First, the definition of turning cutting and grooving:

The cutting and grooving cutter is a special tool for turning applications, mainly used for cutting and grooving. The cutting slotting knife is divided into two kinds of cutting knife and cutting knife, in which the cutting knife head is longer and the blade is long and narrow, so the design purpose is to reduce the material consumption of the workpiece and ensure that the cutting can be cut to the center. Therefore, the length of the cutting tool head must be greater than the radius of the workpiece. The grooving knife is basically similar to the cutting knife, and the difference between the grooving knife and the cutting knife is mainly reflected in the following aspects:

1. Different uses. The grooving knife is mainly used to cut grooves on the workpiece, such as keyways, oil grooves, etc. The cutting knife is used to cut the workpiece so that it is separated into two parts.

2. Different shapes. The shape of the groove cutter usually matches the shape of the groove that needs to be cut. The cutting blade of the cutter is relatively long and narrow.

3. Different cutting methods. When grooving, the tool usually needs to cut along the outline of the groove; Cutting is cutting on a flat surface.

4. Different cutting forces. It is necessary to bear a large cutting force when cutting off, because it is necessary to cut off the workpiece at one time; The cutting force is relatively small when grooving.

5. Tool strength requirements are different. Due to the large cutting force during cutting, the strength of the tool is required to be higher.

6. Different requirements for tool sharpening. The grinding requirements of the two are also different to adapt to their respective cutting tasks.

7. Processing accuracy requirements are different. The precision requirements of grooving may be relatively high, and the precision requirements of cutting mainly lie in the flatness of the cutting surface.

Second, which types of cutting and grooving  tools are divided into:

The types of cutting tools mainly include the following:

1. Manual cutting tools : often used for manual operation, suitable for cutting off small workpieces.

2. Mechanical cutting tools : can be installed on machine tools and other mechanical equipment to achieve automatic processing.

3. High-speed steel cutting tools : with high hardness and wear resistance.

4. Carbide cutting tools : high hardness, excellent cutting performance.

5. Coating cutting tools : improve wear resistance and service life through coating.

6. Adjustable cutting tools : the position and Angle of the tool can be adjusted to adapt to different processing needs.

7. Multi-edge cutting tools : there are multiple blades to improve cutting efficiency.

8. Special shape cutting tools : used to cut special shape workpieces.

Third, cutting, grooving processing form:

Common forms of cutting knives:

Straight line cutting: used to cut the workpiece along the straight line direction.

Rotary cutting: The cutting operation is performed on the rotating workpiece.

Multi-section cutting: cutting the workpiece into multiple parts at one time.

Deep cutting: can be cut to a certain depth.

Precision cutting: Pursue high dimensional accuracy and surface quality.

In the actual processing, according to the characteristics and requirements of the workpiece, choose the appropriate cutting tool processing form. At the same time, it is also necessary to pay attention to the selection of tools, including the material, shape and size of the tool. And the setting of cutting parameters, such as cutting speed, feed and depth of cutting, cooling and lubrication during machining to reduce cutting temperatures and extend tool life. At the same time, ensure that the tool is installed and calibrated to ensure that the position and Angle of the tool is correct. And the workpiece after processing is tested to ensure that it meets the requirements.

Common forms of groove processing:

Through groove: machining along a straight line.

Spiral groove: spiral shape.

T-slot: Shaped like the letter "T".

Dovetail groove: having dovetail shape.

Arc groove: presents an arc shape.

Keyway: A slot for mounting a key.

Oil tank: for lubrication and heat dissipation.

Special groove: customized shape according to special needs.

These groove processing forms play an important role in different fields and applications. (1) Mechanical manufacturing, to ensure the assembly and function of parts. 2. Electronic equipment, providing wiring or connection space. 3. Automotive industry, to meet transmission and connection requirements.

Fourth, the characteristics of cutting and grooving tools:

Grooving and cutting are unique turning applications. The application of cutting and grooving includes outer circle grooving, outer circle cutting, inner hole grooving, end face grooving and tool withdrawal grooving, etc. The grooving shapes include narrow grooves, wide grooves, shallow grooves, deep grooves and forming grooves. For tool applications, each groove has some special requirements, in general, the circular groove is the easiest to work, because gravity and cutting fluid can help with chip removal. In addition, the outer groove machining is visible to the operator and the machining quality can be checked directly and relatively easily. However, some potential obstacles in workpiece design or clamping must be avoided, and in general, the cutting effect is best when the tip of the slotting tool is kept slightly below the center line.

The inner hole grooving is similar to the outer circle grooving, except that the application of cutting fluid and chip removal are more challenging. For internal hole grooving, the best performance is achieved when the tip position is slightly above the center line. In order to better process the end grooves, the tool must be able to move in the axial direction. The machining effect is best when the tip position of the tool is slightly higher than the center line.

The cutting tools used for cutting and grooving are mainly all kinds of grooving knives for turning. Its process features are:

1. A main cutting edge and two auxiliary cutting edges participate in three-sided cutting at the same time, the plastic deformation of the cut material is complex, the friction resistance is large, the feed amount is small during processing, the cutting thickness is thin, the average deformation is large, and the unit cutting force is increased. The total cutting force and power consumption are large, generally about 20% larger than the external turning, while the heat dissipation is poor and the cutting temperature is high.

2. The cutting speed is constantly changing during the processing, especially when cutting off processing, the cutting speed changes from the maximum to zero. Cutting forces and heat of cutting are also changing.

3. The workpiece rotates, the tool is cut continuously, and the actual Archimedes spiral surface is formed on the surface of the workpiece, resulting in the actual front Angle and back Angle are constantly changing, making the process more complicated.

4. Because of the narrow width of the cutting tool, relative suspension elongation, poor tool rigidity, easy to vibration, especially when cutting and cutting deep slots. Chip removal is also a crucial factor in the cutting process. As the tool moves deeper, the less chance there is of breaking chips appearing in the confined space. The chip break groove of the blade is mainly used to form a neat chip, so as to facilitate smooth chip discharge. The result of poor performance in this respect is chip blocking, which leads to poor surface quality, which in turn causes tool breakage.

 

Fifth, the advantages of carbide cutting and grooving tools

1. High hardness and wear resistance: it can effectively resist wear and maintain long-term cutting performance. 86 ~ 93HRA, equivalent to 69 ~ 81HRC);

2. High strength and toughness: it is not easy to deformation or fracture, and has good stability in the cutting process.

3. High temperature resistance: It can work normally in high temperature environment and is not easy to soften or lose performance. (up to 900 ~ 1000℃, maintain 60HRC);

4. Fast cutting speed: improve processing efficiency and reduce production costs.

5. High processing accuracy: high surface quality and dimensional accuracy can be obtained.

6. Long life: reduce the frequency of tool replacement and improve the continuity of production.

7. Strong adaptability: It can be used to cut a variety of materials, including metals with high hardness.

8. Good stability: it can still maintain good cutting performance under complex processing conditions.

9. Good wear resistance. The cutting speed of cemented carbide tools is 4 to 7 times higher than that of high-speed steel, and the tool life is 5 to 80 times higher. Manufacturing mold, measuring tools, life than alloy tool steel 20 to 150 times higher. It can cut hard materials of about 50HRC.

 

Sixth, when choosing cutting and grooving tools, the following factors need to be considered:

1. Select the slot type

It is important to understand the three main types of grooves: outer grooves, inner grooves, and end grooves. The outer grooves are the easiest to work with because gravity and coolant can help remove chips. In addition, the outer groove machining is visible to the operator and the machining quality can be checked directly and relatively easily. However, some potential obstacles in workpiece design or clamping must also be avoided. In general, the cutting effect is best when the tip of the slotting tool is kept slightly below the center line.

The inner hole grooving is similar to the outer diameter grooving, except that the application of coolant and chip removal are more challenging. For internal hole grooving, the best performance is achieved when the tip position is slightly above the center line.

Machining end grooves, the tool must be able to move in the axial direction, and the radius of the tool after the tool face must match the radius to be machined. The machining effect is best when the tip position of the tool is slightly higher than the center line.

2. Processing machine tools and applications

In the grooving process, the design type and technical conditions of the machine tool are also basic elements that need to be considered. Some of the main performance requirements for the machine include: having enough power to ensure that the tool operates within the correct speed range without stalling or jitter; High enough rigidity to complete the required cutting without flutter; High enough coolant pressure and flow to help chip removal; It has a high enough precision. In addition, in order to produce the correct groove shape and size, it is also crucial to perform proper debugging and calibration of the machine tool.

3. Understand the material characteristics of workpiece

Familiarity with some of the properties of the workpiece material, such as tensile strength, work hardening characteristics, and toughness, is essential to understanding how the workpiece affects the tool. When machining different workpiece materials, different combinations of cutting speed, feed rate and tool characteristics are used. Different workpiece materials may also require a specific tool geometry to control chips or utilize a specific coating to extend tool life.

4. Choose the right tool

The right choice and use of tools will determine the cost effectiveness of the machining. The grooving tool can process the geometry of the workpiece in two ways: one is to process the whole groove through a single cut; Second, the final size of the groove is roughed out step by step through multiple cuts. After selecting the tool geometry, a tool coating that can improve chip removal performance can be considered.

5. Shape knives

In large quantities of processing, the use of forming tools should be considered. The forming tool can process all or most of the groove shape through a single cut, which can free the tool position and shorten the machining cycle time. One disadvantage of non-blade forming tools is that if one of the tool teeth breaks or wears out faster than the others, the entire tool must be replaced. Another important factor to consider is the amount of machine power required to control the chip produced by the tool and the form cutting.

6. Select a single point multi-function tool

Multifunctional tool use generates tool paths in both axial and radial directions. In this way, the tool can not only process grooves, but also turn out the diameter, interpolate the radius, and process the Angle. The tool can also be turned in multiple directions. Once the blade is in cutting, it moves axially from one end of the workpiece to the other, while always maintaining contact with the workpiece. The use of multifunctional tools allows more time to be spent cutting the workpiece, rather than changing the tool or moving with no stroke. The multifunctional tool also helps to reduce the machining process of the entire workpiece.

7. Use the correct processing sequence

Reasonable planning of the optimal processing sequence needs to consider a variety of factors, such as the change in the strength of the workpiece before and after the groove processing, because the strength of the workpiece will be reduced after the groove is processed first. This may encourage the operator to use less than optimal feed and cutting speeds in the next process to reduce chatter, while reducing cutting parameters may result in longer machining times, shorter tool life and unstable cutting performance.

8. The role of feed and cutting speed

Feed rate and cutting speed play a key role in grooved machining. Incorrect feed rates and cutting speeds can cause chatter, reducing tool life and extending machining cycle times. Factors that affect feed rate and cutting speed include workpiece material, tool geometry, coolant type and concentration, blade coating, and machine performance. In order to correct the problems caused by unreasonable feed rate and cutting speed, secondary processing is often required. Although many sources of information can be listed for the "optimal" feed rate and cutting speed for a variety of different tools, the latest and most useful information usually comes from the tool manufacturer.

9. Select blade coating

Coatings can significantly increase the life of carbide inserts. Because the coating can provide a lubricating layer between the tool and the chip, it can also reduce processing time and improve the surface finish of the workpiece. Currently commonly used coatings include TiAlN, TiN, TiCN and so on. For optimal performance, the coating must be matched to the material being processed.

10. Cutting fluid

Proper application of cutting fluid means adequate supply of cutting fluid for the cutting point where the slotting blade is in contact with the workpiece. The cutting fluid plays a dual role in cooling the cutting area and aiding in chip removal. Increasing the cutting fluid pressure at the cutting point is very effective for improving chip removal when machining the inner diameter grooves of blind holes. For some difficult to process materials (such as high toughness, high viscosity materials) groove processing, high pressure cooling has obvious advantages.

The concentration of water-soluble oil-based coolant is also critical for the grooving of difficult-to-process materials. Although the typical coolant concentration range is 3% to 5%, in order to improve the lubricity of the coolant and provide a protective layer for the tip, it is also possible to test the effect of increasing the coolant concentration (up to 30%).