Base Alignment for Tube

[[Ni...]]

Hello,

I need help creating a base alignment for a long plastic tube. I've measured true position on top diameters to middle long diameters to verify if the part is straight but I keep getting different numbers based on different alignments.

In this setup, the part is a bit tilted up but it does not compensate for it during calculations in Calypso. It shows the part as straight.
Is there a way to make this also skew to its tilt? or should I just find a way to level out the part from left to right?

Thank You,
Nixon

plastic tube.png

[[Cl...]]

Align it better. Use an indicator to get it within a couple thousandths.
I'd use two circles, one ate either end of the part and construct a 3d
line. Use that for you X+ Spatial.

[[Ni...]]

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Sorry I am still new to Calypso. My X+ Spatial would be the first box where it says Spatial Rotation? and choose X+?

What about for the remaining boxes? Planar Rotation and the origins?

1.PNG

[[Cl...]]

Yes. Don't those fixture kits like the one in your picture come with adjustable screws? Something like that at the end of the part, so you can even out the height. X origin would be the largest horizontal plane on the X- end. Z&Y origins would be the 3d line. You don't need planar unless there is some sort of key way clocking feature?

[[Ni...]]

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This is all I had to work with. I was just hoping there was a way to scan a line on top of that long diameter and be able to skew my alignment to it.
But I was able to get both sides as even as possible with some JBlocks and washers.
I will try your suggestion with the alignment. I will be right back.
Thank You

[[Da...]]

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There is no need for indicator this part within a couple of thousandths. The CMM will align to the part.

[[Jo...]]

in the absence of having two mag vee, I would use four standoffs. Two at each end and the part would nest evenly and level. Lose all that crap on the left side of fixture.

[[Ni...]]

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I am not sure. But I do need to make sure this little opening is facing up for every measurement to keep things organized and consistent. Should I have a planar?

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I tried making a new program with a new alignment by probing the part but it never tilted the model up. My true positions would be taken from the nominal instead of the actual. Or I am sure it was doing the difference between the nominal and actual. But it would change every time I changed the nominal's tilt which was 0 but actual showed 1.1

[[Ni...]]

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Our CMM doesn't reach that low. It needs to be at least 3 inches above the table and we don't have any standoffs that high or any at all. This was the best we could do to hold the part and have it raised up.

[[Da...]]

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Do you have a Print? What are the Datum's?

[[Ni...]]

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tube true positions.png

[[Da...]]

What version of Calypso?

[[Ni...]]

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2019

[[Da...]]

So when you extract Datum -A- and -B- it doesn't change your model after setting it as your base alignment?

[[Da...]]

I haven't started using 2019 it is to new I am still using 6.4 service pack 28
Is this a problem with 2019?

Are you using a 3D line?

[[SH...]]

I think you can use P6 alignment for tubes......

Screenshot_2020-04-29-11-44-50-39.png

[[Er...]]

I would not use P6 alignment. That part is more of a straight pipe than a "tube". And there should not be any trouble using the standard method.

P6 is useful when you use the tube feature/characteristic. (licensed option)

If your base algiment don't "level out", you might need to tick the "set base alignment to zero".

[[Cl...]]

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Getting the part trammed in will prevent possible probe shanking, depending on were some features are.

[[Öz...]]

Do you try loop in alignment. It might work.

[[Ni...]]

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I didn't use A and B as my base alignment. But when I would scan A and B, the model would be straight even though it was slightly tilted up on the right side. The nominals would say 0 for A1 and A2 but the actuals would say 1.
When doing true position I would get a number but if I changed the nominals, that true position number would change.

Which is why I asked for help with the alignment. I have also now leveled the part as much as I can.
I will now try the new alignment using a 3d line like it was recommended up.

[[Ni...]]

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I wasn't. I am going to try that now.

[[Ni...]]

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I haven't tried looping yet. I first am trying to figure out what the best way to make an alignment would be. I was told using a 3D line from end to end would go on spatial rotation, Y and Z origin. Flat surface on the right side would be X origin.
I am waiting to try that now and then possibly add the looping.

[[Ia...]]

If your fixture is repeatable, you could always make your base alignment to the fixture.

[[Da...]]

If you use the fixture you will add a unknown variable could be almost nothing could be a lot just a heads up.

[[Ni...]]

Thank You everyone that has been helping me.

I believe I have come up with an alignment following the recommendations from this group. I just want to show it to you all and see if this is correct. I measured 1 part two times and the measurements were really close to each other. One True Position varied by .001''

I did a 180° Circle scan on each side of the longer middle Diameter( Datum B). Then a made a 3D Line using the Recall option from those two circles.
Then I used Datum A as plane 1.
When measuring true positions I measured Datum B again as a cylinder through the whole part at 3 different spots.

Please let me know if this all is accurate or if something needs to be changed.