For the third time my Z limit switch has gone bad. I’ve already contacted Carbide 3D but I figure I’ll post here and see if anyone has any suggestions. This is what I sent them:
I have a Shapeoko 3XXL with the HDZ, Carbide probe and bit setter. For the second and third time my Z limit switch has gone bad. It registers as on in the CM setting screen. It happened today, the first time after homing - it homed normally (no jamming, grinding or other odd noises), moved forward to ask ti insert a bit, put bit in, hit OK, moved over to bit setter went down to button, moved all the way up and went down excruciatingly slow. Since I recognized this behavior from the last time my Z switch went out, I looked at settings and, sure enough, Z was active. Luckily last time it went out you sent me 2 of them, so I swapped the spare in, turned it on and it did EXACTLY what I described above again!
CM has the HDZ checked and it also has the bit setter checked with the proper location indicated. I feel that since I’ve now gone through 3 of these damn things I must be doing something wrong, but for the life of me I don’t have any idea what. The only possibility I can come up with is that I’m tightening the switch too much. It’s not like I’m using my pneumatic impact driver. I’m only using my Makita impact driver (JUST KIDDING)! Seriously, I use a small hex screwdriver and just make it snug so it won’t rattle around. Like I said, when homing Z goes up , hits the button, drops a mm or so and then moves to right rear corner - just like it always has. Somehow on the first homing the switch is getting stuck on (not the plunger, that works fine), so it is possible I’m over tightening though I really don’t think so.
Based on that, does anyone have any ideas WHY my Z switches are going bad?
My experience with these switches is that they are sensitive to overtravel, and if “over pressed” too far (which isn’t very far) can be permanently damaged. If the carriage has slammed into them (or been forced into them by hand) that will happen, as will manually “fully clicking” them. Pushing them past the point where they make the little “click” is in the overtravel area of the switch.
Have you changed any of the seetings for pulloff? For homing “seek” speed?
I have 40 + years of field engineer experience. When the same part repeatedly goes bad it can one of two things.
There is a manufacturing defect in the part itself. Since you have had 3 of these switches go bad and presumably they came from separate factory runs and very few people are having this problem then I would assume that it is localized to your setup.
When the same part goes bad repeatedly then I would look at the installation method. As mentioned by mikep above look at the activation and how much overtravel there may be after closing. Since you stated that the switch checked bad with a multimeter you can check with power off exactly when the switch activates and watch how much further back the actuator goes. Adjust the switch so it just activates with a minimum of overtravel.
So when I plug my working Y switch into Z it works fine. I activated it many times to see if
there’s some overcurrent or something and it still works - so I guess that’s not it.
The only other writing I see on the switch is “OMRON” and “C003”.
Is there a good source for these switches? I’ve got a couple coming from Carbide 3D, but I’d like to have a few extras. Unless C3D has the proximity switches ready, which I would prefer to go for,
The switches are available from pretty much any specialty electronics shop — but you need the wherewithal to make the connection, either a suitable crimping tool or soldering iron.
Just had the same issue happen with my machine which has all the same accessories as yours. By chance are you running lightburn or a laser? If so did you make the adjustments to the code? I was thinking maybe that when I ran my use laser macro that it did something? Either way I toasted the z limit switch just like you.
I do have a laser, but at the time I was homing for CNC. But I wonder if any of the changes made for laser don’t get reset back with my “use CNC” macro. I’ll have to look into that.But I set
“USE LASER”:
$30=255 - that’s spindle speed max, so shouldn’t have any effect
$31=0 - that’s spindle speed min, again, shouldn’t have any effect
$32=1 - Laser mode, boolean, - don’t really know the effect that would have
$10=0 - Status report, I don’t think that should have any effect
G10 L2 P1 X-812 Y-812 - that reverses the coordinates
USE CNC
$32=0
$10=1
G10 L2 P1 X0 Y0 - sets the coordinates back to normal
Maybe some of the GRBL settings experts here (certainly not me) can say whether any of these settings could affect my Z limit switch
Have the same settings as you. I will note that after I found out the z switch was stuck on I also noticed that my z movements were in reverse? I am waiting to investigate that until I wire up the new z switch when it gets here. Would love a step by step guide to installing proximity switches and programing them.
From what I’ve seen on this forum, Carbide 3D is coming out with a proximity switch upgrade soon, so I’m going to hold out until they have the official, supported set. But I would like to know what, if it’s me (or you) , I’m doing wrong that is killing these switches.
I broke one by using a 4 inch end mill on a 3 inch block of wood on a 1/2 spoil board. After probing it went straight up and broke it, but not trying to probe just backing off of the probe.
