Homing my laser and it hits the frame

Hello! I’ve got a 80w monport (china) laser

My laser was in the middle of a job and all of a sudden hit the frame and threw itself out of calibration. So then I went to home it, and the laser head slammed into the frame as if it just kept going. Anyone ever heard of this? It was working just fine before. I need to address this before I re align. Thanks in advance!


When you have an issue always check over the hardware for loose or other anomalies. Since it happened in the middle of a job, I’d suspect a hardware failure…

On an Ruida, the limit switches are only operational when it’s homing.

Start at the beginning, does it home? If not what does it do?

You can ‘esc’ out of homing from the machines console if it has a problem.


When I just fired it up and homed it. It went straight into the frame along the Y axis and rode it down until I hit the emergency stop button. Maybe it has to do with my belt loosening up?

There is a boot process… The Ruida at power on or reset will seek in the direction of the limit or homing switches. If these fail to operate it will not know when to stop and will hit the frame.

Once it finds the switch each axes will back off the switch then re-approach at a lower speed to get a more accurate ‘home’ position.

Move the head to the middle of the work area and power it up. Pressing ‘esc’ on the console will stop the homing process and allow you to control the machine via the console.

When you power it up does it go in the right direction to activate the limit switches? I’m assuming it goes towards the limit switches.

Do your limit switches operate properly.

The Ruida panel allows you to display the status of the limit switches. Press Z then diagnostics. The state is also seen on the leds on the Ruida controller.

Most of these switches look like mine, which is a hall effect switch.

Here’s a quick video on how you can test them using my machine.


Both the limit switch seems to be working properly. That’s if the light indicator lighting up when metal is over it means it’s working. I tested them with a piece of metal like you said for the X and Y limit switch and both 1 and 3 light up on the inside panned as well. But it’s still smashing into the frame.

Nate, this has happened about five or six times to me(Sculpfun S9) and my only recourse is to immediately switch off the 12 V power supply in great haste. There is no apparent reason for this and I have looked closely. It is most alarming to see this happen as the gantry collides with the end rails with considerable force.

I can reliably prevent this from happening by always doing the following at the start of each new job:

  1. Restart Lightburn.
  2. Restart the controller by unplugging and replugging the USB cable.

Then I have no problems. I have no idea why this does the job.

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Since it’s working into the controller, the only place to check is via the front panel to see if the Ruida internals detects them. Not that it would help you if it did, that’s not user serviceable.

I think you have some kind of hardware issue.

Have you checked the motor drivers to ensure they are ‘green’ and haven’t faulted?
Never seen it run away like this, as the controller tells the drivers when to step.

I hate to say you lost the controller, but it doesn’t sound optimistic, especially since you lost it mid run. That’s never good.

My only suggestion at this point is to ensure you have proper power supply levels, although they are probably fine. Other wise I think you are out a controller…

If you decide to replace the controller, I’d attempt to re-load the firmware, can’t loose anything if the hardware downstream is dead.

Make sure you backup the configuration… no matter what.

Don’t know what else to suggest at this time…

Good luck


Before going down the road of thinking something is broke…realize usually it’s some setting that accidentally got changed or similar. Check your x and y position as it is displayed on your ruida. I bet it is off…meaning it is trying to go to a position that is within the stated bed size but the position of the gantry is off. Usually I see this when for some odd reason enable rotary somehow gets enabled….make sure it’s disabled…it cause this issue….and I promise you I have seen it get enabled without me doing it as I never use rotary. I actually disabled in in the ruida.
Either way move your head to the center of x and y by visually looking at the gantry…just get close. Look at the coordinates and I bet One is way off center by displayed position.
Or just manually move x and y to home…check what the position reads on the ruida display…again I bet it’s way off from 0’0

The problem with that theory is that

Ruida controller can’t have their configuration changed in the middle of a job.


So after looking farther into the limit switch it seems as if they are working when tested but as I jog the gantry over with the controls while simultaneously activating the limit switch it doesn’t stop the gantry. I tested both X and Y with this theory and neither of the switches stopped the gantry while it was jogging. Is it possible the switches are no good even if they are lighting up? Or do you think it’s a loos wife not relaying info? It makes more sense that it’s a switch going bad in the middle of a job….?

is obviously incorrect… :crazy_face:

I believe you missed this comment…

Once it has completed the home cycle, it never ‘looks’ at the switches again.

It uses limit inputs of LmtX+, LmtY+ & LmtZ+ for ‘outside work area’.

I doubt it’s your ‘loos[e] wife’ either… :crazy_face:


I did miss that my bad. So if they’re working properly it shouldn’t run into the frame during the homing process. Is it possible that both switches went bad? But the light still comes on when completing the circuit when tested? Is it possible for the switch to go bad while the light still works?

I did check and see if the rotary setting was turned on and it isn’t.

You can see they are operational by the controllers leds.

Doubt it, but you didn’t answer it from above and this could cause it to not home.

Press ‘esc’ when it’s trying to boot. Does it halt and allow you to control the axes from the console?

Before you power it up, move the head to the opposite corner of home. This gives you more time to press ‘esc’. You might have to press it a few times…


If you have a bad connection on the DIR pin, it will move the same way when it’s trying to go the other way and crash into the endstop. The Ruida will try to home (50/50 it goes towards the homing switch), find the switch, tries to back off until the switch turns off, but will actually continue in the same direction

Yea I have checked the led lights light up on the control. 1 & 3 light up when tested. Is that what you’re talking about?

Hhhm where is the DIR pin? I have all green lights . Except on the Ruida controller. 15 is red and 14 is blinking red. Is that normal?

15 is showing the 5volt supply for the Ruida is ok, 14 is the run light and it’s always just flashing. The one you don’t want to see is 13, that indicates an internal controller detected error.

Here is my driver, you can see all the control signals to the device on the top. The motor connects to the lower connector.


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