LaserUser.com Forum (formerly RDWorksLab)

I am having issues with the limit switches on one of my BOSS LS3655 lasers and I am in need of either figuring out a fix or replacing them. Unfortunately, the only resources that BOSS has is a troubleshooting video.

The Problem: Limit switches do not stop the laser arm at startup from trying to fly off the axes at the top right corner and causes the motor to grind which is knocking the grounding wire off my CO2 tube. I have tried moving the bottom switch around to try and find the "sweet spot" as the Boss representative suggested, but to no avail. I've tested both switches by using one of the large mirror keys and making sure that the switches light up upon contact which they do, but they do not stop the arm. I am at a loss.

If anyone has any suggestions on how to fix this, or directions on how to replace the limit switches, I would greatly appreciate the help.

Thanks!

[ ] Are you new to this machine? How long?

[ ] Is the problem new or long standing? Did it work yesterday but not now?

[ ] Which software are you using and how familiar are you with it?

[ ] Most machines are cabinet models with stepper motors for X, Y, and Z axis- how is
your machine different from these parameters?

[ ] Have you tried to troubleshoot the problem, and what have you tried [with what results].

[ ] If pictures would be helpful, think about what you are trying to show and crop the pictures
so that they are more meaningful. There are many cropping programs built into computers.
If you can put text and arrows on the picts, wonderful, if not explain what the picture is pointing
out to us.

[ ] I've been using the machines for about 9 months, but I'm relatively new to repairing them. This is my first round of maintenance and repairs I've personally done on the machine.

[ ] This issue has been going on for as long as I've been aware (At least since I've worked with them for the last 9 mos. I don't have history available before that)

[ ] Using RDWorks V8 and I'm fairly familiar with the software as I use it daily for work.

{ ] The laser is also a cabinet model with the same motors you mentioned. (I just lack the vocab to describe the parts as I haven't spent much time repairing/maintaining them other than cleaning the lens and mirrors)

[ ] I've tested the switches to see if they are responsive to metal contact as suggested in the troubleshooting video and both are, I've moved the angle and spacing of the switches trying to get them to respond when the stepper motors are drawing the laser head up to the reset position upon startup but to no avail. I also went into the Diagnosis section on the LED panel on the laser and neither switch shows as "ON" there without contact with one of the metal keys. Boss didn't have much other suggestion than "play with it and try to see if you can move it to a sweet spot" and provided no further instruction and as I'm new at the maintenance, I quite honestly don't know what else to do.

[attached are images of the laserr and of the limit switches in question.]

As I was taking the pictures, I noticed that the laser head is activating the light in the limit switch, but is still not recognizing the limit so it tries to continue to the right on the x-axis.

Boss is very responsive - have you contacted technical support?

I've reached out to boss and they replied with this: "We don’t have anything specifically for replacing the limit switches, but we do have a video on how to troubleshoot the limit switches that might help". Their only advice for resolving the issue is to "move it around a little until it works"

Much better, thanks- the limit switches are turned on and have a bunch of settings in the program. Go into Vendor settings [rd8888] and each axis will have the same controls first turn them both on and then experiment with the other settings until you are gratified. There are so many polarity possibilities because there are so many, many ways that these machines can be wired and different switches, etc. If you have a copy of your perimeters saved [you should] you can look at/ edit them also with Notepad++ and compare them to someone else's [or your other machine if that works as expected] with a free plugin to NP++.

My issue is very similar to the one listed in this thread on the forum: viewtopic.php?t=3657

However, I tried the fix in the vendor settings to enable the limit trigger with no luck.

Gene Uselman wrote: Thu Jul 22, 2021 Much better, thanks- the limit switches are turned on and have a bunch of settings in the program. Go into Vendor settings [rd8888] and each axis will have the same controls first turn them both on and then experiment with the other settings until you are gratified. There are so many polarity possibilities because there are so many, many ways that these machines can be wired and different switches, etc. If you have a copy of your perimeters saved [you should] you can look at/ edit them also with Notepad++ and compare them to someone else's [or your other machine if that works as expected] with a free plugin to NP++.

(Didn't see the quote option sorry.)

I tried editing the vendor settings in regards to the motor limits and it still is not helping. I don't have this issue with any of my other lasers and the settings match up. All 5 were purchased at the same time and this is the only one I have an issue with. Do you have any insight on how to replace the limit switch? I'm starting to get the feeling that there must be something wrong with the actual hardware.

Update: I tested the switches at startup and when I place the metal key over the Y axis switch the gantry stops moving. Same with the X axis, I connect metal and it stops moving which tells me that the switches are working. IHowever when the metal plate from the laser head goes over the x axis switch it does not stop, same with the y axis. I guess I can keep adjusting their positioning, but I'm not sure if that's the best solution and I don't want to make the issue worse...

Trevor Martin wrote: Thu Jul 22, 2021 Update: I tested the switches at startup and when I place the metal key over the Y axis switch the gantry stops moving. Same with the X axis, I connect metal and it stops moving which tells me that the switches are working. IHowever when the metal plate from the laser head goes over the x axis switch it does not stop, same with the y axis. I guess I can keep adjusting their positioning, but I'm not sure if that's the best solution and I don't want to make the issue worse...

Hmm. Let me see if I understand what you wrote:
1. This machine has always had this problem (to the best of your knowledge).
2. When the laser head gets near the limit switch, the switch lights up, but the laser head doesn't stop.
3. When you put a piece of ferrous metal (a key) near the limit switch, the switch lights up and the head stops.

Is that correct? The combination of #2 and #3 is really interesting. The fact that the switch lights up tells me that it detects the proximity of the laser head (or any other piece of metal. The light also tells me that the wiring to the switch is good enough to supply voltage to the switch (i.e. it's probably not bad wiring that is causing the problem). If only #2 were true, then I'd suspect a software setting. But the software setting must be correct due to the behavior of #3. If only #3 were true (and the laser head did NOT light up the switch), then I'd think the switch is not mechanically close enough the metal of the laser head.

So the combination of the two is very interesting; please double-confirm that both are true (or please correct me if I've misunderstood ).

You keep asking about how to replace the switch. It's pretty simple. Buy a new one that has the same part # as the old one. Remove the old one and put in the new one. Make sure you have a good connection to the controller (see the controller schematic for your controller). Is there a specific problem or concern you have with replacing it? Do try to make sure the wires are not run anywhere near the High Voltage wire for the tube.

Regards,

-Jeff