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Hexalobe bone screw iterative rotation tolerance

lovethepirk
We run profile of a surface on a hexalobe for several bone screws. Our quantity of checks per order just doubled. When we do an iterative alignment to cycle thru how well the screw hexalobe is oriented we commonly get an iterative error on the rotation. I do not program the part, but have discretion to make changes within reason. All the rotational tolerances are set to .006mm for the iterative tolerance, which is crazy too low in my opinion.

Even if the error pops up at .02mm on the rotation, every operator enters thru the error and the program works fine. Would it seem reasonable to set this at a max of around .0254mm or 1 thou? I don't see how a 1 thou error couldn't be allowed for the program to proceed without an error msg popping up taking a 3min program and turning it into a potential 10 min program if the operator is doing other things.

The vectors on the rotation of the hexalobe rotation are not clean either, they are far from a pure X plane direction, they have plenty of Y in them as well.
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  • If the iterative alignment is only used to find the part and you don't want to constantly get the alignment error message I would use a different method. Having the operators click through that message doesn't seem a very good process to be working to ;(

    Using the same points/features I would use a 3D best fit alignment and iterate this alignment using IF/GOTO statements based on the measured values or tolerance value for the XYZ of each of the features used in the alignment.

    Using this method you can set the number of iterations that you want to perform and the tolerance band for each features measured values.

    You can also control the number of iterations to ensure when the part has been found at a good enough accuracy to ensure the next features are found for the next proper alignment.

    It's probably basically the same thing BUT you have more control over what is happening and don't get the error message.

    You could also prove with the data gathered from the initial features how many iterations it takes to ensure the alignment is good enough for what you need it to do.
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  • If the iterative alignment is only used to find the part and you don't want to constantly get the alignment error message I would use a different method. Having the operators click through that message doesn't seem a very good process to be working to ;(

    Using the same points/features I would use a 3D best fit alignment and iterate this alignment using IF/GOTO statements based on the measured values or tolerance value for the XYZ of each of the features used in the alignment.

    Using this method you can set the number of iterations that you want to perform and the tolerance band for each features measured values.

    You can also control the number of iterations to ensure when the part has been found at a good enough accuracy to ensure the next features are found for the next proper alignment.

    It's probably basically the same thing BUT you have more control over what is happening and don't get the error message.

    You could also prove with the data gathered from the initial features how many iterations it takes to ensure the alignment is good enough for what you need it to do.
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