Hooming and Framing Issue

Have a Jinsoku LC-60A that normally works just fine.

On occasion, when I hit the Home or Frame button in LB, the laser will travel to a spot and just sit there and grind like it’s trying to move but can’t. It doesn’t have to be at the left front home position. Sometimes it seems to want to move forward; other times sideways. Is it just out of alignment with the XY axes or is there some soft limit that should be addressed in GRBL? I don’t seem to be able to stop it with the Stop button in LB or with the Off button on the laser.

What am I missing here?

Thanks!

John T

Check out this post and follow the guidance there:

If you follow the guidance, does this still occur?

Yes, but there’s more, I think problems with the laser itself. Now when I jog left or right in Lightburn, it will only move to the right. When I jog forward or backward, it will only move backward. Must be a problem with a stepper motor or wiring…

Can you run these commands one at a time in Console and then return the full output?

$H
$#
?




Don’t know what an M position is, but since mine is a 600x570, I’m guessing -899 is a problem.Thanks!

Looks to me like your machine is having a problem with homing.

Can you confirm that the machine is engaging both the X and Y switches twice each and then coming to a stop?

No, it’s not. It’s compressing the limit switches but still trying to move. They could be bad, but I’d be surprised if both limit switches went bad at the same time…

Move the laser head to the opposite corner of the machine then try engaging the switches manually with your hand while homing. Do either of the switches stop the direction of travel?

If not, after homing fails try this:

  1. While manually triggering each switch, issue ? command in Console. Then return output making note of which switch was activated for each ? command.
  2. Also review all switch connections. Are they indeed properly connected?

Can you confirm whether or not the switches came with your machine or these were something you installed after the fact?

Yes, they both stopped the direction of the travel when pressed. Yes these are the original switches that came on the machine, and yes they are wired correctly.

I’m really concerned about the negative coordinates. If I have it positioned in the front left corner, that I want to be the home position, shouldn’t that be X=0,Y=0? On the Move window in light burn, it shows the position as X= -599.99 and Y= -559.98. That basically corresponds to the 600x560 size of my workspace. But it’s all negative numbers.

I read something on this forum about offsetting the workspace to make the coordinates positive, but I haven’t found it again. Seems logical, though.

Thanks for hanging in there with me on this. It’s got to be something relatively simple.

These numbers are not reliable if the machine is not properly homing. It’s worth addressing the homing problem before concerning yourself with the coordinates after homing.

If you’re able to manually trigger the switches to stop motion that means that something mechanical is preventing the machine from actuating the switches on its own.

Carefully bring the laser module to the front left and check for switch actuation on both X and Y. What is preventing proper actuation? Identify the issue and correct the cause of the issue.

Once completed and the machine is homing correctly, run these commands in Console and return output:

$H
?

Sorry for the delay. Issue one involved bending out the limit switches a bit so they would properly function. That done, machine is now homing to front left corner using absolute coordinates. Now when I try to frame an object, it still wants to move forward. I’m guessing an offset is needed. Here’s the return on codes.

$H
ok

?
<Idle|Mpos:0.000,0.000,0.000|Bf:15,511|FS:0,0|Pn:HS
WCO:-600.000,-560.000,0.000>
ok

Can you run these commands one at a time and then return the full output?

$H
$#
?

Just for information, my working area is 600 by 540 mm. When I adjusted the limit switches, I also changed the pull off from 2 mm to 5 mm to account for the limit switch trigger sticking out a little more.

$H
ok

$#
[G54:-600.000,-540.000,0.000]
[G55:0.000,0.000,0.000]
[G56:0.000,0.000,0.000]
[G57:0.000,0.000,0.000]
[G58:0.000,0.000,0.000]
[G59:0.000,0.000,0.000]
[G28:0.000,0.000,0.000]
[G30:0.000,0.000,0.000]
[G92:0.000,0.000,0.000]
[TLO:0.000]
[PRB:0.000,0.000,0.000:0]
ok

?
<Idle|Mpos:0
000,0.000,0.000|Bf:15,511|FS:0,0|Pn:HS|WCO:-600.000,-560,0.000>
ok

Am I wrong to think that an offset of 600x540 would put the home coordinates at 0. 000,0.000,0.000?

600x560. Oops!

I’m questioning why you need an offset at all.

Can you first remove and retry.

Run in Console and return output:

G10 L2 P1 X0Y0
$H
$#
?

Starting from: Current Position

G10 L2 P1 X0Y0
ok

$H
(homed to front left corner)

$#
(nothing but zeros on all lines)

?
(nothing but zeros on all lies except Bf:15,511

Starting from: Absolute Position

Everything is exactly the same except at the question mark prompt, following

?
<Idle:… Pn:HS|Ov:100,100,100>

That seems to have done it! No longer trying to move forward when I frame something from the home position. Thank you so much!

Nice. Glad you’re back at it.

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