DMM Dyn4 Drive Faults, Noise/Feedback Issues

[martyscncgarage]

I don't have scales and have emailed PM to see if they know, but i have read several forums and most say around 240-280?
But i am currently away so even i did have a way i couldn't do it now. If you have any advise or suggestions for the best type of counter weighting, i am away now so i could order it so hopefully it would be home by the time i arrive next week?

Rig something up. A counterweigh is about the same weight as the head. Some folks just use a pulley and cable and hang weights on the back of the column. Gas springs like those that hold a good or trunk have been used, but not my favorite.

I would just start buying stuff with out rigging something up and pricing it out. Your other option is to use pulley reduction instead of direct driving the screw. Bottom line, you have to figure out what the problem is first. Rigging up a counter weight is my first though, Even something crude.

[martyscncgarage]

Search cnc mill counterweight
Look at the images for ideas. Even if I rigged up a bar on the top to let a rope or strap connected to the head roll over and put weights on the back side of the mill to test, is what I would try. If successful, then you can decide the best course of action, whether it be belt reduction, or a permanent counterweight or both....just throwing ideas out there

[H&W CNC]

Sounds good i appreciate it and i will get started looking. I am sure i can rig something up crude like to see if that fixes it like you said then go from there. Thanks Again and i will update next week when i return home.

[martyscncgarage]

Another user is asking about gas springs on the forum today. I did do a mill using one of their springs some time ago. They have a very good selection:
https://www.guden.com/Control/Gas-Springs

See what your rough testing does.....then decide

[H&W CNC]

Well i have some encouraging news with the PM-940 build. I put a counter weight on my Z axis and have ran it up and down 8 times without any faults. I let it sit the last 2 hours and it is holding good. It is very crude so I can’t do a lot of testing but as soon as I take it off it faults when I move it in the same manner? The bulldozer roller bearing I am using weighs about 100lbs (When you all said crude this probably tops it ). I have not tried the power yet that DMM asked about (see below).

So does this point to a specific issue with the build?
Motor to small?
Servo just cant hold position?
Drives not setup correctly?
Binding do to head?
Anything at all?

Have you all heard of this issue?
Hey Bradley, thank you for your message,

I really don't think the motors are too small,

What is the AC power supply you are using? I have seen some problems with the 220/240VAC power noise causing this type of problem.

Can you try pulling a 110/120VAC power from a wall outlet to power the system and try again,

[martyscncgarage]

Well i have some encouraging news with the PM-940 build. I put a counter weight on my Z axis and have ran it up and down 8 times without any faults. I let it sit the last 2 hours and it is holding good. It is very crude so I can’t do a lot of testing but as soon as I take it off it faults when I move it in the same manner? The bulldozer roller bearing I am using weighs about 100lbs (When you all said crude this probably tops it ). I have not tried the power yet that DMM asked about (see below).

So does this point to a specific issue with the build?
Motor to small?
Servo just cant hold position?
Drives not setup correctly?
Binding do to head?
Anything at all?

Have you all heard of this issue?
Hey Bradley, thank you for your message,

I really don't think the motors are too small,

What is the AC power supply you are using? I have seen some problems with the 220/240VAC power noise causing this type of problem.

Can you try pulling a 110/120VAC power from a wall outlet to power the system and try again,

Motor probably too small to hold the head. Another use having similar issues. Either get a pair of gas springs from Guden.com, make a counter weight that rides on the back of the column maybe a couple linear rails, or, bigger AC servo.

You should have no issues running the DYN4's on 220V...
Marty

[H&W CNC]

Ok, i am working on it still to hopefully not use that but it looks like i am headed towards the counter balance. I just now looked at it between 2-3 hours and have a fault from it just sitting there of over heat and a solid red light, but it lasted way longer.

[martyscncgarage]

Ok, i am working on it still to hopefully not use that but it looks like i am headed towards the counter balance. I just now looked at it between 2-3 hours and have a fault from it just sitting there of over heat and a solid red light, but it lasted way longer.

If memory serves you think the Z weighed 300lbs?
Maybe get an old scale, a wood block on it and then rest the z on it to see exactly what it weighs....?
Several of you are having similar issues all at the same time...I can't keep up!

[H&W CNC]

I was able to get ahold of Precision Mathews and also confirmed with the gentleman that sold me the Ballscrew Kit who has a PM-940 also and it weighs 220 lbs.

[Black Forest]

It would seem to me that a planetary gearbox between servo and screw would solve these problems and be easy to install. Not some cobbled together counterweight or gas shocks.