Anyone else having issues with loss of z steps on rapid retracts with the new support strut kit?
I’ve had the machine for over a year. Been running an 80mm spindle on it all but the first 2 days.
I’ve had some issues with loss of z steps due to the weight of the spindle in the last. But slowing down z axis max travel speed resolved this a year ago and hasn’t been an issue since.
Carbide released their kit for a support strut which has been on my list of things to make so I bought it. First retract and I loose z steps 1-2” from top of travel. This is with both factor z speed and reduced. If i remove the strut issue goes away.
Everything is lubricated well. Support had me replace the ball nut mounting machine screwed with socket head screws and align. made no change.
I can remove the spindle and the z stepper and everything moved freely. If I install the strut and push the z axis to the bottom and release it. It flies up as expected but nearly Comes to a stop and slowly moved up st the same point I loose steps.
I’m thinking it’s a bad strut or a design issue but I doubt that.
Support has been silent since I sent an email back Sunday. Figured I’d ask here if anyone else has some ideas.
Your ticket is still opened and is assigned to a person who had a temporary internet service outage over the weekend, but they are back online now and working through their queue — we’ll respond as quickly as we can on that basis.
We’ve seen the issue a handful of times. We’ve used this design internally for a few years, so the concept is well-proven. We have a couple of theories on the cause:
Incorrect feeds - these struts are designed to run at the stock CM speeds. If you change the grbl setting, it could cause an issue.
A slightly miss-aligned ball screw.
A bad strut: if there is too much oil in the dampening section, this can cause an issue - but typically, it’s related to the last 5-6mm note 1-2 inches.
I know you have looked at the above.
I’ve asked support to send further tickets directly to me. However, I am issuing some spare parts, which should be with you early next week.
Thanks for the response. I think my length est was way off looking at the video again be wrong on the measurement.
I didn’t come here to complain really. I you guys are normally good about quick responses. I just figured someone was on vacation and I thought I’d ask the hive.
I sent videos with my initial email showing the issue. It does seem to be a lot closer to the top then I thought. Been a long couple days.
I’m having the same exact issue right now and have been in touch with support over it. Their suggestions have had no affect so far (replaced some screws, aligned z axis components, they checked system settings, etc). All logical steps but ultimately not the cause for me.
I am familiar with how gas springs work and what appears to be happening in my case, in my opinion, is due to an over oiled spring or too small of an orifice. When it gets to the end of stroke when the oil causes a dampening affect my spring no longer expands at the rate the z axis is moving so instead of assisting the lift it is now fighting it and causing the stepper to lose steps, you can see it lift off the lower ball at that point which should never happen and is not indicative of a binding issue unless it’s one internal to the gas spring.
This could likely be remedied by using a spring with a longer stroke and correspondingly longer bracket so the dampening is avoided, a different sized orifice or a higher quality/specced springs, etc. I’m sure the system works fine 95% of the time when the springs produced in spec or if the combined load of the force needed for the stepper to force the spring through the dampening effect at the end of the stroke combined with the force needed to lift the weight of the spindle is less than the steppers power, which is likely most cases, but in the cases of a slightly off spring with a heavier spindle it can actually make your issue worse.