Z motor slips on rapid moves

[azlogger]

Hi. I have been having a problem with rapid Z-axis moves (as you may have guessed by the topic title ) the motor "slips" when jogging is set on fast. Lubricating it fixes it for awhile, but lately I have been lubing it every little bit. It really hasn't ever caused a problem until today. Right on starting, sharks make a quick up move and then head down to the work. Today it "slipped" on that up move and therefore lost zero, making it too low.
Please help, thanks

[ohiococonut]

Have you checked the setscrews on the coupler? They can come loose.

[azlogger]

Have you checked the setscrews on the coupler? They can come loose.

I checked them--tight. But I'm sure that's not what's slipping. It's the same thing that slips on any axis when you run it into the end. Clutches or just the magnets not pulling hard enough to move the motor? It doesn't slip if I turn the FRO down to ~80%.

I just can't imagine what's wrong! If it moved that hard it would slip at slower speeds too. It does it moving up or down.

[Bob]

azlogger,
What are you using as a lubricant? Some lubricants build up a residue which can inhibit movement. I use Dupont teflon, silicon lube now. I tried using just teflon lube once and it gummed up the lead screw on the z travel. Some other lubricants attract dust that builds up and, also reduce movement.
Have you cleaned the drive screw or rails? After I cleaned up all moving parts and used the teflon/silicon mix, everything moved smoothly.
Bob

[McBuster]

azlogger

What temperature in your shop? If under 40 degrees, I have found on the Z Axis, High will usually not behave very well. I use Medium for Jogging and make certain I start each day by lubing all the Screws and Guides. That, in cold weather, helps alot. Today, ny garage was at about 15 degrees here in Minnesota.

If Temp is not the problem ...
.

[rungemach]

For what its worth, IMHO the Shark users can suffer from a combination of issues that can create a "perfect storm" of z axis issues.

1} Default speed and plunge values in vectric can be too aggressive for the shark to keep up with.

2) Z axis speed and acceleration values set in the shark may be too aggressive for the z axis to function with any "margin of safety" for temperature, lubrication, etc.

3) The retract move of the z axis requires accelerating and moving the mass of the z axis against gravity.

4) temperature and machine lubrication issues can require additional z axis effort.

5) motor couplers can come loose causing slippage.

So, besides keeping the machine clean and the couplers tight (cap screws help this situation), the best you can to is be careful with the speeds that are assigned to the various tools. I am not sure if the plunge speed of the "tool in use" will affect the fast retract that you are mentioning. If the controller insists on doing the initial retract move at full speed, that speed and acceleration value may need to be changed to prevent the machine from trying to retract too quickly in typical "field conditions". I have seen a number of posts here about loss of z zero, so your situation is not unique.

Since I run Mach3, I can change all these values easily, and have found that slowing down the z axis a little will not affect overall run time of a job very much, and can eliminate any tendency for the z zero to creep down during a job that has a lot of retract movements. I would encourage NWA to revisit the speed and acceleration values for the z axis to allow for typical field conditions, or allow users to reduce their z max acceleration values if they are having z problems due to the weight of heavy routers and dust collection hardware.

[azlogger]

azlogger

What temperature in your shop? If under 40 degrees, I have found on the Z Axis, High will usually not behave very well. I use Medium for Jogging and make certain I start each day by lubing all the Screws and Guides. That, in cold weather, helps alot. Today, ny garage was at about 15 degrees here in Minnesota.

If Temp is not the problem ...
.

You may have the solution! I hadn't thought of the possible effect of temp. I'm guessing all time I've been having this problem it has been about 40-55°F in the shop.

azlogger,
What are you using as a lubricant? Some lubricants build up a residue which can inhibit movement. I use Dupont teflon, silicon lube now. I tried using just teflon lube once and it gummed up the lead screw on the z travel. Some other lubricants attract dust that builds up and, also reduce movement.
Have you cleaned the drive screw or rails? After I cleaned up all moving parts and used the teflon/silicon mix, everything moved smoothly.
Bob

I'm using liquid wrench silicon spray. I don't know of any local source for the DuPont spray that NWA recommends but I'll order some if it's better.

For what its worth, IMHO the Shark users can suffer from a combination of issues that can create a "perfect storm" of z axis issues.

1} Default speed and plunge values in vectric can be too aggressive for the shark to keep up with.

2) Z axis speed and acceleration values set in the shark may be too aggressive for the z axis to function with any "margin of safety" for temperature, lubrication, etc.

3) The retract move of the z axis requires accelerating and moving the mass of the z axis against gravity.

4) temperature and machine lubrication issues can require additional z axis effort.

5) motor couplers can come loose causing slippage.

So, besides keeping the machine clean and the couplers tight (cap screws help this situation), the best you can to is be careful with the speeds that are assigned to the various tools. I am not sure if the plunge speed of the "tool in use" will affect the fast retract that you are mentioning. If the controller insists on doing the initial retract move at full speed, that speed and acceleration value may need to be changed to prevent the machine from trying to retract too quickly in typical "field conditions". I have seen a number of posts here about loss of z zero, so your situation is not unique.

Since I run Mach3, I can change all these values easily, and have found that slowing down the z axis a little will not affect overall run time of a job very much, and can eliminate any tendency for the z zero to creep down during a job that has a lot of retract movements. I would encourage NWA to revisit the speed and acceleration values for the z axis to allow for typical field conditions, or allow users to reduce their z max acceleration values if they are having z problems due to the weight of heavy routers and dust collection hardware.

I can pull the FRO down a bit on startup, but...I would like to find exactly why it's doing what it's doing!

[bgwconstruction]

AZ Logger,

Did you ever figure out what your problem was? My Shark just started doing the same thing, and I thought I'd ask. Thanks.

[majorbdk]

I'm having this same issue. Any suggestions. I'm going to try to lubricate the z axis to see if it helps.

[Rando]

I'm having this same issue. Any suggestions. I'm going to try to lubricate the z axis to see if it helps.

Lower the acceleration values in the control panel (787 password), especially if you have a heavy spindle compared to the standard (relatively) lightweight router motor. Also, watch your vertical feed rate is proper, both for the material and the flex of the system.