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CNC machining center handles black technology of spherical mold - three-axis concentricity test method

Jun 10, 2019

Ball valves are common in spherical molds. Ball valves are a kind of valves. They are widely used in petrochemical, long-distance pipelines, power generation, papermaking, nuclear power, and aviation. The closing member of the ball valve is a ball (or part of a ball) with a through hole, and the ball rotates with the valve stem to open or close the valve. Therefore, the sealing performance is the primary indicator for determining the performance and reliability of the ball valve, and the machining accuracy and surface quality of the closing ball profile are critical to the sealing performance of the ball valve.

The traditional spherical precision machining process is mainly made by manual research and polishing, which consumes a lot of manpower and material resources, and has low production efficiency. With the increase of labor cost and the demand for high-speed and high-efficiency production, coupled with the close CNC machining technology. Progress, CNC spherical grinder equipment came into being.


Regardless of horizontal or vertical spherical grinders, ALLES CNC believes that an important precision measure for spherical machining accuracy is the three-axis concentricity of the machine tool spindle, workpiece spindle and tailstock shaft. The smaller the error, the higher the spherical accuracy. The better the sealing of the ball valve; the hard sealing ball like high-hardness coating such as tungsten carbide, the roundness requirement of the sphere is even within 0.005mm, and the requirements for triaxial concentricity are required in addition to the requirements for other structures. At least 0.004mm or less is required to meet the requirements.


In response to the above problems, ALLES CNC recommends a three-axis concentricity test that accurately verifies the three-axis concentricity error of the spherical grinding head spindle, workpiece spindle and tailstock shaft, providing accurate data for precise adjustment.

A method for inspecting a three-axis concentricity of a spherical grinding machine, comprising the steps of: inserting a first inspection rod in a workpiece spindle, wherein the workpiece spindle coincides with a rotation center of the first inspection rod, and the workpiece spindle is mounted on the workpiece Inspection of the center of concentricity of the center of the grinding head of the workpiece spindle; concentricity inspection of the workpiece spindle with the center of rotation of the tailstock shaft mounted at the top of the spherical grinding machine. With this technical solution, the three-axis concentricity error of the spherical grinding head spindle, the workpiece spindle and the tailstock shaft can be accurately verified, and accurate data is provided for precise adjustment.

Detailed method for testing the triaxial concentricity of a spherical grinder:


First, inserting a first inspection rod into the workpiece spindle, wherein the workpiece spindle coincides with a rotation center of the first inspection rod;

 

Second, the test of the concentricity of the workpiece spindle and the center of rotation of the grinding head spindle mounted on the workpiece spindle:

1 indicator is fixed at the center of the grinding head spindle, so that the probe touches the left side surface of the first inspection rod, note that the probe touches the position of the first inspection rod surface and the center plane of the grinding head as orthogonal as possible ;

2 moving the spindle of the grinding head in the direction of the Z axis, so that the probe touches the highest point on the left side surface of the first inspection rod;

3 oscillating the spindle of the grinding head at a small angle to swing the probe up and down, observing the reading of the indicator, so that the probe touches the minimum point of the indicator reading, which is the left of the surface of the first inspection rod and the center plane of the grinding head. The highest point on the side, record the reading at this point, counted as O left;

4 the grinding head spindle retreats along the Z axis, then flips 180°, flips the indicator probe to the right side of the first inspection rod, repeats steps 2 and 3, and causes the probe to touch the surface of the first inspection rod The highest point on the right side orthogonal to the center plane of the grinding head, and the reading of this point is recorded, which is counted as O right;

5 Concentricity error is half of the difference between O left and O right, ie ∣O left-O right ∣/2;

6 rotating the workpiece spindle, rotating the inspection rod 180°, and detecting the same once again, and the algebra and the half of the two measurement results are the concentricity error between the grinding head spindle and the workpiece spindle rotation center;

 

Third, the concentricity test of the workpiece spindle and the center of rotation of the tailstock shaft mounted at the top of the spherical grinding machine:

1 affixing a second inspection rod between the workpiece spindle and the tailstock shaft, and the second inspection rod is fixed by upper and lower, and the indicator is fixed on the spindle of the grinding head, so that the probe is at The direction of the a touches the second test rod;

2 moving the grinding head spindle in the Y-axis direction, the difference between the readings of the indicators at the two ends of the second inspection rod (9) is the concentricity of the workpiece spindle and the tailstock shaft rotation center in the a direction Degree error, counted as a;

3, the indicator probe touches the inspection rod in the b direction, and moves the grinding head spindle along the Y axis direction, and the difference between the reading positions of the indicator at the two ends of the second inspection rod is the spindle and the tail of the numerical control machining center The concentricity error in the b direction of the center of rotation of the shaft is counted as b.

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