[SCzEngrgGroup]

If one of the servo drives faults, causing an E-Stop, the display on the drive will show an error code, and the drives will have to be power cycled to restore normal operation.

Regards,
Ray L.

[Novakon]

This is true, however we should isolate the cabling and adapter board between the BOB and each driver. A grounding feed back signal could feed back to the RESET input. The more hardware we eliminate the better it is to isolate the source. The only signals that can cause a RESET beyond the BOB are the servo drivers and the "soft E-stop" input. If the plug for the soft E-stop was unplugged on the BOB and we are still experiencing the RESET...it could be originating from driver or associated wiring. Just being through by the process of elimination. There is a small chance it is a servo driver...very small.

Regards,
Novakon Team

[LeeWay]

I would also suggest that you look at the diagnostics screen when it does estop next time. Can't hurt to take a peek.

[engnerdan]

Now I have been out checking the mill. As I said before I felt like the X axis was grinding a bit. So I removed the servo from the screw but the grinding was still there. So I decided to tear everything apart to see what was the issue. Removed the right side bearing first and was then able to puch the table to clear the ballnut. Luckily the ballnut was fine. Even though the ballscrew had a lot of metal dust on it. Looks like it comes from when it was ground. Cleaned the screw up with wd40 and used the lubing system to puch fresh oil in to the nut.

Checked the bearing on the right side and there was the issue. Could clearly feel it kind of grinding, like a over tensioned bearing does. Loosened the nut that tightens the bearings but it felt the same way. Used a plastic mallet trying to get the whole assembly of the screw but it would not go all the way. So I pushed it back in again. When it was back in place the bearings felt ok! Tightened the nut again and still ok. So mounted the mill back together and tested. Sound gone! Could still hear some whining from the motor. This time it worked to adjust the driver.

My conclusion is that one or both bearings must have been out of alignment in the bearing housing. It seems fine now but I don't know if the bearings was damaged from this. I'm not very impressed...

Attachment 265186

I felt the same way, take a look at the pictures here of the condition my ball screws were in and the grinding dust and dirt in them. BTW that dust is not from making the ball screws, its from a poor job during the building of the mill. When new the ball screw and ball nut should be perfectly clean except for the grease to assemble them.

Take a look at the pictures halfway down the first post in this link.

http://www.cnczone.com/forums/novako...ml#post1479042

I have already replaced one set of bearings in end block of one of my ball screws and I think I need another set now. From the measurements I took, it appears that the bearing pockets were not bored into the cast iron block in line and parallel to each other. Just so you know those bearings are angular contact bearings #7004. Cheap ones will cost $12-20 USD and brand name ones are $100-200 USD.

-Dan

[MBViklund]

Hello Khai (?)

I think the bearing was not properly seated when tightening the nut at the factory. And it was probably tightened to much as well. I had to use tools and quite some force to get it of. One thing I thought was strange was that the side of the bearing housing facing the table looked like a 10 year old with a course disc on a grinder had finished it of. There is no way that the bearings is the housing are parallel with the screw or table.

The picture shows the gib being higher than the slide. Will take a new photo tomorrow.

Will test drive one axis at the time with the other ones powered off to see if it one of the axis causing estop. But it happens at least 3-4 times in one evening when i am just setting everything up.

Will also check the cable and the panel with the usb connections.

Homing is okay. That was only me doing it wrong... I used G28 instead of the homing button in mach3, So there was probably newer anything wrong with it.


Today when I came out to the mill head had fell down. I always power the mill down over night. I had no tool in and the spindle and it only stopped in the rubber cylinder at the bottom of the z axis so nothing was damaged. Today when i powered the mill down the head fell down instantly. I turned the power back on and it stopped. Put a piece of wood in between the spindle and the table to prevent it from falling. Should it be this way? Seems dangerous if the power goes away and the head just falls.

The good news is that i milled my first part today. Was just out of a plate of polyethylene but everything worked very good! :-)

Best regards/Daniel

[SCzEngrgGroup]

Daniel,

I'd like to ask a question re: the problem you've had with the PDB LCD display getting scrambled. Did this happen at random times, or did the scrambling always occur when the PDB was being operated? I'm trying to get to the root cause of that problem, which is difficult, since I can't replicate it here. I have made a firmware change that will get it straightened out without having to press the reset button, but that's a band-aid. I'd really like to know what's really causing it, and fix it there.

On the E-Stop issue: Next time it happens, before doing anything else, look at what's on the LCD displays on the drivers, and also note the state of the LEDs on the BOB, especially the ones on the MCU board (the little 1"x2" board standing on edge on the BOB). What LEDs are lit, if any are changing, are they blinking, pulsing, etc. That will help narrow down what the cause of the E-Stops is.

The head on my machine started falling, slowly, on power down a while back. I assumed the gas spring was going, so got a replacement. Oddly, it made no difference, despite the fact that the spring is incredibly stiff - I can't compress it at all by hand, even putting my full weight on it. Those bloody linear rails and ground ballscrews just just don't have enough friction! :-)

Regards,
Ray L.

[MBViklund]

Daniel,

I'd like to ask a question re: the problem you've had with the PDB LCD display getting scrambled. Did this happen at random times, or did the scrambling always occur when the PDB was being operated? I'm trying to get to the root cause of that problem, which is difficult, since I can't replicate it here. I have made a firmware change that will get it straightened out without having to press the reset button, but that's a band-aid. I'd really like to know what's really causing it, and fix it there.

On the E-Stop issue: Next time it happens, before doing anything else, look at what's on the LCD displays on the drivers, and also note the state of the LEDs on the BOB, especially the ones on the MCU board (the little 1"x2" board standing on edge on the BOB). What LEDs are lit, if any are changing, are they blinking, pulsing, etc. That will help narrow down what the cause of the E-Stops is.

The head on my machine started falling, slowly, on power down a while back. I assumed the gas spring was going, so got a replacement. Oddly, it made no difference, despite the fact that the spring is incredibly stiff - I can't compress it at all by hand, even putting my full weight on it. Those bloody linear rails and ground ballscrews just just don't have enough friction! :-)

Regards,
Ray L.

It still happens and it has never happened during a tool change. It just happens randomly.

Will take a look at the drives and BOB. Will take a few pics and post.


The problem is that mine is not falling slowly. I had to hurry to power it up again before it hit the rubber. Not really a problem as long as i know about it. But it is just weird it started so suddenly. Before there was no movement at all.

[SCzEngrgGroup]

The problem is that mine is not falling slowly. I had to hurry to power it up again before it hit the rubber. Not really a problem as long as i know about it. But it is just weird it started so suddenly. Before there was no movement at all.

There are only two things that keep it from falling: friction, and the air spring. Maybe your air spring suffered a seal failure. I don't see what else could make it happen suddenly. Mine took at least a year to get to where it is, and it still doesn't fall fast.

Regards,
Ray L.

[LeeWay]

You could design an electronic brake for the Z axis. Power off and it clamps down. Engage power and it releases.

[FineLineAuto]

You could design an electronic brake for the Z axis. Power off and it clamps down. Engage power and it releases.

But it shouldn't be falling. I have never had that happen on my Pro.


Nate
Fine Line Automation
Home - Fine Line Automation

[SCzEngrgGroup]

You could design an electronic brake for the Z axis. Power off and it clamps down. Engage power and it releases.

I am considering adding that to the ATC. If the head falls when the arm is engaged with the carousel or spindle, nothing good will happen....

Regards,
Ray L.

[kvom]

The head on my machine started falling, slowly, on power down a while back. I assumed the gas spring was going, so got a replacement. Oddly, it made no difference, despite the fact that the spring is incredibly stiff - I can't compress it at all by hand, even putting my full weight on it. Those bloody linear rails and ground ballscrews just just don't have enough friction! :-)

Mine does the same thing, but only when it's at the top of the rails. It moves down only an inch or so.

[LeeWay]

I had it happen some on my little home made mill until I put a 75 pound gas strut on it. The Torus had dovetails and gas struts. The pulsar has dovetails and no gas struts. Neither of those moved at all on power down.

If you do not want to design an electrical stop, you can use a mechanical one. They sell different types of spring plungers. I use some in some of my products. Mine are non lock out type. Here is an example of a loock out type.

J.W. Winco, Inc. - Metric Size, Indexing Plungers with Steel Plunger Pin, Plate Mount, Lock-Out Type

After I posted this, I can see problems on a non stepper type machine if you forget to disengage the pin.

[MBViklund]

I had it happen some on my little home made mill until I put a 75 pound gas strut on it. The Torus had dovetails and gas struts. The pulsar has dovetails and no gas struts. Neither of those moved at all on power down.

If you do not want to design an electrical stop, you can use a mechanical one. They sell different types of spring plungers. I use some in some of my products. Mine are non lock out type. Here is an example of a loock out type.

J.W. Winco, Inc. - Metric Size, Indexing Plungers with Steel Plunger Pin, Plate Mount, Lock-Out Type

After I posted this, I can see problems on a non stepper type machine if you forget to disengage the pin.

i think i will have a look at the gas spring first. :-) If it is broken maybe novakon can send one together with the bearings.

The spring is the one fastened in the bracket in front? the one with the rubber damper on?

[MBViklund]

Today i bought some measuring tools. Actually i bought a lot of measuring tools. Everything you see in the pictures on the attached links. (there is a button "Nästa bild" under the miniature pics that will show you more miniatures) Will sell a lot of it and keep what i need. But i hate not being able to measure the things i need to measure.

Klaravik auktioner

Klaravik auktioner

[SCzEngrgGroup]

i think i will have a look at the gas spring first. :-) If it is broken maybe novakon can send one together with the bearings.

The spring is the one fastened in the bracket in front? the one with the rubber damper on?

Yes. It's easy to replace - un-bolt the cap from the top of the head, just forward of the motor. Unscrew from the bracket at the bottom. Takes about 10 minutes.

Regards,
Ray L.

[MBViklund]

I have been working a little bit with the mill during the weekend. I still have problems with the E-stop, most times when going really slow as when I probe or home the machine. Attached is a picture showing what is going on with the litte card on the BOB. Attachment 265918


Otherwise i finished my first little cnc project. As many others I decided to do a Toolholder too. :-) Attachment 265920

Here is a picture of how the gib looks on the x-axis. It sits about 0,5 mm higher. Attachment 265922Attachment 265924


This is what i have been doing almost all day. Enclosure for the upgraded stand. The design is almost finished. It is inspired from Tormachs Enclosure. The doors will work and be mounted the same way.
Attachment 265926

[SCzEngrgGroup]

Daniel,

The LED on the BOB MCU blinks whenever the firmware is running, to indicate the firmware is alive.

The Status LED on the BOB blinks in a few patterns, depending on what's going on:

"Pulsing" - i.e. - smoothly getting brighter, then dimmer over a period of a few seconds. This indicated DriveEnable is turned off.

Fast Blink (10 Hz) - This indicates Drive Enable is turned on.

DriveEnable will be on whenever a valid Mach3 Charge Pump signal is being received by the BOB. The Enable state should also be reflected in the Enable LED on the BOB.

I can't tell from your photo which, if any of the other BOB LEDs are on. They all look off to me....

In the photo you seem to have almost everything disconnected from the BOB. What was actually connected when you got the E-Stop?

The height of the gib only matters if it's dragging on the underside of the table? Is it?

"The doors will work and be mounted the same way." - Trust me, you *really* don't want to hang your enclosure doors the way it's done on the Tormach enclosure. That really does not work well at all, and makes the doors hard to open and close. There are FAR better ways to do it that cost no more, and give MUCH smoother motion. The doors on my enclosure are just sheets of Lexan, hanging on UHMW glides I made on my table saw, running in aluminum T-Track. They open and close absolutely smoothly, silently and effortlessly. Total cost (not counting the Lexan) about $20, and an hour of my time.

Regards,
Ray L.

[engnerdan]

I thought I would share what I found in one of my ball screw stationary bearing blocks. These two pictures show an exaggeration of what I found. The blue lines represent the bottom of the bearing pocket for the angular contact bearings. This explains why I could never get my bearings to run smoothly.

Attachment 266014Attachment 266016

In the pictures
I = Inside or side the ball screw is on
O = Outside or the side the drive motor is on.

These are the measurements I made using a depth mic from the face of the block.
Attachment 266018

So if you continue to have problems, make sure to check your bearing blocks. I am fairly certain my X is the same way. The Y axis after correcting the skew and miss alignment is so smooth and easy to turn now.

-Dan

[LeeWay]

That has got to be hard to even machine it like that. Much less unintended.