CN102909612A - Method for grinding self-centering drill bit - Google Patents

Abstract

The invention belongs to the technical field of sharpening the cutting edge of a drill bit, in particular to a method for grinding a self-centering drill bit. In this method, after the centering bit is fixed, the centering bit is ground with a grinding wheel. Specifically, the method adjusts the angle between each grinding surface of the centering bit and the grinding wheel with a sharp angle, and sequentially The first flank of the centering drill, the first flank of the drill point, the second flank of the tool point, and the second flank of the drill point are ground. The method realizes the grinding of the drill bit through the existing common grinding equipment, has high practicability and reduces the use cost.

Description

The method of grinding self-centering drill bit

technical field

The invention belongs to the technical field of sharpening the cutting edge of a drill bit, in particular to a method for grinding a self-centering drill bit.

Background technique

According to the groove type, the drill bit can be divided into two types: straight groove and spiral groove. According to the direction of the helix angle, it can be divided into positive helix angle and reverse helix angle. The helix angle can be large or small according to actual needs. From the tool material, there are cemented carbide, high-speed steel, and welded PCD drills. There are two kinds of handles: straight handle and tapered handle. Most of the current drill bits are cemented carbide straight shank drill bits, because the current tool holders are all fixed in the form of hydraulic pressure, heat expansion and lateral solidification. Only a few special machines still use tapered shank drill bits. According to the top angle of the drill bit, the traditional concept of 118 degrees for the top angle of the drill bit is also abandoned. There are more drills with top angles of 130 degrees, 135 degrees, 140 degrees, and 150 degrees. According to different requirements, there can be more drill angles. . According to the form of the drill point, there are common drill points and the self-centering drill point mentioned in this program, as well as a special thin-walled drill point. In the current high-speed cutting era, ordinary drill points and self-centering drill points are mostly used, and ordinary drill points are the most widely used. Because of the difficulty in grinding and maintaining self-centering drills, even the programming of CNC grinding machines is sometimes very difficult, and cannot be as unified as mass production by tool manufacturers. Therefore, ordinary drill bits are widely used, but in order to quickly and accurately locate and improve production beats, many companies still use this self-centering drill to achieve fast and accurate positioning to achieve high-number cutting.

With the increasing progress of the manufacturing industry, the requirements for the precision and processing efficiency of the workpiece are getting higher and higher. Self-centering drill points are gradually replacing ordinary drill points. In this way, high-speed cutting and rapid positioning can be realized to improve production efficiency, but this type of grinding and maintenance is very difficult. Because the drill tip of this type of drill bit is composed of two parts, one is the drill tip for rapid positioning, and the other is the tool tip for high-speed cutting. When using ordinary equipment for grinding, because ordinary grinding equipment can only complete ordinary linear motion, it cannot realize the function of compensating for deviations in programming like a CNC grinder. The tool tip interferes when grinding the drill tip, and the drill tip interferes when grinding the tool tip. . Even the use of high-precision five-axis grinding machines requires particularly high skills for programmers. It brings great inconvenience to the sharpening and repeated utilization of the cutting tool. The cost of the tool is high, because the tool cannot be repaired by itself after it is worn out, it needs to be assigned to an external unit or returned to the factory for regrinding, and the cost is generally 30% or more of the new knife. It is necessary to pay a high amount of grinding costs, resulting in high tool costs for the enterprise; at the same time, due to the long tool grinding cycle, it is necessary to increase the turnover of the tools so as not to affect the normal use, causing capital occupation for the enterprise and bringing economic losses to the enterprise. loss.

Contents of the invention

In order to solve the deficiencies in the prior art, the present invention provides a method for grinding self-centering drill bits, which realizes the grinding of drill bits through existing common grinding equipment, has high practicability, and reduces the use cost.

In order to achieve the above object, the method for grinding the self-centering drill bit of the present invention, after the centering drill bit is fixed, adopts a sharper bowl-shaped or butterfly-shaped emery wheel to grind the centering drill bit, the method adjusts the centering drill bit The angle between each grinding surface of the centering drill bit and the grinding wheel with sharp corners, the first flank of the centering drill bit, the first flank of the drill point, the second flank of the tool point, the second flank of the drill point The second flank is ground.

As a limitation to the above manner, the grinding wheel is a bowl-shaped grinding wheel or a butterfly-shaped grinding wheel.

Specifically, the method for grinding self-centering drill bit of the present invention comprises the following steps:

Step 1, fixing the self-centering drill bit, clamping the centering drill bit on the tool clamping shaft, so that the center line of the centering drill bit is parallel to the axis of the tool clamping shaft;

Step 2: Grinding the first flank of the tool tip, adjusting the angle of the grinding wheel so that the grinding wheel is upturned, and the grinding wheel forms a first relief angle of 7 to 10 degrees relative to the first flank of the tool tip; feed and grind the centering drill bit, Use the grinding wheel to grind the first flank of the centering drill to the tool tip, and grind the first flank of one of the tool tips in place; after rotating the self-centering drill 180 degrees, grind the first flank of the other tool tip Flank grinding position;

Step 3: Grinding the first flank of the drill tip, adjusting the tool clamping axis so that it has half the angle of the drill tip with the end face where the sharp corner of the grinding wheel is, and grinding the first flank of the drill tip to the tool through the grinding wheel At the first flank of the drill point, grind one of the first flanks of the drill point in place; after rotating the self-centering drill 180 degrees, grind the other first flank of the drill point in place;

Step 4: Grinding the second flank of the tool tip. Based on step 3, raise the tool clamping axis by 10~15 degrees. Taking the edge band as the reference, control the grinding length of the second flank of the tool tip, and use the grinding wheel to The second flank is ground to the tip of the tool, and the second flank of one tool tip is ground in place; after the self-centering drill is rotated 180 degrees, the second flank of the other tool tip is ground in place;

Step 5: Grinding the second flank of the drill tip, adjusting the tool clamping axis so that it has half the angle of the drill tip with the end face where the sharp corner of the grinding wheel is located, and controlling the amount of grinding to form the width of the first flank of the drill tip , use the grinding wheel to grind the second flank of the drill tip to the second flank of the tool tip, and grind one of the second flanks of the drill tip in place; after rotating the self-centering drill 180 degrees, the drill tip Another second relief ground in place.

Further, in step six, cut the chisel edge, and grind the transverse toughness with a width of 0.2mm-0.3mm by the grinding wheel.

As a limitation to the above method, after each flank of the self-centering drill is ground in place in each of the above steps, an equal amount of grinding is processed.

As a further limitation on the above manner, the above grinding amount is 0.2mm.

As an improvement to the above method, the above self-centering drill bit is fixed on the tool clamping shaft through a spring collet.

As a limitation to the above method, a runout inspection step is included before step 1. When the self-centering drill is clamped and installed on the tool clamping shaft with a spring collet, the axial runout of the tool relative to the tool clamping shaft is checked.

As a further limitation to the above manner, the said tool runout is 0.02mm.

By adopting the above-mentioned technical scheme and using the characteristics of the sharp corner of the bowl-shaped grinding wheel or the butterfly-shaped grinding wheel, the flank face of the self-centering drill bit is ground sequentially in sections to achieve a better grinding effect and solve the problem of self-centering. The repair equipment of the drill bit is put into use, so that the self-centering drill bit can be used again after grinding, and the requirements for equipment and personnel are relatively low. the

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

Fig. 1 is the overall structure schematic diagram of the self-centering drill bit that the present invention relates to;

Fig. 2 is the right side view of Fig. 1 .

In the picture:

1. Drill tip; 11. First flank of drill tip; 12. Second flank of drill tip; 2. Tool tip; 21. First flank of tool tip; 22. Second flank of tool tip.

Detailed ways

Taking the existing typical cemented carbide straight flute self-centering drill as an example, the method of the present invention is described in detail below:

As can be seen from Figure 1, the cutting part of the self-centering drill is mainly composed of drill tip 1 and tool tip 2, and it can be seen from Figure 2 that the self-centering drill has drill tip 1 and tool tip 2 Composite Structure. Wherein, the drill point 1 has the first flank 11 and the second flank 12 of the drill, and the point 2 has the first flank 21 and the second flank.

When repairing the above-mentioned self-centering drill bit, the general idea of the repair is to decompose the drill bit, adjust the angle between each grinding surface of the centering drill bit and the grinding wheel with a sharp angle, and sequentially correct the centering drill bit. The first flank 21 of the tool tip, the first flank 11 of the drill tip, the second flank 22 of the tool tip, and the second flank 12 of the drill tip are ground. The grinding wheel adopts bowl type grinding wheel (11V9) or butterfly grinding wheel (12V9).

Its concrete grinding method comprises the steps:

Step 1: Clamp the centering drill bit with a spring sleeve and install it on the equipment with the tool clamping shaft. Use a magnetic gauge or a dial indicator to detect the runout of the drill bit installation. Specifically, attach the magnetic gauge base to the equipment to detect two For the height of the tool tip, touch the gauge head to the tip of the tool and record the reading on the dial indicator, then rotate the tool 180 degrees to measure the height of the other tool tip. If the difference is too large, it means that there is a problem with the tool clamping and needs to be adjusted to ensure that the tool’s runout is within 0.02 mm, so that the centerline of the centering drill coincides with the axis of the tool clamping shaft;

Step 2, the first flank 21 of the tool tip is ground, and the clamping shaft with the tool is adjusted to a horizontal state to ensure that the main cutting edge of the drill bit to be ground is perpendicular to the center line of the drill bit. At this time, the grinding wheel is parallel to the tool. Adjust the angle of the grinding wheel so that the axis of the grinding wheel is lifted up by 7~10 degrees, so that the grinding wheel forms a first relief angle of 7~10 degrees relative to the first flank of the tool tip. Here, try to use the largest diameter of the grinding wheel to ensure repair. The quality of the drill tip. By manually feeding the centering drill, the first flank 21 of the centering drill tip is in contact with the grinding wheel to start grinding. The feed rate of the centering drill is preferably 0.01mm each time. Grind the first flank 21 of the knife tip to the tip of the knife, grind the first flank of one of the knife tips in place, and then feed and grind the grinding amount of about 0.2mm, record this position after the grinding is in place; After rotating the self-centering drill bit by 180 degrees, after the first flank 21 of the other tool tip is ground in place, the grinding amount of about 0.2mm is also ground in feed to grind the worn part well;

Step 3: Grinding the first flank 11 of the drill tip. Taking the angle of the drill tip part as 120 degrees as an example, adjust the tool clamping axis so that the tool clamping axis and the sharpest part of the grinding wheel form a single angle of 60 degrees. Use the grinding wheel to trim the first flank of the drill tip to the first flank of the tool tip, stop the feeding of the grinding wheel, then grind the other side, and let the tool advance about 0.2mm after repeated grinding; rotate the self-centering drill After 180 degrees, after grinding the other first flank of the drill tip, let the tool advance about 0.2mm to realize the seamless connection between the first flank 11 of the drill tip and the first flank 21 of the tool tip;

Step 4: Grinding the second flank face 22 of the tool tip. In this step, the state of the grinding wheel and equipment is basically the same as that of Step 2, but based on Step 3, the tool clamping axis is raised by 10~15 degrees, and the grinding is gradually advanced. . The method is basically the same as that of grinding the first flank of the tool tip, but the amount of grinding should be controlled to control the width of the first flank. Generally, the width of the first flank is about 0.3~0.5mm, because it is not easy to disassemble. Measurement, so this width can be based on the margin of the tool, and the same width as the width of the margin can make the length of the second flank consistent with the length of the first flank, by controlling the grinding length of the second flank of the tool tip , use the grinding wheel to grind the second flank to the tip of the tool, and grind the second flank of one of the tool tips in place, and then feed and grind the grinding amount of about 0.2mm; rotate the self-centering drill 180 degrees Finally, grind the second flank of the other tool tip in place, and then feed the grinding amount of about 0.2mm;

Step 5: Grinding the second flank 12 of the drill tip. This step is basically the same as Step 3. The difference is that based on Step 4, the tool clamping axis is adjusted so that it forms a 60-degree clamp with the end face where the sharp corner of the grinding wheel is located. horn.

Step 6, cut the chisel edge, and grind the transverse toughness with a width of 0.2mm-0.3mm by the grinding wheel.

Claims (9)

1. A method for grinding the self-centering drill bit, after the centering drill bit is fixed, the centering drill bit is repaired by using an emery wheel, it is characterized in that: the method adjusts each grinding surface of the centering drill bit and has a pointed Grinding the first flank of the centering drill bit, the first flank of the drill point, the second flank of the tool point, and the second flank of the drill point in sequence. 2. The method for grinding a self-centering drill bit according to claim 1, wherein the grinding wheel is a bowl-shaped grinding wheel or a butterfly-shaped grinding wheel. 3. The method for grinding self-centering drill bit according to claim 1 or 2, characterized in that the method comprises the steps: Step 1, fixing the self-centering drill bit, clamping the centering drill bit on the tool clamping shaft, so that the center line of the centering drill bit is parallel to the axis of the tool clamping shaft; Step 2, grind the first flank of the tool tip; adjust the angle of the grinding wheel so that the grinding wheel is upturned, and the grinding wheel forms a first relief angle of 7~10 degrees relative to the first flank of the tool tip, feed and grind the centering drill bit, Use the grinding wheel to grind the first flank of the centering drill tip to the tool tip, and grind the first flank of one of the tool tips in place; after rotating the self-centering drill 180 degrees, grind the other tool tip The first flank grinding is in place; Step 3: Grinding the first flank of the drill tip, adjusting the tool clamping axis so that it has half the angle of the drill tip with the end face where the sharp corner of the grinding wheel is, and grinding the first flank of the drill tip to the tool through the grinding wheel At the first flank of the drill point, grind one of the first flanks of the drill point in place; after rotating the self-centering drill 180 degrees, grind the other first flank of the drill point in place; Step 4: Grinding the second flank of the tool tip. Based on step 3, raise the tool clamping axis by 10~15 degrees. Taking the edge band as the reference, control the grinding length of the second flank of the tool tip, and use the grinding wheel to The second flank is ground to the tip of the tool, and the second flank of one tool tip is ground in place; after the self-centering drill is rotated 180 degrees, the second flank of the other tool tip is ground in place; Step 5: Grinding the second flank of the drill tip, adjusting the tool clamping axis so that it has half the angle of the drill tip with the end face where the sharp corner of the grinding wheel is located, and controlling the amount of grinding to form the width of the first flank of the drill tip , use the grinding wheel to grind the second flank of the drill tip to the second flank of the tool tip, and grind one of the second flanks of the drill tip in place; after rotating the self-centering drill 180 degrees, the drill tip Another second relief ground in place. 4. The method for grinding self-centering drill bit according to claim 3, characterized in that: Step 6, cut the chisel edge, and grind the transverse toughness with a width of 0.2mm-0.3mm by the grinding wheel. 5. The method for grinding the self-centering drill according to claim 3, characterized in that: after each flank of the self-centering drill is ground in place, an equal amount of grinding is processed. 6. The method for grinding the self-centering drill bit according to claim 5, characterized in that: the grinding amount is 0.2mm. 7. The method for grinding a self-centering drill bit according to claim 3, characterized in that: said self-centering drill bit is fixed on the tool clamping shaft through a spring collet. 8. The method for grinding self-centering drill according to claim 7, characterized in that: before step 1, a runout inspection step is included, when the self-centering drill is clamped with a spring collet and installed on the tool clamping shaft , to check the axial runout of the tool relative to the tool clamping axis. 9. The method for grinding the self-centering drill according to claim 8, characterized in that: the runout of the tool is 0.02mm.

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