HELP! - Spindle cutting off without command

[Chris Robinson]

Hi Everyone,

 

I have a large projet to get out and I'm having a problem that I can't diagnose. I'm running Mastercam Router v9 with latest updates. Machine is a Thermwood Model 40.

 

For some reason, the spindle is cutting off at the bottom of the plunge. It has happened on different tool holders and different functions. I used the drill function, mask on arc, then selected the parts and allowed Mastercam to select all arcs that were within the .001 tolerance. It would bore the cluster of holes and then on the fifth from last hole, the spindle would stop and the machine would try to finish the last 5 holes. There are no plc errors logged, there isn't an errant M05 stuck in there either!

 

It has also happened on contour toolpaths. It does appear to only happen in the quarter quadrant closest to the machine home. I can take the drawing and re-order the toolpath and it will work without incident! If any of you have ever run across this, I could really use a few tips!

 

I need to finish cutting the next 30 sheets of parts and be ready for shipment by Monday!

 

Thanks,

 

Chris Robinson

[email protected]

[BernieT]

I can't imagine what would cause this except a machine malfunction.

 

Good luck on your project !! Sounds like it might be a long weekend for you!

[George_Gerhard]

Chris

are you sure there is no other command that would cause a spindle stop? Perhaps M00 or a toolchange command?

Next check to see if your inverter is still receiving a run command. If it is then check to see if you are loosing the analog signal to the inverter which makes it run. this will be a dc voltage between 0 and 10 volts. at max rpm the inverter should be getting 10 volts

I dont know how old your thermwood is but if it has a HSD spindle there are three sensors and one of them checks that the tool is clamped, if this signal is lost the spindle WILL stop. You can adjust these sensors they are cam mounted.

There is a good chance this is your problem. Also please check all your connections.

 

good luck

George

[Jack Mitchell]

quote:

---

For some reason, the spindle is cutting off at the bottom of the plunge. It has happened on different tool holders and different...

---

I wonder if the spindle is overloading then tripping with a thermal protect somehow. It seems odd that the machine tool would continue processing as if the was no error present. This might even be a flaw in the control/manufacturer interface.

 

Regards, Jack

[Lars Christensen]

Thats a way to start the new year.

It defently do not sounds like a code problem to me, what = the machine.

~~~~~~~~~~~~~~~~~~~~~~~~~

appear to only happen in the quarter quadrant closest to the machine home.

~~~~~~~~~~~~~~~~~~~~~~~~~

Could it be a cable with a short that get trickered?

 

Is it posible for you to skip that quadrant of holes, and make a second setup, so you can get the job done before mondays shipment?

 

Lars

[Chris Robinson]

I have double checked the code and there isn't a tool change command or M00. That was the first thing I checked out.

 

The machine is new and does have an HSD spindle. I'll check the 3 sensors and also check to insure there isn't any apparent damage to the lines. I'm going to go back and see if there were any plc errors indicating tool unclamped. Although that should send the machine into e-stop.

 

Thanks everyone for your help. We'll get through this and learn a little too!

 

Thanks,

 

Chris R

[Jack Mitchell]

I re-read your post and I think you should check the leads going into the spindle itself, these might be loose, be touching on metal, or perhaps crossing. Check that all wire insulation is intact and not bare at any point. If this is occurring at the near home position then the wires might be bunching up and shorting. If there is a short there should be some carbon around the affected areas.

Also check your leads going into the spindle controller itself – power down & lock out the breaker before attempting these inspections. Take care since the capacitors retain a charge even after being disconnected.

A thermal overload would kick out the way that bimetal contacts work – this excess heat condition is within the motor itself and not something that sensors are usually attached.

 

Regards, Jack

[Chris Robinson]

First off, forgive me for my bad manners. Happy New Year to All!

 

With further testing, the spindle has shut down near center of the table. I have inspected all wires coming and going from spindle and haven't found anything. The wires are properly insulated and protected within a harness.

 

The last time, I wanted to check repeatability. So, when the spindle cut off, I immediately e-stopped and noted the program line number. Re-initialized, and ran the file again. This time, it did it in two locations, the first occurance being a new location. When the spindle approached the original place it did cut off, but on a different line number.

 

I don't like how this year is starting off! I have trouble shot to the limit of my ability.

 

I'll get a tech in here Monday. It looks like I'm not going to get the parts out by Monday either which stinks. But I've now destroyed about $300 in tooling and it's happening on every sheet.

 

On a side note, even though this is obviously a machine issue, you guys still offer constructive advise and help! Thanks!

 

Chris Robinson

[Chris Robinson]

Ok, one last ditch effort...

 

I opened the plc cab so that I could watch the vfd. I loaded the last file that had the problem. I removed the material and handling sheet and started the program.

 

When the spindle stopped, I didn't hit e-stop and just let it keep running. It completed the rest of the geometry and then upon executing the next tool change command, gave the error: "The PLC program in the control did not respond to the tool change request."

 

So, I ran it again. This time watching the vfd. The spindle stopped and the vfd didn't show any alarms and the frequency didn't change.

 

I ran it again, this time watching the control screen. The interesting thing is that the spindle shut off on line 278, skipped lines 279-329 and that's where it faulted for the error given above. I'll paste in lines 277-330 below.

 

When I ran another program, the same thing happened, only that time, there wasn't an error message after tool change. The tool change occured and the spindle ramped up rpm and continued it's merry way! Arrgghhhh. I hate inconsistency. The only apparent consistency is that this thing is KILLING me!

 

So, take a look at the code. Am I missing something?!

 

G1Y-18.4298 (Line 277)

G2X-85.728Y-18.5548I-.125J0.

G1X-95.103

G2X-95.228Y-18.4298I0.J.125

G0Z.25

 

 

Y-12.7798

Z.1

G1Z0.F75.

Y-7.7798Z-.1346F468.

G2X-95.103Y-7.6548Z-.1399I.125J0.

G1X-85.728Z-.3922

G2X-85.603Y-7.7798Z-.3975I0.J-.125

G1Y-12.7798Z-.5321

G2X-85.728Y-12.9048Z-.5374I-.125J0.

G1X-95.103Z-.7897

G2X-95.228Y-12.7798Z-.795I0.J.125

G1Y-12.0367Z-.815

Y-7.7798

G2X-95.103Y-7.6548I.125J0.

G1X-85.728

G2X-85.603Y-7.7798I0.J-.125

G1Y-12.7798

G2X-85.728Y-12.9048I-.125J0.

G1X-95.103

G2X-95.228Y-12.7798I0.J.125

G0Z.25

 

 

Y-7.1298

Z.1

G1Z0.F75.

Y-2.1298Z-.1346F468.

G2X-95.103Y-2.0048Z-.1399I.125J0.

G1X-85.728Z-.3922

G2X-85.603Y-2.1298Z-.3975I0.J-.125

G1Y-7.1298Z-.5321

G2X-85.728Y-7.2548Z-.5374I-.125J0.

G1X-95.103Z-.7897

G2X-95.228Y-7.1298Z-.795I0.J.125

G1Y-6.3867Z-.815

Y-2.1298

G2X-95.103Y-2.0048I.125J0.

G1X-85.728

G2X-85.603Y-2.1298I0.J-.125

G1Y-7.1298

G2X-85.728Y-7.2548I-.125J0.

G1X-95.103

G2X-95.228Y-7.1298I0.J.125

G0Z.25

 

T505 M3

S18000

[George_Gerhard]

Chris

under no circumstance should the machine continue to run if the spindle stopped in the middle of an operation. I would ask the mechanic from Thermwood if the plc looks at the arrival signal from the inverter. NO MATTER what he tells you this is a basic of interfacing a control to a machine. I write ladder logic for machines and I can tell you with certainty that the machine must stop if the spindle is active, the program is active and the run command is lost.

 

good luck

George

[Die Sinker]

I've had a Haas continue to run after a spindle overloads. Large cutter and big die blocks-very scary! Sure sounds like a spindle overload considering it occurs on plunge.

[Charles Davis]

What does the load meter show when you are plunging?

 

I'd suspect a spindle overload too. Router have very fast spindles, but low torque compared with VMC's.

[Bill Craven]

Chris,

 

Do you have a M31 or M32 (spindle on and up to speed) in your program?

 

Also, if you change your Z fixture offset in the machine so that you run the program above the part, does the spindle shut off?

[Chris Robinson]

Hi All,

 

At the outset, I wanted to ascertain whether spindle load had something to do with it. I took off the substrate and handling sheet and ran the exact program again. Without the substrate and handling sheet, I knew that the cutters wouldn't come in contact with anything.

 

The spindle cut off and the machine kept running. I don't have a visible load meter on the spindle. I watched to see if the vfd showed a change in Mhz indicating that the control was telling the spindle to stop. It did not change.

 

Bill, I just did a search of the posted program and there wasn't a M31 or M32! I went back and looked at cut files that were generated by Thermwood's eCabinet Systems software. There is a M31 command after every tool change. It moves the spindle to the first xy coordinate and just before z-plunge, calls M31.

 

Now, that would stop the machine before it plunges into the part if the spindle wasn't on or up to speed but would it stop the machine during a cut sequence if the spindle speed dropped or stopped?

 

Tim, my brother and partner will be in on Monday to help diagnose the spindle. He's a trained Industrial Maintenance Engineer and does this for a living. And we'll be on the phone with Thermwood as soon as they get in!

 

The only thing that makes me doubt it's spindle overload is that it does it at the same location, air cutting or loaded. It sort of sounds like a control issue. I'll keep you all posted.

 

Thanks,

 

Chris R

[wildcat99]

You could have a broken or kinked wire somewhere since it seems to be random, but occurs in about the same position everytime.

 

On our HSD spindle there is a junction box with 2 wire connectors on top. The smaller one I believe has the connections for the thermal overload sensor. These are a pain and the pins have to be seated just right. If these are loose, we get a "false" overload error, but it also e-stops the machine.

 

I'm sure Thermwood can point you in the right direction now that we're through the Holidays. Let us know what you find out.

Good Luck

[Chris Robinson]

Well people, I have good news. The problem has been resolved.

 

It turns out that Thermwood's control doesn't look for spindle speed on a constant basis. If there isn't a M31 command following a tool change, the mysteriously stopping spindle issue occurs. The programmer told me that as the controller looks ahead 50 lines or so, it may run across a spindle speed command and it looks back for that M31 command and if not there, it get's confused and allows the spindle to stop unbeknownst to the plc.

 

So, when I went back through all of the programs and looked where the spindle would stop, it was always near 50 lines before a S-command. Qwerky to say the least. You would think that the plc would always be polling the vfd or something.

 

Anyway, after modifying the post to include a M31 after every tool change command, it resolved the problem. What say you?!

 

Thanks to everyone for their help. Live and learn, that's all we can hope to do.

 

Chris

[Müřlıń®]

Ya Chris you didn't know when you got into CNC's that you were going to have to be a machine tool tech did ya?

 

 

HEH....Good job man

[BernieT]

Thanks for the feedback, Chris.

What a strange problem, I'm glad you got it resolved!!!!! Bill Craven was sure on the right track!!!

[wildcat99]

Glad to see you found the culprit and it sounds like an easy fix too. It's always a relief to find the cause, especially on something intermittent like that.

[Chris Robinson]

Thanks guys! I'm learning. At least it was an easy fix and not a bad vfd, spindle or plc!

 

I'll get new tooling in tomorrow and get that job out.

 

Thanks everyone, you guys ROCK!

 

Happy New Year,

 

Chris