Upgrade Issues. Drive Faults and Jerky behavior-RESOLVED

[DannyB]

Thanks to all who have helped me here. I feel as though I have made a huge amount of progress. I was actually cutting parts today even though I know I still have some lingering noise issues. They all stem from the Motor/VFD I believe. My noise issues all disappear when the spindle is off. I have taken every step I know of to eliminate the interference. At this point I suspect the VFD is creating an enormous amount of noise. I have relocated it as far from the existing data lines as is practical. The machine runs but when I check the error log I see I am getting a ton of MPU resend requests. I don't think I am getting them with the spindle off. I have also tested the ethernet connection with all the inputs and outputs unplugged. A basic bench test. No issues.
SO:
Does the length of the power cable leading into the VFD have a bearing on noise? Mine is like 15-18 ft long and it runs under my machine to the outlet. It does run through an EMI filter prior to entering the VFD. My output cable is a shielded VFD cable.
I am thinking of trying a new VFD at this point. Does anyone have a recommendation? I have a 1.7Kw HSD air cooled spindle.
I am powering it with 240V single phase
My existing VFD is a Mitsubishi A800.....I think the 800 stands for the cost:) ...I know this thing is about that much money to buy. It is so complicated. It literally has around 1500 parameters. It's a nightmare for non electrical guys like me. But I need to try something else. Don't know what else to look at at this point.

Hey Shinosky,

I've converted a bunch of shopsabre machines to centroid (Oak + servos though). The mitsubishi vfd's work just fine as long as the proper types of cable are used and they are shielded/grounded properly.

[Shinosky]

Ha! Tell me about it. You can't know how many times I told my wife that I thought I had it. Only to be let down again. I will let you know how it goes.

[Shinosky]

Thanks DannyB! The Mitsubishi VFDs are high end so I wouldn't normally expect any issues. I was running out of options though. Having converting all those ShopSabres what is your opinion of the machines and their engineering choices? Just curious because of some of the things I found on mine. Of course they will say the SS23 is marketed to hobbyists so they cut corners to keep price down. Which is not a good excuse when you are using $800 VFDs.

[DannyB]

Having looked at a lot of them, i actually think they are very well done for what they are.
Now, are these things comparable to the design in the high end biesses?
No.
But they aren't meant to be

There are some annoyances, but they use mostly standard parts (the only weird part is the X axis ballscrew on a lot of them, but maybe that's standard too).

For reference:

I've created new Z axises for them, changed out all the gears/servos, etc. Upgraded the bearing blocks to the quiet versions, replaced the linear rails with high precision versions.

It all is very easy to do.

In fact, now that they mount the X axis ballscrew on the back of the gantry, they are even more rigid, and there is plenty of space to add linear encoders if you want.

The most annoying thing i think exists on them at this point is that they have no mechanism on the longer Y to keep them from oscillating (which is natural, even though people think it's broken).

This is also easy to fix though using spring-loaded supports that get pressed down as the ballscrew nut moves by. Because they rotate the nut and not the screw on the Y axis, this is trivial to retrofit.
(it would be much more annoying to build supports if they rotated the screw)

It would be nice if they just did it for you, but ...

They have also gotten consistently better.
The pro3636 i had did not have the greatest electrical box layout, etc.
The next one i saw had a much more professional box.
The latest ones i've seen are very very well laid out.

etc

[Shinosky]

Well, That's good to hear. One of the shocking things I noticed on the SS23 model that I have is the lack of Angular contact bearings on the ballscrews. I was looking at it one day wondering how in the world they fit them into that small bearing block. So I took it apart to find that the only bearings on either end of the ballscrew were some cheap, simple radial bearings. There is nothing designed in to take the axial thrust. It made me angry when I saw it. Surprisingly it still functions well. But I suspect those bearings won't hold up under constant use. I think there is some preload designed in to eliminate backlash. So.....they use an $800 VFD but use $1.50 bearings on the ballscrews...ugh. That's my experience. They also claim 600 IPM rapids but the fastest this machine would go was just under 400IPM if you went into the settings and maxed it out. The stock speed was 300IPM. A lot of slight of hand it seems.. I was not happy about some of these things. That and WINCNC costs a fortune to upgrade. I am loving the Centroid experience.

[Dmiller223]

Sorry for resurrecting an old post, but curious if you could post a picture of how you grounded the BFF wire in both ends. I’m having similar issues myself