The cutting piece is widely used for its high efficiency, convenience, economy and other special properties, but many people neglect to make a reasonable selection of the cutting piece according to the occasion of their use, depending on the occasion of the thin flat cutting disc. The cutting discs can be divided into cutting and grinding types. Most of the cutting machines are fixed mobile, the power of the machine has high power and low power, and the cutting speed will also have high speed cutting and ordinary cutting.
There are many kinds of materials to be cut during cutting, such as stainless steel, titanium alloy, ordinary just, sticky metal, high carbon steel, non-metal, etc. The performance requirements of the cutting piece are different for different occasions, so it is important to choose a reasonable cutting piece. To choose a good cutting piece according to the occasion you use, you can only have a more safety factor.
The power of the cutting piece is small to reduce the radial frictional resistance, so that the cutting piece is thin and has a certain elasticity, and it feels sharper when cutting.
The cutter piece must be statically balanced after it has been mounted on the flange. The static balance is to make the center of gravity of the cutting piece and its center of rotation. The specific static balance method is: the flange is placed on the mandrel and placed on the balance rail.
If it is unbalanced, the heavier part of the cutting piece will always turn to the bottom, move the balance block position in the ring tip of the flange end face, balance the center of the entangled cutting piece, and repeat until the cutting piece is free on the guide rail. The position can be still, and the cutting piece reaches a static balance. After installing a new cutting piece for static balancing, attach the grinding machine to the shape of the cutting disc for stainless steel with a diamond pen, then remove the cutting piece and perform static balance for installation. Two static balances before and after can ensure better use of the cutting piece.
If the cutting piece manufacturer does not perform static balance, it will cause the cutting piece to vibrate at high speed, which will affect the processing result. In severe cases, the cutting piece will be broken and the machine tool will be damaged. Therefore, the cutting piece must be statically balanced.
The abrasive grains on the grinding wheel are different in size and fall off. Why is the grinding accuracy higher than turning and milling?
Accuracy includes surface quality and geometrical tolerances. Nowadays, there are more grindings in the car, which can achieve the surface quality of cut off disc for stainless steel but the geometrical tolerance is not enough. On the one hand, the precision of the grinding machine itself, on the other hand, the grinding mechanism of the grinding wheel. Grinding is equivalent to working with many blades, the blade is more retentive, and the grinding wheel can be self-sharp and interpolated, which determines the precision of grinding is better.
The reason is that the milling process cannot achieve the small amount of feed and the amount of back-feeding (single depth of cut) that can be achieved by grinding. In general, the machining accuracy of the workpiece is related to the grain density (directly determines the roughness) and the processing heat effect (thermal deformation and machining stress and hardness change during processing). Due to the fact that the cutting speed of ordinary turning and milling cannot reach the ultra-high speed similar to grinding, the processing heat is transferred to the workpiece body and the tool during the turning and milling process, so that the hardness of the workpiece and the tool changes. At the same time, the hardness of the turning tool is lower than that of the grinding tool (grinding wheel) and cannot be removed by machining the abrasive particles like the thin abrasive cutting disc for metal . The processing heat also causes the ultra-high speed that cannot be achieved by turning and milling. Because of this, the milling and milling process can not achieve the processing of small cutting speed and large cutting speed (which will cause the tool to deteriorate in superheat hardness and overheat deformation of the workpiece, and the high temperature workpiece will produce localized hardness and thermal deformation due to the expansion of the cutting fluid. ), and the larger amount of cutting will cause stress deformation, of course, there is no spindle speed limit. For ultra-high-speed turning and milling with a line speed of 10~30m/s cutting speed, the machining method of the workpiece before the contact point between the tool and the workpiece is realized, and the workpiece body is subjected to less heat conduction, so that the small cutting amount is high and the cutting speed is free of cooling. The processing method is realized. This also achieves machining precision close to fine grinding and even super finishing.
The machining mechanism of grinding and the machining mechanism of machining are completely different. In the cutting process, the tool cuts into the material, causing the material to plastically deform first and then break from the material. The tool also has a certain amount of compression and friction on the machined surface. Microscopic defects exist when the material is torn directly from the workpiece. The frictional extrusion of the tool on the machined surface creates surface stresses. The workpiece material being machined is also an affected factor. Grinding is to scribe and extrude the surface of the workpiece by abrasive particles. The grinding speed is very high, so there will be a large number of abrasive grains to scribe the surface of the workpiece in a short time and improve the surface quality. After the abrasive grains are blunt, the cutting force becomes large and they are forced to fall off. The shedding of the abrasive particles has little effect on the surface quality. And the size of the abrasive particles is not different.
In the conventional industry, the buffing technique is a process of cutting the surface of a metal part by means of the rotation of a special buffing plate to which the abrasive adheres. With the development of the industry, the manufacturing technology of the China cutting disc for metal is also constantly improving. When the traditional polishing sheet is polished, the grinding will not deteriorate, but the red part on the surface will be deteriorated. After the polishing, the original color will not deteriorate, because the deterioration has been worn away. However, in the polishing, our operators should also pay attention to the fact that the intergranular body of the polishing sheet will definitely change, that is, the bending or the tube will cause the intergranular body to be misaligned, which is only slight and will not seriously change the material. If there is a phenomenon of sharpening the transition, it will lead to a change in the composition of the tempering.
Stainless steel polishing sheets contain less than 18% ferritic stainless steel, which has good machinability because the structure is slightly brittle and the chips are easily broken. In terms of machinability, these steels are attributed to low carbon martensitic stainless steels. Stainless steel polishing sheets are difficult to cut because they are vicious and have long chips, and these steel grades are similar to cutting austenitic stainless steels.
Onboard measurement Many gear grinding machines are more accurate due to the onboard measurement system. Because the machine is used for measurement, thin abrasive cutting disc for metal is not necessary to remove the gear from the workbench and send it to other places for inspection, which avoids the secondary installation error during rework. During processing, the gear is first analyzed by the on-board measurement system, and the measured parameters are compared with the theoretical design parameters to determine the required correction amount. After the control system collects these correction data, the grinding gear processing state is automatically adjusted, and then the grinding is performed. And measurement. Repeat the cycle until the required accuracy is reached. The integrated on-board measurement and on-board correction system make modern gear grinding machines more efficient.
Although there are many types of cut pieces on the market, how to choose the right suitable cut piece is the most important. Today we will come to understand the correct choice of cutting blades.
First, the occasion of use
When we choose the China cutting disc for metal, we first choose the right one depending on the occasion of the cutting piece. Because the performance requirements of the cutting piece are different for different applications, it is important to choose a reasonable cutting piece. We need to choose the cutting piece according to the occasion we use, which can increase the safety factor, improve work efficiency and reduce our use cost.
Second, the choice of cutting blades for ordinary cutting machines
Ordinary cutting machines usually refer to fixed cutting machines, cutting machines with a power of
1. The cutting disc machine must have a person responsible for maintenance, replacement of the China cutting disc for metal, fastening screws, etc., must wear goggles when sharpening.
2. Before driving, check whether the connecting parts of the cutting disc machine are loose or not and whether the cutting disc has cracks.
3. After the inspection is completed, the person must stand on the side of the cutting disc and test the machine for a few minutes without any problem.
4. When sharpening, hold the workpiece tightly, and clamp the small piece with pliers. The surface should be lightly attached to the cutting disc. Do not use excessive force to avoid the cutting disc being crushed or the workpiece flying out and hurting people.
5. When sharpening, the sharpened workpiece should be rolled to the left and right on the circumferential surface of the cutting disc so that the cutting disc is evenly worn without grooves, and both sides of the cutting disc should not be sharpened to prevent damage to the cutting disc.
6. People should not stand on the front of the cutting disc to prevent the cutting disc from flying out and hurting people.
7. Excessive workpieces and tools are not allowed to be sharpened on the cutting machine.
8. If there is any abnormality, it should be stopped immediately. After use, it must be stopped.
9. Clean up the workpiece, clean the site, and keep the site clean and hygienic
The use of abrasive grinding for workpieces is the finishing and precision machining of the surface of the parts. The demand for precision machining on the market is constantly increasing. Many people wonder whether the standard cut off wheel for metal can meet the current processing needs. To understand these, we must understand the following characteristics of precision machining.
1. High precision of grinding size Grinding uses a very fine powder to grind a very thin layer of metal at low speed and low pressure. The heat generated during the grinding process is small, the deformation of the workpiece is small, and the surface metamorphic layer is very slight, so that a highly accurate surface can be obtained. Grinding dimensional accuracy can reach 0.01um.
2. High surface shape accuracy The grinding volume is small, the motion is complex, and it is not affected by the motion accuracy, so high shape accuracy can be obtained. On the other hand, since the amount of cutting of the grinding is small, the original positional error cannot be completely corrected, so the grinding cannot improve the positional accuracy of the part.
3. Surface rent roughness value There is a certain relative motion between the small part and the lap. Each movement trajectory will not be repeated with the previous movement trajectory, so the peak on the surface of the part can be evenly removed to reduce the surface roughness. The surface roughness of the abrasive surface is generally up to Rd.01M.
4. Improve the surface resistance of the surface The surface roughness of the polished surface is small, the surface friction coefficient is reduced, and the effective contact area is increased to improve the wear resistance.
5. Improve the surface fatigue strength of the part The surface layer has compressive stress, which is beneficial to improve the fatigue strength of the surface of the part.
6. Good processability The equipment of Yantan is simple and easy to manufacture: grinding is not only suitable for single-piece manual production, but also suitable for batch mechanized production; grinding can process steel parts, cast iron, various non-ferrous metals and non-gold scraps. For example, hard and brittle materials such as glass, ceramics, and diamonds can be studied.
7. Wide range of applications Grinding is widely used in the processing of various precision parts in modern industrial production. Various block gauges, optical glass, precision tools, semiconductor components, precision mating surfaces, etc. need to be ground.
Turning dressing method: Single-grain diamond (or diamond-shaped diamond trimming block made of fine-cut diamond) is the most common dressing method for tool turning wheels. The diamond cutter mounted on the tool holder is usually inclined by about 5° to 15° in both the vertical and horizontal directions; the contact point between the diamond and the grinding wheel should be 0.5 to 2 mm below the axis of the grinding wheel, and the diamond is uniformly fed at a low speed during trimming. mobile. The smaller the surface roughness after grinding is, the lower the feed rate should be. If the surface roughness of Ra 0.16-0.04 μm is to be achieved, the trimming feed rate should be lower than 50 mm/min. The total amount of trimming is generally about 0.1mm on one side, and it is reciprocally trimmed several times. The depth of the roughing is 0.01 to 0.03 mm each time, and the finishing is less than 0.01 mm.
Diamond roller dressing method: a diamond roller made by injecting a large amount of diamond particles on the surface of a steel roller by electroplating or powder metallurgy, and rotating at a certain speed to produce grinding and rolling effects on the surface of the high-speed rotating 7'' cut off disc for metal, so that the grinding wheel can be obtained and A sharp working surface with a roller profile. Diamond wheels are complex to manufacture and costly, but they are durable and highly efficient, and are suitable for dressing grinding wheels for special forming surfaces (such as threads, gears and turbine blade teeth) in high volume production.
Grinding wheel grinding and dressing method: the ultra-hard-grade silicon carbide grinding wheel with low-speed rotation and the high-speed rotating grinding wheel are used to achieve the purpose of dressing.
Rolling dressing method: using a carbide disc, a set of rollers made of wavy white iron discs or grooved hardened steel sheets, and grinding and pressing of the grinding wheel. The roller is generally mounted on the dressing fixture for manual operation, and the dressing efficiency is high, which is suitable for the dressing of the coarse grinding wheel.
Generally referred to as cemented carbide, it is a type of alloy produced by a pulverization, molding, and sintering process composed of a refractory metal hard compound and a binder metal. Commonly used metal compounds are tungsten carbide (WC), titanium carbide (TiC), tantalum carbide (TaC), and the like. The bonding metal is mainly cobalt, as well as nickel and a small amount of other metals. Cemented carbide is a composite material composed of a refractory metal hard compound and a binder metal. The refractory metal carbide generally refers to tungsten, titanium, niobium, vanadium, niobium, etc. of Groups IV, V and VI of the periodic table. The carbides of the elements, the most widely used in cemented carbides are WC, TiC, TaC, etc. One or more of these carbides and alloys composed of bonded metal drills are often called hard alloys. Alloys generally have high hardness, good wear resistance, good red hardness, high chemical thermal stability, high compressive strength and corrosion resistance.
The use of cemented carbide: Cemented carbide has a series of excellent properties, its use is very extensive, and its use continues to expand over time. The main uses are as follows:
(1) Cutting tools: Cemented carbide can be used as a variety of standard cut off wheel for metal. The amount of cemented carbide in China's cutting tools accounts for about one-third of the total cemented carbide production, of which about 78% is used for welding tools and about 22% is used for indexable tools. The hard alloy for CNC tools only accounts for about 20% of the hard alloys for indexable tools. In addition, there are solid carbide drills, solid carbide small garden saw blades, and carbide micro drills.
(2) Geological mining tools: Geological mining tools are also a major use of cemented carbide. China's geo-hard alloys account for about 25% of the total cemented carbide production, mainly used for impact rock drill bits, geological exploration drill bits, mining oilfield down-the-hole drills, roller drills and coal cutter picks. , building materials industry impact drills, etc.
(3) Mold: The hard alloy used as various types of molds accounts for 8% of the total production of hard alloys. There are drawing die, cold die, cold extrusion die, hot extrusion die, hot forging die, forming die. And drawing mandrel rods, such as long core rods, spherical core rods, floating core rods, etc., the use of various types of hard alloy rolls for rolling wire has increased rapidly in recent ten years, and the hard alloys for rolls have occupied hard 3% of total alloy production.
(4) Structural parts: There are many products used for hard alloys as structural parts, such as rotary seal rings, compressor pistons, lathe chucks, grinding machine spindles, bearing journals, etc.
(5) Wear-resistant parts: wear-resistant parts made of hard alloys include nozzles, guide rails, plungers, balls, tire studs, snow shovels, and so on.
(6) Cavity for high pressure and high temperature: The most important use is to produce top hammers and pressure cylinders for synthetic diamonds. Hard alloys for top hammers and cylinders account for 9% of the total cemented carbide production in China.
(7) Other uses: The use of cemented carbide is becoming more and more widespread. In recent years, it has been expanding in the civilian sector, such as bracelets, case, zipper heads for high-grade bags, and carbide labels.
Steel structure cutting refers to the process of cutting the steel structure as needed in industrial production. Generally refers to the process in which industrial gas and oxygen are mixed and burned to meet the cutting requirements, and the steel structure is melted, slaged and divided. The techniques currently used include flame cutting, water cutting, plasma cutting, and numerical control cutting. The most commonly used is flamecut off disc for stainless steel, which has the characteristics of low cost, simple operation, mature technology and wide use. It is the most widely used cutting technology in the industry. Natural gas cutting is a new technology developed in recent years. It has the advantages of low carbon environmental protection, safety and stability, low cost and abundant gas source. It is a technically popularized technology of the country, with broad prospects for expansion of ordinary natural gas. The flame temperature does not reach the flame temperature of acetylene combustion, and the temperature-increasing combustion additive must be added to the complex reaction with the gas. After the heat is catalyzed, the cutting temperature required for natural gas cutting can be achieved.
Flame cutting: Flame cutting is currently the most widely used cutting technology, mainly using gas and oxygen mixed combustion to produce high temperature to oxidize and dissolve steel, so as to achieve the purpose of cutting. The gas used is natural gas, acetylene, propane, and the like. Acetylene has been eliminated by the state. Natural gas and propane are new types of gas technology. It is necessary to add Cuihua, Cuihua and activated to achieve the cutting purpose.
Water cutting: It is a newly developed cutting technology in recent years. It uses high-pressure punching water column to cut steel plate. It has advanced technology and high cutting precision. It is suitable for cutting thin steel plate with medium thickness and high precision. The disadvantage is that the cost is high, and the general industrial cutting does not require high-precision cutting, so it is not suitable for ordinary industrial cutting.
Plasma arc cutting: A processing method that uses the heat of a high temperature plasma arc to locally melt (and evaporate) the metal at the workpiece cut and to remove the molten metal by high-speed plasma momentum to form a slit. Plasma cutting with different working gases can cut a variety of oxygen cutting difficult to cut metal, especially for non-ferrous metals (stainless steel, aluminum, copper, titanium, nickel) cutting effect; its main advantage is to cut metal with a small thickness At the time, the plasma cutting speed is fast, especially when cutting ordinary carbon steel sheets, the speed can reach 5-6 times of the oxygen cutting method, the cutting surface is smooth, the thermal deformation is small, and there is almost no heat affected zone.