KR19980022395A - Manufacturing method of cemented carbide twisted hole drill material - Google Patents

Abstract

The present invention relates to a method of manufacturing a carbide twisted oil hole drill material, and more particularly, the oil hole in the twisted drill is most commonly used in various applications for drilling holes or grooves of metal or nonmetal materials. In the drill manufacturing method having, a molding step for molding the rod body consisting of WC, Co, TiC, TaC, and the tube body consisting of WC, Co, TaC, VC, the shrinkage in the subsequent sintering step, respectively, An oil hole forming step of forming an oil hole through which oil is supplied to the outer circumferential surface of the rod, and a rod body subjected to the oil hole forming step is inserted into the simplified body through the molding step, and then the sintering ratio is differently sintered by a vacuum sintering furnace. And a sintering step of integrating the tube body and a spiral groove forming step of forming a spiral groove on the circumferential surface of the integrated tube body to improve productivity. It is possible to stabilize the quality of the primary sintering furnace and to quickly remove chips during cutting operations, and especially to manufacture the carbide twisted oil hole drill material that can maintain the original shape even after grinding the tip. It is about.

Description

Manufacturing method of carbide twisted oil hole drill material

The present invention relates to a method of manufacturing a carbide twisted oil hole drill material, and more specifically, the most widely used drills used for drilling holes or grooves of metals, non-metals, materials, oil holes in the twisted drill In the drill manufacturing method having a, forming the rod body consisting of WC, Co, TiC, TaC, and the tubular body consisting of WC, Co, TaC, VC, but the molding step that can vary the shrinkage rate in the subsequent sintering step and After the oil hole forming step of forming an oil hole for supplying oil to the outer circumferential surface of the bar body, and inserting the bar body undergoing the oil hole forming step into the tube through the forming step, the shrinkage ratio is sintered differently by a vacuum sintering furnace And a sintering step of integrating the pipe body and a spiral groove forming step of forming a spiral groove on the circumferential surface of the integrated pipe body. It is possible to improve the quality of the primary sintering furnace, and to quickly remove chips during cutting operations, and especially to the manufacturing method of carbide twisted oil hole drill material which can maintain the original shape even after grinding the tip. It is about.

In general, the drill is used in a variety of applications for drilling holes or grooves of metal, non-metal materials, the most commonly used is the twisted drill.

However, during the formation of the hole using the drill, frictional heat between the drill blade and the base material is generated, and the chip is subjected to the resistance of the cut chip, so that the chip can be removed quickly. When the drill is overheated, the cut cutting blade is blunt. In the case of severe and severe melting of the area around the hole of the base material in which the hole is formed, a means for preventing overheating is required.

Accordingly, in the related art, cooling oil (or water) is externally lubricated at the distal end of the drill in contact with the plate to be drilled during the drilling operation to prevent the cutting surface of the drill from being overheated.

However, in the conventional drill, when the groove or the hole of the plate is drilled to a depth more than four times the diameter of the drill, the tip of the drill that is in contact with the bottom of the groove or the hole is not sufficiently supplied with coolant and the tip of the drill is overheated. .

Therefore, the conventional drill has a problem that the wear of the tip is made quickly, as well as a good drill can not be achieved.

In order to solve the above problem, the present inventor has filed a patent application No. 93-25065 (name of the invention: a method of manufacturing a cemented carbide drill).

Looking at this roughly in the method of manufacturing a drill, as shown in the claims, the rod body of the first material consisting of WC, Co, TiC, TaC and the tubular body of the second material consisting of WC, Co, TiC, VC Forming each, forming a rod of a first material by sintering in a vacuum sintering machine, forming a supply path of a coolant on a circumferential surface of the first sintered rod, and supplying the coolant. Inserting the rod formed with the furnace into the molded tube of the second material and secondly sintering the tube formed of the second material by a vacuum sintering machine to integrate the rod and the tube; And forming a spiral groove on the circumferential surface of the sintered tube.

However, the above-described invention is already sufficiently deflated and firm in the step of forming a coolant supply path on the circumferential surface of the first sintered rod, and thus, a long time is required in the process of forming the coolant supply path, thereby reducing productivity. There is a problem in ensuring the stability of the second sintering furnace of the first and second sintering.

The present invention has been made to solve the above-mentioned problems, the main purpose is to supply a coolant oil to the tip of the drill during the drilling operation to prevent the tip from overheating and to reduce the wear of the tip as well as to perform a good drill The present invention provides a method of manufacturing a cemented carbide twisted hole drill material.

Still another object of the present invention is to provide a method of manufacturing a cemented carbide twisted hole drill material which can improve productivity and ensure stability of only one sintering furnace.

In order to achieve the above object, the present invention, by forming a bar body consisting of WC, Co, TiC, TaC, and a tube body consisting of WC, Co, TaC, VC, but different shrinkage rate in the subsequent sintering step The shrinkage rate is differently sintered by a vacuum sintering furnace after inserting the rods undergoing the molding step and the oil hole forming step and the oil hole forming step to form the oil holes supplied with the oil on the outer circumferential surface of the rod into the tube through the forming step. To provide a method of manufacturing a cemented twisted oil hole drill material comprising a sintering step of integrating the rod and the tube and a spiral groove forming step of forming a spiral groove on the circumferential surface of the integrated tube.

1 is a structural diagram of a drill according to the present invention

Figure 2 is a perspective view after the in-process forming step according to the present invention

3 is a perspective view before the sintering step during the process according to the present invention

4 is a perspective view after the in-process sintering step according to the present invention

5 is a cross-sectional view of FIG.

* Explanation of symbols for main parts of the drawings

10: drill 20: spiral groove

30: tube 40: rod

50: Pickled 60: Land

70: oil hole 71: shank

72: body

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 5.

1 is a structural diagram of a drill according to the present invention, Figure 2 is a perspective view after the in-process forming step according to the invention, Figure 3 is a perspective view before the sintering step in the process according to the invention, Figure 4 is a sintering in the process according to the present invention 5 is a cross-sectional view of FIG. 4 after the step.

Looking at the basic configuration of the present invention first, forming the rod body 40 consisting of WC, Co, TiC, TaC, and the tubular body 30 consisting of WC, Co, TaC, VC, but shrinkage in the subsequent sintering step The tubular body which has undergone a molding step and an oil hole forming step for forming an oil hole 70 through which oil is supplied to the outer circumferential surface of the rod 40 and an oil hole forming step for forming the rod 40, which may be different from each other. After inserting into the 30, the sintering step is differently sintered by the vacuum sintering furnace to integrate the rod 40 and the tubular body 30, and the spiral groove 20 is formed on the circumferential surface of the integrated tubular body 30. It is configured to include a spiral groove forming step.

The twisted drill 10 made of cemented carbide is composed of two parts, a shank 71 which is a bag portion and a body 72 which is a body portion, and a pair is provided on the body 72. A pair of picklings (50, (cutting edges)) are formed at the tip of the spiral groove 20, and an oil hole 70 for supplying a coolant oil in the drill is spirally formed in the lengthwise direction of the drill. Dogs or two or more dogs are formed.

Further, lands 60 (land), which are portions forming the outer circumferential pickles 50 of the drill, are formed.

In the method of manufacturing the twisted drill having the above structure, a suitable powder composition of WC, Co, TiC, and TaC is mixed to make a mixed powder, which is then placed in a jar with a nucleic acid solution and then placed in a ball mill. By grinding.

Subsequently, a temporary binder such as paraffin or wax is uniformly mixed with the slurry mixed powder by a stirrer, the mixed powder is placed in a mold, and the sealing body 40 is pressed at a constant pressure to complete the sealing body forming step. do.

Then, a mixture of WC, Co, TaC, and VC is mixed to make a suitable powder, and then mixed into a container with a nucleic acid solution, and then milled by a ball mill.

Subsequently, a temporary binder such as paraffin or wax is uniformly mixed with the slurry mixed powder by a stirrer, and then the mixed powder is placed in another mold and the tube 30 is pressed under a constant pressure. Is done.

At this time, the inner diameter formed in the longitudinal direction of the formed tubular body 30 should be larger in size than the diameter of the rod 40 and the length of the tubular body 30 should be smaller than the length of the rod 40.

In addition, the rod 40 and the tubular body 30 should be molded in consideration of the shrinkage in the sintering step, which is a subsequent process, and if the shrinkage ratios of the rod 40 and the tubular body 30 are compared with each other, the rod 40 will be described. This is also natural because the shrinkage ratio of the tube 30 is less than the shrinkage ratio so as to be integrated in the sintering step.

Two spiral oil holes 70 are formed on the circumferential surface of the rod 40 which has undergone the forming step (oil hole forming step).

At this time, one or three oil holes 70 may be formed along the circumferential surface of the rod 40.

Since the oil hole forming step is performed before the sintering step, i.e., the oil hole 70 is formed before the rod body 40 is contracted, the oil hole forming operation is easy and the time is consumed less, and the productivity is about twice as before. The degree is improved.

In Figure 3, the oil hole 70 is inserted into the inner diameter of the tubular body 30, which has been formed on the circumferential surface, and then subjected to a sintering step of sintering by injecting in a vacuum sintering furnace.

After making the internal state of the vacuum sintering furnace into a vacuum state, the internal temperature of the sintering apparatus is repeated by the temperature raising step and the temperature holding step, and the temperature raising step specifies that the temperature increase rate is lowered in proportion to time.

When the internal temperature of the vacuum sintering furnace rises a certain temperature, the power supply is stopped so that the internal temperature of the vacuum sintering furnace is left in a vacuum state for about 6 hours to maintain room temperature.

As described above, keeping the interior in vacuum is intended to prevent oxidation.

In this way, the rod 40 and the annulus 30 are contracted in the longitudinal direction as well as the radial direction, but the rod 40 is less contracted and the annulus 30 is further contracted to be integrated.

Preferably, the shrinkage of the rod 40 is preferably 17% to 20%, and the shrinkage of the ring 30 is preferably 20.5% to 23%.

In addition, the Co of the rod 40 and the tube 30 is converted into a solid phase from a solid phase to a liquid phase as the sintering step proceeds.

In FIG. 5, the outer periphery of the rod 40 is completely coupled to the inner diameter of the tubular 30 sintered and shrunk, and thus the rod 40 and the tubular body 30 are integrated.

In this case, the inner diameter of the tubular body 30 reduced by the sintering process should not be smaller than 1% compared to the diameter of the rod 40 which is also reduced.

If the inner diameter of the tubular body 30 reduced by the sintering process is smaller than 1% compared to the diameter of the rod body 40 that is reduced together, the tubular body 30 may be easily broken.

Thereafter, the twisted drill 10 as shown in FIG. 1 is completed through the spiral groove forming step of forming the spiral groove 20 on the circumferential surface of the tubular body 30 integrated with the rod 40.

In this case, in order to form the spiral groove 20 on the circumferential surface of the sintered tubular body 30, it is necessary to accurately grasp the position of the oil hole 70 integrally formed on the circumferential surface of the rod body 40, and thus the tubular body 30. It is natural that the length of the rod 40 should be greater than the length of the tubular body 30 in order for a portion of the rod 40 integrated into the inner portion of the tubular body 30 to protrude out of the tubular body 30.

Therefore, the present invention forms a spiral oil hole 70 on the circumferential surface of the cemented carbide rod 40, the rod 40 and the rod 40 in the state inserted into the inner diameter of the cemented carbide tube 30 Carbide twisted oil hole drill having the oil hole 70 therein can be easily manufactured by integrating the rod body 40 and the tube body 30 by sintering the tube body 30 simultaneously with different shrinkage rates.

As described above, the present invention provides a coolant oil to the tip of the twisted drill during drilling to prevent overheating and to reduce wear of the tip, as well as to achieve good drilling and to improve productivity during the manufacturing process. It is a very useful invention that can stabilize the quality of only one sintering furnace.

Claims (2)

Forming the rod body 40 consisting of WC, Co, TiC, TaC, and the tubular body 30 consisting of WC, Co, TaC, VC, and the molding step and the shrinkage in the subsequent sintering step can be different An oil hole forming step of forming an oil hole 70 through which oil is supplied to the outer circumferential surface of the bar 40 and a bar 40 having undergone the oil hole forming step are inserted into the tubular body 30 which has undergone a molding step and then vacuum sintered. Carbide including a sintering step of sintering different shrinkage ratio by the furnace to integrate the bar body 40 and the tube 30 and the spiral groove forming step of forming the spiral groove 20 on the circumferential surface of the integrated tube 30 Method for manufacturing twisted oil hole drill material. The method of claim 1, wherein the shrinkage of the rod 40 in the sintering step is 17% to 20% and the shrinkage of the ring 30 is 20.5% to 23%. .