A method for axial tool setting of CNC lathe

Abstract

The present application provides an axial tool setting method for a CNC lathe, which converts the calculation of coordinate points into the calculation of distances between reference surfaces. There is no need to consider the specific shape of the workpiece too much. As long as points on the workpiece that are easy to measure and can be used to set tool setting points are found, any one of them can be selected as the tool setting point. According to the calculation formula of the h value, the coordinate value of the tool setting point can be easily calculated. Based on the technical solution of the present application, the method for selecting the tool setting point is simple and easy to understand, and the process of calculating the coordinate value of the tool setting point is simple and accurate, which is very suitable for promotion and application in actual work.

Description

Technical Field

[0001] The invention relates to the technical field of tool setting methods for numerically controlled machine tools, and in particular to an axial tool setting method for a numerically controlled lathe. Background Art

[0002] Cutting a workpiece using a machine tool involves the movement of the tool's cutting edge relative to the workpiece. Prior to machining, the relative position of the tool and workpiece must be established. Tool setting determines the location of the program origin within the machine tool's coordinate system. Tool setting points can be located on the part, fixture, or machine tool. Tool setting should ensure that the tool setting point coincides with the tool position point. Ball cutters are a common tool. Common programming points for ball cutters include the ball center and the contact point between the tool and the workpiece. The following explanation uses the ball center as the programming point.

[0003] Many aircraft engine components have highly complex structures. When machining complex shapes, complex ball cutters are often required to machine complex cavities or shapes. However, some special workpieces cannot be axially aligned at the workpiece's zero point due to tooling interference or complex shapes. Instead, alignment must be performed on the opposite plane of the cavity or shape.

[0004] like Figure 1 The ball cutter structure 1 shown in the figure comprises: a spherical cutter 1-1 and a tool holder 1-2. The radius of the cutter 1-1 is R. The tool holder 1-2 is mounted on a turning tool arbor 1-3 of a machine tool. Figure 2 Before the irregular workpiece 2 shown in the figure is processed, a tool setting process is required. Usually, the parts on the ball cutter that can be set include four directions: up, down, left, and right. Figure 1 In the ball cutter structure 1 shown, the positional relationship between the tool handle 1-2 and the tool 1-1 cannot be changed, and the tool 1-1 can be set in three directions: up, down, and right. The tool setting of the ball cutter structure includes axial setting and radial setting. Figure 2 In the figure showing the irregular workpiece 2, the left-right direction is the axial direction. Due to the specific structure of the ball cutter structure 1, the ball cutter structure 1 cannot directly perform tool setting at the Z0 point of the irregular workpiece 2 (the starting position on the rightmost side of the irregular workpiece 2 is the 0 point of the coordinate Z axis).

[0005] During the axial tool setting process, ignoring interference from fixtures, equipment, and other factors, other possible tool setting points on irregular workpiece 2 include points 2-1, 2-2, and 2-3. Assume that any one of these three points is selected as the axial tool setting point. In this case, the workpiece's current position in the axial coordinates is a negative value. Furthermore, to account for product deformation, engineers often include allowances in various planes during programming. Therefore, the operator must consider these allowances and calculate the coordinates of the tool setting points.

[0006] In actual work, due to the complexity of the workpiece shape and the tool shape, technicians need to rely on their own experience to select the tool setting point. The points selected by less experienced technicians will be more difficult to calculate. At the same time, after selecting the tool setting point, because there are many conditions to consider, when setting the tool with the reverse center of the ball, less experienced operators will often miscalculate the tool setting value, resulting in overcutting or scrapping of the workpiece. Summary of the Invention

[0007] In order to solve the problems in the prior art of difficulty in selecting tool points, time-consuming and error-prone calculation of tool point coordinates when using complex tools to set tool on complex workpieces, the present invention provides an axial tool setting method for CNC lathes, which can quickly select tool points and accurately calculate the coordinate values ​​of tool points.

[0008] The technical solution of the present invention is as follows: a method for axial tool setting of a CNC lathe, characterized in that it comprises the following steps:

[0009] S1: Confirm the tool setting surface and the tool setting direction between the tool and the workpiece;

[0010] The tool setting direction includes: axial tool setting and radial tool setting;

[0011] S2: Set the allowance reference plane;

[0012] The allowance reference plane is perpendicular to the tool setting direction;

[0013] The allowance reference plane is located at the coordinate point of the coordinate axis 0 along the reverse direction of the workpiece plus the machining allowance A;

[0014] S3: Based on the tool setting surface on the tool and the tool setting direction, after eliminating all interferences, confirm all points on the workpiece where tool setting points can be set, and select one of them as the tool setting point;

[0015] At the same time, the tool setting point satisfies the requirement that the distance from the allowance reference plane can be obtained by a single measurement with a measuring tool;

[0016] S4: Setting a tool position reference plane, wherein the tool position reference plane is perpendicular to the tool setting direction;

[0017] The tool position point reference plane is located on the tool setting point;

[0018] S5: measuring the distance between the tool position reference plane b and the margin reference plane a;

[0019] Let: the distance between surface a and surface b be B;

[0020] S6: Calculate the absolute value h of the coordinates of the tool position point;

[0021] When the tool position point is located on the b surface and is adjacent to the allowance reference plane:

[0022] h=|BAR|

[0023] When the tool position point is located on the b surface and is also located away from the allowance reference plane:

[0024] h=|B-A+R|

[0025] When the tool position point is located on the a plane and is close to the 0 point of the coordinate axis:

[0026] h=|RA|

[0027] Among them, R is the tool radius and A is the preset machining allowance;

[0028] S7: According to the positional relationship between the tool setting point and the zero point, add a positive or negative sign to h, which is the coordinate value of the tool setting point.

[0029] It is further characterized by:

[0030] The tool radius R has a value range of R≥0.

[0031] The present application provides an axial tool setting method for a CNC lathe, which converts the calculation of coordinate points into the calculation of the distance between reference surfaces. There is no need to consider the specific shape of the workpiece too much. As long as a point on the workpiece that is easy to measure and can be used to set a tool setting point is found, any one of them can be selected as the tool setting point. According to the calculation formula of the absolute value of the coordinate h, the coordinate value of the tool setting point can be easily calculated; based on the technical solution of the present application, the method for selecting the tool setting point is simple and easy to understand, and the process of calculating the coordinate value of the tool setting point is simple and accurate, which is very suitable for promotion and application in actual work. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is an embodiment of a ball cutter structure in the prior art;

[0033] Figure 2 This is an embodiment of an irregular workpiece in the prior art;

[0034] Figure 3 Schematic diagram of the method for calculating the absolute value of tool setting point coordinates during forward tool setting in this application;

[0035] Figure 4 Schematic diagram of the method for calculating the absolute value of tool setting point coordinates during reverse tool setting in this application;

[0036] Figure 5 This is an embodiment of calculating the tool setting point coordinates and calculating the reverse tool setting based on the technical solution of this application;

[0037] Figure 6 This is an example of forward tool setting for calculating tool setting point coordinates based on the technical solution of this application. DETAILED DESCRIPTION

[0038] like Figure 3 and 4 As shown, the present invention includes an axial tool setting method for a CNC lathe, which includes the following steps.

[0039] S1: Confirm the tool setting surface and the tool setting direction between the tool and the workpiece;

[0040] The tool setting directions include: axial tool setting and radial tool setting.

[0041] S2: Set the allowance reference plane;

[0042] The allowance reference plane is perpendicular to the tool setting direction;

[0043] The allowance reference plane is located at the coordinate point of the coordinate axis 0 along the opposite direction of the workpiece plus the machining allowance A.

[0044] S3: Based on the tool setting surface and tool setting direction on the tool, after eliminating all interferences, confirm all points on the workpiece where tool setting points can be set, and select one of them as the tool setting point;

[0045] At the same time, the tool setting point satisfies the requirement that the distance from the allowance reference plane can be obtained by a single measurement with a measuring tool.

[0046] The tool setting point should not be set at a point where there is measurement interference or tooling interference. At the same time, the tool setting point should be set at a point where the distance to the allowance reference plane can be obtained with a single measurement. The point location should be considered from the perspective of measurement convenience and reduced calculation steps, reducing the probability of errors caused by measurement during the calculation process.

[0047] S4: Set the tool position reference plane, which is also perpendicular to the tool setting direction;

[0048] The tool position point reference plane is located on the tool setting point.

[0049] like Figure 3 The figure shows a schematic diagram of positive tool setting. The workpiece is located on the right side of Z0. When setting the allowance reference plane a, the machining allowance A is added in the negative direction along the left side of Z0 to obtain the allowance reference plane a. Figure 4 This is a schematic diagram of reverse tool setting. The workpiece is located on the right side of Z0. The machining allowance A is added in the positive direction along the right side of Z0 to obtain the allowance reference plane a.

[0050] In this calculation method, the machining allowance A is directly reflected at the 0 point of the coordinate axis. When calculating, the 0 point of the coordinate axis is directly increased by A in the opposite direction of the workpiece. The method is simple, not prone to errors, and easy to understand.

[0051] S5: Measure the distance between the tool position reference plane b and the allowance reference plane a;

[0052] Let: the distance between surface a and surface b be B;

[0053] S6: Calculate the absolute value h of the coordinate of the tool position point;

[0054] Figure 3 and Figure 4 In the figure, the point marked 5 is the point represented by the allowance reference surface a.

[0055] When the tool position point is located on the b surface and is located on the side adjacent to the allowance reference plane, such as Figure 3 and Figure 4 The point marked as 2:

[0056] h=|BAR|

[0057] When the tool position point is located on the b surface and is also located away from the allowance reference plane, such as Figure 3 and Figure 4 The point marked as 3:

[0058] The calculation method of h at point 3 is: h=|B-A+R|

[0059] When the tool position point is on the a plane and close to the 0 point of the coordinate axis, such as Figure 3 and Figure 4 The points marked as 1 in the chart are:

[0060] h=|RA|

[0061] Among them, R is the tool radius and A is the preset machining allowance.

[0062] Based on the solution of this application, there may be multiple points on the same workpiece that are suitable for tool setting, such as: Figure 3 and Figure 4 In the example, both the point marked 4 and the point marked 3 meet the above tool point selection conditions. Then, you can select either point 4 or point 3.

[0063] The calculation method of the h value of point 4 is: h=|C-A+R|, where c is the distance between the tool position reference plane c and the reference plane a where point 4 is located.

[0064] The calculation of coordinate values ​​is converted into the calculation of the distance between surfaces. The calculation method is simple and easy to understand. At the same time, based on the actual situation, three possible situations of the tool point and the reference surface are determined. When calculating, the measured data is substituted into the calculation formula of h to obtain the absolute value of h, without the need for technicians to perform the conversion themselves.

[0065] S7: Based on the positional relationship between the tool setting point and the zero point, add a positive or negative sign to h to obtain the coordinate value of the tool setting point. That is, with the coordinate axis zero point as the center, when the workpiece is located in the negative coordinate system, the tool setting is reversed and the coordinate value of the tool setting point is negative; otherwise, it is positive.

[0066] This method is also applicable to non-spherical center tool setting scenarios, so the value range of the tool radius R is R≥0.

[0067] like Figure 5 In the illustrated embodiment, the ball cutter 3 can be set in three positions: up, down, and right. Therefore, it is not possible to set the tool directly at the Z0 point on the workpiece 5; a separate setting point must be selected. In this embodiment, the ball cutter is set at the center of the circle, with a machining allowance A of 0.5 mm. The workpiece is located in the negative coordinate system, and the tool is set in the reverse direction. The tool radius R3 = 2 mm.

[0068] Based on all possible tool setting points, excluding tool interference points and points that are difficult to measure, such as point ③, assume that point ④ in the figure is selected as the tool setting point. Set the tool position reference plane b at this point. Measure the machining allowance size using a dial indicator. Add the machining allowance A at point 0 along the opposite direction of the workpiece and set this as the allowance reference plane a.

[0069] The distance between surface a and surface b was measured using a dial indicator and found to be 12.6 mm.

[0070] Point ④ is located on the side of the tool position point reference plane b away from the coordinate axis 0, so calculate the absolute value h of the tool position point coordinate:

[0071] h=|B-A+R|=|12.6-0.5+2|=14.1

[0072] Because the tool setting is in the reverse direction, the coordinate of the tool setting point should be -14.1;

[0073] Use the machine handwheel to move the tool to the plane of point ④. The operator enters Z-14.1 on the machine tool setting interface. Tool setting is complete.

[0074] like Figure 6 In the embodiment shown, the ball cutter 3 can be set in three directions: left, right and bottom. Figure 6 For the workpiece 6, the ball cutter 4 cannot directly align the tool at the Z0 point of the workpiece.

[0075] Based on the structure of the ball cutter 4 and the structure of the workpiece 6, point ⑦ marked in the figure is not suitable for tool setting. Assuming that point ⑥ marked in the figure is selected as the tool setting point, the tool position point reference plane b is set at that point; based on the size of the machining allowance measured by the dial indicator, the machining allowance A is added to point 0 of the coordinate axis in the opposite direction of the workpiece and set as the allowance reference plane a; in this embodiment, the tool setting is based on the center of the ball cutter, the machining allowance A is 0.5mm, the workpiece is located in the positive coordinate system, the tool setting is positive, and the tool radius R4=1mm.

[0076] The distance between surface a and surface b is measured to be 4mm based on the dial indicator;

[0077] Point ② is located on the side of the tool position point reference plane b close to the coordinate axis 0, so calculate the absolute value h of the tool position point coordinate:

[0078] h=|BAR|=|4-0.5-1|=2.5

[0079] Because the tool setting is in the reverse direction, the coordinate of the tool setting point should be +2.5;

[0080] Use the machine handwheel to move the tool to the plane of point ②. The operator enters Z+2.5 on the machine tool setting interface. Tool setting is complete.

[0081] In the present application, the coordinate calculation of the tool setting point is converted into the calculation of the distance between two mutually parallel reference planes: the allowance reference plane and the tool position point reference plane, while taking into account the positional relationship of the ball cutter radius R, which greatly simplifies the calculation process. After using the technical solution of the present application, regardless of the experience of the technician, the tool setting point can be quickly determined, and the coordinate value of the tool setting point can be accurately calculated. The method of the present application is applicable to forward and reverse tool setting, and is also applicable to ball cutters and ordinary non-ball cutters. Using the method of the present application, the operator can quickly determine the tool setting point, substitute the corresponding parameters into the calculation formula of h, and calculate the correct tool setting value, effectively reducing the probability of quality accidents caused by human calculation errors.

Claims

1. A method for axial tool setting of a CNC lathe, characterized in that: It includes the following steps: S1: Confirm the tool setting surface and the tool setting direction between the tool and the workpiece; The tool setting direction includes: axial tool setting and radial tool setting; S2: Set the allowance reference plane; The margin reference plane is perpendicular to the tool setting direction; The allowance reference plane is located at the coordinate point of the coordinate axis 0 point along the reverse direction of the workpiece plus the machining allowance A; S3: Based on the tool setting surface on the tool and the tool setting direction, after eliminating all interferences, confirm all points on the workpiece where tool setting points can be set, and select one of them as the tool setting point; At the same time, the tool setting point satisfies the requirement that the distance from the margin reference plane can be obtained by a single measurement with a measuring tool; S4: Setting a tool position point reference plane, wherein the tool position point reference plane is perpendicular to the tool setting direction; The tool position point reference plane is located on the tool setting point; S5: measuring the distance between the tool position reference plane b and the margin reference plane a; Assume: the distance between surface a and surface b is B; S6: Calculate the absolute value h of the coordinates of the tool position point; When the tool position point is located on the b surface and is located adjacent to the allowance reference plane: h=|BAR| When the tool position point is located on the b plane and at the same time is located away from the allowance reference plane: h=|B-A+R| When the tool position point is on the a plane and close to the 0 point of the coordinate axis: h=|RA| Among them, R is the tool radius, and A is the preset machining allowance; S7: According to the positional relationship between the tool setting point and the zero point, add a positive or negative sign to h, which is the coordinate value of the tool setting point.

2. The axial tool setting method for a CNC lathe according to claim 1, characterized in that: The value range of the tool radius R is R≥0.

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