Coordinate needle calibration process

For CMM surveyors, the accuracy of the calibration diameter directly affects the measurement accuracy, so the CMM needs to be calibrated before starting the CMM operation. The calibration of the measuring needle requires careful completion by the operator to lay the foundation for the operation of the CMM. In the actual measurement operation, the parts can not be moved and turned over at will. In order to facilitate measurement, the direction and length of the head should be selected according to the actual situation. Measuring needles of different shapes (. Column. Needle). To make these different head measurements position. The elements measured in different measuring needles can be directly calculated, and the relationship between them should be measured and converted during the calculation process. So need to check the probe.

1. Before probe calibration, it is necessary to define probe and select test base according to the requirements of measurement software. Probe. Extension rod. Measuring needle. Standard ball diameter, etc. At the same time, it can be distinguished from different angles. The azimuth or length of a probe number.

2. Reset the replacement probe in the measurement software. Three coordinate seat measurement in software. Probe. Extension rod. Measuring needle set correctly; Application direction of the probe. Standard ball diameter input is correct, probe calibration speed setting is consistent with the measurement.

3. Check the direction of a single probe and pay attention to the investigation of the measuring needle diameter and standard error of the CMM. The measuring needle diameter of CMM should be similar to that of normal calibration, with good repeatability, and the standard error should be as small as possible (when the measuring head is lengthened, the diameter is small and the error is large).

4. When correcting the direction of multiple CMM test heads, in addition to investigating the above results, the calibration of the CMM measuring head's direction should also be used to measure the standard ball and investigate the change of the spherical center coordinate value. The value should be similar to the display value error or detection error.

5. Use a manual joystick. In a large range of the standard ball, the active way to touch more than 5 points (generally recommended 7~11 points), the distribution of points should be uniform.

6. After receiving these points, the computer software (the center coordinates of the gem ball (X.Y.Z value) will carry out the fitting calculation of the ball and obtain the center coordinates of the fitting ball. Diameter and shape errors. Subtract the diameter of the fitting ball from the diameter of the standard ball to conclude that the needle gem ball "diameter" (to be exact, it should be "proofreading value" or "proofreading diameter") is measured after proofreading.

How to choose the right coordinate measuring needle?

CMM measuring needle is a part of CMM measuring head system, mainly used to touch the workpiece surface, through the mechanical device of the measuring head shift, generate signal trigger, collect measurement data. Ruby measuring needles are widely used in the market.

For contact detection, choosing the correct CMM measuring needle can ensure the accuracy and efficiency of measurement.

For the measuring needle, the measuring needle of the large measuring ball should be selected as far as possible when selecting the three-coordinate measuring needle.

The measurement of the ball can increase the distance from the maximum diameter of the ball to the surface of the measuring needle, thus reducing the probability of the collision of the measuring needle caused by false trigger.

Because the surface finish of the measured workpiece directly affects the accuracy of the CMM measurement results, the larger the diameter of the measuring needle and ball, the lower the requirement of measuring the surface finish of the workpiece.

General knowledge of Zeiss needle measuring accessories

I. Thread specifications

It is known that Zeiss measuring needles or extension rods and other accessories are tightened through threads. Therefore, when using optional accessories, it is important to first understand the specifications of the accessories thread supported by the current device.

How to check the thread specification of the attachment? Refer to the thread diagram of the measuring needle below

Thread specifications depend on the type of sensor selected for the device. Take Zeiss equipment, for example

1. Equipped with VASTXTGOLD or VASTGOLD probes (active probes)

Accessory thread selection is flexible, the default thread size is M5(for measuring needle, you can also choose M2 or M3 specifications according to the actual situation, just purchase M2-M5 and M3-M5 adapters separately)

2. Equipped with VASTXXT or VASTXDT probes (passive probes)

Default thread size: M3(M2 can be selected according to the actual situation, just purchase M2-M3 adapter separately)

3. Equipped with RENISHAW probe (TP20/TP200 etc.)

Default thread size: M2

II. Materials

Different spare parts are made of different materials. The different materials correspond directly to the weight, stiffness, durability and price of the accessories. In general,

1. Equipped with VASTXTGOLD or VASTGOLD accessory probes (active probes)

Steel, aluminum alloy, titanium alloy can be selected a variety of materials, steel, aluminum alloy, titanium alloy, THERMFOIT, ceramic (needle gauge rod) can be selected

Ruby, silicon nitride, diamond and ceramic (large diameter measuring needle, more than 15mm), steel (custom measuring needle or large diameter measuring needle).