Superhard materials, high-speed cutting tool in the field of exclusive advantages, increasing its practical application. In such tool in PCD (polycrystalline diamond) tools are a high-speed cutting aluminum and non-metallic materials, the best choice, and diamond coated tools are not only practical, and growth has been gaining momentum; PCBN (polycrystalline cubic boron nitride products) to higher-speed cutting tool for Cast Iron, of hardened steel and other materials, CBN (cubic boron nitride) coating tool is also expected significant technological breakthroughs in the near future.
In order to have enough high-speed cutting tool life and low cutting forces, workpiece materials, according to the different tool to select the best geometry. Compared with ordinary cutting, high-speed cutting tool rake angle are generally smaller or even negative anterior horn, posterior horn to be slightly larger, and the rounding or chamfering often used to increase the blade tip front angle, to prevent the tip at thermal wear. Due to the high-speed rotary cutting tool in the work of a high speed, centrifugal problem is very prominent, and called for its structure and the knife blade clamping structure should be very reliable, while balancing device on the need to undergo a rigorous balancing, the most Good to further install components on the machine together with the spindle dynamic balance.
In general speed between the tool and spindle cone coupling is widely used 7:24, when the high-speed rotation, because the solid can not be like the spindle taper hole by centrifugal force occurring as "swell," the gap between the two will lead to the tool in cone hole swing, causing the tool axis position error and the destruction of the structure of dynamic balance. To overcome this disadvantage of poor performance, high-speed connection, have developed a number of suitable high-speed cutting of the link methods, such as: HSK and Capto tool system tool system.
The following details the tools, knife handle and cutting selection.
1, the tool material
To achieve high-speed cutting tool material is the key. High-speed cutting materials include cemented carbide, coated cutting tools, metal pottery, ceramics, Cubic boron nitride and diamond tools. They have advantages for different workpiece materials and different cutting speed range. Should be noted that the tool material and workpiece material has a fit between the vice problem, that is, a tool material and workpiece material properties are good, but when processing another workpiece material is not ideal, in other words, there is no one kinds of universal tool material suitable for high-speed processing of all workpiece materials.
High-speed cutting tool material must be processed according to the nature of the workpiece material and processing options. In general, the ceramic cutting tools, coated cutting tools, and CBN cutting tools suitable for processing high-speed steel and other ferrous metal processing; PCD cutting tools suitable for aluminum, magnesium, copper and other high-speed processing of nonferrous metals. The table lists the tool material are suitable for processing some of the workpiece material.

Ceramic tool has been applied to processing of various cast iron, steel, thermal spray coating materials, such as nickel-base superalloy.

Diamond tool is suitable for processing nonmetal materials, nonferrous metals and alloys. Poor thermal stability of the diamond cutting at 800 ℃, it will lose its hardness. Because diamond and iron have a strong chemical affinity, the iron atoms in the high temperature interaction of carbon atoms so easily into a graphite structure, tool very easy to damage, so not suitable for processing of diamond tool steel materials, ferrous metals when cutting , PCD cutting tool carbide cutting tool life is dozens or even hundreds of times.

Cubic boron nitride cutting tools can not only capable of hardened steel, bearing steel, high speed steel, chilled cast iron of the crude, refined car, but also qualified for high-temperature alloys, thermal spray materials, carbide and other high-speed machining difficult materials. CBN tool is to achieve a car instead of grinding is one the best tool.
2, tool
The following describes the processing center of the shell used on the processing tool.
1 cutter
In face milling, because the relationship between the cutter and workpiece, size and location are important factors. In the Select tool, the workpiece diameter cutter width of the decision. For processing small pieces The general tool diameter 30% larger than the workpiece is more desirable, but the machine power and the stability in many cases play a decisive role. Face milling cutter is often necessary to go several times to complete.
Milling results in the optimization, the cutter blade is another important factor. If at any time milling of the blade while cutting the number of participation is more than one advantage, but participation is cutting too many shortcomings of the blade. At the cutting edge of each cutting can not simultaneously cutting the required power and participate in cutting the number of the cutting edge. On the chip formation process, loading and processing the results of cutting edge, the cutter relative to the position of the workpiece plays an important role. In face milling, the cutting width with a ratio of about 30% of large and will be milling cutter location near the center of the workpiece, then the chip thickness changed little. Qie Ruqie out of the chip thickness in the center than the thickness of a little cutting cutting thinner.
To ensure that a high enough average chip thickness / feed per tooth, you must correctly identify the process for milling cutter teeth. Cutter pitch is the distance between the effective cutting edge. Cutter according to this value will be divided into three types - fine-toothed cutter, tooth cutter dredging, special fine-toothed cutter.
And milling the chip thickness was also associated with the main face milling angle. Main angle is the main cutting edge and blade angle between the workpiece surface, mainly 45 degrees, 90 degrees and round blades. The direction of cutting force as the main angle changes of the different great changes will be: 90 degrees for the main angle cutter mainly produce radial force acting on the feed direction, which means that the surface to be machined will not put too and more pressure, the workpiece for the milling of the structure is relatively less reliable.
Main angle of 45 degrees radial cutting force and axial milling roughly equal, so the pressure generated a more balanced, the machine is relatively low power requirements, particularly suitable for milling chips have broken the short collapse debris material workpiece.
Means that the main circular cutter blade angle from 0 degrees to 90 degrees continuous change, depending on the depth of cut. The strength of the blade cutting edge is very high, due to the direction along the length of the cutting edge thin chips produced, so for a large feed. Radial cutting force along the direction of blade changing, and in the process will depend on the pressure generated by the cutting depth. The development of modern groove blade geometry that has a smooth circular cutting blade effect, lower power requirements on the machine, good stability. Today, it is no longer an effective rough milling, milling and milling in the face of a wide range of applications in both.
Relative to the workpiece and the cutter feed direction of rotation in two ways. The first is the smooth milling, milling and cutting direction of rotation of the feed direction is the same, at the beginning of cutting the workpiece and the cutter to cut the last bite of the chip. The second is the inverse of milling, milling and cutting direction of rotation opposite the feed direction, the cutter must begin before cutting a slip on the workpiece to begin cutting the thickness of zero to the end of the cutting thickness of cutting max.
In the face milling cutters, milling or face milling some time, cutting force with different directions. Face milling, the cutter just outside of the workpiece, the direction of cutting force should be special attention. Climb milling, the cutting force pressure to the workpiece table, when the cutting force in milling the workpiece against the table to leave.
As milling cutting along the best, usually along the preferred milling, thread exists only when machine problems or a climb milling gap can not solve the problem only when considered against the mill.
In the ideal case, the cutter diameter should be large than the width of the workpiece, cutter and workpiece axis line should always be left some distance from the center line a little. When the tool is placed on the machining center, the easy to produce glitch. Cutting edge cutting into the cutting in and out of the direction of the radial cutting force will continue to change. Spindle vibration and may damage the surface of the blade may be broken and the process would be very rough. Slightly off-center milling, cutting force direction will no longer fluctuate - Mills will receive a pre-load. We likened the center of the road milling center to drive.
Each cutter blade into the cutting, the cutting edge should withstand impact load, the load depends on the cross-section of the chip, workpiece material and cutting type. Qieru Qie out, the cutting edge and the workpiece is correctly between the bite is an important direction.

In Figure a, milling width of axis lines lie entirely outside of the workpiece and in the impact of the time is cut by the outermost tip of the blade affordable, this would mean the initial shock load from the most sensitive parts of the tool under . The last, to leave the cutter tip piece, which means that the cutting blade to the left from the beginning, the cutting force has been acting on the outermost tip, until the impact of unloading up. Figure b, the cutter edge of the workpiece center line right in line, when the chip thickness reaches the maximum when the blade from the cutting, when the Qie Ruqie the maximum impact load. Figure c the cutter axis line is located within the width of the workpiece, the initial shock load when cut along the cutting edge and far from the tip away from the site of the most sensitive subject, but also in more stable retraction exit when the cutting blade.
For each blade, when cutting out the cutting edge to leave the way of the workpiece is important. Remaining close to retract when the blade gap to how much material may be reduced. When the chips from the workpiece along the blade rake will produce a transient tensile strength and are often produced in the burr on the workpiece. The tensile force in dangerous conditions threaten safety of the chip edge.
When the cutter and workpiece axis line coincident or close to the edge line of the edge of the line parts (Figure b), the situation will be very serious. Milling to achieve a better summary:
① search machine power and rigidity to ensure that the required cutter diameter used in the machine.
② the tool spindle to reach the shortest possible overhang. Figure cutter and workpiece axis location of the impact load of
③ suitable for the process using the correct pitch cutter to ensure there is not much in the cutting blade and workpiece while meshing vibration caused by the other in the milling or milling narrow cavity of the workpiece when the blade and ensure that adequate workpiece mesh.
④ ensure that using the feed of each blade so that when the chip is thick enough to get the correct results and thus reduce the cutting tool wear. Trough with positive rake angle of the indexable inserts, to obtain a smooth cutting performance and lowest power.
⑤ use the cutter for the width of the workpiece diameter.
⑥ choose the correct main angle.
⑦ cutter right place.
⑧ only when necessary to use cutting fluid.
⑨ follow the rules of maintenance and repair of the tool and monitoring tool wear.
2 bit
Hole drill is the most widely used tool in the tool, particularly when drilling holes ф30mm following, the bit from the structure into the overall style and indexable drill, as automobile pursuit of high productivity more shoulder and chamfer drill composite applications are more extensive.
Many jobs require drilling a hole on or a few holes, and today most of these holes are CNC machine tools and processing centers on the process. In principle, there are many different types of holes in these holes is the difference between the most popular with the gap. These holes include threaded holes, has an excellent hole with the requirements of the pipeline as well as the removal of the weight of the hole machined holes and so on. The holes are through holes or blind holes, cutting tools and methods for different requirements.
In the drilling process, in order to effective way to achieve satisfactory results, need to consider four main factors.
① the ratio of diameter and hole depth
② needs to be machined hole accuracy and surface roughness
③ workpiece material type, quality and hardness
④ machine tools, especially the processing conditions and the spindle speed
These factors will affect the type of drill bit selection and application. In all processing, the workpiece, machine tool and process stability of the system is the most important. In considering what type of drills for machining operations, the drilling process plays a role in certain constraints. The smallest indexable 12.7 mm in diameter,
3, boring
Boring tool according to the structure into the overall style, and adjustable clamping style, is divided into fine-tune the adjustable type and differential. In the automotive transmission housing process commonly used in fine tuning the main type is a single blade knife and edged rough boring boring.
Rough boring tool using the axial adjustment mechanism, so that exactly the same height edged, to achieve the desired balance to prevent vibration. Feed fine boring head screws are the lifeline paired in the number of manufacturers producing method, the screw and nut backlash limited to between the smallest and the highest reliability. Boring holes in the back, they often need to be loaded against the workpiece, or rotary table, not only a waste of time, and it is difficult to ensure concentricity in Japan produced by EWN BIG fine boring head can be reversed only to the blade anti-Boring processing, which is to ensure accuracy and improve productivity. For high precision arbor hole requires a high balancing effect produced in the BIG hole high-speed moving the balance rings fine boring head, containing both the balance of the block will move, according to the instructions of the relevant data, will balance the loop transfer to the appropriate location can enable the boring head in the balance.
Four, tapping
There are two processing centers in the tapping mode, high-precision automatic screw down to offensive device, the highest speed of 6000r/min, the role of compensation without any rigid tapping. Tapping the way both advantages and disadvantages, so choose according to processing requirements, in mass production, the quest for high efficiency, automatic control down to offensive thread will be conducive to production, but it is a complex mechanism, many accessories, maintenance is not easy expensive. Now, with the use of CNC machining centers to increase the number of rigid tapping to become more prevalent.
When using rigid tapping, CNC machining center as axial feed control system, so the tap itself, without the burden of control tasks, rigid tapping, the tap spindle rotation speed and mechanical axial feed is 100% synchronization, tap can be clamp in a fixed holder, without any floating function.
Tapping is generally used for flexible clamping handle.
5, the composite tool
In order to maintain high efficiency, we must make "in the cutting" time to maximize, so do not spend way related to the actual cutting time is minimized. The tool, how to make the shortest cut, that is, compound tool, a tool for the tool change the work process - the rapid movement of the tool or the table - cutting moves - fast tool change back, if the two composite tool , you can save a tool change time, fast-moving time, and cutting 3-5 mm before the start of a safe distance. The main composite tool with chamfered composite drilling tools, boring and chamfering composite rough boring. However, if the tool must be calculated or test compound to the shortest processing time standards.