Cutting head started cutting at 14-15 mm above the sheet - Amada LC-2415 Alpha III

[SS37]

We just had the short z-sensor cable replaced, and the machine worked fine for 1 day. The next day, the head did not detect the sheet metal but stopped at 14-15 mm above the sheet and start cutting.

We are using HS-2000 sensor. Head calibration worked fine (with Trace OFF). See Video here:

https://youtu.be/p-_nVzMZH2Y

Problem was when we ran program (Trace Off not lit) that the head refused to come down and detect the sheet before starting to cut. See Video here:

https://youtu.be/5BFi9CGT-sY

Local technicians tried replacing the cone, the nozzle, the internal sensor cable, the short sensor cable, and the HS-2000 board. They even restored the entire machine parameters from SRAM backup. Nothing seemed to solve the problem.

Any idea, please?

 

[SS37]

By the way, we don't know how to test for shorting to the cone... so we removed the cone from the head and placed it outside the machine on the concrete floor. Then we connected the Z-sensor and Ground cables to it.

No Z-sensor wire break alarm... but the "Trace Data" remained stuck at 20-28... no change in reading whatsoever.

 

[ausman]

This signal should be 8.9V at nozzle gap
with 2.0mm, 0V with 1.5mm, -8.9V with 2.8mm
Check & advise

Carefully Do this check, what happens?
G32 R_ ; Z-axis follow mode ON
G33 ; Z-axis follow mode OFF
R_ indicates a nozzle gap amount. For example, when R=1.5, the nozzle gap is 1.5mm.
When R=0.3, the nozzle gap is 0.3mm.

 

[SS37]

@ausman
Thank you very much for your info... please advise:
1. Did you get those readings with JA6 cable plugged in to Fanuc board (or without)?
2. I believed you meant to type "-8.9V with 0.8mm", is that correct?

We will try the G32 R_ command tomorrow and reply.

 

[SS37]

Attached is the detailed voltage output of the HS-2000 board.

 

[ausman]

From Amada documentation (there is no reason for me to doubt these values)
This signal should be 8.9V at nozzle gap
with 2.0mm, 0V with 1.5mm, -8.9V with 2.8mm

Have you tried testing the head with the aluminium function selected? this function enables a slow response mode on the HS98.
Might or might not do anything for you, worth checking.


Based on he differences you have JA6 plugged in & not plugged in
I would check the PCB actual output voltages with JA6 not plugged in.
If you confirm the voltages are correct on the HS98 PCB at the about the 3 different gap amount then I would believe the problem is not the HS98.

Maybe the A/D chip on the Fanuc PCB is shagged?
Might explain the large voltage differences when JA6 plugged in and the fact that the trace data is not showing the correct digital gap values.

If you want to get technical, do this at your own risk
get a small variable DC power supply, (one with adjustable knob & LCD screen for the voltage readout)
Use this on lieu of the HS98 connected to the Fanuc analogue board to imitate the HS98 output voltage of -9.8 volt to 9.8 volt)
Then check your trace data values are where there are supposed to be.
this should determine the if analogue to digital fanuc board is functioning correctly.

Just things I would be testing if I was in your shoes.

 

[IvanBr]

maybe ceramic below nozzle?

 

[LASERNINJA]

I realize this is late in the fourth quarter. But another idea I had was to check the resistance of the wecone and wire assembly. It's similar to other tests you have done but I am better at interpreting the results doing it this way.

From the nozzle to the center of the coax cable should be about one ohm or less. Then, add the short cable to the test. It should be a bit higher but less than two ohms. Then please check the nozzle to everything else around the nozzle itself. It has to be open. Not kilo ohms, not mega ohms.

Finally the big brown cable should be around 11 ohms. I know u said this stuff was all new but based on the fantastic help you have gotten already... It really should be in one of these three places.

P.S. I don't think it's the JA6 anymore. The nozzle wouldn't bounce / flutter if it was disconnected.

 

[LASERNINJA]

 

[LaserSpyder]

fixed??

 

[SS37]

At last, we found the problem... a very simple one.

The JA6 cable was plugged into the wrong socket (on the wrong board).

See the attached picture... someone mistakenly made red-color marks on the JD6A socket and the JA6 plug... so even though we checked the JA6 plug so many times, it was naturally plugged back into the wrong socket. Nobody noticed the JA6 socket on the adjacent board.

It was the Fanuc technician who pointed that out (on his 2nd service call). Amada technicians already spent more than 40 man-hours on this machine... never crossed their minds.

It was a very funny incident... and yet so sad.

Anyway, thank you everyone for your help and advice... you all had been very supportive... I really appreciated it.

 

[ausman]

Glad to see it resolved, what initiated unplugging JA6 to begin with? Was there another issue that you resolved in this fault finding process that you didn't note?
Thanks

 

[SS37]

This machine is serviced by Amada, Fanuc, in-house technician, and private service company... no one knew exactly how this could happen.

Our current focus is on a different issue. Due to the rather inexperienced technicians from Amada... during their 2-month troubleshooting sessions, our HS-2000 board malfunctioned and needed to be replaced (this costs around USD7000).

The focus is now on why the HS-2000 board malfunctioned and who is going to pay for it.

So the headache continued.

 

[hookie1985]

Man I will say we went through a similar thing a couple years ago. wont go into all the details bet we Left Amada and went to laser experts which was an even worse situation. Now i just do as much of our in house stuff as possible. If I cant figure it out Laserninja and Laserspider have saved me on more than one occasion. I guess i cant complain too much though honestly because ive learned more over the past 3 years than i ever thought possible. Just hang in there good sir.