Z axis creep, had to remove a spring to get it to cut right


(Ivan Nix) #21

I contact support again and they are sending me some new springs again. Supposible these they are looking at including with all their new machines. So I will be giving it a shot. I am like you 1 spring works so running with it I am. I will give it a shot when they do come in, springs that is.


(Michael Teahan) #22

Same problem here, but not just creep. It will actually jump over 1/2" on retract, that sound it makes when the stepper motor won’t hold. I am down to one spring and it seems to be working ok, though with power removed the router carrier drops.

I will contact Carbide about replacement springs, but was actually considering a counterweight of some kind so that there is little or no force on the stepper (think counter weight for an elevator). The weight of the router would be neutral to the stepper regardless of extension and could make longer Z axis travel mods workable.

I haven’t done much yet with the Shapeoko, been working out the designs of the project first. The single spring will get me through this phase for now.


(Ivan Nix) #23

I got 2 new springs from Carbide the other day. It seemed to help a little but I ended up going only using one. I got better cuts using the 1 spring. Also I had my dewalt all the way down in the craddle. I moved it to half way and that may have helped.

I wish there was a counter balance, I think the Z motor is working to hard and with the added springs it doesn’t help which cause it to slip or not have the power when 2 springs are attached. I think some more though in the design is needed on the Z axis.

I emailed support about the position of the router in the collert to find the correct postion because nothing states were the router should be.
They indicated it is a preference but there is some chatter in the system if the router is at the bottom or all the way down in the collar. they also indicated because it is a preference it will depend on your cutting surface and how far down you want to cut as well.

This is what I got from William from support

The vertical location of the spindle is a balancing act, and a matter of some tradeoffs:

  • further down makes reaching the work easier, and allows for one to work on thicker stock, or with a thinner spoilboard — but increases lever effects and may increase chatter along the Y-axis
  • further up pretty much requires a spoilboard, or limits stock thickness — but decreases lever effects and will make chatter less likely

I hope this helps!

Please let us know if there’s anything else which you need!

William


(Jeff Hillyer) #24

FYI to all with the same issue. I contacted support and they sent me another set of springs and it fixed the issue for me

I am running 1" pine on a shapeoko xxl with a dewalt. Stock is sitting on the stock table top. I have run 26 plinth blocks, 40 rosettes and were both very intricate. Depth of cut was 3/8 from top.

As far as I knew the issue is resolved with the springs sent. Hope it works for all of you.


(Jerry Gray) #25

Thanks for the update.
They seem to have pretty good support here.
Whenever I’ve needed anything, I usually get it within a few days.


(Ivan Nix) #26

What Router you using I have the dewalt. I got the new springs a few weeks ago, tested them, it did help a little but I got better results when taking off 1 of them. So I am running 1 spring.


(Kurt Bieberbach) #27

I had this same issue. I ran the same job three times and every time right around the same spot (though not exactly) the machine would hiccup and jump up a few millimeters. I thought there was something wrong with the gcode. I came onto the forum to post my files and see if I could get some help. I found this thread though and thought I would try removing a spring and what do you know, it worked perfectly.

The carrier does drop when I power down though. I think I will try stretching the springs a little until I reach “neutral buoyancy” and see if that works.

Is there any danger in doing that? Any danger in running with one spring?

I have the DeWalt router with a dust collector boot. Along with the weight of the vacuum hose, my carrier is heavier than the router alone.


(Jerry Gray) #28

Just keep an eye on the v wheel adjustments. Running a spring on one side also pulls unevenly, but I haven’t had any problems, and have been doing it for weeks.
I plan to add another thick-ish spoil board, raise my router in the holder(for better support), and put them back on.


(PJ) #29

So I have run into an interesting issue that resembles the problem mentioned in this thread and have come up with a theory. To start, I have created an intricate finishing tool-path using fusion 360 for a deep relief carve (by deep I mean about -11.5 mm from top of stock) and ran into an issue where the Z offset would plunge like it should to -11.5 mm but then shoot up to some random position (more than 11mm it would shoot up) . My setup is the shapeoko XXL with the Dewalt router, homing switches and a 3d printed dust boot with bristles. What I have noticed during debugging is that the issue has noting to do with springs (or in my case dustboot bristle z axis force) but the z-axis motor not staying engaged (not holding position) after movement. It seems that there is enough of a delay in engaging the Z axis motor between movement operations that whatever pressure be it springs or in my case the bristles on my dust boot in the Z direction causes the gantry to move up to some random position. It is as if you turned off the machine and tried to move the gantry up manually. I am not sure what a top of the line CNC router does but I bet that they never cut the power to the motors after a plunge operation movement. I am now currently running the exact same milling operation but this time without the dust boot and everything is working fine without the z-axis creep. What do you guys think about this?


(Dan Nelson) #30

I had this issue last year and decided it was one or more of 3 things:

  1. Super cold in my garage at the time, like sub freezing, thought maybe belts were stiffening and slipping (don’t know where you live, but I’m guessing it’s not that cold this time of year).

  2. Springs too strong. I think the stock springs are over speced, but I’d done deeper cuts without issue until this point (Dewalt router, longish bit, router seated all of the way down in holder).

  3. Dust boot. At the time I was using a router mounted dust boot and cutting small, but deep pockets. I think the bristles were fouling on the material outside the pockets.

Solution: I readjusted belts, but none were loose. I adjusted v-wheels, but none were really out of adjustment. I slowed my plunge rate of my cut, no joy there either. I never messed with the springs, but I had cut deeper without issue before. And finally, I took the brush off my dust boot and all was well.

I think looking back there’s projects that a dust boot that moves with Z is a good thing, like shallow cuts, cuts where you need to dodge your clamping solution, etc… But I also think there’s projects where a fixed height dust boot is more appropriate. So I bought one of each. There’s probably other projects where a dust boot just gets in the way, and I’ll leave it off and just clear chips with a vacuum in hand.

Just my $0.02, YMMV.

Dan