Probe Lobing

[Hilton Roberts]

We have been tasked with providing some form analysis for some repair sleeves that go into parts we refurbish for the Army.

In order to get ready for that, I wanted to determine how well a TP2 and TP200 compared when probing a ring gage.

I knew from the design of the trigger mechanism of the TP2 that I would see lobing. What I did NOT expect was to see lobing on the TP200.

I thought the TP200 was a transducer and lobing was not an issue with the design. It seems that assumption is incorrect.

We measured 360 points both with the TP2 and TP200 and we are seeing essentially the same data. Diameter variation and point deviation correlation is out to the 5th decimal place.

We have turned the ring 90 degrees to see if the lobing is in the ring or the probe. Program is running as I type this. The ring I have is a Bowers 46mm bore setting ring. It is the best class ring I can get my hands on at this time.

Any of you have similar experiences?

Thanks!

Hilton

[Mike N.]

Hilton,

Another interesting test would be to rotate the ph10 to A0B90 to see if the lobing follows with that rotation. This is assuming you are at A0B0 with your readings.

regards
Mike

[Hilton Roberts]

I here that. Fortunately, this particular part can be measured with an A0/B0 tool. I don't want to get into the effects of probe droop and gravity at this point. Until I can figure out what is going on here, I want to keep it simple.

I need a formscan to accurately trace the form of the ring and I do not have access to one. Bowers seems to make a pretty good ring but I would feel better with a Bendix or Glastonbury ring in place of what I have. It has been so long since I purchased XXX or XXXX ring gages, the makers I refer to might not even be in business........

I am showing my years......

H

[Mike N.]

I here that. Fortunately, this particular part can be measured with an A0/B0 tool. I don't want to get into the effects of probe droop and gravity at this point. Until I can figure out what is going on here, I want to keep it simple.

I need a formscan to accurately trace the form of the ring and I do not have access to one. Bowers seems to make a pretty good ring but I would feel better with a Bendix or Glastonbury ring in place of what I have. It has been so long since I purchased XXX or XXXX ring gages, the makers I refer to might not even be in business........

I am showing my years......

H

NO you missed the point ... NOT rotating A ....just B axis of ph10 leaving A at 0

[Wes Cisco]

I ran a similar test

Hilton,
I acquired a tp200 in Feb. of this year. I set up identical 1.5 x 60 mm tips on both the tp200 and the tp20 and ran a little program to check an O.G.I. XX ring. I took 25 hits in the ring at 3 levels. All as auto circles.

I ran the program 6 times for each tip on 3 consecutive days. My results were consistant to within .0003 for all runs. I was only using 4 decimal places and all inch measurments.

The tp20 reported size .0005-.0007" different from that stamped on the ring. And reported a roundness of .0019"

The tp200 reported size exact to .0001" different from that stamped on the ring.
And reported a roundenss of .0005".

I was only trying to get an idea of how much differnce in accuracy there was between the two probes for both size and roundness and this gave me the information I was after. I do not know if this information will help you, but thought it might.

[Hilton Roberts]

Mike,

I did not read your post closely enough. The lobing ( on the TP2) has stayed the same rotating the ring and leaving the probe alone. The actual pattern has smoothed. I am not sure why except that by virtue of taking a lot of points, a little temperature has been introduced. The apparent lobing on the TP200 is not determinable now ( izzat really a word? )

H