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IndustryArena Forum > MetalWorking Machines > Kitamura > Kitamura Mycenter 0 "Spark Changer" ATC (Machine Alarm 14)
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  1. #1
    Join Date
    Apr 2007
    Posts
    144

    Kitamura Mycenter 0 "Spark Changer" ATC (Machine Alarm 14)

    Greetings,

    We have a '93-vintage Kitamura Mycenter 0 w/Yasnac MX3 control that is giving us problems with the ATC.

    The ATC is controlled by a cam-box driven by a Mitsubishi Freqrol drive. Several times a day we are getting
    the MACHINE ALARM 14: ATC LIMIT SW. ALARM following a toolchange command.

    The symptom is that the ATC arm is overshooting at the end of the cycle, such that it actually moves away from
    its HOME position even though the Cam Motor Revolution command is OFF. When that happens, the Arm Zero
    Position signal is then OFF too. (PS9 / #1008.1= 0) generating the alarm.

    The cam motor has a electromagnetic brake mounted on it and I'm thinking that perhaps the brake is not working
    properly allowing the cam motor to continue to rotate (slightly) after the cycle is finished.

    Can anyone with experience with these machines chime in an provide their experience / opinion about this?

    Please advise.

    emexcee380

  2. #2
    Join Date
    Mar 2011
    Posts
    67

    Re: Kitamura Mycenter 0 "Spark Changer" ATC (Machine Alarm 14)

    I would agree that the brake seems at fault. If that is true you may also see the overshoot problem if you try a tool change with no tools in spindle or pocket. When the arm comes in to grab the tool, if the brake is not working the motor will overshoot a bit and begin to drop the arm down instead of stopping right at the tool grab position.

  3. #3
    Join Date
    Apr 2007
    Posts
    144

    Re: Kitamura Mycenter 0 "Spark Changer" ATC (Machine Alarm 14)

    tpodgwaite,

    Thanks for your response. I haven't had a chance to work with this machine for about a week
    but hope to be back at by early next week. (Too many fires to put out !!)

    FYI: Our ATC works fine in most every other respect: 1. Arm engages tool in spindle and tool
    in pot. 2. Tool unclamp. 3. Arm rotates 180 4. Arm up to insert tool in spindle/tool in pot. 5.Tool
    clamp. 6. Arm to home position.

    Step 6 is where it will typically overshoot. Occasionally the ATC will execute a few good (complete)
    toolchanges, but most often not.

    Kitamura Service was not much help. (Certainly they've seen this many times on older machines and
    should know what most likely the problem is. But they acted like they had no experience with it. WTF?)

    I think the motor brake only stops the cam motor at the end of the cycle. All the other functions are controlled
    by the ATC cam. If you know differently, please advise.

    Onward thru the fog....

  4. #4
    Join Date
    Jan 2006
    Posts
    175

    Re: Kitamura Mycenter 0 "Spark Changer" ATC (Machine Alarm 14)

    Mine has a Fanuc control, but the ATC should work the same. I would start by checking the sensors that read the cams on the front side of the ATC. The machine has two cams there and depending on the age of the machine, the cams are either monitored by roller switches or proximity sensors. A flaky sensor on the back cam or a loose cam will allow the overshoot you are talking about. The proximity sensor above the ATC arm is the one that watches for the condition and triggers the out of position alarm.


    Sent from my iPad using Tapatalk

  5. #5
    Join Date
    Apr 2007
    Posts
    144

    Re: Kitamura Mycenter 0 "Spark Changer" ATC (Machine Alarm 14)

    [QUOTE=tcom-frazzled;2149658]Mine has a Fanuc control, but the ATC should work the same. I would start by checking the sensors that read the cams on the front side of the ATC. The machine has two cams there and depending on the age of the machine, the cams are either monitored by roller switches or proximity sensors. A flaky sensor on the back cam or a loose cam will allow the overshoot you are talking about. The proximity sensor above the ATC arm is the one that watches for the condition and triggers the out of position alarm.


    Tcom,

    Thanks for your response. Fortunately our machine doesn't have alot of production pressure on it now so I can work on it whenever I have time.

    The cam box prox's work correctly, as does the ATC ARM HOME detection prox. I tried tweaking on the CAM HOME position prox.but it only seemed to make the final arm position overshooting worse.

    I took the brake off the back of the ATC cam motor and inspected and tested it. It's strong ! I was not aware that the brake gets energized (90vdc) to UNCLAMP it, not CLAMP it. When it gets energized at the start of the ATC cycle the disc gets pulled toward the electromagnet, compressing three small (stout) springs. When the CAM MOTOR ROTATION command is OFF, the electromagnet releases and the springs cause the disc to contact the stationary element, not unlike a clutch pressure plate.

    But still the cam overshoots at the end of the cycle, causing the ATC arm to bypass its HOME prox. generating the ALARM 14.

    I'm currently scrutinizing the Mitsubishi FREQROL inverter drive that controls the cam motor. It's possible that it has its own dynamic brake (via braking resistor) and that could be faulty or need adjustment of its parameters. Mitsubishi was as helpful as could be expected providing support for an obsolete inverter drive.

    I must say that I was completely disappointed with the response I got from Kitamura. I was a service tech for a distributor back in the 90's and actually installed approx. 10 of these Mycenter 0's ("Sparkchanger") during that time. Kitamura's tech support was outstanding then ! When I called for some insight last week the (alleged) service tech acted like he'd never heard of such a problem.
    (R-i-i-i-g-g-h-h-t-t-t-t ....):bs:

    Onward thru the fog....

    emexcee380

  6. #6
    Join Date
    Dec 2022
    Posts
    11

    Re: Kitamura Mycenter 0 "Spark Changer" ATC (Machine Alarm 14)

    Having a kitamura mycenter 2x 1997 with yasnac I80M controler i loste all paramaetres including offset,macro.common and aux2 data.
    Anyone can help ill be soooooo thankful.

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