B89 ball bar

[dave_voecks]

Looking for a B89 ball bar program for pcdmis 2012MR1

[Wes Cisco]

Looking for a B89 ball bar program for pcdmis 2012MR1

Just to clarify:

Are you looking for a program to measure a ball bar in the B89 positions and report for interim testing purposes?

or

Are you looking for a program to perform a B89 Certification of a CMM?



The former is not too hard to find, (start by scrolling down to see similar threads), or make yourself. The later is a big can of worms, to start is you ball bar certified/calibrated?

HTH

[dave_voecks]

A program to perform a B89 Certification of a CMM
yes I have a certified and calibrated ball bar

[Wes Cisco]

A program to perform a B89 Certification of a CMM
yes I have a certified and calibrated ball bar

I doubt you find anyone who will "give" you such a program.

If you do, they likely did not create it themselves and how will you know if it actually does everything needed to satisfy the standard or not?

The standards define what the program must do, if you read and understand them, writing your own program to achieve that should not be a bridge too far.

Like I said, big can of worms.

Do you know the older B89 that only used the ballbar is considered obsolete?

This is because it only evaluates the squareness and repeatability of the CMM but not the accuracy of linear dimensions.

Do you have a copy and/or have you read the B89 standard(s)?

Do you know the newest standard incorporates ISO 10360.2?

I have not read the new B89 standard, but if it fully incorporates 10360 then it also requires tighter environmental controls than the old B89 did as well.

Here are some links you might find helpful.

http://www.leica-geosystems.com/down...O_10360_en.pdf

https://www.asme.org/products/codes-...reverification

http://files.asme.org/Catalog/Codes/PrintBook/25586.pdf

http://www.nist.gov/pml/div683/grp01...nstruments.cfm


HTH

[dave_voecks]

Thanks for the info!

[Rondog]

I doubt you find anyone who will "give" you such a program.

If you do, they likely did not create it themselves and how will you know if it actually does everything needed to satisfy the standard or not?

The standards define what the program must do, if you read and understand them, writing your own program to achieve that should not be a bridge too far.

Like I said, big can of worms.

Do you know the older B89 that only used the ballbar is considered obsolete?

This is because it only evaluates the squareness and repeatability of the CMM but not the accuracy of linear dimensions.

Do you have a copy and/or have you read the B89 standard(s)?

Do you know the newest standard incorporates ISO 10360.2?

I have not read the new B89 standard, but if it fully incorporates 10360 then it also requires tighter environmental controls than the old B89 did as well.

Here are some links you might find helpful.

http://www.leica-geosystems.com/down...O_10360_en.pdf

https://www.asme.org/products/codes-...reverification

http://files.asme.org/Catalog/Codes/PrintBook/25586.pdf

http://www.nist.gov/pml/div683/grp01...nstruments.cfm


HTH

Your right, the Ball Bar is obsolete but it is the recommended method to do interim checks of the machine (this is written in the newer standard - B89.4.10360).

I don't think you need to get a 'program' to do this (not talking about a part program). If you dump your measurements into a spreadsheet you can easily calculate the range. The standard specifies how to do this (range = longest - shortest). For an interim check this would be fine. You can add any other tests or functions that you feel are important even if they are not part of the standard. For example, you could do a visual inspection of the probing and record the results as part of the interim check, inspect the air filters and perform a virus scan of the computer and record that it was done and so on.

I am under the impression this is just for internal machine checks (not using this to calibrate someone elses machine). A ball bar is good in this case. Is is better then nothing.

Note: A ball bar is usually not calibrated. If you can dismantle it then the length is unknown.

[VinniUSMC]

.....

Note: A ball bar is usually not calibrated. If you can dismantle it then the length is unknown.

But the spheres on either end should be of known diameter and roundness, hence calibrated, no?

[Wes Cisco]

Your right, the Ball Bar is obsolete but it is the recommended method to do interim checks of the machine (this is written in the newer standard - B89.4.10360).

I don't think you need to get a 'program' to do this (not talking about a part program). If you dump your measurements into a spreadsheet you can easily calculate the range. The standard specifies how to do this (range = longest - shortest). For an interim check this would be fine. You can add any other tests or functions that you feel are important even if they are not part of the standard. For example, you could do a visual inspection of the probing and record the results as part of the interim check, inspect the air filters and perform a virus scan of the computer and record that it was done and so on.

I am under the impression this is just for internal machine checks (not using this to calibrate someone elses machine). A ball bar is good in this case. Is is better then nothing.

Note: A ball bar is usually not calibrated. If you can dismantle it then the length is unknown.

Most ball bars are not calibrated for length, but some are. Not all ball bars are designed to be broken down on a regular basis. On some, the balls are more or less permanently affixed to the bar. If it is calibrated for length, then you also have a known length standard being checked when you run the B89 patterns.


A ball bar is one of the most effective and quickest interim checks. Unless you need a task specific check, I think a ball bar is the best general interim test.


They want to Certify CMMs, I asked already and the OP replied:

A program to perform a B89 Certification of a CMM
yes I have a certified and calibrated ball bar

But the spheres on either end should be of known diameter and roundness, hence calibrated, no?

As the lowest requirement, the spheres just have to be certified for sphericity and matching in size.

Most people who certify many different CMMs have the type of ball bar that can be configured in many different lengths, and those lengths are NOT certified.

[VinniUSMC]

As the lowest requirement, the spheres just have to be certified for sphericity and matching in size.

Most people who certify many different CMMs have the type of ball bar that can be configured in many different lengths, and those lengths are NOT certified.

D'oh! I meant sphericity!

I don't know much about the B89 standard. I've never read it. All I know is from whatever answers the HexaTech will give me when I'm sticking my nose all up in their biznizz.

[Rondog]

They want to Certify CMMs, I asked already and the OP replied:

A program to perform a B89 Certification of a CMM
yes I have a certified and calibrated ball bar

As the lowest requirement, the spheres just have to be certified for sphericity and matching in size.

Most people who certify many different CMMs have the type of ball bar that can be configured in many different lengths, and those lengths are NOT certified.

I did see this comment before I posted. 'Certification' is one of those buzz words that don't really mean anything. I just ignore it. Besides, if the original poster was looking to perform machine calibrations I would assume he knows what he needs to put together for a presentable report. It does seem to be from an internal check point of view.

The sphericity is important but not something I would consider worthy of saying 'the ballbar is calibrated' just because of this.

[Matthew D. Hoedeman]

Most ball bars are not calibrated for length, but some are. Not all ball bars are designed to be broken down on a regular basis. On some, the balls are more or less permanently affixed to the bar. If it is calibrated for length, then you also have a known length standard being checked when you run the B89 patterns.


A ball bar is one of the most effective and quickest interim checks. Unless you need a task specific check, I think a ball bar is the best general interim test.


They want to Certify CMMs, I asked already and the OP replied:







As the lowest requirement, the spheres just have to be certified for sphericity and matching in size.

Most people who certify many different CMMs have the type of ball bar that can be configured in many different lengths, and those lengths are NOT certified.

Do they REALLY need to be matching in size?

Just buy a couple of these, then throw them out every year instead of spending HUGE money to get them 'certified' each year

$13.34 each for chrome steel balls, 1" in diameter, size ±0.00005 and sphericity 0.000025"

Plenty good enough for interim checks, probably good enough to calibration checks as well, but, no way would I try to do my OWN calibration, that's like putting the fox in charge of the hen-house. IMO, one of the big 'things' about having someone come in and calibrate your CMM is that they are NOT you, but a 3rd, dis-interested party. They don't 'care' if your machine is within specs for not, they are there to (hopefully) put it into spec if it is not, or to tell you that it IS in spec. Makes no difference to them, KWIM?

http://www.mscdirect.com/browse/tn/R...692+4288243518

[VinniUSMC]

I think size matching is important only on the order of your prehit/retract/check distance for interchangeability. That way whatever way the ball bar is facing doesn't matter. That speaks nothing to the spec though.

And sphericity because if your balls are not spherical, depending on where you hit, the center point will change, which will affect your numbers.

[Wes Cisco]

Do they REALLY need to be matching in size?

Just buy a couple of these, then throw them out every year instead of spending HUGE money to get them 'certified' each year

$13.34 each for chrome steel balls, 1" in diameter, size ±0.00005 and sphericity 0.000025"

Plenty good enough for interim checks, probably good enough to calibration checks as well, but, no way would I try to do my OWN calibration, that's like putting the fox in charge of the hen-house. IMO, one of the big 'things' about having someone come in and calibrate your CMM is that they are NOT you, but a 3rd, dis-interested party. They don't 'care' if your machine is within specs for not, they are there to (hopefully) put it into spec if it is not, or to tell you that it IS in spec. Makes no difference to them, KWIM?

http://www.mscdirect.com/browse/tn/R...692+4288243518

That depends on what you are trying to achieve Matt. I am familiar with your setup and as an interim test it meets your needs, but I am sure you would agree it would be woefully inadequate to "certify" a CMM.

My statement came from what I read about ball bars before recommending we buy some for interim testing, (which we did).

One of the primary sources I used was Balltec.( https://www.precisionballs.com/all_ball_bar.php)

The accuracy of the Ball Bar (Dumbbell) is only limited by the roundness of the two spheres and their common size. The ANSI-B89.4-1-1997 specification for "The Performance Evaluation of Coordinate Measuring Machines" requires that the quality of the Standard Ball Bar (Dumbbell) Spheres be round and common size within five millionths of an inch (.11 micrometers).

[Matthew D. Hoedeman]

That depends on what you are trying to achieve Matt. I am familiar with your setup and as an interim test it meets your needs, but I am sure you would agree it would be woefully inadequate to "certify" a CMM.

My statement came from what I read about ball bars before recommending we buy some for interim testing, (which we did).

One of the primary sources I used was Balltec.( https://www.precisionballs.com/all_ball_bar.php)

This is really when a reality check is needed. Yes, those "specs" are what is needed to cover 'all' machines.

When the machine you are working on has a spec of +/-0.0005", with a probing system that has a spec of 0.0002", 5 millionths of an inch (0.000005" or 0.00011mm) is over-kill, by a factor of 10. To 'certify' my machine, with it's specs, using the 10-1 rule, those $14 balls are better than required.

I will also say again, that attempting to be your own cmm calibration tech is a no-no.

[VinniUSMC]

This is really when a reality check is needed. Yes, those "specs" are what is needed to cover 'all' machines.

When the machine you are working on has a spec of +/-0.0005", with a probing system that has a spec of 0.0002", 5 millionths of an inch (0.000005" or 0.00011mm) is over-kill, by a factor of 10. To 'certify' my machine, with it's specs, using the 10-1 rule, those $14 balls are better than required.

I will also say again, that attempting to be your own cmm calibration tech is a no-no.

But, who calibrates Hexagon's CMMs?