Instructions for the hottest ceramic cutting tools

2022-09-20
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Instructions for ceramic tools

ceramic tools are a new type of material tools in modern metal cutting. It can not only improve production efficiency and process superhard materials that some ordinary blades cannot process, but also is a supplement to all kinds of existing tools. It is a new force in the tool family and plays a very important role in the mechanical processing industry. Ceramic cutting tools are produced with special ceramic powder materials, scientific formulas, special production processes and modern equipment. It is characterized by high hardness, high strength, high hardness, high wear resistance, excellent chemical stability and low friction coefficient. Its cutting efficiency is times that of ordinary cemented carbide. It is generally applicable to the rough, semi precision and finish machining of turning, milling, boring, planing and other machine tools in machining, and is more suitable for the use of modern machine tools such as CNC CNC lathes, milling machines and machining centers with the elongation of various parts of materials above 1000%

I. the cutting performance of Chongqing Lite cutting tool is

1, and the hardness of high hardness

Lite ceramic blade at room temperature has exceeded the hardness of the best cemented carbide blade and reached 92 HRA, which greatly improves the cutting ability and wear resistance. It can process all kinds of hardened steel and hardened cast iron with hardness up to 65hrc, thus reducing the annealing process and saving power. The excellent wear resistance not only prolongs the cutting life of the tool, but also reduces the number of tool changes in processing, thus reducing the labor intensity of workers and improving production efficiency

2, high strength

the bending strength of Lite ceramic blade has reached MPa, and its compressive strength has exceeded high-speed steel and is close to ordinary cemented carbide

3, high resistance to high temperature oxidation

Lite ceramic blade has good heat resistance and high temperature oxidation resistance, and can maintain high hardness and strength for long-term cutting even when cutting at high temperature of ℃. Therefore, the machining speed is much higher than that of cemented carbide tools to achieve high-speed cutting. Its cutting speed can be times higher than that of cemented carbide tools, so it can greatly improve the production efficiency

4, good fracture toughness (K1C)

fracture toughness value is one of the important indicators to evaluate the damage resistance of ceramic blades, which is related to the composition, structure, process and other factors of materials. The fracture toughness of Lite ceramic blade is up to 5 5MPa · m, close to some brands of cemented carbide blades, so it has good impact resistance. Especially in milling, planing, boring and other intermittent cutting, it can show its advantages

5, high thermal shock resistance

the thermal shock resistance of ceramic materials refers to an important index to evaluate the damage resistance when withstanding sharp temperature changes

thermal shock resistance index of Lite Si3N4 series ceramic blades Δ T. As high as ℃, it is obviously superior to other series of ceramic blades (℃) due to its high strength and low coefficient of thermal expansion. Therefore, it shows unique advantages in the blank processing of high-strength intermittent parts

6, suitable for processing materials

① all kinds of hardened steel (58 ~ 65hrc)

② chilled cast iron (80 ~ 90hs)

③ high manganese steel

④ nickel (Ni), chromium (CR) alloy

⑤ all kinds of cast iron (HB)

⑥ all kinds of non-metallic materials, graphite, ceramic blank, glass fiber reinforced plastics, refractories, etc

II. Requirements of Chongqing Lite ceramic blade for machine tools

ceramic tool materials are sensitive to impact and vibration loads. Although the new generation of Lite ceramic tool materials have made great progress in impact resistance and vibration resistance, their weaknesses have not been fundamentally changed

the weak rigidity of machine tool workpiece tool process system is the main reason for reducing the durability of ceramic tools or causing edge collapse. In addition to the rigidity of the workpiece and the tool itself, the smaller the rigidity of the machine tool, the greater the vibration and the lower the durability of the tool

practice has proved that machine tools suitable for machining ceramic tools must have good rigidity, sufficient power and high revolutions

from the current situation of domestic machine tools, medium-sized machine tools can basically meet the requirements in these three aspects of precision and semi precision machining (but the speed is still too low). For the machining of hard to machine materials such as hardened steel or hard nickel cast iron, the power is sufficient even if ceramic tools are used for machining because of the low cutting speed. In the finishing of ordinary steel or cast iron, these three aspects are often not easy to meet. Therefore, foreign countries have designed special machine tools to process automotive parts with Ceramic Cutters in the automotive industry. Heavy duty machine tools have good rigidity and sufficient speed and power. As long as they are used properly, the success rate of using ceramic cutting tools is often high in the processing of heavy industry

in addition, when analyzing the rigidity of machine tools, we must pay attention to the rigidity of machine tool workpiece tool process system, rather than the rigidity of an isolated machine tool. For example, it is necessary to consider whether the rigidity of the workpiece, the rigidity of the fixture, the rigidity of the center and the rigidity of the tool, and the height of the tool center are consistent with the machining workpiece center. Insufficient rigidity and improper operation of any link will greatly reduce the cutting performance and efficiency of ceramic tools (for example, some factories install a small tool holder on the large vertical lathe, and then install a small tool on the small tool holder, making this small tool become a weak link in the whole process system, and it is simply unable to bear the cutting of heavy workpieces)

in a word, the electronic universal testing machine with ceramic cutting tools under 30t has more advantages. Even if it is not ideal at the moment, the original machine tool must be carefully overhauled to make it meet certain quality standards before it is used. Do not use those machine tools that are in disrepair for a long time and are fast falling apart

III. requirements for machined parts

1, part blank

although Lite ceramic tools can carry out blank cutting without annealing for most castings and forgings, it is not that the worse the blank is, the better. For example, serious sand inclusion and sand holes on hard casting blanks will cause many unnecessary cutting, increasing the consumption of ceramic cutting tools. It will be much better if the blank can be properly treated before cutting. For example, some factories use hand grinding wheel to clean and correct the defective part before cutting, and get a better effect

the machine tool should match the condition of the added parts to avoid the phenomenon of "small horse pulling the cart"

formula: chamfer shall be made at the "cut in" and "cut out" parts

for those blanks with high hardness and irregular shape, it should be noted that chamfering must be carried out first and then cutting with ceramic tools (chamfering can be carried out with carbide tools at low speed)

the chamfer at the blank cut-in can avoid the initial damage caused by excessive impact load (generally, the chamfer angle is better to be slightly smaller than the main deflection angle of the tool) when the ceramic tool just contacts the work

the chamfering at the cut-out of the blank is mainly to prevent the ceramic cutter from being damaged by the left edge when cutting away from the part

you should know that any rough edge of a high-speed rotating high-hardness blank may damage the ceramic tool, but cutting from a rounded blank can be stable for a long time, so don't ignore the "small" problem of chamfering

2, the influence of blade geometry on blade strength

the thickness of the ceramic blade, the arc of the tip, the radius and the angle of the tip are the factors that affect the strength of the tool. The smaller the thickness of the blade, the lower the strength; The larger the arc radius of the tool tip, the better the strength; The smaller the angle of the tip, the lower the strength

in principle, large thickness, large tip arc radius and large tip angle are selected for rough turning. On the contrary, select small thickness, small radius and small angle to finish machining

IV. reasonable selection of cutting parameters

1, selection of cutting depth AP

in the processing of ceramic tools, in order to shorten the processing time, we should choose a larger cutting depth as far as possible, so as to cut part of the allowance after one cutting (only the finishing allowance of subsequent processes is left). However, because the cutting depth is limited by the machine tool power and the rigidity of the process system, generally, the maximum allowable cutting depth for rough machining of steel and cast iron is mm, usually ap>1.6mm, and AP < 0.6mm for finish machining; The machining of hardened steel is generally semi finishing or finishing, with small allowance and cutting depth. When the rigidity of the process system is poor, a smaller cutting depth should be taken, otherwise it is easy to cause vibration and damage the blade

2, selection of feed rate f

reasonable selection of feed rate is the key to the successful application of ceramic tools. However, the size of the feed rate is mainly affected by the strength of the ceramic blade and the rigidity of the process system, and the finish machining is also affected by the surface roughness of the machined surface

because the strength of ceramic blade is lower than that of cemented carbide blade, the feed rate should also be lower. Generally, the pre selection can be smaller and gradually increased through practice. For rough turning ordinary steel and cast iron, the feed rate f is taken as 0 75mm/r; Finish machining takes f=0 25mm/r。 During end milling, the feed rate of each tooth af=0 3mm/Z。

for processing hardened steel, the feed rate f is selected according to the hardness. Generally, turning f=0.1- 0.3mm/r; End milling feed per tooth af=0 15mm/Z。 Select the feed rate according to the machined surface roughness. F

if there are surface roughness requirements, select it according to the data in the right table:

note that the feed rate has a greater impact on tool damage than the cutting speed. Selecting a smaller feed rate is conducive to preventing or reducing tool damage. Therefore, ceramic cutting tools should be selected with a small feed rate and as high cutting speed as possible

3, the choice of cutting speed V, Lite ceramic tools are suitable for high-speed cutting

for a certain workpiece material, the cutting speed is mainly limited by the machine tool power. Combined with the selected cutting depth AP and feed rate F, if the cutting speed is selected too low due to insufficient machine power, it is not only not conducive to giving full play to the advantages of ceramic tools, but also prone to edge collapse. The feed rate and even the cutting depth should be appropriately reduced in order to improve the cutting speed. At present, although the cutting speed of ceramic cutting tools has been up to 1500m/min in some countries, most of them are still v=m/min for processing ordinary steel and cast iron; Machining hardness HRC v. grinding of ceramic tools

for ceramic tools, diamond grinding wheels are generally used for grinding, and their grinding quality has a great impact on cutting performance. In principle, the indexable ceramic blade is not reground, because the clamping size and positioning size of the blade change after regrinding, and the feed size must be readjusted in the machining of CNC machine tools to ensure the consistency of workpiece size. However, in order to reduce consumption and make the best use of things, some factories can also use diamond grinding wheel for grinding on tool grinder or tool grinding machine. The main parameters of diamond grinding wheel can generally be used:

particle size: 180 ~ 280 # concentration: 75 ~ 100%

hardness: K, l, m, P bond: resin bond

generally, semi fine grinding adopts coarser particle size, finer fine grinding particle size, lower semi fine grinding hardness and higher fine grinding hardness. Its grinding speed is generally 18 ~ 22m/s for dry grinding, which can be increased to 20 ~ 28m/s when adding grinding fluid. During grinding, the feed should not be too large or too fast to prevent the ceramic blade from cracking

Lite company has a large experimental journey. It produces all kinds of cutting tools and blades according to ISO international standards, and also designs and produces all kinds of non-standard cutting tools for users, and provides good pre-sales and after-sales services. Keep informed of users' usage, feed back users' opinions and suggestions, and constantly improve our product quality and service quality, so that our products are constantly improved and our company continues to

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