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AVHC (I know)

Discussion in 'CNC Cutting' started by Chalres Wheeler, Jan 26, 2017.

  1. Chalres Wheeler

    Chalres Wheeler New Member

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    So I have extensive experience using Plasmacam tables and have never had as many issues with height control as I have with this TMX table we recently received. I fully understand all the concepts involved with the AVHC. The table is properly grounded, good continuity, etc.

    So far, I have yet to get this thing to make a cut where it either 1. Dives too far into the metal during a cut and the breakaway for the Z comes loose; 2. Makes one cut fine then dives into the metal for the second cut; 3. Starts the torch too far away from the metal; 4. Tells me to clear the slag and won't start when there is no slag on the torch.

    I have read the VMD user manual extensively; the concepts are explained very well but there are virtually no instructions on how to set up any of it. I am using the recommended height settings in the Hypertherm manual.

    What exactly is the proper initial set-up for the Torchmate AVHC using the TM VMD and Accumove 3 to actually make and repeat a cut?

    Much of your documentation is related to older versions and is so scattered I don't know how you expect anyone to find it. Please don't refer me to one of the YouTube videos, I've already watched them all more than once.

    I appreciate the assistance.
     
  2. LECS-Chad

    LECS-Chad Moderator Staff Member

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    1. I would want to know which version of the software you are running. LOG ON as ADMIN (password 1234) Go o machine settings and press VERSION INFO.

    2. Next run a LINE SPEED TEST in MANUAL mode with these settings. PH .16 CH .8 and enter the pierce height for the amperage and material you are cutting.

    3. Determine the proper speed for the amperage/thickness of material. Once that is determined create a small part and run at that speed.

    4. Once the part is cut out. Set to AUTO and set SAMPLE VOLTAGE ON. This will then read the input voltage coming from the plasma and enter into the SET VOLTAGE which will then profile the material.

    If you are not getting a reading in the HEIGHT CONTROL STATUS / ARC VOLTAGE box then we wouldn need to start talking wiring/polarity connections from the HT to your VFC box. It is reads 200 or 0 then either polarity is wrong or not wired at all.

    I provided a "quick start" guide that you should follow when setting up you machine to cut. Hence you have a TMX the DATUM will take care of the first couple of steps.

    Also I would recommend calling into the tech line if requires a follow up. 8665711066 ext 4

    Chad
     

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  3. Chalres Wheeler

    Chalres Wheeler New Member

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    LECS-Chad, I appreciate the response. I am using VMD version 1.0.20. I have managed to get it to work by enabling sample voltage almost all the time. Every so often the torch will still retract all the way on the Z-axis for no reason (even in the middle of a cut) and that messes up cuts but I am able to work through it.

    One issue I still have is anytime I cut a hole, for example in your test cut with the circle in the center of the square; the torch dives at the end of the circle when the metal falls out and knocks the Z-axis breakaway loose stopping the program. I have adjusted the debounce time and tried adjusting lead-ins, lead-outs, cutting speeds and a few other things to get it to stop but no matter what I do the torch dives about 70% of the time at the end of the cut. Would you think this is an issue with kerf settings?
     
  4. LECS-Chad

    LECS-Chad Moderator Staff Member

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    1. The Z retracting is a breakaway error. So the head will hit the plate or dross and trip but then clear and give no indication of an error. Bring that you are talking DEBOUNCE time I would set both your breakaways to have a debounce of 200. this will give the breakaway 200 ms before signaling an error.
    AUTO and SAMPLE VOLTAGE ON should always be used as then the voltage will be constantly monitored and adjusted by the system.

    2. If the head is following the drops then either a OVERLAP is being generated or a lead out and the head is following the voltage so crashing into the material. You can test this by putting the AVHC into manual. This will keep the head in the measured distance without adjusting. So that would be the only thing that causes the head following the drops.
     
  5. James Coakley

    James Coakley New Member

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    I'm running the same table at my job amd have been for a while, we have the settings correct and the height controll status seems to be reading and profiling the material but it keeps running into the sheet at high points. I beleive the VMD is 4.0.42. I havr tried everything any help you have would be appriciated.
     
  6. LECS-Chad

    LECS-Chad Moderator Staff Member

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    1. Are you using SAMPLE VOLTAGE?
    2. What is the voltage coming in ranging from? "High Points"?
    3. What material/amperage
     
  7. nwaPLASMA

    nwaPLASMA Well-Known Member

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    Something to also consider, OP said they were using the recommended height settings stated in the hypertherm manual. I run a Hypertherm 85 and my actual settings vary greatly from the book. Best practice is to feeler gauge your initial pierce and cut heights. While this doesn’t affect your cut after avhc takes control it does ensure your starting at the right height. I watch my lifter station at the start of a cut, my goal is to have as little z axis movement as possible during the transition from initial cut height to avhc control.

    I also have the end of hole problem when I’m cutting steel thinner than 18g or aluminum thinner than 1/8”. Its just blowing away the material before it finishes the cut so the torch is diving to compensate for the voltage change. Tricky to get that right.
     
  8. LECS-Chad

    LECS-Chad Moderator Staff Member

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    This is also dependent on which height control you are using. The Blue Screen runs off of an ACME thread so it isnt as "exact" to the measurement. I will use .20 for a PH and a .16 for a CH and like is a song with the ol Blue Screen.

    The AM controller is A LOT more precise on the lifter measurement. So the PH and CH will be closer to the right measurement.

    Your HOLE PROBLEM, is because your PIERCE DELAY is creating a larger hole because of the thinner material. Reduce your pierce delay and the pierce hole will be a little smaller. Also verify you are not adding a OVERLAP/LEAD OUT.
     
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  9. James Coakley

    James Coakley New Member

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    I have sample voltage on and material ranges from .357 to .160, i keep the set voltage around 127
     
  10. James Coakley

    James Coakley New Member

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    the high points get me to a -10 to a minus -15 in the error box
     

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