Z axis is sticking

Has anyone experienced issues with the z axis sticking when it’s travelling down? When I use the dial to raise my torch it works fine but when I lower it, the head keeps sticking in different places. I put a small temporary spring to apply more pressure downward and seemed to help. Before I go opening up the machine I’d like to know if anyone has experienced this and if they have a solution.
The best way to describe what’s happening is that it seems like the machine thinks it’s touching the material when it’s not and it doesn’t stop in the same place every time

Clean the two guide rails on the Z head, move the head so you can wipe down as much as you can and remove the shoe that holds the torch for better access. Then apply light oil like 3 in1. Make sure your torch lead isn’t impeding movement.

Thanks for the advice but that was the first thing I tried the equipment is only a couple weeks old and I’ve only used it several times getting things dialed in, I wouldn’t think the issue is at the head. From what I’m observing it’s something with the cable into the arcdroid itself.

@Colin I would check the freedom of movement of the Z slides again. The cable and servo pulls the Z up but it is the spring and gravity that moves the head down as the cable is let out. Any hang up and the head will stop. You can’t push on a string…….

Thanks I think you may be right because when I added a small spring on the head it worked better I didn’t want to put anything too strong just in case it would reck something. I may pull the surround off the unit and just see if can witness anything with the cables

@Colin Take the torch mount off of the droid arm. Use the control knob and move the Z fully down. Using your hand, pull up on the drive cable casing at the head. You’ll pull the Z up. Let it down and see if it hitches up. You’ll both see and feel if things are sticking.

I have found this issue with my hand held torch, make sure you support the cable from above as the torch and cable just hanging has to much weight on one side of the guide rails.

So I dug deeper today and found the issue but I don’t know any simple fix for it. I will try and explain. The issue is with the length of the the cable, if the cable coating was just a few inches longer I don’t think it would happen. When the droid arm is fully extended the angle of the cable where it enters the droid triggers the limit switch prematurely, with the arm closer to the droid it’s working fine.

This photo shows the distance that it will travel downward when fully extended

This picture shows the travel it has when the cable enters the droid at a more perpendicular angle

Here is a picture of my complete set up the table is a princess auto table modified but it is a perfect size

@Colin The ball end of the cable casing accounts for its ability to handle that angle. The switch is to detect the casing when it lifts up as the torch makes contact. You do not want to be operating in the extreme down position your showing. You need to be keeping good spring compression for the Z to work right. Between the bracket mounts, dovetail and torch mounting you want the plasma tip contacting more in the upper travel area of the Z.

Yes I agree I was planning on doing some modifications tomorrow to lower the droid platform so the torch floats higher on the head but I’m still concerned that there’s still an issue because with my torch mounted with the current setup, the head doesn’t have to travel as low as it is in the picture. The head still seems to stop inconsistent. I will let you know how it goes, thank you for all your help it’s much appreciated

Are you cutting within the specified cut area ?

I am also having this issue. I have tried cleaning and oiling rails. All that seems to work is to stand there and put light pressure down with fingers untill it starts to cut. Its getting annoying

Make sure your plasma cable support is not causing problems, binding or pulling. Keep the Z working range in the upper area of the slide so that you have the most spring pressure coming into play.

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