Homing the Z-Axis

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ElliotD4
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Homing the Z-Axis

Postby ElliotD4 » Thu May 30, 2019 3:41 pm

Hi there,

A while back I set the z-axis to be 30mm below the nozzle and accidentally set as the home position thinking that this button would bring it back to the original position.

Now when I try to jog it back up 30mm it displays a negative value but does not move the bed back up closer to the nozzle. When I jog downwards it moves just fine.

How do I return it to the original position?

Thanks,

Elliot

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Vicky@Raise3D
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Re: Homing the Z-Axis

Postby Vicky@Raise3D » Thu May 30, 2019 5:34 pm

Please check whether there is anything stuck on your endstop board which may cause the board think that the Z screw has reached to the original position.
Attached a document to show you where and what does the board look like.
https://support.raise3d.com/Pro2-Series ... 4-275.html

ElliotD4
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Joined: Thu May 30, 2019 3:34 pm

Re: Homing the Z-Axis

Postby ElliotD4 » Fri May 31, 2019 8:00 am

Vicky@Raise3D wrote:Please check whether there is anything stuck on your endstop board which may cause the board think that the Z screw has reached to the original position.
Attached a document to show you where and what does the board look like.
https://support.raise3d.com/Pro2-Series ... 4-275.html

Hi Vicky,

Thanks for replying so quickly. No the Z-endstop is completely free, it's almost as if the printer thinks it's going to crash the bed into the nozzle so chooses not to raise it. The bed lowers just fine and moves up to the endstop normally when printing, but it just homes in the wrong position meaning that I can't set the nozzle height using the feeler gauge. Also this is an N2 printer.

Attached a photo of the home position.

Thanks,

Elliot
Attachments
20190531_084357.jpg

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Vicky@Raise3D
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Re: Homing the Z-Axis

Postby Vicky@Raise3D » Fri May 31, 2019 5:50 pm

Would you like to move the bed down a little bit further and home Z then use your finger to press the button on Z endstop switch to see whether it will see the movement of Z homing or not?

You can also contact our tech support at http://help.raise3d.com for tech service.

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jetdillo
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Re: Homing the Z-Axis

Postby jetdillo » Tue Jun 09, 2020 1:57 pm

I'm also running into this problem after doing some hot-end maintenance. In the past when I've had a large print and shut the printer down before homing it again, I've been able to manually lift the build platform back to the top and get the printer to reset and "notice" that it had been homed. Now it's shuddering and refuses to move the platform up or down. The screws turn freely when the printer is powered off. I've tested the Z-home switch and it is intact and functional.

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jetdillo
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Re: Homing the Z-Axis

Postby jetdillo » Fri Jun 12, 2020 3:06 pm

jetdillo wrote:I'm also running into this problem after doing some hot-end maintenance. In the past when I've had a large print and shut the printer down before homing it again, I've been able to manually lift the build platform back to the top and get the printer to reset and "notice" that it had been homed. Now it's shuddering and refuses to move the platform up or down. The screws turn freely when the printer is powered off. I've tested the Z-home switch and it is intact and functional.


I figured this out.

It looks like the board for the Z-axis switch is broken. I took it off the printer, hooked it up to a multimeter and was able to confirm the switch itself works, but the solder between the switch contacts and the PCB was damaged, causing a short. Okay, I resoldered it, re-installed it and it worked for maybe 2 minutes before developing a short in it again. The stuttering on the motors comes from the fact that it has failed closed. So the mainboard is detecting that the Z-axis is already homed against the switch(even when its not) and won't move the motors.

I was also able to beep out the cable between the switch connector and the other end plugged into the mainboard inside the electronic box. So the cable is intact.

Is there a replacement for this ? This is a bigger switch with a longer lever bent to cover the Z-height screw. It doesn't look like the replacement end-stop switch for the X/Y axis that is available on the Raise site.
I could probably dig through my bits box and come up with something if I had to, but I'd prefer to get an actual replacement part from Raise3D if I could.
Just to remind, this is an N2+ .

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ccclarke
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Re: Homing the Z-Axis

Postby ccclarke » Fri Jun 12, 2020 3:30 pm

"Okay, I re-soldered it, re-installed it and it worked for maybe 2 minutes before developing a short in it again."

If you re-flowed the solder joint and it "shorted" it didn't just happen and then decide to happen again after some heat was applied. Unless it's a case of a very low resistance connection, (and they're very rare) re-flowing the joint accomplished nothing except heating up your soldering iron and the joint. It's like "sort-of-pregnant" a short either is - or isn't. Switches fail, and are easy and inexpensive to replace.

CCC
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Vicky@Raise3D
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Re: Homing the Z-Axis

Postby Vicky@Raise3D » Fri Jun 12, 2020 10:16 pm

Would you like to share the picture of the parts you are looking? We do have bother Endstops for Pro2 series and N series selling online.

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jetdillo
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Re: Homing the Z-Axis

Postby jetdillo » Sat Jun 13, 2020 12:50 am

Vicky@Raise3D wrote:Would you like to share the picture of the parts you are looking? We do have bother Endstops for Pro2 series and N series selling online.

20200612_165835.jpg


The top switch is the Z-axis limit switch, with a spare X/Y axis limit switch I have for comparison, which, as you can see is considerably smaller.
Are the switches electrically the same (wired NC vs. NO) ?

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jetdillo
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Re: Homing the Z-Axis

Postby jetdillo » Sat Jun 13, 2020 1:38 am

ElliotD4 wrote:
Vicky@Raise3D wrote:Please check whether there is anything stuck on your endstop board which may cause the board think that the Z screw has reached to the original position.
Attached a document to show you where and what does the board look like.
https://support.raise3d.com/Pro2-Series ... 4-275.html

Hi Vicky,

Thanks for replying so quickly. No the Z-endstop is completely free, it's almost as if the printer thinks it's going to crash the bed into the nozzle so chooses not to raise it. The bed lowers just fine and moves up to the endstop normally when printing, but it just homes in the wrong position meaning that I can't set the nozzle height using the feeler gauge. Also this is an N2 printer.

Attached a photo of the home position.

Thanks,

Elliot


Huh, interesting. You obviously have a later-model N2 than I do because that's the switch I have on my X/Y endstops.

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ccclarke
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Re: Homing the Z-Axis

Postby ccclarke » Sat Jun 13, 2020 8:32 pm

Those look like subminiature DH series Cherry micro-switches; I've used them at work for twenty years. These switches are identified by their type, (NO or NC) and lead configuration (straight, 90 degree).

https://www.mouser.com/catalog/supplier ... itches.pdf

If you know how to de-solder and can solder a new switch in, first identify the switch type, (NO/NC) - which is easy to do with a multi-meter, and buy a few from Digi-key; they're very inexpensive.

There's a trick to soldering them properly. If flux is used help flow the solder joint, and any kind of cleaning agent is used to clean the joint afterwards, (like IPA) there's a tendency for the flux to flow along the leads into the interior of the (unsealed) switch (you can clearly see the seams on the switch body) and contaminate the contacts. I've used these in high-reliability applications, and use minimal (dry -never liquid) flux followed by a clean, short-trimmed (so it's stiff) acid brush to clean off the remaining residue. Then I clip a multimeter to the leads and cycle the switch fifty times to ensure reliability. Soldered this way, the switches are very reliable.

CC
Male Modeler / Sub-Human

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Vicky@Raise3D
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Re: Homing the Z-Axis

Postby Vicky@Raise3D » Mon Jun 15, 2020 7:50 pm

They work the same. But you will need re-calibrate Z homing screw after putting the new limit swith on.

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jetdillo
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Re: Homing the Z-Axis

Postby jetdillo » Sun Jul 05, 2020 8:59 am

Vicky@Raise3D wrote:They work the same. But you will need re-calibrate Z homing screw after putting the new limit swith on.

Okay,
I'm stumped here. I swapped out the switch and am still seeing the same behavior as before:

    -The Z-axis motors shudder when trying to move.
    -If I tap "Down" on the Z-axis control on the GUI, the build plate shudders down.
    -If I tap "Up", it shudders down as well.
    -With the printer turned off or motors "Disabled" from the GUI, I can hand-turn the screws for the Z-axis smoothly.
    -Visually inspecting everything, there doesn't appear to be anything blocking or stuck on the screws.
I got out my Multimeter and was able to beep out connectivity between the two ends of the cable for the -Z cable, so there are no electrical breaks in the wires in the cable. It's plugged into the -Z socket on the main controller board.

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Vicky@Raise3D
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Re: Homing the Z-Axis

Postby Vicky@Raise3D » Tue Jul 07, 2020 3:13 am

The issue sounds very likely related to motor driver cable, but I can't 100% confirm.
Please open a support ticket at http://help.raise3d.com to ask our support team to help you do further diagnose.


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