The flatness and smoothness of the cut edge of the cut object depend on the blade sharpening angle, the sharpening quality and the degree of passivation of the blade edge. The blade angle is generally about 19°, and the blade angle should be larger when cutting harder paper.

　　Each time the edge is sharpened, it must be cooled sufficiently to avoid annealing the edge. In order to make the knife edge sharper and smoother, the knife edge should be finely sharpened with whetstone before use. When cutting, soap or stone wax should be applied frequently to the edge of the knife to prolong the durability of the cutter and make the cut edge smooth. If you find that there is a paper pulling phenomenon on the cutting edge of the cutting object, you should use whetstone to trim the edge or re-sharpen the blade edge at any time.

　　Replacement of the cutter

　　Due to the use of high-efficiency flat bread torus worm reducer, which itself is not self-locking, the main motor stops, the cutter cutter selection switch is pulled out to the tool change position, the transmission has lost the brake, the safety device has lost protection, and the tool bed has the possibility of sliding down in a stationary state, which may seriously endanger safety.

　　When changing the cutter knife, first turn off the main motor, wait for about 2 minutes, and confirm that the transmission belt is completely stopped, put two wooden cutter changers (provided by the manufacturer) under the blade, put the cutting switch cutter selection switch on the switch panel in the tool change position "", the cutter bed function selection switch must be in the cutting position, rotate the pulley end face nut with the sleeve, remove all the connecting screws on the blade, and then use the Allen wrench to push the hanging knife device inward for about 4MM to make the hanging knife device brake detached, The rotating knife hanging device makes the blade fall smoothly on the two wooden knife changers, install two tool changer handles, remove the blade, and pay attention to holding the blade to prevent it from tipping over and hurting people.

　　Remember: 1. Confirm the purpose of the operation, do not press or mismove the button.

　　2. Do not put your arm under the knife bed and paper press

　　Install the cutter

　　First, confirm that the main motor start button is in the stopped state, and confirm that the main motor pulley is stationary, install the sharpened blade on the tool changer, and then push the tool changer and blade together with the blade to the blade in front of the paper press, and place the cutting switch tool selection switch (Fig. 3.5) at the right end of the tool change position. , rotate the knife hanging device according to the method mentioned above, raise the blade to the highest position, install the blade connection screws and tighten them, then unscrew the two handles on the tool changer, remove the tool changer, install the rest of the blade connection screws and tighten them;

　　Adjustment of the cutter

　　Every time a new blade is installed, or the old blade after sharpening, the height of the tool bed should be manually adjusted to adjust the cutting volume of the blade, so as to avoid accidents caused by deep cutting caused by the large height of the new blade.

　　The adjustment steps are:

　　(1) Make sure that the paper cutter is in the tool change state, first stop the main motor, press the main motor stop button, confirm that the main motor is in a stationary state, and then put the cutting cutter selection switch in the middle tool change position.

　　(2) Determine the cutting depth of the blade: use a socket wrench to rotate the nut on the end face of the pulley to make the tool bed move to the lowest point, and observe whether the depth of the blade cutting into the cutting strip is reasonable (normal cutting 0.5-1 mm).

　　If the cutter edge is in contact with the knife bar at only one end, it can be solved by adjusting the eccentric shaft behind the main frame.

　　If the blade is worn and cannot cut through the paper, the blade should be moved down in the direction of the long hole until it can completely cut the paper.

　　The specific adjustment method is as follows: turn off the main motor and power switch, loosen all the blade connection screws, put the tool bed at the lowest point in a manual way, use the Allen wrench to push the hanging knife device inward by about 4MM, so that the hanging knife device brake is disengaged, and rotate the top knife cam to make the blade cut off the paper.

　　Warning: 1. When the depth of the cutter is adjusted, the main motor cannot be started.

　　2. The top knife cam can only be fine-tuned, if the adjustment range is too large, the brake of the hanging knife device must be disengaged, otherwise it will cause damage to the hanging knife device!

　　When the blade is worn about 20-25mm, the second row of screw holes under the knife should be used, and 2 top cutter blocks (random accessories) should be added to the end face of the blade (blade figure 4-M5). When the blade is worn out again to the point of being unusable, it should be replaced with a new one.

　　The blade and the tool bed must be properly connected and not installed arbitrarily, and the new blade should be installed in line with the blade and the first row of screw holes on the right side of the tool bed.

　　Note: Before the new blade is installed, the edge chamfer must be trimmed according to the blade diagram, and the hole spacing size should be according to the manufacturer's knife size.

　　How flexibility changes on a milling cutter with passive vibration dampening and how does it affect the service life of the tool. In addition, the flexibility of the turning tool has been tested in the previous process of turning, and now the results of this test are compared with the test results of the milling process, and the conclusions obtained from the next experiment are introduced.

　　During milling, the tool is subjected to alternating loads due to the process method. Such loads can be mechanical or thermal. In terms of mechanical loads, special mention is made of the inlet impact of the blades. The moment the cutting edge enters the material, the cutting force is significantly increased.

　　For example, when milling in the same direction of feed, the cutting edge of the tool will experience an input impact of the tool every time it enters the material. This effect is significantly enhanced by the brittle and hard oxide layer, which often occurs on cast or similar workpieces.

　　Lubricant enhances alternating loads

　　On the one hand, the process heat conducted by the tool will increase the heat load of the tool; On the other hand, temperature changes caused by cutting air on the cutting edge can also increase the heat load on the tool. The thermal alternating load is further exacerbated by the use of lubricants.

　　The Institute for Production Technology is sponsoring a project funded by the German Research Association to improve the service life of tools during cutting by changing flexibility at the input of the tool. The project explores mechanical overload and experimentally demonstrates that this mechanical overload can be minimized by changing the flexibility close to the point of action. The reason for initiating this research project is based on the results achieved in several previous works. These results show that the rigidity of the machine drive has a certain impact on the service life of the tool.

　　For example, a machine tool with a highly rigid motor spindle wears out faster than a machine tool with a less rigid drive. However, due to the many advantages of motor spindles that are currently widely used, there is a possibility of an option that is inexpensive and optimizes the parameters of flexibility and service life without changing the drive scheme. Conventional turning tools have a ground hard metal backing plate underneath the rotating punching blade to ensure a secure blade position. While the other parameters of the pad remain unchanged, we have modified the material of this backing board.

　　Similar to the trials done on lathes in the early stages of this project. First, a milling head tool holder was developed, which allowed materials with different flexibility to be placed on the tool. In order to make the test results as comparable as possible with those obtained in previous turning tests, the milling head tool holder is designed to accommodate the same rotating punching inserts as in the previous tests. The milling head tool holder is shown with a backing plate that is mounted between the rotating punching blade and the tool body.

　　When choosing the material of the backing plate used, the results of the previous test were referred to, and it was found that the material with low strength and low elastic modulus was not suitable. The materials used for the test, resin impregnated paper (elastic modulus 7GPa), acyl glass (4GPa), magnesium (40GPa) and aluminum (70GPa), showed that insufficient strength and too small elastic modulus would lead to excessive elastic deformation and excessive plastic deformation, which offset the prestress of the cutting blade and could not continue to be used.

　　For this reason, only materials with high strength and elastic modulus can be selected for backing plate materials. Specifically, it is the cast iron materials EN-GJS-250 (elastic modulus 110GPa), EN-GJS-600 (170GPa), and steel S 235 JR(210GPa)。 The use of the elasticity modulus of the backing plate as a landmark standard is because the modulus of elasticity is the only variable in the flexibility of the backing plate when the size remains the same.

　　Indexable blade breakage becomes the standard for service life

　　Two requirements are put forward for workpiece materials, one is that they will wear out the tool in the process of economical and fast operation, and the other is that they can be applied in daily cutting work. Finally, an aluminum alloy (AlSi10Mg) was chosen, which is a cast iron (EN-GJS) with multiple layers of graphite 260 Gr), and a structural steel (S 235 JR)。 The standard for service life is the breakage of indexable inserts detected when the cutting force increases are measured. Service life is defined as the impact of the indexable blade at the edge entrance before it breaks.

　　Some exceed the recommended maximum

　　The selected cutting test process parameters are adjusted to the corresponding cutting material and the indexable insert used, so that the cutting edge breaks within an appropriate period of time. This means that in specific cases, the parameters must be adjusted higher than the maximum recommended by the manufacturer.

　　S 235 JR、EN-GJS 260 Gr and AlSi10Mg, each of which is combined with three different backing plates. Ten trials were done in each series of nine possible combinations, running until the blade broke. In addition, when machining structural steel, the tool manufacturer Tübinger is used The original backing plates from Walter AG were also tested.

　　Cutting tests with aluminum alloys have not yielded usable results. Even when the cutting speed varies between 500 m/min and 3675 m/min, it does not cause edge breakage within an appropriate foreseeable period of time. So only the results of processing steel and cast iron materials are listed.

　　Machining S 235 The load cycles achieved by JR materials before the blade breaks are listed on the various pads for the elastic modulus of the corresponding material. It is clear from this that changes in the backing plate can have an impact on the service life of the tool. The use of steel pads can increase the average service life by 176% compared to hard metal original backing plates.

　　Conversely, the average lifespan of backing boards made of gray ductile iron was reduced by about 30%, while those made of multi-layer graphite cast iron increased by 42%.

　　EN-GJS 260 The test of GR for materials is a different situation. Compared to steel backing plates, both ductile iron (330% improvement) and multi-layer graphite cast iron (37% improvement) have clear advantages in terms of service life.

　　The individual extreme differences in tool life of machined cast iron materials are partly due to fluctuations in the results and require continued approval. These results are difficult to contrast with those obtained in the previous turning tests, because some of them are contradictory.

　　Backing plates are required for all processing

　　However, it seems that this does not answer the question of flexibility for universally applicable ****. Instead, the question should be asked, what kind of flexibility is for what kind of conditions. For example, there are various machining processes (milling, turning), and various workpiece materials that are difficult to compare with each other, and need to be judged according to the results, and different flexibility or backing plates are adjusted according to the corresponding processing situation.

　　The results of service life tests fluctuate greatly, and there is no universally applicable flexibility, which requires continued testing of the effects of flexibility while reducing interference. At the same time, the question is also raised whether the results achieved by making simple changes in flexibility on the basis of the pad will disappear in the range of fluctuations.

　　Later follow-up studies by the WBK Institute also showed that one possibility of achieving more reliable results was to design an active milling head that could be infinitely flexible and continue to enhance the desired effect. For example, a hydromechanical tool system with a variable pressure tank behind the indexable insert can be envisaged, allowing for variable flexibility and vibration damping.

　　In order to ensure the quality of welding, the welded turning tool should be carefully inspected to find out the cause of the defect and improve it. Before inspection, the turning tool should be sandblasted or gently ground to remove the solder and impurities adhered to the blade surface, and cleaned with kerosene. The items and requirements to be inspected are as follows:

　　1. Check the weld strength: Grind the back of a turning tool with a green silicon carbide grinding wheel and check the thickness of the solder layer, the thickness is required to be less than 0.15 mm. There should be no pores and insufficient solder at the bottom of the tip support, and the weld that is not filled with solder should not be greater than 10% of the total length of the weld. If there are pores, the blade will fall off when cutting.

　　2. Check the position of the blade in the tool groove: if the blade is misaligned and sagging exceeds the technical conditions, it should be re-welded.

　　3. Check the welding strength: use a wooden hammer or copper hammer to hit the blade with medium force, or use an I hammer to hit the knife bar strongly, at this time the blade does not fall off the knife groove to qualify. Check the welding strength of the blade, not necessarily check each one, but also use the spot check method.

　　4. Check the flatness of the blade: If there is an obvious pit on the blade, it means that the blade is overheated and deformed, and the new blade should be burned and re-welded.

　　5. Check for cracks: After the blade is cleaned by kerosene, if the blade has cracks. Kerosene penetrates into the cracks and black lines appear, which can be observed with the naked eye. It can also be observed with a magnifying glass of 10-40 times.

　　To check for blade cracks, you can also use the color flaw detection method: use a solution of 65% kerosene, 30% transformer oil and 5% turpentine, and add a little Sudan red. Place the turning tool blade part in this solution 10-15 minute, then wash with water, apply a layer of white clay (kaolin), and observe its surface after drying, if there are cracks on the blade, the color of the solution will be revealed on the white clay, which can be seen with the naked eye. Cracked blades cannot use, need to be re-soldered.

　　In recent years, our country's mechanical development has been advancing by leaps and bounds, whether it is the accuracy of the machine tool or the cost of the machine tool is more accurate step by step, the price is also slowly declining, although in the major high-precision and ultra-precision machine tools, our country is still in the development stage, but in the process of development, we have been in a state of rapid progress.

　　As far as the current various machine tools and processing machines are concerned, the wear and tear of mechanical blades is very large, but fortunately, because our country attaches great importance to the development of machinery in recent years, our country has been able to develop and manufacture these mechanical blades by itself. But in the process of manufacturing and design, we also need to pay attention to the performance aspect.

　　Performance is an important attribute of mechanical blades, from the perspective of the parts made, it can generally be divided into sufficient hardness and strength of the blade, the toughness of the blade, and the high temperature resistance of the blade. Sufficient strength and hardness can ensure that the blade is not easily destroyed by the workpiece in the process of contact with the workpiece, but under long-term processing, it will cause wear and tear on the mechanical blade, so the mechanical blade must be replaced regularly. The high temperature resistance of the blade is also an important part of the process of early blade manufacturing, the workpiece is running at high speed in the machine, and the blade will produce considerable friction, if the material of the blade itself does not have high temperature resistance, it may be blown in the processing process.

　　The last one, the toughness of the blade, if there is a vibration in the process of processing, it will have a great impact on the blade mechanical blade, if there is no fairly good toughness, the machine tool or other machines will be directly broken while the machine tool or other machines are vibrating.

　　The use of carbide tools for hard turning, this technology has been developed and popularized for more than ten years, and has obtained huge economic and social benefits. The following takes roll processing and other industries as an example to illustrate the popularization and application of superhard tools in production.

　　Roll processing industry

　　Many large roll enterprises in China have used superhard tools to carry out rough turning, rough turning and fine turning of various types of rolls such as cold hard cast iron and hardened steel, and have achieved good benefits7, improving the processing efficiency by 2~6 times on average, saving 50%~80% of processing time and electricity. For example, the roll mill of Wuhan Iron and Steel Company has increased the cutting speed by 3 times when turning rough and semi-fine iron rolls with a hardness of HS60~80, saving more than 400 yuan in electricity and labor costs, and saving nearly 100 yuan in tool costs, and has achieved huge economic benefits. For example, when our school uses FD22 cermet tools to turn HRC58~63's 86CrMoV7 hardened steel rolls (Vc=60m/min, f=0.2mm/r, ap=0.8mm), the single-edge continuous cutting roll path reaches 15000m (the width of the blade surface wear band after the tip VBmax=0.2mm), which meets the requirements of turning with a wheel instead of grinding.

　　Industrial pump processing industry

　　At present, 70%~80% of domestic ballast pump production plants have used superhard tools. Ballast pump is widely used in mining, electric power and other industries, is an urgently needed product at home and abroad, its sheath and guard plate are HRC63~67 Cr15Mo3 high-hard iron castings. In the past, it was difficult to turn this material with various tools, so it had to be annealed, softened, roughened, and then quenched. After using superhard tools, a hardening process was successfully realized, eliminating the need for two processes of annealing and quenching, saving a lot of man-hours and electricity.

　　Automotive processing industry

　　In the processing of crankshafts, camshafts, transmission shafts, cutting tools, measuring tools and equipment maintenance in automobiles, tractors and other industries, the processing of hardened workpieces is often encountered. For example, a rolling stock factory in our country, in the equipment maintenance needs to process the bearing inner ring, the hardness of the bearing inner ring (material GCr15 steel) is HRC60, the inner ring diameter is f285mm, using grinding technology, the grinding allowance is uneven, it takes 2h to grind well; First, use a superhard tool to process into an inner ring in only 45 minutes.

　　After years of research and exploration, our country has made great progress in carbide tools, but the application of carbide tools in production is not widespread. The main reasons are as follows: manufacturers and operators do not have enough understanding of the effect of hard turning with carbide tools, and generally believe that hard materials can only be grinded; Think the cost of the tool is too high. The tool cost of hard turning is higher than that of ordinary carbide tools (such as PCBN is more than ten times more expensive than ordinary carbide), but the cost allocated to each part is lower than that of grinding, and the benefits are much better than that of ordinary carbide; the research on the processing mechanism of carbide tools is insufficient; Specifications for carbide tool machining are not sufficient to guide production practices.

　　Therefore, in addition to in-depth research on the machining mechanism of carbide tools, it is also necessary to strengthen carbide tools.

　　Tool technology and market In the future development of tools in China, in terms of tool manufacturing technology, the structure of the cutting edge has always been an extremely important factor in the working performance of the cutting edge together with the matrix material and coating technology. In terms of cutting edge geometry itself, there will still be a steady stream of edge structures, but the goal will most likely be to achieve a higher level of balance in terms of sharpness, impact resistance, chip breakage and stress and heating.

　　When it comes to tool manufacturing, an important measure to improve tools is to choose the right tool coating. There are two main methods of tool coating: chemical vapor deposition (CVD) and physical vapor deposition (PVD). At present, carbide indexable inserts for machining steel and cast iron parts, especially turning inserts, are mainly coated with CVD, while other tools, including solid carbide tools, are mainly coated with PVD. CVD coatings Currently, there are relatively few coating varieties that can be adapted: they are mainly used for Al2O3 coating and diamond (PCD) coating. Although there are not many suitable varieties, this technology still has great development prospects because one of these coatings (Al2O3) has a large market demand because it is especially suitable for processing steel and cast iron, and the other (PVD) is especially suitable for aluminum alloys for lightweight automobiles and carbon fiber reinforced composites such as aerospace and wind power. The author predicts that the development direction of Al2O3 coatings should be in obtaining thicker α phase Al2O3 layers, controlled nucleation and directed growth technology of grains, grain refinement technology, and reducing and eliminating microcracks and droplets of coatings. The development of PVD technology should show a diversified trend due to its own characteristics. It is expected that PVD coating will mainly be achieved by adding trace elements to improve the wear resistance of the coating, improve the heat resistance of the coating, reduce the friction of the coating-chip friction pair or the coating-workpiece machined surface friction pair, and reduce the transfer of cutting heat to the tool. On the other hand, the mechanical and chemical properties of the coating itself will be improved by refining the coating grains.

　　1. Appropriate control of cutting force and cutting speed

　　Properly controlling the cutting force and cutting speed of the tool is also one of the effective means to reduce the temperature of the machining area and extend the service life of the cutting fluid. When processing difficult-to-machine materials, finely ground tool edges are generally used, and the cutting depth and cutting width should not be too large. When selecting cutting line speed, consider factors such as different material types, part structures, and machining equipment. In general, if the processing material is a nickel-based alloy, the linear speed should be controlled at 20 to 50 meters per minute; The processing material is titanium alloy, and the linear speed should be controlled at 30 to 110 meters per minute; The processing material is PH stainless steel, and the linear speed should be controlled in the range of 50 to 120 meters per minute.

　　2. Choose a reasonable cutting method

　　For difficult-to-machine materials, the choice of different cutting methods can make a big difference in the damage of cutting fluid. Regardless of the cutting method chosen, the principle is the same, that is, to reduce the cutting force and the temperature of the cutting area as much as possible. The cycloidal cutting method can minimize the cutting area, so that the actual cutting angle of the cutting fluid can reach a small angle, thereby extending the heat dissipation time of each tooth of the tool and reducing the cutting temperature. The use of spiral interpolation method can make the cutting amount of each tooth relatively uniform, avoid the cutting force concentrated on a few teeth and accelerate the wear, which is more obvious at the corners. The large feed cutting method is used to effectively reduce the cutting force with a small cutting depth and a large feed, so that the cutting heat is generated in the machining and the temperature of the processing area is low.

　　3. Ensure timely and effective chip breaking

　　In metal processing, there will generally be a large amount of cutting heat generated on the cutting chip, if the length of the chip can be controlled to ensure timely and effective chip breaking, this part of the cutting heat can be taken away by the chip, so chip breaking is an effective way to control the cutting temperature. When processing difficult-to-process materials, in the rough machining process, under the premise that the rigidity of the processing system allows, it should be made as much as possible to produce chips during the whole processing process. At the same time, use cutting fluid with good settling performance to settle and discharge the cutting chips, and do not let the cutting chips rub against the surface of the machined workpiece. When mixed with water, it forms a stable clear solution. This product has good settling, lubricity, rust resistance, cooling and cleaning properties. It has strong anti-microbial decomposition ability, can still maintain its stability under different water hardness conditions, and its service life is more than 5 times that of ordinary emulsified oil.

　　Turning knives

　　No matter what knife you choose, you must know:

　　What is the material of processing? What machine tool is used for processing? Finishing or roughing? Are there any drawing requirements? What is the compression method? How many knife squares? Blade model?

　　1. Cylindrical turning tools:

　　What degree is the main declination angle of the tool required? Are there any drawing requirements? What is the material of processing? Are there any hardness requirements?

　　2. Inner hole turning tools:

　　What is the diameter? How deep is the hole? What is the inner diameter of the machine tool sleeve? Is there any interference with the inner hole?

　　3. Grooving knife:

　　How deep should you cut? How wide is the groove? Is it an outer round groove or an inner groove cutter? What is the maximum and minimum machining diameter? (End face groove knife special question)

　　4. Cutting knife:

　　What diameter to cut? What is the required groove width?

　　5. Thread turning tools:

　　Threaded turning tool forehand and backhand? External or female? Metric or imperial? What is the pitch?

　　Knife clips

　　Milling cutters: (taking machining center as an example)

　　How do tools connect to machine tools? BTNTCATISOR8DINEHSKMT

　　1. Clamping drill bits:

　　Do you want elastic chucks or three-jaw centering? How big of a knife to hold? How much is ER?

　　What size of the handle is the cone handle? What is the length?

　　2. Clamping and milling cutters:

　　What size is the milling cutter that is required to be clamped? Powerful, standard or high-speed?

　　What size handle is the cone handle? How big is a threaded hole?

　　3. Clamping tapping:

　　Require rigid tapping or flexible tapping? How big is the tap?

　　4. Clipping face milling discs:

　　What is the diameter of the cutterhead? How big is the inscribed circle of the cutterhead? Metric or imperial holes? Are there any length requirements?

　　5. Boring Knife:

　　a. Rough boring knife

　　Modular or all-in-one? What is the scope of the required processing? The length of the process? Is it required to add a long pole?

　　b. Fine boring knife

　　Modular or all-in-one? What is the accuracy of the machining? What is the length of the process? Is it necessary to add a long rod to increase the processing range?

　　6. Knife setting:

　　Do you want a table or digital display, or a projection? What is the range of measurement? What is the measurement accuracy?

　　Knives

　　One. Milling cutter:

　　1. Integral milling cutter

　　Do end mills want high-speed steel or carbide? What is the hardness of the machining? Less length requirements? How many blades? Ball head or flat head? How many degrees is the shank? How many threads? What kind of coating? How many degrees is the spiral rise angle?

　　2. Blade milling cutter

　　1) Mandrel milling cutter

　　What is the required diameter? Is there a requirement for the angle of the blade? What is the length of the process?

　　2) Cutterheads;

　　What diameter? What is the required angle of the blade? Finishing or roughing? Is there a requirement for knife clearing?

　　Two. Drill bit:

　　1) Straight shank drill bit

　　Is the drill bit required to be high-speed rigid or carbide? What is the machining diameter? What is the depth of processing? Are there any requirements for the blade?

　　2) Taper shank drill bit

　　What size is the original knife cover of the knife? What is the machining diameter? What is the required machining depth? Are there any requirements for the blade?

　　Three. Tap:

　　1) Spiral tapping

　　Do you want left-handed or right-handed tapping? What is the required thread size? Is it metric or imperial? What is the machining accuracy? What is the material of processing? Which country's standard is the handle?

　　2) Straight groove tapping

　　What is the material of processing? Is it a hand attack or a machine attack?

　　Four. Chamfering Knife:

　　What is the required range of chamfers? What is the angle in degrees?

　　Five. Reamer:

　　1) Straight handle reamer

　　What is the depth of processing? What is the accuracy of the machining? What is the diameter of the machine?

　　2) Taper shank reamer

　　What size is the original taper bush? What is the depth of processing? What is the accuracy of the machining? What is the diameter of the machine?

　　The whiskers added to the cemented carbide material can absorb the energy of crack propagation, and the amount of absorbed energy is determined by the bonding state between the whiskers and the matrix. The toughening mechanism of whiskers is mainly manifested as follows: (1) Whisker pull-out toughening: When the whiskers are pulled out of the matrix under external load, part of the external load energy is consumed due to interfacial friction, so as to achieve the purpose of toughening, and its toughening effect is affected by the sliding resistance of the whiskers and the interface. There must be sufficient bonding force between the whisker and the matrix interface to effectively transfer the external load to the whiskers, but not too large to maintain sufficient pull-out length. (2) Crack deflection toughening: When the crack tip encounters the second phase with an elastic modulus greater than the matrix, the crack will deviate from its original forward direction and expand along the interface between the two phases or within the matrix. Because the non-planar fracture of the crack has a larger fracture surface than the planar fracture, it can absorb more external energy, thereby acting as a toughening effect. The addition of whiskers or particles with high elastic modulus to the matrix can cause crack deflection toughening mechanisms. (3) Whisker bridging toughening: When the matrix is broken, the whiskers can withstand external loads and play a role in bridging between the broken crack surfaces. The bridged whiskers can generate a force on the matrix to close the cracks, consume external loads to do work, and thus improve the toughness of the material.