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Old problem and again I struggle...CAD, Cyl shaped part, alignment

d.evans
I have a part that basically looks like a Gauge Pin with a hole drilled thru it (90 perp to the longitudinal axis of the cyl).

I am having a very difficult time trying to get this thing aligned using CAD. I have tried 3 points on one of the flat ends, then 2 points along the length, and a single point on "top" about halfway between the thru hole and the nearest end.

Get Iterative Alignment error.

If I dont use iterative alignment, and instead use cir at one end, a cir at the other end, and the thru hole, I can't get the features to "stick" to the CAD.

I've got the part laying on its side inside a R&R AVP 11-20 V-shaped standoff, with the thru hold pointing up, and the length of the part inline with the machine's X-axis.

Running PCDMIS 2013MR1
Attached Files
  • I think this would be a good example of when to use the CAD=part button. Do your two circles and the thru hole and use CAD=part.
  • Make a plane on 1 end of your gauge pin, now measure 2 circles 1 near the plane, the other at the far end. Create a LINE then measure a circle in the board hole. Rotate the hole about the line. HTH
    Your alignment should be (not in proper order):
    X origin = plane
    Level = line
    Y & Z origin = line
    rotate about x = line to circle
  • Datums. Align to the datums.

    OR, measure the OD as a cylinder.
    Measure that ID as a cylinder
    Measure a POINT on one end.

    Level to OD cylinder
    Rotate to ID cylinder
    Origin to OD Cylinder (2 axis) and point on end

    6 DOF locked.

    If that ID cylinder isn't square to a rotate axis, so what? You MUST KNOW what it's angle is to the cad axis, you do the LEVEL, ROTATE, ORIGIN, ORIGIN, ORIGIN, then ROTATE ABOUT using the angle it is off 'square', then do origin (axis) OFFSETS if needed.

    Looks pretty simple to me really.
  • With ID cylinder 'square' to an axis 

    P001       =FEAT/CYLINDER,RECT,OUT,LEAST_SQR
            THEO/0,0,-71.235,0,0,1,26.587,117.686
            ACTL/934.703,213.551,-770.086,0.0536924,0.998557,-0.0010399,26.587,117.686
            MEAS/CYLINDER,6
            HIT/BASIC,NORMAL,-2.369,13.07,-130.078,-0.1783672,0.983964,0,918.483,155.498,-767.711,USE THEO = YES
            HIT/BASIC,NORMAL,-13.29,0.5,-129.318,-0.999294,0.0375702,0,931.029,155.596,-756.738,USE THEO = YES
            HIT/BASIC,NORMAL,-4.631,-12.449,-128.503,-0.3486576,-0.9372502,0,944.04,155.703,-765.342,USE THEO = YES
            HIT/BASIC,NORMAL,-4.741,-12.431,-12.392,-0.3563372,-0.9343574,0,950.255,271.647,-765.353,USE THEO = YES
            HIT/BASIC,NORMAL,-13.271,0.654,-13.224,-0.9987876,0.049228,0,937.109,271.53,-756.878,USE THEO = YES
            HIT/BASIC,NORMAL,-2.407,13.084,-13.976,-0.1809328,0.9834955,0,924.702,271.433,-767.794,USE THEO = YES
            ENDMEAS/
P002       =FEAT/CYLINDER,RECT,IN,LEAST_SQR
            THEO/-8.731,0.245,-65.274,0.9999983,0,-0.0018668,11.113,3.05
            ACTL/934.741,219.528,-761.362,0.0041265,-0.0031328,-0.9999866,11.113,3.05
            MEAS/CYLINDER,8
            HIT/BASIC,NORMAL,-10.223,-5.292,-64.695,-0.0001931,0.9946388,-0.1034099,940.296,219.81,-759.847,USE THEO = YES
            HIT/BASIC,NORMAL,-10.239,-0.197,-59.746,-0.0018609,0.0798187,-0.9968077,935.474,225.026,-759.858,USE THEO = YES
            HIT/BASIC,NORMAL,-10.256,5.813,-65.139,-0.0000443,-0.999719,-0.0237034,929.183,219.963,-759.861,USE THEO = YES
            HIT/BASIC,NORMAL,-10.244,1.551,-70.659,0.0018143,-0.2355648,0.971857,933.142,214.223,-759.849,USE THEO = YES
            HIT/BASIC,NORMAL,-7.223,1.568,-70.665,0.001813,-0.2383993,0.9711655,933.138,214.214,-762.87,USE THEO = YES
            HIT/BASIC,NORMAL,-7.234,5.741,-66.168,0.0002989,-0.9870963,0.1601276,929.212,218.928,-762.881,USE THEO = YES
            HIT/BASIC,NORMAL,-7.219,-0.218,-59.747,-0.0018603,0.0834823,-0.9965075,935.507,225.02,-762.878,USE THEO = YES
            HIT/BASIC,NORMAL,-7.205,-5.29,-64.695,-0.000195,0.9945309,-0.1044426,940.306,219.806,-762.865,USE THEO = YES
            ENDMEAS/
P003       =FEAT/POINT,RECT
            THEO/-7.84,1.811,0,-0.0012686,0.0536875,0.998557
            ACTL/936.687,284.79,-762.328,0,1,0
            MEAS/POINT,1
            HIT/BASIC,NORMAL,-7.84,1.811,0,-0.0012686,0.0536875,0.998557,936.687,284.79,-762.328,USE THEO = YES
            ENDMEAS/
ALIGN01    =ALIGNMENT/START,RECALL:STARTUP, LIST= YES
            ALIGNMENT/LEVEL,ZPLUS,P001
            ALIGNMENT/ROTATE,XPLUS,TO,P002,ABOUT,ZPLUS
            ALIGNMENT/TRANS,XAXIS,P001
            ALIGNMENT/TRANS,YAXIS,P001
            ALIGNMENT/TRANS,ZAXIS,P003
            ALIGNMENT/TRANS_OFFSET,XAXIS,0
            ALIGNMENT/TRANS_OFFSET,YAXIS,0
            ALIGNMENT/TRANS_OFFSET,ZAXIS,0
            ALIGNMENT/END



    With ID Cylinder 12.7 degrees to an axis 
    P001       =FEAT/CYLINDER,RECT,OUT,LEAST_SQR
            THEO/0,0,-71.235,0,0,1,26.587,117.686
            ACTL/934.703,213.551,-770.086,0.0536924,0.998557,-0.0010399,26.587,117.686
            MEAS/CYLINDER,6
            HIT/BASIC,NORMAL,0.562,13.271,-130.078,0.0423174,0.9991042,0,918.483,155.498,-767.711,USE THEO = YES
            HIT/BASIC,NORMAL,-12.855,3.409,-129.318,-0.9665861,0.256342,0,931.029,155.596,-756.738,USE THEO = YES
            HIT/BASIC,NORMAL,-7.255,-11.126,-128.503,-0.5461784,-0.8376689,0,944.04,155.703,-765.342,USE THEO = YES
            HIT/BASIC,NORMAL,-7.358,-11.084,-12.392,-0.5530341,-0.8331586,0,950.255,271.647,-765.353,USE THEO = YES
            HIT/BASIC,NORMAL,-12.803,3.556,-13.224,-0.9635292,0.2676033,0,937.109,271.53,-756.878,USE THEO = YES
            HIT/BASIC,NORMAL,0.528,13.293,-13.976,0.0397116,0.9992112,0,924.702,271.433,-767.794,USE THEO = YES
            ENDMEAS/
P002       =FEAT/CYLINDER,RECT,IN,LEAST_SQR
            THEO/-8.463,2.159,-65.274,0.9755328,-0.2198458,-0.0018668,11.113,3.05
            ACTL/934.741,219.528,-761.362,0.0041265,-0.0031328,-0.9999866,11.113,3.05
            MEAS/CYLINDER,8
            HIT/BASIC,NORMAL,-11.137,-2.915,-64.695,0.2184792,0.970347,-0.1034099,940.296,219.81,-759.847,USE THEO = YES
            HIT/BASIC,NORMAL,-10.032,2.059,-59.746,0.0157325,0.078275,-0.9968077,935.474,225.026,-759.858,USE THEO = YES
            HIT/BASIC,NORMAL,-8.727,7.925,-65.139,-0.2198276,-0.9752507,-0.0237034,929.183,219.963,-759.861,USE THEO = YES
            HIT/BASIC,NORMAL,-9.652,3.765,-70.659,-0.0500181,-0.2302005,0.971857,933.142,214.223,-759.849,USE THEO = YES
            HIT/BASIC,NORMAL,-6.702,3.118,-70.665,-0.0506425,-0.2329653,0.9711655,933.138,214.214,-762.87,USE THEO = YES
            HIT/BASIC,NORMAL,-5.795,7.191,-66.168,-0.2167177,-0.9630122,0.1601276,929.212,218.928,-762.881,USE THEO = YES
            HIT/BASIC,NORMAL,-7.09,1.374,-59.747,0.0165385,0.0818489,-0.9965075,935.507,225.02,-762.878,USE THEO = YES
            HIT/BASIC,NORMAL,-8.192,-3.576,-64.695,0.2184536,0.9702421,-0.1044426,940.306,219.806,-762.865,USE THEO = YES
            ENDMEAS/
P003       =FEAT/POINT,RECT
            THEO/-7.25,3.49,0,0.0105654,0.0526529,0.998557
            ACTL/936.687,284.79,-762.328,0,1,0
            MEAS/POINT,1
            HIT/BASIC,NORMAL,-7.25,3.49,0,0.0105654,0.0526529,0.998557,936.687,284.79,-762.328,USE THEO = YES
            ENDMEAS/
ALIGN01    =ALIGNMENT/START,RECALL:STARTUP, LIST= YES
            ALIGNMENT/LEVEL,ZPLUS,P001
            ALIGNMENT/ROTATE,XPLUS,TO,P002,ABOUT,ZPLUS
            ALIGNMENT/TRANS,XAXIS,P001
            ALIGNMENT/TRANS,YAXIS,P001
            ALIGNMENT/TRANS,ZAXIS,P003
            ALIGNMENT/ROTATE_OFFSET,12.7,ABOUT,ZPLUS
            ALIGNMENT/TRANS_OFFSET,XAXIS,0
            ALIGNMENT/TRANS_OFFSET,YAXIS,0
            ALIGNMENT/TRANS_OFFSET,ZAXIS,0
            ALIGNMENT/END


    The angle of the ID cylinder to the OD cylinder along the length of the OD cylinder makes no difference, it's ONLY the angle to the axis PERP to the OD cylinder and ID cylinder that matters.
  • Datums. Align to the datums.

    OR, measure the OD as a cylinder.
    Measure that ID as a cylinder
    Measure a POINT on one end.

    Level to OD cylinder
    Rotate to ID cylinder
    Origin to OD Cylinder (2 axis) and point on end

    6 DOF locked.

    If that ID cylinder isn't square to a rotate axis, so what? You MUST KNOW what it's angle is to the cad axis, you do the LEVEL, ROTATE, ORIGIN, ORIGIN, ORIGIN, then ROTATE ABOUT using the angle it is off 'square', then do origin (axis) OFFSETS if needed.

    Looks pretty simple to me really.


    Everything is when you know how though isn't it?



    A couple of things - it doesn't look like the CAD co-ord system is as you've got it on the CMM


    Use Opeation>Graphics Display Window>Transform to get it to match how you've got it on the machine

    Now..

    Change workplane to xplus or minus
    Create the OD cyl on the CAD (Level in xplus or minus depending on the vector of the cylinder, and origin in Y and Z)
    Create the ID cylinder on the CAD, and rotate to ZPLUS about X
    Create a point on either end face (depending on the drawing datums) and origin in X (unless the drawing has the datum coming from the through hole, in which case Origin X in the ID cyl

    Now run the program and measure the features in the right order and direction etc.
  • Thanks folks. I will try some of these. I'll let you know how it comes out. In the old 3.7MR3, I used to have a little trouble with these type parts, but it has been so long since I used it, I've lost my mind on it, apparently.

    BTW, I've never tried to change the CAD axis to match how I have it on the machine before. I'll muddle my way thru it, and see how it goes.
  • I transformed first, but it took a few tries. That dialog box isn't very self-explanatory.
    Then, I did the OD cyl, ID cyl, point at one end.
    Then aligned w/o using iterative. Bingo.

    Thanks. Just needed you fine folks to clear my head.Slight smile
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