Exploring the future development of cutting tools

2022-08-01
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Explore the future development of cutting tools from the machining challenge

in recent years, the metal processing industry has developed rapidly, and its power comes from many aspects. For example, the globalization of economy, the intensification of market competition, the use of difficult to process materials and the awareness of environmental problems. As a result, the end user of the tool puts forward the requirements for continuous improvement to the tool manufacturer. The general trend of metal processing industry is to develop more advanced processing technology. Although most of the epoch-making inventions in the history of tool development come from specialized scientific research institutions, the majority of tool manufacturers are directly facing the specific processing challenges. Because tool manufacturers are in the forefront of developing new tool materials, tool structures and machining methods

this paper will give specific cases for several machining challenges, and explain how tool manufacturers can promote the development of tools in practice

processing challenges of new materials

powder metal parts are an economical alternative. Parts made using powder metal technology have many unique advantages. Powder metal technology makes the processed complex parts close to the final size and contour, thus significantly improving the processing efficiency. Usually all that is needed is a finishing. In addition, the powder metal technology deliberately leaves residual porosity in the parts, which is very beneficial for self lubrication, weight reduction and noise elimination. Some complex parts are difficult or can not be manufactured by traditional casting process, and can be easily produced by powder metal technology. In summary, powder metal technology provides an economical method for the production of parts. So what are the challenges of processing powder metals

The processing difficulty of powder metal materials is often underestimated. Because powdered metal materials often contain hard particles in a soft, sometimes porous structure, the hardness value of the material is often misled by the processing personnel. The particle hardness is as high as HRC70, while the macro hardness is as low as hrc10. Hard particles and porosity can lead to micro fatigue of cutting edges. The cutting edge of the tool cuts in and out as if passing between particles and holes. Repeated small impacts lead to small cracks on the cutting edge. These fatigue cracks become larger and larger, and eventually lead to micro collapse of the cutting edge. This micro chipping is so subtle that it looks like normal wear and tear. The common deviation between grain hardness and macro hardness means that machining powder metal parts is like machining a grinding wheel

the unique performance and machining characteristics of powder metal parts mean that the high CB with increased wear resistance is the basic requirement for machining after long-term development of N content and fine particle size to improve the toughness of cutting edge. Cbn200 blade is composed of very fine particle material with high content of CBN, which just meets these requirements. In addition, there is a unique metal adhesive, which makes cbn200 an ideal processing solution. Its excellent wear resistance and toughness are ideal for minimizing processing costs

by matching the reverse force deformation angle, width and cutting edge grinding, we have strengthened the cutting edge, thus increasing the tool life, improving the surface roughness and machining tolerance, and enabling customers to achieve higher productivity and reliability. This cutting edge design is especially suitable for the powder metal materials which are difficult to machine

the valve seat on the cylinder head of the automobile engine is a typical powder metal part. The service life of the tool for finishing the valve seat hole with PCBN is 5000 pieces, while the service life of the tool with cemented carbide is 300 pieces, with a difference of more than ten times. It has become a trend that superhard tool materials such as PCBN replace cemented carbide tools in more and more applications

the challenge of chip breaking of difficult to machine materials

titanium alloy is a well-known poor heat conductor, that is to say, the high temperature kept at the cutting point can lead to alloying tendencies such as welding, bonding and diffusion, and the cutting edge will be quickly damaged. The cutting characteristic of titanium alloy is to produce a kind of thin high-speed chip, which is difficult to break into controllable chips. Usually, this kind of chip will offset the traditional cooling transmission system, resulting in a lack of coolant at the cutting point and damaging the parts. The use of conventional tools with large rake angles and sharp cutting edges can minimize these effects, but the long chips generated are difficult to control

in response to the demand of the aviation industry for improving the cutting performance of titanium alloys, yamago developed jetstream tools. It is a revolutionary new solution to the old and difficult problem of accurately transferring coolant to the cutting area

The working principle of the jetstream tool is to direct the concentrated high-pressure coolant jet at high speed to the best position close to the cutting edge. This coolant jet lifts the chips away from the rake face, improves chip control and tool life, and can improve the applied cutting parameters. It is not only applicable to aviation materials. Jetstream tools have been proven to be effective for almost all material groups and have a wide selection of coolant pressures

efficient heat dissipation from the cutting area is one of the most important factors affecting tool performance. The advantage of using coolant to dissipate heat is clear. Until now, coolant is simply used to flush the area. For the coolant to be truly effective, it should be able to quickly remove heat from the cutting area, and the directional coolant flow will be much more effective in delivering the coolant exactly where it is needed

in order for the blade to work effectively, both the workpiece and the blade need to reach a certain temperature level. Too much heat will shorten the tool life; If the heat is insufficient, chips will not form normally. When the chip forms, the heat contained in it needs to be taken away. The failure to quickly remove heat leads to a kind of chip with good ductility, which is flexible and can not be broken, and its continuous curling makes it very inconvenient for operators to operate

The

jetstream tool is very effective in removing heat from the cutting area, which makes the chips cool rapidly, and the hardening of the chips makes them brittle. The resulting chips are easy to break and can be removed from the cutting area

with the jetstream tool, Yamaguchi understands the importance of the concept of transferring coolant directly to the tool/workpiece contact surface. It uses a minimum amount of coolant to provide effective cooling and also makes the chips brittle enough to break more easily, thus allowing for increased cutting speed and longer tool life (due to reduced work hardening and groove wear). Not to mention eliminating downtime and part damage associated with tangled long chips

in the test of Yamaguchi, the common cutting tool produces Ti6Al4V parts with a cutting speed of 40m/min, a feed rate of 0.25 mm/rev and a cutting depth of 2mm, and the machining cycle is 5min. With the jetstream tool, the cutting speed can be increased to 80m/min, the machining cycle can be shortened to 3min, and the productivity can be increased by 40%

the challenge of processing efficiency

the times are changing, and the increasing efficiency competition requires more and more efficient processing methods. High feed milling is the key to keep the company in a leading position

high feed milling is actually a rough machining method developed for high metal cutting rate to improve production rate and save machining time. Combine the shallow cutting depth (no more than 2mm) with the large cutting arc radius or small main deflection angle to turn the cutting force towards the axial machine tool spindle

this milling method can achieve 3 times faster processing speed than the traditional method. It does not use a larger cutting depth (which will shorten the tool life) when cutting, but from the opposite direction. It uses a shallow cutting depth and a high feed per tooth in pairs to protect the tool. And the metal removal rate is higher than that of common processing

this method has many advantages. For example, the cutting force points to the machine spindle in the axis direction; Reduce vibration and thus prolong tool life; The high feed milling (HFM) method makes use of a small principal deflection angle; The radial cutting force is minimized and the axial cutting force is maximized; Reduce the risk of vibration and obtain stable processing; This method can even improve the cutting parameters in large overhang machining

machining with smaller cutting depth and faster feed per tooth can remove more than 1000cm3 of workpiece material per minute. In fact, sometimes the feed speed can be increased to 10 times the normal value. And even if it is a rough machining method, it can still obtain the shape close to the finished product. This allows the user to skip semi finishing and proceed directly to the final finishing. Give each machine the possibility to produce more parts

hfm method is very effective for cavity milling, especially for mold machining. In addition to cavity milling, it can also be used in plane milling, spiral interpolation milling and insert milling. HFM method has been adopted in more machining fields, and tool manufacturers are also exploring ways to improve machining economy. In addition to the most common triangular inserts, square inserts with four cutting edges have also been used for high feed milling cutters

the challenge of processing economy

square shoulder milling occupies a large share in the field of milling processing. No matter what difficulties are encountered in processing, users all hope to obtain an economic tool solution that can not only improve productivity but also reduce unit cost. Multi cutting edge tools already exist, but users are still looking for tools that can provide the lowest cost per edge

the economy of square shoulder milling is also reflected in the following aspects. The user hopes to realize the real 90 ° straight wall for the first time without using another expensive and time-consuming milling process. Some multi blade cutters have great noise, and the vibration hydraulic oil is subjected to external force to produce relative motion, so the effect of surface roughness is not ideal. Milling tools with low noise and vibration are required, and smaller tolerance blades (peripheral grinding) and blade holders must be used. Customers need high-precision tools to achieve the best quality surface roughness. Reducing the inventory of different tools will help improve profits. Customers need square shoulder milling cutters that can be used for a variety of different machining (including plane milling). In fact, customers want a reliable, cost-effective and preferred solution for general processing

the Square-6 product of Sango tool company is a unique square shoulder milling cutter with triangular blade. The turbo whirlwind milling cutter with 2 cutting edges per blade is the most common square shoulder milling cutter. It has the advantages of light cutting and high machining efficiency. The drawback is that the number of effective cutting edges of the blade is small, and it lacks advantages when talking about economy. Square-6 has 6 cutting edges, so the cost of each cutting edge is low and very economical. The axial rake angle of the blade seat is negative, but the positive angle cutting edge on the blade can ensure that the cutting rake angle is positive, so it can ensure high performance. Square-6 has three different blade geometric angles and three different tooth pitches, which makes it able to provide the same high performance in a wide range of materials, processing and working conditions. The main deflection angle of 90 ° ensures that the true 90 ° square shoulder can be obtained in only one processing, thus saving production time. Coated tool bodies have longer tool life. The pre hardened tool body and the peripheral finely ground blade have better accuracy and reliability, and can also improve the accuracy and tolerance of the machined parts

the triangular square shoulder milling cutter blade has 6 cutting edges, which increases the manufacturing difficulty of the cutter body. The common turbo whirlwind milling insert and square blade are single-sided blades, which are composed of 2 and 4 cutting edges respectively. The Square-6 blade is double-sided

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