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  1. #1
    Join Date
    Apr 2013
    Posts
    15

    BMC 2416 ATC arm

    I finally got the arm on my 2416 adjusted right so it changes tools. The problem is it seems to actuate from 0 to 60 VERY hard and very fast and slams against the tool holders. When it does this, the arm eventually slips on the end of the shaft which requires me to re-adjust/reset it. My air pressure for the machine is set at 90-95 psi and the all the oil levels seem OK. I cant find any flow controls on the actuator or valve assembly. How do I fix this?:drowning:

  2. #2
    Join Date
    Jun 2008
    Posts
    1104
    Sounds like your damper piston for the top rack has jammed. Probably due to a broken spring. You'll need to drop the changer off and pop the back plate to see the two racks. Once you're in there, just make sure not to alter the relative position of the racks to the dampers.

  3. #3
    Join Date
    Apr 2013
    Posts
    15
    Quote Originally Posted by bloke View Post
    Sounds like your damper piston for the top rack has jammed. Probably due to a broken spring. You'll need to drop the changer off and pop the back plate to see the two racks. Once you're in there, just make sure not to alter the relative position of the racks to the dampers.
    Is there a way to check this without pulling the whole ATC assembly. Is it similar to the dampening piston for the other rack that's accessible from the front of machine? I checked that one and the spring is good. I'm pretty sure you're right on because it only slams going from 0 to 60, it doesn't slam when it goes from 60 to 0. Also, I drained the oil and it seemed like there was an excessive amount in it, how much is it actually supposed to contain?

  4. #4
    Join Date
    Jun 2008
    Posts
    1104
    You can't overfill it really. To check the spring, you'll need to drop it off though.
    It's not as bad a job as you'd think.
    Remove the sheet metal cover.
    Close the air off and drain the receiver.
    Mark and disconnect the pipes to the back two cylinders and the top cylinder. Mark and remove the small pipes to the pilot valves.
    Remove the bottom 180 roller switch.
    Mark and disconnect the two proximity switches (leave the switches in place as you don't need to remove them).
    Remove the arm.
    You are now four cap head screws away from having it on your bench. With the weight supported, loosen the last four screws and slide it off the dowels.

    When you undo the back plate, you'll see the two rack blocks and the jammed piston. there's nothing in there that's gonna jump out so don't worry. Take off the plate that supports the racks and keep the slider discs in the right order. Keep the little standoffs in the same order as it'll minimise any setting up later.
    The 60 deg rack has a stop that limits the travel so that when it retracts back to 0 deg, the back of the arm won't interfere with the head. If you don't adjust the total travel, it'll always be right. Measure how far the piston on the cylinder is screwed into the rack block and always return to this measurement. If you unscrew the stop on the damper end, always return it to the same dimension. Likewise, mark the shaft at 0 deg and make sure the rack block returns to the same teeth on the shaft on rebuild.
    Unscrew the piston from the rack block and remove the block.
    Once the damper is repaired, reverse the above procedure.
    Check once the toolchanger is back on that there is no interference between the head of the machine and the back of the arm.

    There were two types of damper - ones with a line of holes drilled down them and ones with an angled flat ground down it. If you need to modify it slightly (maybe to remove score marks), you can use thicker oil to compensate or maybe mix compatible oils to reach a grade that works at the 60 deg position. Altering the 180 deg damper to suit is easy with the toolchanger mounted on the machine.

  5. #5
    Join Date
    Apr 2013
    Posts
    15
    Thank you VERY much for the advice, I'm planning on taking the ATC apart Sunday. I'm just writing to ask If you mind me asking you a few questions now and then. I've been a working as a maintenance machinist in a large hose production facility for the past 17 years so I'm very familiar with pneumatic,hydraulics, and general machine repair/millwright type work but this is my first Hurco. Do you have an email address you wouldn't mind sharing with me. Just FYI the machine is a 1999 BMC 2416 with Ultimax 4 split screen control.

  6. #6
    Join Date
    Jun 2008
    Posts
    1104
    I'll be at a wedding until sunday lunchtime so the replies may be a bit spaced out. Once you get it off, you'll see exactly what you need to do. The most important thing is to make sure you line it back up again. Having said that, if you do manage to get it out of sync, remember that the one, fixed area of it all is when the shaft is half way between racks and centred on the guide key.
    If you get it to this point, just move the top rack to 60 deg and hold it there, hard against the damper and then push the shaft back up into mesh. Then you can rotate the shaft back to 0 deg.
    These are quite a nice, satisfying little number to do.

    Send me a PM for my mail.

  7. #7
    Join Date
    Apr 2013
    Posts
    15
    I tried but you box is full, you can email me your contact info. [email protected]

  8. #8
    Join Date
    Jun 2008
    Posts
    1104
    Sorry, fella! I didn't realise the old inbox was full!

  9. #9
    Join Date
    Sep 2021
    Posts
    3

    Re: BMC 2416 ATC arm

    Quote Originally Posted by rb07565 View Post
    Thank you VERY much for the advice, I'm planning on taking the ATC apart Sunday. I'm just writing to ask If you mind me asking you a few questions now and then. I've been a working as a maintenance machinist in a large hose production facility for the past 17 years so I'm very familiar with pneumatic,hydraulics, and general machine repair/millwright type work but this is my first Hurco. Do you have an email address you wouldn't mind sharing with me. Just FYI the machine is a 1999 BMC 2416 with Ultimax 4 split screen control.
    Bonjour, Auriez vous des schémas de la configuration du changeur ATC. Moi je cherche les références de joints des vérins pneumatiques du bras ATC car je doit les changer.

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