Beyond Z axis stall

[texasinmi]

My B CW gave me a Z axis stalll message. I consulted the forum and checked and reseated the cables. Restarted and I then got a clean the Z axis rails which I did. Now, after sliding to the start point and making the dive into the board to cut, I get a quick up/down motion from the z truck, like chatter, 2 maybe 3 times and it stops, then gives me the z stall error.

Any thoughts?

texasinmi

[bergerud]

First guess -z encoder disc loose. Second - FFC wire

[cestout]

If you move the Z truck manually, how does it feel? Are all four rollers turning freely? Is there junk in the belt area?
Clint

[texasinmi]

I have looked in the support area and there are no description where those parts are. Any pic or diagrams that you can show me?

texasinmi

[texasinmi]

The belt area is clean, the up down motion feels like it always has. The bearings move freely. What kind of lubricant should I use on the z rods?

texasinmi

[bergerud]

I found an old post with some pictures: Not so good - Al - help

http://forum.carvewright.com/showthread.php?14748-Z-Axis-Stall-Error-303-Fixed&p=123187#post123187

[texasinmi]

I checked the optical encoder, there was no sawdust inside the cap and the encoder seemed tight. It isn't like I can grab it with a screw driver or anything, but I wiggled the edge with my finger.

However, now the giggling up and down happens more frequently, like once I have aborted the project it giggles headed to Home. The weird thing is for all up/down motion prior to the cut motor kicking in, checking the bit, checking the board height, everthing is fine. It is only after the cut motor kicks in that it giggles. The fact that I changed the behavior by wiggling the edge of the optical sensor should tell someone something, I just do not know what.

Thanks,

texasinmi

[bergerud]

This is a weird one. Sounds like the problem is sensitive to the vibration of the cut motor. I am now thinking the flat FFC ribbon wire. (You would have also been moving it around as you inspected the z encoder.) A bad connection on its end or a broken wire in the ribbon might be susceptible to vibration. Check the end connection and look for kinks or places where wires could be broken. I think a bad electrical connection is what you are looking for.

[SouthernSigns]

Check the roller bearings as well. Sounds like the "giggling" could be a bearing sticking somewhere along that rail. Just another possibilty...Let us know!

[texasinmi]

I checked the bearings and they seem fine. The issue appears only to occur when the cut motor turns on. All other up and down motions are smooth and cause no problems.

More thoughts?

Texasinmi

[SouthernSigns]

Check the y tension screw while you have the cover off the machine. It s a clip with a set screw on the right hand side of machine. Make sure it is not loose, but not over tightened either. Just snug.


I checked the optical encoder, there was no sawdust inside the cap and the encoder seemed tight. It isn't like I can grab it with a screw driver or anything, but I wiggled the edge with my finger.

However, now the giggling up and down happens more frequently, like once I have aborted the project it giggles headed to Home. The weird thing is for all up/down motion prior to the cut motor kicking in, checking the bit, checking the board height, everthing is fine. It is only after the cut motor kicks in that it giggles. The fact that I changed the behavior by wiggling the edge of the optical sensor should tell someone something, I just do not know what.

Thanks,

texasinmi

[Digitalwoodshop]

My first thought is that this is a Z Motor problem.

The quickest way to half split this troubleshooting is to replace the Z Motor and Gearbox...

That then tests the FSC Cable and the Big Circuit Board that it plugs into.... That Big Circuit Board has been know to have a cracked copper trace casusing just this type vibration related problems.

So back to the Z Motor the most likely problem area... Since this is a position problem when vibration is present then it comes down to two possible reasons. The first and LESS likelly and that is the position servo voltage actually moving the motor. It is still possible and the weak area is that Encoder Circuit Board. And the Plug Soldered into the Circuit Board. What happens is that the plug is not pushed all the way into the board, only short a fraction of an inch... The Wave Soldering Machine does it's job and all is well. But over time vibration pushes the plug and the Donut hole of copper eventually pushes away from the board snapping or fracturing the connection between the donut and the trace leaving the donut. I made a living at Sony fixing similar plug problems.

The problem can be in any of the leads but is likely in the encoder lines...especially if the Z cuts at the wrong depth... This points at the second part of the Z Motor, the Position Feedback.... The Encoder Pulses....

A TEST of the Encoder.... Move the head to the TOP Mechanical Pin and hold it... on the Keypad call up Sensor Data and Z Data. It will show 0000 when you call it up and where the Z is sitting. To TEST... Move the head up and down slow and return to the top PIN. IF all is WELL you should return to the pin and read 0000. Remember the pulses add or subract 0001, 0002, 0003..... AS you move the head.

Do this test a few times and see that the results is the same.

Next test do the same up down test while carefully flexing the FSC Cable SINCE the Encoder Pulses go through the cable and while moving the head if the cable has a BAD WIRE and opens then the puleses will STOP during the open wire and when you return to the top PIN the number will be different....

So lets say BOTH movement and flexing the FSC Cable give you GOOD Results then you pull out my Secret Weapon.....

A Orbital Sander.... YEP.... Place a Board in the machine and CRANK it down... Leave enough sticking out of the machine to place the Sander on the board.... Now do the up and down test while shaking the machine with the orbital sander.... This will likely show the broken or fractured donut solder holes on the Encoder...

So we are also talking BOTH ends of the FSC Cable.... The Circuit Boards... A Cracked Copper Trace or FSC Cable PLUG soldered to the board could be bad too.... LOTS of Options for bad.... :)

So with ALL that being said... I did replace a Servo Motor years ago that developed a "TICK" or CLICK vibration... I swapped it out and fixed the problem then swapped it back to see if it was a loose connector and the "Tick" was back... So I replaced it for good.... Bad Motor...

A TV Repair guy could re solder the contacts of the plug IF he could reach them... But as you can see by the pictures, the Encoder Board is tucked into the board with the Donuts hard to reach...

Replacing the FSC Cable is FIRST as the vibration can also cause the broken or fractured ends of the cable to touch and not touch TOO...

Good Luck,

AL

[texasinmi]

Bergerud called the cable the FFC, Al calls it the FSC. Are these the same cables of are they 2 different cables?

I will call Houston on Monday and order whatever you tell me is the correct one. If that does not get it done the the Z Axis. What is the ordering name for the big circuit board you mention?

texasinmi

[Digitalwoodshop]

Same big flat cable.... It has been called both over the years... Here is a invoice that calls it a FFC Cable..... The most correct term... FFC.....

A A907 Kit should contain a 14 pin cable and both circuit boards... one for each end of the FFC Cable....

If you don't have cut motor brushes on hand for the 250 cut hour replacement, now would be a good time to place them on order to combine shipping. Getting socked shipping for 2 carbon brushes later would hurt... We see posts all the time on shipping cost... They last over 300 hours but sometimes less... then can snap a $40.00 bit when the cut motor fails to start... so replace early and save a Bit....

CB 001 Carbon Brushes.... The prices on that invoice are very OLD and out of date.

AL

[lynnfrwd]

Txinmi...don't you have b machine? It should not need a907. Head term board, z-motor and FFC cable.

[texasinmi]

Test results;

1. Z truck against top stop, Z reading is .0000,down/up a few times always returns to .0000

2. Wiggle the cable attached to the truck, still .0000. Pushed truck down and watched the signal while wiggling the cable, no changes for the reading.

3. Orbital sander test, down/ups always returned to the same number at the top pin.

4. Thinking it had fixed itself, which happens with computers from time to time, I set up a project and got the same chatter once the cut motor started. However, after the CW stopped itself with the z stall, without touching anything on the Z truck, I rechecked the Z output and it was a negative number, like -.503. It was not against the top stop pin. When I moved the truck to the top pin, it read -1.184. At home, off the board, I push the truck all the way down and the number was +.874. The top of the board I was using reads close to zero. I am guessing this is normal since the CW must do some sort of autozero after reading the top of the board. I thought I would report it none the less. Is that the normal dynamic range for the z signal, 2.058 counts?


Thoughts?

texasinmi

[texasinmi]

Yes, I have a B machine.

texasinmi

[texasinmi]

I have some brushes and will replace them.

John

[fwharris]

With out sorting back through, what chuck do you have on the B machine? QC (quick change) or Ct (CarveTight).

[texasinmi]

I have serviced the y & z idlers, I have serviced the y & z rods, I took out the cut motor brushes and they we basically new, maybe 1 mm of wear, so I put them back in. I still get the same chattering problem with the z axis.

Thoughts?

texasinmi

[texasinmi]

I have a QC, brand new, just replaced it.

texasinmi

[fwharris]

Are these the first carves since you put on the new QC? My first guess is that maybe the QC is out of balance.

[texasinmi]

Good idea, but I have 6 weeks of carves on the new QC.

Thanks,

texasinmi

[lynnfrwd]

Did you replace the bit adapters when you replaced the QC?

[texasinmi]

I did not replace them, but have been using them for 6 weeks with no problems.

texasinmi

[lynnfrwd]

BB marks on adapters can very quickly ruin a new QC.

[liquidguitars]

I have a QC, brand new, just replaced it.

The QC chuck should be removed and replaced with the Carve tight if your cutting anything other than air.

[liquidguitars]

Link to happiness.

http://store.carvewright.com/product.php?productid=20563&cat=285&page=1

[texasinmi]

BB marks on adapters????

texasinmi

[texasinmi]

I did a test where I unplugged the cut motor and started a project and everything went according to plan, no up/down chatter.

texasinmi

[fwharris]

I did a test where I unplugged the cut motor and started a project and everything went according to plan, no up/down chatter.

texasinmi

Ok that says there is probably no problem in the Y and Z bearings. Now for the next test, from the main menu select 0,8. this will take you to the user tests for the X,Y,Z and cut motor. Arrow down to the cut motor and follow the prompts on the display. They should be, load board, remove any bits and press continue. The cut motor should turn on. To stop it press any button.

Let us know the results.

[texasinmi]

I did as directed, the cut motor revved up to a high speed for about 5 seconds and then the up/down chatter started which got me a z stall error.

texasinmi

[fwharris]

Then I would say it is a unbalanced QC and you should replace it with the CT like liquidguitars suggested. You will be much happier.

[liquidguitars]

chatter started which got me a z stall error.

Chatter got me thinking, the small z pack motor connected to the truck gear box is connected with two black small screws if the screws are loose you will get "chatter" as the pulley belt slips the gear.The simple fix is to re-tighten the z pack to the truck case.

[fwharris]

Chatter got me thinking, the small z pack motor connected to the truck gear box is connected with two black small screws if the screws are loose you will get "chatter" as the pulley belt slips the gear.The simple fix is to re-tighten the z pack to the truck case.


Good observation LG! It very well could be...

[texasinmi]

If I decide to go with the Carvetight, what else would I need to adapt my Probe and other carving bits?

texasinmi

[lynnfrwd]

Scanning probe adaptor $10. 1/4" split collet $20 1/4" & 1/2" rubber stop collars $6 each set of 10. (I think it's 10 per set.)

[texasinmi]

I just check the tightness of the 2 screws on the back of the z motor mount, one was 1/8 turn lose. Checked for something to be out of balance on the QC check and did not see anything.

Retried the cut motor test, 0,8, still chatters.

What could have made to QC go out of balance?

texasinmi

[unitedcases]

Do you have the capabilities to actually measure the play in the qc itself?

[Digitalwoodshop]

I just check the tightness of the 2 screws on the back of the z motor mount, one was 1/8 turn lose. Checked for something to be out of balance on the QC check and did not see anything.

Retried the cut motor test, 0,8, still chatters.

What could have made to QC go out of balance?

texasinmi


Here is what the BB Marks look like... And like posted above with the QC you MUST replace the QC and ALL Bit Holders at the same time... We sadly did not understand this in the early years and with a new QC a bad bit holder with BB Marks will FLOP AROUND inside the QC and DESTROY IT in as little as one carve.... IF you grab the tip of the bit and move it in 4 directions likely you will feel the movement..... And if you replace all the Bit Holders and put them in a WORN OUT QC, within as little as one project, the Bad QC will put BB Marks into the new Bit Holders.... That is WHY you must replace ALL at the same time....

The CT will end that cycle of replacement... When we got the ROCK Chuck, the first Aftermarket Chuck, it made the machine sound like a 3/8 Drill in Quiet where the Worn QC makes a BIG RACKET...

In the 2nd picture I was blaming the latest release of Designer for the Burnt Bit.... And if you look close as in the first picture you can see the BB Marks... The Burnt Bit was because of the BB Marks and the BIT FLOPPING AROUND in the cut heating the side of the bit black... Boy was I WRONG.... The software was fine.... My eyesight.... in hindsite 20/20... at the time.... blind.... so as you can see.... I CAN and HAVE been Wrong in the past.... :)

AL

[texasinmi]

Aha, so that is a BB. I have seem them and when I did, I threw out the adapter.

texasinmi

[texasinmi]

Gentlemen,

Thanks for all the help. As he said, liquidguitar had it right. I replaced the OC with a Carvetight and voila, all is well.

Thanks,

texasinmi