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Hello all,
I am encountering this alarm on a Star SR-16/20 FANUC 16-TTA CNC screw machine. Our techs have identified that it may be the shot pin that holds the collet in place during a side drilling process. The shot pin itself actuates magnetically and two sensors are attached to the casing around then pin.
Are there any other ways to solve this problem?
Thanks,
Michael Sanders
Hi Mike,
Many Proxy switches have a red light indicating that they sense whatever is in place. Do you see a red light on either one of them? If you see a light on one, then command the shot pin to fire, does the other one light up? If not, that is a strong indication that the switch is either misaligned, dead, has a loose connection, or broken cable.
The M-Fin alarm usually means that a Proxy switch has not been activated after a certain time period defined by a parameter or in the ladder. If it happens during indexing as you mention in your other post, it is likely something to do with a "in place" sensor. This happened to me once on my Tsugami because I programmed a 36* index, but it only had 5* indexing (no full C axis), so when the shot pin fired it never found a groove to drop into and thus never activated the "in place" proxy switch. The machine would sit there for a few seconds then alarm out.
Can you tell me what M21/M22 is?
If you have a competent machine tech at your disposal, they can look in the ladder and see which switch is causing the alarm, then test the switch or cable.
Hey MCImes,Quote:
Originally Posted by MCImes
The red lights are working. For some reason it will work one day or alarm out every 10-15 parts, and then some other days it will alarm out on every single part.
Our machine is doing the same thing in that "The machine would sit there for a few seconds and then alarm out". Perhaps that shot pin is not finding the groove to drop into. What would cause that to happen?
M21/M22 is Error detect ON/Error detect OFF respectively.
Thanks,
Michael
Intermittent problems like that are often the hardest to pinpoint, so that’s tough. When the machine alarms, then look at any prox switch you can see. If its operating normally, that wont tell you anything. The other thing is, are you sure you even have a pin or mechanical brake? Many newer machines have no mechanical lock, or they have a disc brake type rotor/caliper that can lock at any angle.
Unfortunately, problems like this probably wont be solved without a machine tech that can look at the ladder and identify the exact switch. My best advice would be, the next time the machine alarms out with the M-Fin alarm, don’t hit reset and let a machine tech look at it. They can look in the ladder with it alarmed out and see which switch is not registering. Obviously that's tough if you work at a smaller shop and don't have a full time maintenance guy on staff. Other than that, there isn’t much you can do that I know of.
The FIN signal is used in the ladder collectively for all M codes sent from the CNC side to the PMC (ladder) side.
For M codes, a FIN signal is issued in the ladder to indicate to the CNC side to continue after a M code is completed.
Some MTB's set a timer in the ladder that will time out and alarm if the M code does not complete rather than just hang there waiting.
As mentioned already It would seem that a function at the end of the operation is either delayed and exceeding the time out and/or fails to operate, if you have a hard copy of the ladder you can see which input it is most likely to be and then call it up in the ladder and watch the status change (or not).
Al.
Hi Msanders,
With this type of machine and when you are using the spindle locking device you may find the relay that controls this device may be faulty as they tend to stay on at all times.
Also the LED may have gone off on the sensor but the sensor is still on.
Due to the types of relays and sensors that were used after a period of time they become magnitized and stick.
Remedy tempory tap the switch or relay with the handle of a screw driver and tap gently and not break the devices.
Shock will get rid of magitized objects.
If this does not work then the parts have to be replaced
Regards
Peformance99
hi all. i am not sure if this thread is till active. i am having same issue. Attachment 443790Attachment 443792
when i knock the right sensor it starts to work. today it has stopped accepting knocks. i am looking for these sensors, can any one have any information about these sensors?