Machine All messed up

[Ballnose]

I have a FANUC @! iM controller machien with. The machine model is 3020 VMC. Could someone help me with an electronic problem in the machine.

[Al_The_Man]

Need a little more information, like a description!!!.
Also Correct model #!!
Also it should be in the Fanuc Forum.
Al.

[machintek]

Let me guess.
Bridgeport VMC3020, but there were 2 versions. One had a 21iM control and the other had a 0M control. Which do you have?
What is your diificulty?

George

[Al_The_Man]

I think the @! iM must be 21iM
Al.

[Ballnose]

The Machine is a Bridgeport 3020 VMC with a Fanuc 21iM control. The machine was installed in 1999.

The problem appeared almost 6 months back and is as follows:

The machine works fine with no problems or inaccuracies. Suddenly there is a large sound of all axes simultaneously turning with a lot of force in the positive direction for say something like two inches. After that the machine may do one of the following:

1) keep working as normal but the refernce is usually lot or offset (Machine loses its zero position)

2) All axes may stop working at all with no error message but the machine completely loses its refernce and has to be referenced again.

3) May give a 410 servo motor excess error or 50x limit switch error on x or y axis.

4) May give a spindle error.

5) Has also once before lost all parameters and had to be reloaded.

The frequency of the error is very erratic. Sometimes the machine may give this shock while it is idle and we just remove the emergency stop switch. The machine becomes completely locked and you cannot move the machine axes at all. At this time we turn the control on and then off and the machine starts to work normally. At other times it may happen during build say after 2 hours,5 minutes or even the largest period of operation we have had is 22 days before it broke a tool and destroyed the job.

There are some observations that we have made.

1) the jerk is always in the positive direction and in all the axes.
2) there is a UPS behind the power so no problems there
3) all relays have been cleaned and are working well
4) Thee power supply in the axis interface card (FSSB Module that connects the controller to all the 3 axes) has a +/-15 volt power supply with a 5mV noise on the +ive side and a 30mV noise on the -ive side.

Waiting to hear form you

[Al_The_Man]

It almost sounds like a incomming power supply problem, how sure are of how clean you power is?
Often a UPS will take care of brown-outs, but does this one look after voltage peaks or surges?
In N.America you can often get the power supply company to put a chart recorder on the line over a period to test this.
If it proves to be this you might want to look into a CVS (constant voltage supply) these are made by a company called Sola, there are others I believe.
Al.

[machintek]

I agree with Al.
In addition, a 410 error needs you to look in the diagnostic parameters. By what bit is made, it may give additional clues. Look at your FANUC maintenance manual.

George

[machintek]

An alarm 410 is a position deviation error on a specific axis. The triggering value is a set parameter. Either you have a position loop problem or a power problem. Since you are having errors with the spindle as well, I believe that you are back to square one and had better check the power. meters such as my FLUKE can monitor power and give you HIGH and LOW values it has recorded. All 3 axis need to be checked. Do you have a good ground?

George

[Ballnose]

I have tried the power problem and completely removed the machine from factory power, shifted to UPS only, and also have tried a separate generator but all of these have given the same problem. As far as the ground is concerned, the machine has a good ground and also the machine has been grounded at different points to remove any threat of grounding problems. We have however found that there are ground cables returning from the motors to the cabinet. If these grounds are disconnected the machine tends to give lesser amount of jerks for a given time however they are not removed.

The manual suggests us to tune the motors if there is such a jerk problem. I have just recieved the tune up kit, will try to tune the motors and then will let you guys know if any thing happens. Thanks for all the support though.