Detection methods of graphite electrode chaser 

1 Tooth top/tooth bottom straightness error

The straightness error of the tooth top/tooth bottom is the connection line of the corresponding points of each tooth top and each tooth bottom of the chaser. Its direction has nothing to do with the taper angle of the thread. During the detection, the chaser is placed horizontally, and the coordinates of each point are measured and recorded. The method evaluates the magnitude of the straightness error. The evaluation of straightness error generally has the following 3 methods: (1) the method of connecting the two ends; (2) the least mean square approximation method; (3) the minimum area method.

According to the characteristics of the chaser, the two-end point connection method is adopted (see Figure 3), the measurement method and operation steps:

(1) Place the chaser horizontally on the loading platform, and adjust the focal length of the Universal Tool-Measuring Microscope to make the edge of the chaser under test clear and identifiable.

(2) Adjust the angle of the rudder wheel of the Universal Tool-Measuring Microscope eyepiece to 0°, and adjust the eyepiece field of view to make the double cross auxiliary line clear and legible.

(3) Operate the Universal Tool-Measuring Microscope to make the x-axis dotted line of the double cross auxiliary line tangent to the first tooth tip of the tested chaser, and the y-axis position mark is used as the point coordinate of the first tooth tip; use the same method to measure the point coordinates of the tooth tip of the last tooth in the measuring range of  the tested chaser, adjust the micro-adjustment bolt of the Universal Tool-Measuring Microscope  loading platform to make the y-axis coordinates of the above two points consistent. Graphite Electrode for furnace steelmaking.

(4) Use the method described in step (3) to measure the point coordinates of all tooth tips within the measuring range of the chaser under test, and record the y-axis coordinates of each point as y_{tooth top}.

(5) The operation of the Universal Tool-Measuring Microscope adopts a gradual approach method to make the X-axis dotted line of the double cross auxiliary line coincide with the bottom line of the tooth between two adjacent teeth of the chaser under test to the greatest extent, and the y-axis position mark is used as the tooth bottom of the tooth. Repeatedly measure the point coordinates of all the tooth bottoms in the measuring range of the chaser under test in the same way, and record the y-axis coordinates of each point as the y_{tooth bottom}.

(6) The straightness error of the tooth top/bottom of the tested chaser can be expressed as the difference between the maximum reading and the minimum reading of the y-axis coordinate of each point, namely: tooth top straightness error = y_{tooth top max}-y_{tooth top min}, Tooth bottom straightness error = y_{tooth bottom max}-y_{tooth bottom min}.

2 Establish measurement coordinate system

Establish a measurement coordinate system based on the thread taper angle of 9°27′44″, and correspond the parameters of the chaser to be tested with the readings of the x-axis and y-axis of the measurement coordinate system. The specific methods and steps are as follows:

(1) Place the chaser horizontally on the loading platform, and adjust the focal length of the Universal Tool-Measuring Microscope to make the edge of the chaser under test clear and identifiable.

(2) Adjust the angle of the rudder wheel of the Universal Tool-Measuring Microscope eyepiece to 0°, and adjust the eyepiece field of view to make the double cross auxiliary line clear and legible.

(3) The operation of the Universal Tool-Measuring Microscope adopts the method of gradual approximation so that the two solid lines with an included angle of 60° on the double cross auxiliary line are both tangent to the tip circle of a certain tooth of the chaser under test. At this time, the x-axis and y-axis are sitting mark the point coordinates (x₁, y₁) of the top of the first tooth.

(4) Use the same method as step 3 to measure the point coordinates (x₂, y₂) of the tooth tip of the last tooth in the measuring range of the chaser under test.

(5) Seek the placement angle of the chaser so that the coordinates of the above points satisfy the formula (1):

tan(9°27′44″)=(y₂-y₁)/(x₂-x₁)                                         (1)

(6) Repeat steps (3) ~ (5) to correct the difference in the coordinates of the tooth apex caused by changing the angle of the chaser.

(7) When the point coordinates of the top of the first tooth (x₁, y₁) and the point coordinates of the top of the last tooth (x₂, y₂) are stable, fix the current placement angle of the chaser. At this time,  the reading of each measurement parameter of  the chaser is the x-axis and y-axis coordinates of the Universal Tool-Measuring Microscope corresponding to each measurement point. At this time, the measurement coordinate system is established. Graphite products shows here.

It should be emphasized that the measurement of the chaser cutter parameters such as the tooth profile half-angle, tooth height, tooth bottom width, and various pitches described below, unless otherwise specified, need to be tested in this measurement coordinate system.