PC-DMIS Programming Help

[blewis]

I need help finding an internal diameter using PC-DMIS 4.1

I need to find an internal diameter at the top of a radius (intersection of a cone and radius). When I measure the cone and the radius in 8 places around the origin (8 partial circles), I am unable to construct a circle using the intersecting points of all 8 circles to the cone. I can, however, create pierce points for each circle and a line measured along the wall of the cone, but still can not create a circle out of these constructed pierce points.

We used pin gauges initially to gather this data, but our customer does not care for this technique and has requested we use our CMM to measure. I have attached a copy of the program that I am trying to use. If anyone has any ideas how I can measure this internal diameter at the point that the radius intersects the cone using PC-DMIS, I would appreciate it.

Thanks!

Brian

[cmmguy]

A drawing is much more useful than your program....

[blewis]

I'm sorry.....have posted before on other sites, but not this sort of question.

I have attached a side view and a section view showing the part that I am working with. The diameter that I am trying to measure is not called out on the print, but can be seen easily on the section AA drawing. It is located 8mm deep and is actually the intersection of the 2mm radius and the 8mm deep cylinder. This is a cast part, so the cylinder has a 1.5 degree draft.

Thank you again for your help.

Brian

[Boomer]

How are you inspecting the 8mm depth. If you do this with PC-dmis, you could construct an offset plane by that distance, measure a cone on the bore, and construct a circle at the intersection of the cone and plane. If you measure the 8mm distance manually you could have a keyin value for the 8mm distance and offset the plane from the keyin distance.

[blewis]

I don't feel that there is enough of a surface at the top of the radius to measure this depth with a cmm (still learning though.....there may be).

I had hoped that I could measure the radius in 8 places around the bore and the bore itself (as a cone), then construct a circle out of the 8 intercection points between the radius and the bore. I could then use location feature to find the constructed diameter as well as the depth at the same time. This did not work. I could not construct an intersecting point between the radius (circle) and the bore. I found that I could measure the radius and a line down the length of the bore and construct a pierce point between the two, but after completing this task in 8 places around the bore, I was not able to construct a circle from the 8 pierce points.

Brian

[Boomer]

construct plane

if you have checked the radius in 8 places, try consrutucting a plane from all the radii, then construct an offset plane the average of the 8 radii. measure a cone inside the diameter and then construct a circle at the intersection of the cone and the offset plane. Not sure if this will work, but you might want to give it a try.

[#2#]

I found that I could measure the radius and a line down the length of the bore and construct a pierce point between the two, but after completing this task in 8 places around the bore, I was not able to construct a circle from the 8 pierce points.

Brian

That is what I was going to suggest. I don't know why you couldn't construct the circle. Workplane maybe?

[blewis]

Boomer,

Not sure how to construct an offset plane from the average of the measured radii? Please explain how to do this.

Goodluck,

I was in the Z+ working plane when I tried to construct a circle through all of the pierce points. Z+ working plane put me in the plane looking down upon all of the points (as a circle rather than viewing them from the side as a line). Maybe one of the pierce points was higher than all the others making it difficult for PC-DMIS to construct a circle out of them.

Thanks for everyone's help!

Brian

[blewis]

I went back and tried to construct a plane out of the 8 circles measured around the radius (using them only and not any of the pierce points) and could not even do that. I keep getting a math error from PC-DMIS.

[cmmguy]

I went back and tried to construct a plane out of the 8 circles measured around the radius (using them only and not any of the pierce points) and could not even do that. I keep getting a math error from PC-DMIS.

Those points may look like 2d points to PCDMIS. Can you convert them to 3D first before trying to construct them into a plane?

[cmmguy]

I need help finding an internal diameter using PC-DMIS 4.1

I need to find an internal diameter at the top of a radius (intersection of a cone and radius). When I measure the cone and the radius in 8 places around the origin (8 partial circles), I am unable to construct a circle using the intersecting points of all 8 circles to the cone. I can, however, create pierce points for each circle and a line measured along the wall of the cone, but still can not create a circle out of these constructed pierce points.

We used pin gauges initially to gather this data, but our customer does not care for this technique and has requested we use our CMM to measure. I have attached a copy of the program that I am trying to use. If anyone has any ideas how I can measure this internal diameter at the point that the radius intersects the cone using PC-DMIS, I would appreciate it.

Thanks!

Brian

Can you find the individual points one by one using a line on the cone and radial slice on the radius?
[IMG]http://www.*******.com/misc/pcdmis/lineradius.JPG[/IMG]

Find each point and then do the diameter construction from these points?

[Tested]

BLEWIS,

If you can get a good reading for the depth of the cone i.e. bottom of the 2mm radius. All you need to do from there is measure the cone and construct a circle with the cone function using depth. You can assign the measured depth to this same dimension to have it create the circle you are looking for at the depth you measured.

[cmmguy]

BLEWIS,

If you can get a good reading for the depth of the cone i.e. bottom of the 2mm radius. All you need to do from there is measure the cone and construct a circle with the cone function using depth. You can assign the measured depth to this same dimension to have it create the circle you are looking for at the depth you measured.

This is a good idea. But since finding the location of the point from the Cone depth is not easy(why they dont use apex puzzles me), you could create a generic plane at the "constructed point" and then construct a circle from the generic plane and the cone.

[#2#]

How are you inspecting the 8mm depth. If you do this with PC-dmis, you could construct an offset plane by that distance, measure a cone on the bore, and construct a circle at the intersection of the cone and plane. If you measure the 8mm distance manually you could have a keyin value for the 8mm distance and offset the plane from the keyin distance.

This is a good idea. But since finding the location of the point from the Cone depth is not easy(why they dont use apex puzzles me), you could create a generic plane at the "constructed point" and then construct a circle from the generic plane and the cone.

I believe this was suggested in post #4.

[cmmguy]

Post 4 did not solve the "measurement" part of the problem. The OP still had no solution. I was trying to tie them together.... Sorry