Proper variables to increase dc steppers

There are alot of things that you don't necessarily need to have in the ini, they either use some default value or don't have the limit that the entry implies. You were correct, HOME_SEARCH_VELOCITY is the speed that the axis moves until it first contacts the sensor HOME_LATCH_VELOCITY is the speed that it will make its second move toward the switch/sensor for a more precise position as you would set this slower. I believe the distance that it retreats from the sensor is the HOME_OFFSET (not 100% sure) even though home offset is also the value that it sets 0 in the opposite direction of the switch.

It's good that you're going through and trying to fine tune and adjust the ini settings. You can get much more out of your machine when everything is set up well.

Hey Folks,

I haven't had much time to play with the settings shared in this post until lately, I have issues someone may be able to help with.

I have done numerous tests and not been able to identify what causes the following:

If I call out a feed speed any higher than 30 inches a minute when carving (Z axis in play while on the move in X or Y) sooner or later I get a grunt, bark, or squeal out of the Z axis motor, I'm losing steps when it dose this, I think it's only when it is pulling the spindle up (never down).
If I were doing more than testing the cutter would dig into the material or even the table.
Also, if I allow this to go on, eventually the Z axis stops moving all together while X or Y still moves as programed.

Can anyone tell me what this might be?

I hope it's a setting in my ini I've not yet realized.

Thanks in advance

Could also be too high accel value for Z axis, or maybe you need to add a counterweight or spring to balance out the Z axis. But by all means check your alignment and gibs while you're at it.

I would try reducing velocity and acceleration in your ini file. You are simply going too fast is my guess. It is normal for the steps to be missed on up travel rather than down travel as you are fighting against the force of gravity. This means you need more torque to go up!

What voltage are you running your steppers at? Low voltage significantly reduces torque.

I thought the rails or screw might be an issue at first myself, those all checked out.
Interesting idea to give Z help to lift the spindle, I may look for ways to remove weight from that assembly as well.

I'm not sure I have a choice at what voltage I can run these at, the motor and drive show 5.5 volt, I'll look closer and see if I can test the actual voltage and check current as well and report back.

I can take another look at my ini as well.
Can I set different axis at different speeds and get them to play nice together?

Thanks for the ideas.

One of the key advantages of LinuxCNC over other solutions is that you can have not only different max speeds on different joints, but different accel values as well. (Obviously as long as it's not a ganged joint like a dual-motor gantry.) Mach3 for example requires you to have the same accel values on all axes, which can really limit the overall feed rates a machine is capable of. The Z axis usually doesn't need a very high accel value since in most applications it doesn't move very far during a cycle.

Todd,
Would you be willing to PM me so I can ask some questions?

Thanks, Allen

What would you like to know?

Todd,

I think I have the same drive you have used or are using (Anaheim DPF73004), when I run at higher speeds X and Y do just fine, X is hauling the carriage with Y and Z on it so it isn't light duty, and Y has Z with the it's spindle, dust collection system and what have you, so it isn't all that mild either, those aren't dealing with gravity the way Z is but still they are moving weight.
The Z axis is the one I have an issue with.
I run the same program on each test run, I have the problem I mentioned earlier in this thread in the same place in the code, if I let the program keep running I get a "Fault" on the drive and have to reset.
I called AA and they think it's wiring or a bad motor, if I turn down the velocity and/or acceleration I don't have the problem, I'm not sure their conclusion fits.

Have you had any experience with this sort of thing on your machines?
What would you look for?

I am going to move the Z axis wires to another position on the drive to see if the problem follows, would you try something different before trying that?

Any objective thoughts or ideas before I go nuts here will be appreciated.

Thanks, Allen