Dial Caliper Calibration - Metrology Training Lab
27.9 هزار بار بازدید -
6 سال پیش
-
In this episode of the
In this episode of the Metrology Training Lab , we’re going to revisit the calibration of calipers and look at a specific issue with dial caliper calibration.
In a past episode, we thoroughly covered the calibration of calipers, following the guidelines from the American National Standard ASME B89.1.14. In that episode, we focused on the more popular digital caliper, and we missed discussing an issue that is important to consider for dial calipers.
Let’s do a very brief review and summary of how to calibrate calipers. I’m going to first use a digital caliper, and I’m not going to try to be particularly precise in this example, so please forgive me for that.
For the outside jaws, we take a series of measurements over the measuring range, and vary the location across the jaws.
We then use a gage block on a surface plate for the depth and step measurements.
I’m going to now repeat some of the same measurements, this time using a dial caliper. I want you to look closely at the angular position of the pointer in the dial.
Due to our choice of measurement standards, the pointer is in the 12:00 position for every measurement.
Dial calipers use little gears, and the gears can wear. It is possible for there to be errors within a rotation of the dial that you won’t see if the calibration method results in the pointer always being at the 12:00 position. For this reason, the ASME B89.1.14 standard requires some test points that put the pointer in additional angular positions.
For example, I have two gage blocks here wrung together. This is the 0.125 block and this the 0.150 block – these are standard blocks from an inch set of gage blocks. For this style dial caliper, if I measure the 0.125 block, the pointer should be at the 3:00 position. If I measure the 0.150 block, the point should be at the 6:00 position. And if I measure the two blocks wrung together, the pointer should be at the 9:00 position.
So two gage blocks, three additional easy test points, not too difficult to test the accuracy of the caliper with the pointer in different angular positions. The ASME B89.1.14 standard does not prescribe specific test points, so you have lots of flexibility here, but we wanted to show you one option that does the job and is pretty easy to implement.
#mitutoyocalipers #metrology #calipercalibration
In a past episode, we thoroughly covered the calibration of calipers, following the guidelines from the American National Standard ASME B89.1.14. In that episode, we focused on the more popular digital caliper, and we missed discussing an issue that is important to consider for dial calipers.
Let’s do a very brief review and summary of how to calibrate calipers. I’m going to first use a digital caliper, and I’m not going to try to be particularly precise in this example, so please forgive me for that.
For the outside jaws, we take a series of measurements over the measuring range, and vary the location across the jaws.
We then use a gage block on a surface plate for the depth and step measurements.
I’m going to now repeat some of the same measurements, this time using a dial caliper. I want you to look closely at the angular position of the pointer in the dial.
Due to our choice of measurement standards, the pointer is in the 12:00 position for every measurement.
Dial calipers use little gears, and the gears can wear. It is possible for there to be errors within a rotation of the dial that you won’t see if the calibration method results in the pointer always being at the 12:00 position. For this reason, the ASME B89.1.14 standard requires some test points that put the pointer in additional angular positions.
For example, I have two gage blocks here wrung together. This is the 0.125 block and this the 0.150 block – these are standard blocks from an inch set of gage blocks. For this style dial caliper, if I measure the 0.125 block, the pointer should be at the 3:00 position. If I measure the 0.150 block, the point should be at the 6:00 position. And if I measure the two blocks wrung together, the pointer should be at the 9:00 position.
So two gage blocks, three additional easy test points, not too difficult to test the accuracy of the caliper with the pointer in different angular positions. The ASME B89.1.14 standard does not prescribe specific test points, so you have lots of flexibility here, but we wanted to show you one option that does the job and is pretty easy to implement.
#mitutoyocalipers #metrology #calipercalibration
6 سال پیش
در تاریخ 1398/01/12 منتشر شده
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