CN116276361A - Diameter dimension reworking method for rod-shaped part with length-diameter ratio larger than 8 after cadmium plating - Google Patents

Abstract

The diameter dimension reworking method of the rod-shaped part with the length-diameter ratio of more than 8 after cadmium plating comprises the following steps: grinding wheel and guide wheel trimming, centerless grinding, cleaning and passivation. The invention finds a new reworking method through exploration in the processing, improves the reworking qualification rate and solves the problem of out-of-tolerance dimension in the product processing.

Description

Diameter dimension reworking method for rod-shaped part with length-diameter ratio larger than 8 after cadmium plating

Technical Field

The invention relates to a diameter dimension reworking method of a rod-shaped part with an aspect ratio of more than 8 after cadmium plating.

Background

The problem of unqualified rod size is encountered when manufacturing a small hexagon head bolt f7 in a polish rod tolerance zone for HB 1-106-6X 90 hinge connection.

The structure of the small hexagon head bolt f7 with the polish rod tolerance zone for HB 1-106-6X 90 hinge connection is shown in figure 1, and the small hexagon head bolt consists of a hexagon head, a polish rod and threads, wherein the surface is plated with cadmium, the thickness of the cadmium is 5-8 microns, the material is 30CrMnSiA, and the performance sigma b=1175+/-100 MPa. The product has the following difficulties: the surface is provided with a cadmium plating layer, and the final polish rod size phi 6f7 (-0.010-0.022) is difficult to ensure.

The existing processing technology comprises the steps of material preparation, heat treatment, shape counting, rod grinding and cadmium plating; the problem is that in cadmium plating, due to the tip effect in electroplating: the electric lines of force at two ends are more concentrated, the current density at two ends is larger than that in the middle, and the current density is in direct proportion to the deposition speed of the plating layer, so that the thickness of the plating layer is thick at two ends of the polished rod and thin in the middle of the polished rod; therefore, the size phi 6f7 (-0.010-0.022) of the bolt polish rod part is unqualified, and if the middle part of the polish rod is qualified, the two ends of the polish rod are large, and the size is 0.02-0.03.

The common reworking method is to re-plate cadmium, select qualified use, and continue cadmium plating if unqualified.

However, the reworking method for re-plating cadmium is difficult to rework and qualified due to the tip effect during electroplating, and the reworking qualification rate is low. The reworking method for re-cadmium plating is only suitable for products with length-diameter ratio less than about 6 under the condition that the length of a polish rod is relatively short.

Disclosure of Invention

The invention aims to solve the technical problems of finding out a new reworking method, improving the reworking qualification rate and exceeding the dimension of a product in processing through exploration in the processing.

In order to solve the technical problems, the invention adopts the following technical scheme:

the diameter dimension reworking method of the rod-shaped part with the length-diameter ratio of more than 8 after cadmium plating comprises the following steps:

step one: dressing a grinding wheel and a guide wheel; firstly, a grinding wheel dresser is used for dressing the outer circle surface of a grinding wheel by a diamond drilling pen, and the grinding particles on the working surface of the dressed grinding wheel form micro-blades with different thickness degrees; the fine-trimmed grinding wheel has extremely fine micro-blade pitch and is distributed on the same rotation circumference, so that the fine-trimmed grinding wheel has better micro-blade equal height; the diamond pen turning method is used for trimming the grinding wheel, and the diamond pen is used as a tool to trim the grinding wheel in a turning mode; the diamond pen is a trimming tool for welding large-particle diamond on a special cutter bar; the sharp angle phi of the diamond drill is 70-80 degrees; when the diamond is trimmed, abrasive particles touch the hard sharp corners of the diamond, and the diamond is cracked or falls off completely, so that a new micro-blade is generated; the contact area between the diamond and the grinding wheel is small, and the elastic deformation is small, so that a fine and smooth surface can be obtained; the installation angle is 5-10 degrees; trimming the guide wheel by the same method;

step two: centreless grinding; the product after cadmium plating is subjected to centerless grinding, a workpiece is placed between a grinding wheel and a guide wheel of a centerless grinder for grinding, cooling liquid is not used, the workpiece is prevented from being polluted, surplus plating allowance is removed by grinding, and the polish rod size phi 6f7 (-0.010-0.022) is ensured;

step three: cleaning; ultrasonic cleaning to remove dirt such as greasy dirt, dust and the like on the surface;

step four: passivating; after the workpiece is ground, the ground part is white, the part which is not ground is golden yellow, and the appearance requirement after cadmium plating is not met; therefore, the ground workpiece is soaked in the special passivation solution in the surface treatment tank, and a golden film layer is formed on the surface of the workpiece after a certain time, so that the surface color of the workpiece meets the requirements.

The beneficial effects of adopting above-mentioned technical scheme are:

the invention finds a new reworking method through exploration in the processing, improves the reworking qualification rate and solves the problem of out-of-tolerance dimension in the product processing.

Drawings

FIG. 1 is a schematic diagram of the structure of a small hexagon head bolt f7 with a polish rod tolerance zone for the hinge connection of the processed products HB 1-106-6X 90.

In the figure: 1-hexagonal head, 2-polish rod, 3-screw thread M6.

Fig. 2 is a schematic view of a diamond drilling pen used in the present invention.

In the figure: 4-diamond, 5-solder and 6-pen holder.

Fig. 3 is a schematic view of the installation angle structure of the diamond drilling pen of the invention when trimming the grinding wheel.

In the figure: 4-diamond drill.

FIG. 4 is a schematic diagram of a reworked polished rod with a small hexagonal head bolt f7 for centerless grinding HB 1-106-6X 90 hinge connection.

Fig. 5 is a top view of fig. 4.

In the figure: 7-processing products, 8-grinding wheels, 9-supporting plates and 10-guide wheels.

Detailed Description

The present invention is described in further detail below:

the diameter dimension reworking method of the rod-shaped part with the length-diameter ratio of more than 8 after cadmium plating comprises the following steps:

step one: dressing a grinding wheel and a guide wheel; firstly, a grinding wheel dresser is used for dressing the outer circle surface of a grinding wheel by a diamond drilling pen, and the grinding particles on the working surface of the dressed grinding wheel form micro-blades with different thickness degrees; the fine-trimmed grinding wheel has extremely fine micro-blade pitch and is distributed on the same rotation circumference, so that the fine-trimmed grinding wheel has better micro-blade equal height; the diamond pen turning method is used for trimming the grinding wheel, and the diamond pen is used as a tool to trim the grinding wheel in a turning mode; the diamond pen is a trimming tool for welding large-particle diamond on a special cutter bar; the sharp angle phi of the diamond drill is 70-80 degrees; when the diamond is trimmed, abrasive particles touch the hard sharp corners of the diamond, and the diamond is cracked or falls off completely, so that a new micro-blade is generated; the contact area between the diamond and the grinding wheel is small, and the elastic deformation is small, so that a fine and smooth surface can be obtained; the installation angle is 5-10 degrees; trimming the guide wheel by the same method;

step two: centreless grinding; the product after cadmium plating is subjected to centerless grinding, a workpiece is placed between a grinding wheel and a guide wheel of a centerless grinder for grinding, cooling liquid is not used, the workpiece is prevented from being polluted, surplus plating allowance is removed by grinding, and the polish rod size phi 6f7 (-0.010-0.022) is ensured;

step three: cleaning; ultrasonic cleaning to remove dirt such as greasy dirt, dust and the like on the surface;

step four: passivating; after the workpiece is ground, the ground part is white, the part which is not ground is golden yellow, and the appearance requirement after cadmium plating is not met; therefore, the ground workpiece is soaked in the special passivation solution in the surface treatment tank, and a golden film layer is formed on the surface of the workpiece after a certain time, so that the surface color of the workpiece meets the requirements.

Claims (1)

1. A diameter dimension reworking method of a rod-shaped part with an aspect ratio of more than 8 after cadmium plating is characterized by comprising the following steps: it comprises the following steps:

step one: dressing a grinding wheel and a guide wheel; firstly, a grinding wheel dresser is used for dressing the outer circle surface of a grinding wheel by a diamond drilling pen, and the grinding particles on the working surface of the dressed grinding wheel form micro-blades with different thickness degrees; the fine-trimmed grinding wheel has extremely fine micro-blade pitch and is distributed on the same rotation circumference, so that the fine-trimmed grinding wheel has better micro-blade equal height; the diamond pen turning method is used for trimming the grinding wheel, and the diamond pen is used as a tool to trim the grinding wheel in a turning mode; the diamond pen is a trimming tool for welding large-particle diamond on a special cutter bar; the sharp angle phi of the diamond drill is 70-80 degrees; when the diamond is trimmed, abrasive particles touch the hard sharp corners of the diamond, and the diamond is cracked or falls off completely, so that a new micro-blade is generated; the contact area between the diamond and the grinding wheel is small, and the elastic deformation is small, so that a fine and smooth surface can be obtained; the installation angle is 5-10 degrees; trimming the guide wheel by the same method;

step two: centreless grinding; the product after cadmium plating is subjected to centerless grinding, a workpiece is placed between a grinding wheel and a guide wheel of a centerless grinder for grinding, cooling liquid is not used, the workpiece is prevented from being polluted, surplus plating allowance is removed by grinding, and the polish rod size phi 6f7 (-0.010-0.022) is ensured;

step three: cleaning; ultrasonic cleaning to remove dirt such as greasy dirt, dust and the like on the surface;

step four: passivating; after the workpiece is ground, the ground part is white, the part which is not ground is golden yellow, and the appearance requirement after cadmium plating is not met; therefore, the ground workpiece is soaked in the special passivation solution in the surface treatment tank, and a golden film layer is formed on the surface of the workpiece after a certain time, so that the surface color of the workpiece meets the requirements.

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