Process control method for axial linear size of inner groove of micro part

Abstract

The invention belongs to the technical field of machining, and particularly relates to a process control method for the axial linear size of an inner groove of a micro part. Comprising the steps that 1, an inner hole and an end face on the opposite side of a control edge of an inner groove are machined to theoretical sizes; 2, machining an inner hole in the corresponding side of the control edge of the inner groove to a first size, wherein the first size is obtained by subtracting the first value b from the theoretical value; 3, determining a tool nose fillet R; 4, machining the inner hole in the corresponding side of the control edge to a first size by adopting a tool nose with a fillet R; 5, machining the inner groove to a first groove width by using a tool nose with a fillet R, wherein the inner groove and the inner hole on the corresponding side of the control edge form a measuring surface; step 6, measuring the distance from the end face on the opposite side of the control side to the measurement surface by using a depth micrometer; and 7, under the condition that the distance meets the threshold value, an inner hole in the side corresponding to the control edge of the inner groove is machined to the theoretical size through a tool nose with a fillet R, and the width of the inner groove is changed into the theoretical groove width from the first groove width at the moment.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and in particular relates to a process control method for the axial linear dimension of an inner groove of a micro part. Background Art

[0002] Features of the reversing valve parts: The total length of the parts is 13mm, the inner hole diameter is less than ф5mm, and the axial linear dimension tolerance of the inner groove is 0.02mm. Only by accurately controlling the axial linear dimension of the inner groove can the axial position of the sealing steel ball of the reversing valve be guaranteed, thereby ensuring the low-pressure sealing and starting pressure of the product.

[0003] The inner hole of the reversing valve parts is small, and the axial linear dimension of the inner groove is the line-to-plane dimension. Currently, it cannot be detected during the processing process. The only way to detect the size is to cut the first piece and then use a universal tool microscope to measure the size. During the first piece processing, it is necessary to adjust the processing according to the measurement results. During the processing, there are dimensional changes caused by tool wear and the dimensional adjustment cannot be performed, which leads to the part size being out of tolerance. Summary of the invention

[0004] Purpose of the invention: To provide a process control method for the axial linear dimensions of the inner groove of a tiny part, so as to solve the problem that the axial linear dimensions of the inner groove of the parts of reversing valves and similar products cannot be detected by conventional means.

[0005] Technical solution:

[0006] A process control method for the axial linear dimension of an inner groove of a micro-part comprises:

[0007] Step 1: Process the inner hole and end surface on the opposite side of the control edge of the inner groove to the theoretical size;

[0008] Step 2: Process the inner hole on the side corresponding to the control edge of the inner groove to a first size, where the first size is the theoretical value minus the first value b;

[0009] Step 3: Determine the tool tip radius R;

[0010] Step 4: Use the tool tip with rounded corner R to machine the inner hole on the corresponding side of the control edge to the first size;

[0011] Step 5: Use the tool tip with rounded corner R to machine the inner groove to the first groove width, and the inner groove and the inner hole on the corresponding side of the control edge form a measuring surface;

[0012] Step 6: Use a depth micrometer to measure the distance from the end face on the opposite side of the control edge to the measuring surface;

[0013] Step 7: When the distance meets the threshold, the inner hole on the corresponding side of the control edge of the inner groove is processed to the theoretical size using the tool tip with a rounded corner R. At this time, the inner groove width changes from the first groove width to the theoretical groove width.

[0014] Furthermore, the first value b is greater than 0.5 mm.

[0015] Furthermore, the tool tip radius R is determined according to the axial dimensional accuracy.

[0016] Furthermore, when there are chamfers θ on both sides of the bottom of the inner groove and θ is less than 90°, the distance Lmeasured from the end face on the opposite side of the control edge to the measuring surface satisfies: Lmeasured=L+a, where L is the theoretical axial distance of the control edge of the inner groove, and a is the axial distance between the measuring surface and the control edge.

[0017] Further, R<a<M, M is the axial distance between the intersection of the extended line of the angle θ and the inner hole of the first size and the control edge, and M=b / tanθ.

[0018] Furthermore, the first groove width=theoretical groove width+a.

[0019] Furthermore, the tool tip radius R is less than or equal to 0.1 mm.

[0020] Furthermore, it also includes: Step 8: performing a non-deep cutting pass on the control edge.

[0021] Beneficial effects:

[0022] The present invention effectively solves the problem of detecting the axial linear dimension of the inner groove during the processing process through the process method of intermediate transition control. The first processing of the part no longer requires sectioning, and the processing process no longer requires sectioning to confirm the processing quality and accuracy of the size. At the same time, the problem of part out-of-tolerance caused by the inability to detect during the processing is avoided.

[0023] The present invention reduces the cutting, detection and waiting time in the part processing process, can realize the rapid detection of the processing process, effectively ensures the quality of the part, and the axial linear dimension accuracy of the inner groove edge of the part reaches 0.01mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The schematic diagram of the process control method for the axial linear dimension of the inner groove of a tiny part;

[0025] Figure 2 This is the dimension control diagram of the process control method for the axial linear dimensions of the inner groove of tiny parts. DETAILED DESCRIPTION

[0026] The present invention adopts the setting of the intermediate process, converts the line-to-surface distance into the distance between the surface and the surface, adopts the universal detection method to check the inner groove size, solves the problem of detecting the axial linear size of the inner groove during the processing, and uses a universal tool microscope to detect the first piece of the part after cutting. Due to the influence of sharp edge burrs and sharp edge R, the detection error of the universal tool microscope is 0.03mm, and the distance between the surfaces is detected through the intermediate process. A depth gauge with a table can be used, and its detection accuracy is 0.002mm. The error of the reserved measurement surface margin a depends on the accuracy of the machine tool, and the axial accuracy of the machine tool is not more than 0.003mm. Therefore, by adopting the process method of the present invention, its finishing and detection accuracy can be controlled within 0.01mm, which can fully meet the parts demand of ±0.02, and is better than the original process, while saving waiting time and improving processing efficiency.

[0027] The present invention proposes a process method for intermediate transition control, which reduces the size of the intermediate hole of the valve body of the reversing valve (the size of the intermediate hole is only related to the size of the measuring surface and does not affect the final measurement accuracy), and converts the axial size of the inner groove from line to surface to surface to surface distance, thereby solving the problem of requiring sample sectioning for detection, such as Figure 1 By setting the intermediate process hole, the axial linear dimension of the inner groove edge is changed from line to surface to the dimension between two surfaces, and the surface-to-surface detection can be carried out by conventional metrology methods.

[0028] A process method for eliminating the tool tip R is proposed: by leaving a margin in the middle hole and extending the groove edge R downward, the tool tip R can be removed during subsequent hole processing.

[0029] The measuring plane is formed directly from the groove edge, and an inner R will appear at the transition position (see Figure 2 ), which ultimately cannot be eliminated.

[0030] By controlling the tool tip R, a margin is left in the middle hole, and the groove edge R extends downward, and R can be removed during subsequent hole processing.

[0031] Measuring surface and slot width calculation scheme:

[0032] By measuring the actual value of the middle hole, b is the hole allowance, the tool tip R≤0.1mm, the measuring surface is a ring b of not less than 0.5mm (the axial offset dimension a of the measuring surface), the hole allowance and the angle θ are calculated, the measuring plane size is determined, and the calculation formula for the measuring plane and the slot width size is proposed.

[0033] L measurement = L + a (R < a < M, a is a constant) (1)

[0034] M=b / tanθ (2)

[0035] Slot width = theoretical slot width + a (3)

[0036] Process the middle hole and inner groove (idle pass to eliminate sharp edge burrs) to the drawing size, while ensuring the axial linear size of the inner groove edge.

[0037] The groove edge R is extended downward by leaving a margin through the middle hole, and the inner groove width is increased. The present invention controls the groove width by setting the axial dimension constant of the process plane.

[0038] A supplementary processing scheme for process holes is proposed: the processing scheme for supplementary processing of process holes includes processing the middle hole and the inner groove. When processing the inner groove, an empty pass is required to eliminate sharp edge burrs.

[0039] Example:

[0040] A process control method for the axial linear dimensions of the inner groove of a micro-part, wherein the theoretical values ​​of the inner holes on both sides of the inner groove of the micro-part are respectively:

[0041] Step 1: Process the inner hole and end surface on the opposite side of the control edge of the inner groove to the theoretical size;

[0042] Step 2: Process the inner hole on the side corresponding to the control edge of the inner groove to a first size, where the first size is the theoretical value minus the first value b;

[0043] Step 3: Determine the tool tip radius R;

[0044] Step 4: Use the tool tip with rounded corner R to machine the inner hole on the corresponding side of the control edge to the first size;

[0045] Step 5: Use the tool tip with rounded corner R to machine the inner groove to the first groove width, and the inner groove and the inner hole on the corresponding side of the control edge form a measuring surface;

[0046] Step 6: Use a depth micrometer to measure the distance from the end face on the opposite side of the control edge to the measuring surface;

[0047] Step 7: When the distance meets the threshold, the inner hole on the corresponding side of the control edge of the inner groove is processed to the theoretical size using the tool tip with a rounded corner R. At this time, the inner groove width changes from the first groove width to the theoretical groove width.

[0048] In another possible embodiment, the first value b is greater than 0.5 mm.

[0049] In another possible embodiment, the tool tip radius R is determined according to the axial dimensional accuracy.

[0050] In another possible embodiment, when there are chamfers θ on both sides of the bottom of the inner groove and θ is less than 90°, the distance Lmeasured from the end face on the opposite side of the control edge to the measuring surface satisfies: Lmeasured=L+a, wherein L is the theoretical axial distance of the control edge of the inner groove, and a is the axial distance between the measuring surface and the control edge.

[0051] In another possible embodiment, R<a<M, M is the axial distance between the intersection of the extended line of the angle θ and the inner hole of the first size and the control edge, and M=b / tanθ.

[0052] In another possible embodiment, the first groove width=theoretical groove width+a.

[0053] In another possible embodiment, the tool tip radius R is less than or equal to 0.1 mm.

[0054] In another possible embodiment, the method further includes: Step 8: performing a non-deep cutting pass on the control edge to remove sharp edge burrs.

Claims

1. A process control method for the axial linear dimension of the inner groove of a micro-part, characterized in that: include: Step 1: Process the inner hole and end surface on the opposite side of the control edge of the inner groove to the theoretical size; Step 2: Process the inner hole on the side corresponding to the control edge of the inner groove to a first size, where the first size is the theoretical value minus the first value b; Step 3: Determine the tool tip radius R; Step 4: Use the tool tip with rounded corner R to machine the inner hole on the corresponding side of the control edge to the first size; Step 5: Use the tool tip with rounded corner R to machine the inner groove to the first groove width, and the inner groove and the inner hole on the corresponding side of the control edge form a measuring surface; Step 6: Use a depth micrometer to measure the distance from the end face on the opposite side of the control edge to the measuring surface; Step 7: When the distance meets the threshold, the inner hole on the corresponding side of the control edge of the inner groove is processed to the theoretical size using the tool tip with a rounded corner R. At this time, the inner groove width changes from the first groove width to the theoretical groove width.

2. The method according to claim 1, characterized in that: The first value b is greater than 0.5 mm.

3. The method according to claim 2, characterized in that Determine the tool tip radius R based on the axial dimension accuracy.

4. The method according to claim 3, characterized in that When there are chamfers θ on both sides of the bottom of the inner groove and θ is less than 90°, the distance Lmeasured from the end face on the opposite side of the control edge to the measuring surface satisfies: Lmeasured=L+a, where L is the theoretical axial distance of the control edge of the inner groove, and a is the axial distance between the measuring surface and the control edge.

5. The method according to claim 4, characterized in that R<a<M, M is the axial distance between the intersection of the extended line of angle θ and the inner hole of the first size and the control edge, and M=b / tanθ.

6. The method according to claim 3, characterized in that First groove width = theoretical groove width + a.

7. The method according to claim 3, characterized in that The tool tip radius R is less than or equal to 0.1mm.

8. The method according to claim 3, characterized in that Also includes: Step 8: Make a zero-cut pass on the control edge.

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