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Gage R&R Type 2 on automated test equipment - Should it not be Type III?

Discussion in 'Gage R&R and MSA - Measurement Systems Analysis' started by Gazlar, Jun 12, 2017.

  1. Gazlar

    Gazlar New Member

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    Hi,

    New to the forum and fairly new to MSA studies.

    One thing that comes up at my works which causes arguments time and time again is the need for a Gage R&R Type II on automated test equipment.

    Our procedure for an MSA, which I guess is the same for others, is to do a Type 1 first.
    If you know an operator can influence the test result, then you do a Type II, otherwise you do a Type III.

    Now, the test equipment in question is an automated In-circuit tester which performs various Resistance, Capacitance tests on components on a PCB. To load the tester you have to place the PCB onto a bed of nails/pins. This can only be placed in 1 way due to location pins. You then pull the lid down and the testing starts. The PCB is affectively shielded from the outside world as its inside a box.

    I personally feel that because the test equipment is automating the test, a Type II is not required.

    I also guess the real question is what is meant by operator influence? does it mean something the operator can do during the test/measurement? or something they can do before the test/measurement?

    For the test equipment in question, yes influence before could be done by an operator by rubbing there hands together, then touching a component to warm it up and place it inside the tester. That could change the results.
    But in regards to influence during the test/measurement, once its inside and the test starts it is impossible to then try and influence the test/measurement.
     
  2. Miner

    Miner Moderator Staff Member

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    The deciding factor should be whether the operator may, in a reasonably foreseeable manner, influence the results. By reasonable influence, I mean can the operator by the manner in which they prepare the part, load it into the test fixture and initiate the test have some influence on the results? If so, run the Type 2 test. I have seen "fully automated" tests that were still sensitive to how the operator loaded the part into the fixture. However, if the operator must do something no reasonable operator would ever do, run the type 3 study.

    Another option when you have multiple nests/stations, is to replace the operator with the nest/station. Reproducibility becomes nest to nest variation instead of operator to operator variation.
     
    Bev D likes this.
  3. Gazlar

    Gazlar New Member

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    Thanks for the reply. I suppose the only thing I could think of that, even under strict controlled conditions, the operator could unintentionally affect things by prepping and loading is where they grip the PCB because they will be applying heat to that area.

    Just another point to add to the question. What if the test equipment was conveyer fed? I only ask this because we have a production line where an operator loads the product onto a pallet and this travels to the tester and is loaded automatically. Now during its travel the product can wobble a little and because of this it is deemed that a type II must be done because the operator may place it on the pallet incorrectly. My personal view is that actually you have a process issue and that the pallet needs redesigning to not allow this. The operator could place it on the pallet perfectly but if it wobbles during the travel and causes it to fail then this could be looked as operator influence, when actually it isn't.
     
  4. Miner

    Miner Moderator Staff Member

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    Does this wobbling occur between the test/retest part of Repeatability? If so, it is being captured there.
     
    Last edited: Jun 12, 2017
  5. Gazlar

    Gazlar New Member

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    I would imagine so because once the test is complete it will be eject and the pallet carry's on down the line. The pallet will then have to hand lifted back up the line for it go back in for a repeat test.
     

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