Need Help!- 4020A Z Crash

[lumberjack]

The short version of the problem.

A student set the Z's 0 in the fixture ofset instead of the tool offset. This obviously resulted in a crash. As it crashed the student hit the E stop (Rapid was set at 100%, the student didn't know it could be slowed down).

The problem is the machine has "lost" it's cold start, it consistently comes in .080" in Z- which means the ATC doesn't line up, and thus isn't usable. Tools can be changed manually, but where's the fun in that?

(Below is second hand info)
Fadal said that most likely a coupler/coupling slipped and that it'd be $800-1k to fix.

Anyone have experiance with this and/or have a solution?


Thanks for your time

Carl

[DareBee]

To Fix the coupler you need to pull the spindle motor.
Then remove the coupling. I have not had the actual coupling off before, but I would assume they are keyed. Once the couplings are off you will need to decide if they are broken/slipped whatever. Repair the problem and put back together.
Now is where the fun starts 1:3 chance of getting it together correctly the first time because the coupling has a 3-lobe spider. The only way I know of is trial and error by assembling, doing a CS and seeing if the tool change lines up - if not, pull the motor and try the next 1/3 engagement.
I am not a Fadal tech and I figure it is a 1.5 hour job for me (7.5 if the students help ;-0)

Typically if there are no coupling issues and you are pulling the spindle motor for other reasons just mark the coupling during disassembly so it can be assembled on the correct lobe the 1st time.

Manuals and schematics are available at http://www.compumachine.com/Support/DL-Fadal.htm if you wish.

[makingchips]

Originally Posted by lumberjack The short version of the problem. A student set the Z's 0 in the fixture ofset instead of the tool offset. This obviously resulted in a crash. As it crashed the student hit the E stop (Rapid was set at 100%, the student didn't know it could be slowed down). The problem is the machine has "lost" it's cold start, it consistently comes in .080" in Z- which means the ATC doesn't line up, and thus isn't usable. Tools can be changed manually, but where's the fun in that? (Below is second hand info) Fadal said that most likely a coupler/coupling slipped and that it'd be $800-1k to fix. Anyone have experiance with this and/or have a solution? Thanks for your time Carl

Did you reset the cold start? Turn off the machine, turn off the main power for 5 minutes turn it back on. Jog the machine to the cold start lines type CS then hit the enter key.

You can also try moving the Z up or down the .08 then type CS. I have had this happen with operators who were not paying attention and they end up crashing the tool changer or dropping a tool. I reset the cold start smack the operators fingers with a 8 pound sledge (10 pound if one is handy) and all is happy.

Unless I'm misunderstanding.


MC

[lumberjack]

MC, we've set and reset CS to no avail.

DareBee, thanks for the link, I'm going through it now. I'm not the instructor, but I told him I'd look in to finding directions/schematics so more isn't damaged in the attempted repair.

Is there any reason we should pay $800 for the coupler assuming it can be made in house? I'll look at pulling the motor tonight and see what I see.


Thanks again

Carl

[scadvice]

Originally Posted by DareBee To Fix the coupler you need to pull the spindle motor.

...the Z axis motor??
Steve

[Hartmetall]

Hi,
this is not an unusual problem.
There is an offset setting that is used to fine tune the centers of each axis,
I think you can adjust about .080 either way.Somewhere in the Parameters
section.
Give Neal at Fadal a call,he should be able to help you.

Thomas

[DareBee]

Oooh shoot.

I FORGET TO MENTION THAT YOU NEED TO BLOCK THE HEAD BEFORE YOU REMOVE THE MOTOR. Gently jog the motor down so it is sitting on wood resting on the table. And yes I meant the Z-axis motor not the spindle motor.

I wouldn't just adjust the parameters because there is obviously something wrong mechanically that could go really bad at any time.

[advt001]

I'll just about bet that the servo mounting bracket is broken.I have replaced 2 of them and think its about $200.00.

[lumberjack]

The instructor already scheduled a Fadal service call for tomorrow.

I'll post what is found out.

[DareBee]

Originally Posted by advt001 I'll just about bet that the servo mounting bracket is broken.I have replaced 2 of them and think its about $200.00.

That makes good sense, the coupling is pretty heavy to damage without having a near catastrophic explosion.

[lumberjack]

It was a bent coupler. I meant to bring it home and take pics, but alas I forgot.

The coupler was far from robust, it didn't have a key way, and the thin aluminum that connected the two ends was bellowed (designed to crumple).

The part was less than $100 to get the "upgraded" part. Labor/drive time made up the difference to get a $980ish bill.

[DareBee]

AFAIK the "thin aluminum that connected the two ends" is meant to accommodate minor misalignment as opposed to being a "crumple zone".
My machine uses a rather large LoveJoy coupling - quite robust indeed.
Either mine is not factory or you have a newer machine that is victim of cost cutting (or some other engineering reason).