

1) The side plastic panel?

2) The side aluminum (dibond) panel?

3) The rear metal stepper cover?

If #3 then you might need to raise your fans by 1mm or so. Maybe you could take a photo with the machine off at the position where the head hits the "side of the case".

The 2 side fans should be symmetrical - same height and same distance sideways. The folded metal part that holds the side fans has been a problem for the early UM2's and yours might not be bent properly (not the right shape). Or your fans might be loose - not only has the metal been in the wrong shape, the screws that hold the fans on keep getting loose and sometimes fall out. Some people have added a rubber band to hold it together better (so it is quieter). UM is experimenting with different types of screws and rivets.

 

It was hitting the side plastic panel. Both fans were level as far as I could tell. Incidentally what sort of screwdriver are those? (torx 8 is my estimate but I don't have one of those to hand since I moved house).

Anyway, I've solved the problem but simply using long nosed pliers to introduce a bend in the metal contact for the back microswitch. The result being that the print head now causes the switch to depress that little bit sooner so now the head will stop about 4mm from the edge of the case when homing.

 

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Your UM2 should have come with a screwdriver for that. It's a very very nice one. It should be in the same bag as with the blue roll of tape and the green grease (for your Z screw). Look for these items. If you are sure you didn't get a screwdriver write a support ticket.

 

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Your UM2 should have come with a screwdriver for that. It's a very very nice one. It should be in the same bag as with the blue roll of tape and the green grease (for your Z screw). Look for these items. If you are sure you didn't get a screwdriver write a support ticket.

I did get a screw driver (a nice blue one) but it is definitely too small (T6 is my estimate). Either that or my UM2 was build with larger screws for some reason.

 

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I too got the blue T6 torx screwdriver, it's useless for anything but the small screws on the cooling fans. I also got a few allen keys that work on the other screws.

That's the problem. The small screws on the cooling fans on my UM2 are T8 screws (I estimate) as the T6 screw driver is way too small (doesn't even engage at all) which means the T6 screwdriver I got is useless for any of the screws on my unit.

 

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The UM1 has the same screw head ON EVERYTHING. Too bad they couldn't do that with the um2. I think the screwdriver that comes with it fits quite a few things - for example the screws that hold the panels together perhaps?

 

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The UM1 has the same screw head ON EVERYTHING. Too bad they couldn't do that with the um2. I think the screwdriver that comes with it fits quite a few things - for example the screws that hold the panels together perhaps?

 

Not on the UM2. The screws that hold the panel together are actually used everywhere that I can see and can be removed using the smaller of the 2 allen keys that are supplied. Not yet found a need for the larger one it comes with.

 

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Mine came with a T6 screwdriver, and some Allen keys. So far I haven't found anything that the screwdriver fits. Pulleys, fans and frame all use larger screws.

 

Weird as on mine the only thing that seems to have the Torx screws are the side fans. Everything else is using the small allen key headed screws, even the pulleys and the pulley sprockets.

 

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Oh, ok. The screws holding my fans to the shroud are pretty tiny. Perhaps they've changed to a bigger screw in response to the early problem reports and forgot to change the screwdriver.

 

The evidence does seem to point in that direction. With the differences in screws used, tolerances, rear fan problems and other variations from one UM2 to another, I am concerned Ultimaker needs to be tighter on either their build version control and/or quality assurance perhaps.

It is a real shame though as in general the UM2 is beautifully designed and made but these, seem to be common, niggles risk giving them a bad reputation. I understand that experimentation with design tweaks is part of the game but are Ultimaker going to send out these little refinements as kits to all UM2 owners? I suspect not although they really should in my opinion.

 

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