mazak/hundai qt15n chuck sometimes wont open so alarms out when bar pulling
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  1. #1
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    Default mazak/hundai qt15n chuck sometimes wont open so alarms out when bar pulling

    Has anybody with a mazak or hyundai qt15n ever experianced the chuck not opening when commanded on occasion?

    Sometimes it take me 2 or 3 presses of the foot pedal to get the chuck to open which is no real issue when running parts 1 at a time but when i set up to bar pull and want to leave it running sometimes it will be fine for 50 parts and then another time it will not work for 25 of the 50 parts so the chuck times out and the errors say 'chuck clamp time exceeded'

    When you press the pedal you can hear a solenoid/relay set up click which is obviously to do with the hydraulic pressure switches but ive found nothing obvious, oil level is good, hydrualic fluid is good, foot pedal switch is good

    Without completely stripping down the entire hydrualic system which i dont want to do, does anybody have any ideas?

    Thanks
    Marc

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    You have to make sure your spindle is completely at rest before opening the chuck ... chuck is interlocked with spindle to prevent chuck opening while spindle is turning, even very slowly.

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    Hi

    The spindle stops completely before the bar puller goes in to grab the bar, then chuck opens (halftime the time lol) then pulls bar out, chuck closes and program runs again

    So itís definitely not the spindle still turning causing the error

    Thanks
    Marc

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    Could be a weak solenoid that is not actually shifting the valve. Might try to switch just the solenoid with another one on machine and see if follows or stays with the chuck.

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    Il try and swap a couple over and see if that solves the problem

    Thanks
    Marc

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    Quote Originally Posted by Red James View Post
    You have to make sure your spindle is completely at rest before opening the chuck ... chuck is interlocked with spindle to prevent chuck opening while spindle is turning, even very slowly.
    After looking into this further I think there may be a set delay time that the spindle has to be stopped for before the chuck is allowed to open either that or it is just coincidence

    Yesterday I set the bar pull to start from a littler further away from the stock so it takes around 4 seconds longer before the open command,

    So far today I ran 100 parts and it did not alarm out at all

    Thanks
    Marc

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    Just to update,

    It did it again today so the time delay was not the answer, just coincidence!

    Thanks
    Marc

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    slow to pop open can be simple dirt
    crappy chuck that is getting into a bind
    actuator that is blowing by
    my first test would be to clamp it up tight, hit the open signal one time
    do this until you are sure you have failed to open with one command (manuel m-code would be best, then you are sure control got command)
    then smack the bar with a hammer
    if it then pops open you now know its a mechanical bind
    find it in the above suspects or others



    if you cant get it to pop open ever with a good smack
    start looking for weak coils, directional valves, ice cube relays, lose wires

    good luck

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    Well I had another good go over the machine today,

    For good measure I drained the hydraulic fluid completely

    I removed the chuck, tailstock, turret indexing and turret clamp directional valves,

    I stripped each 1 cleaned and rebuilt,

    All seemed ok,

    The solenoids on the other hand I’m not so sure, problem is I can’t find replacements,

    The solenoid part number on mine is

    Bosch 1 837 001 255

    And to be sure I’d want at least 2 new ones

    Thanks
    Marc

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    Update to this again

    I have found what i beleive to be an intermitent ice cube really for the chuck open so i have ordered a new 1 and will update after a few days use

    Thanks
    Marc

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    Marc,

    You can swap out ice-cube relays to test them.

    Remove one from a function you're not currently using (tail quill FWD, coolant ON, machine light ON...), plug into your questionable chuck close (or open) relay socket, and give it a try.

    Good luck,

    ToolCat Greg

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    a burned ice cube can imply a high current load down stream your crappy coil
    i get those ice cubes out of mcmaster, just match the coil voltage and pin number and size (high current low current big pin little pin)

    those directional valve coils will swap around too

    All World Machinery
    (opps, reread the UK part, not sure about old world connections on this stuff but will leave links for possible future victims)

    might sell you just a coil
    not sure
    they can definitely cross the whole valve (which are most generlly suitable to generic match up)
    when spending someone else's money i never rebuild a directional valve, mom and pop might be different, never had the pleasure

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    Ok so hereís a link to my YouTube channel as Iíve uploaded a short video showing the issue

    I was confident it was a bad relay but Iíve fitted 2 new ones and itís not made a difference but I have now noticed that if when it fails to open I tap/knock the UCH relay then it will then work and carry on!

    This tells me itís a loose connection, or bad socket or solder joint but I removed the entire relay board from the machine, the joints for the sockets looked ok

    So just to be sure I have ordered 2 new sockets and I will solder them in just to be sure

    But visibly there isnít anything obvious I can see and a socket canít really be bad can it?

    Could it be the relay not receiving correct voltage to switch maybe?

    Any ideas

    Thanks
    Marc

    Mazak Hyundai QT15n chuck opening issue - YouTube

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    Whilst google searching relay issues I came across this topic that is not lathe/mazak related but is the exact issue I have so maybe it could be a relay power supply issue

    Here’s a copy and paste I done from google

    I have a question about relays used by an arduino. I know how to wire them and they work fine for the most of the time.

    But sometimes the relays doesn't correctly switch on or off. I can clearly see that the LED on the relay is in the correct state. I can also hear a faint "click" sound. But the relay is not really switching.

    Even funnier, then I physically hit/punch the relay with i.e. screwdriver it starts to switch to the desired state...

    Usually the problems start when the arduino is running for a few days.

    I have also tried completely different relays and have the same issue with them,


    And here’s what someone suggested and worked in this persons case


    I think the problem is with the way the relay is being powered. The voltage regulator on Arduino is not sufficient enough to provide the needed amperage for switching the relay properly and thus even if the led lights up the relay contacts are not touching with enough force.

    I would recommend you to use an external 5V source for powering the relay. Or if you are supplying your Arduino Nano with 5V then connect the relay's VCC to VIN of Arduino.

    Also, do keep in mind that if the relay is not supplied with proper power, it can lead to internal sparking of switching contacts which can damage the relay


    I realise my relays are not 5v they are 24v DC but same symptoms
    My relays are also sparking slightly as can be seen in the video so maybe supply voltage is an issue?

    Thanks
    Marc

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    i'd quit with the off brand relay and do like toolcat said and steal a relay from the tail stock or something
    what catches my eye is the relay you are hitting never reacts first its the one next to it
    i have no idea what that means but it seams very strange
    alot of times for safety reasons mfg will use a "stackup" circuit so two actions cant be attempted by mistake or error from something else
    so
    n.c. on one is defeating n.o. on the other
    or visa versa
    not sure what that means but its something i'll bet

  19. #16
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    Could well be,

    The left relay is labelled UCH and the right is labelled CH

    I guess that stands for UNCHUCK & CHUCK ???

    So as 1 opens it makes sense for the other to close,

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    yes..............

  21. #18
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    im on the right track but i have no idea how
    one of those relays is stopping the other from working
    try your dwell on the chuck line instead of unchuck
    it could be a prox that is hairline off instead if working just right

    maybe

    or not

    you dont have a proper latch on the "chuck" function somehow

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    Edited as this reply is not relevant anymore
    Last edited by M K; 11-06-2020 at 06:54 AM.

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    I’ve spent all day literally, 12 hours fault finding and trying to narrow down the issue and it is 100% to do with the interlocking of the chuck & unchuck relays that’s causing the issue

    The chuck is the only circuit where the relays are interlocked so they can’t try to both energise at the same time as mentioned before,

    I temporarily re wired the chuck so it could be controlled by the tailstock quill forward and reverse switch, which worked every time as those 2 relays are not interlocked, and on the flip side i powered the tailstock quill via the chuck relays and as suspected it had the same issue and wouldn’t open without tapping the chuck

    I re wired the spark killers incase they were not working properly causing the issues with the relays but it made no differences,

    I did a manual override on the control valve to eliminate them and the problem still persisted,

    I ran new cables from the control valve coils direct to the board to eliminate old wiring but that also made no difference,

    I also soldered jumper cables to the rear of the pcb to eliminate and bypass the sockets mounted on the pcb and that also made no difference

    I’m at a bit of a loss again now as I do t know what to try

    It’s been a long day with no progress

    These are the bad days of being a 1 man shop when time is money and your just wasting it away

    Thanks
    Marc


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