BF vs. BFRE

[TRD_racing]

Hi All,

Can anyone tell me the best time to use BF or BFRE on circles. I am using points to make circles then cylinders. I am also usings mutiple wrist angles. Does this make a difference?

Thanks
Dale

[Mike N.]

I cant tell you about the Bf or BFRE but.....I wouldn't suggest using multiple tip angles if it is possible to probe greater than 180 of a circle with one probe position. Also if it is absolutely necessary to use several probe angles I would take individual surface points with sample hits to get proper vector compensation then construct the circles or cyl's. It has been stated before that you should have at minimum 3 levels for your cyl's to avoid any trouble with vectors repeating for the constructed cyl feature.

[george frick]

i was told in training to alwaysuse BFRE when constructing circles from points. i have used both and have seen no difference in the results though.

[Cumofo]

About time toyota got a real CMM program!!

[TRD_racing]

Thanks Mike,

I am doing most of that, I didn't use 3 levels because the thickness is small. I only have about .750" thickness so I took points on each side of surface.

thanks

[TRD_racing]

by the way, how do you get the picture to show up by you names?

[tking]

Click on the user/cp.
Click on edit avatar.
Select upload for your computer.
Note the size limitations.

Use www.resize2mail.com to reduce the size if you need. Let's see a good one!

TK

[cmmguy]

Stop drooling back to the question

It depends on your accuracy requirements. It would seem to me that since each different probe orientation would have a different effective tip radius (and therefore compensation), you would need to comp each touch and then only do a BF of all of the points.

If you do that then you would need fairly accurate vectors to the ACTUAL surface. This then means that you should pre-measure the bore and establish the actual centerline and then go through again for your final check.

This would apply also if you are using a star probe(which i despise).

ps.
Dale send me an email. I haven't talked with you since you left AMP
J

[tking]

Good pix, Dale.

TK

[TRD_racing]

Thanks for the help. I didn't realize my pictures were to big. Got it now.

Thanks

[Andrew Gardner]

I haven't had too much trouble measuring circles with different probe angles. I take individual points, right on the centerline, and at the exact Z levels. Then create the circle from the 4 points

[TRD_racing]

That’s what I do also Andrew. I been working on some testing this afternoon and I am leaning towards the block was bad. I just recalibrated, measured several other Ø's the same way as my program and all 3 are within .00002" of each other. The gremlins must be around this week. That is all I can figure.