February 28, 2017
Manufacture ofcarbide cutting toolswith diamond grinding process can make the physical mechanical properties of the tool surface layer to improve. Bad or UWIE212 type CNC tools in the German SAACKE company (15kW) on the whole grinder grinding cemented carbide spiral edged cutter as an example, the process of coarse slotting (Mo Goucao) diamond wheel line speed 14 ~ 20m/s the feeding speed of the machine tool, the axial selection of 50 ~ 200mm/min, the radial feed amount of coarse grinding machine 210 ~ 510mm, 0.2 ~ 0.5mm grinding; open tooth process (before and after the blade end, cogging, partial back margin processes collectively) diamond wheel line speed of 14 ~ 24m/s, axial feeding speed of the machine tool selection from 100 to 400m/min radial feed machine, coarse grinding 0.3 ~ 1.0mm, 0.05 ~ 0.1mm. grinding mill and cutter face adopt the feed return light grinding to improve its surface roughness.Such as imported grinding wheel, allowing selection The grinding wheel speed and the radial feed rate are higher than the domestic grinding wheel.
Verification of the effect of grinding process improvement measures
More than 6800 pieces of whole cemented carbide cutter grinding process improved (of which there are nearly 4000 pieces of high speed milling cutter) using the same after emulsification fluorescence penetrant detection method for testing.The results show that not only the tool grinding surface quality greatly improved,grinding crack rate of nearly 20% by the process improvement before gradually reduce for improved process 15% 10%, 6%, 0.5%, until the best improvement process, grinding tool surface burns (not shiny, pale and blue, purple, brown, yellow, black, dark) and surface roughness (Rz0.2 ~ 0.8 m) also significantly improved; and the grinding efficiency is increased, the diameter of 20mm edged the whole cemented carbide high speed milling cutter as an example, the process improvement before the completion of each tool grinding 30 ~ 40min,the improved process is only 20 ~ 30min,if the better quality of the imported cooling oil and imported diamond sand The grinding efficiency of the optimum process can be increased to 14 ~ 20min.
All in all,the main reason for grinding cracks of solid carbide cutting toolsfor grinding process and inappropriate parameters lead to local instantaneous temperature grinding contact zone caused by high near surface layer of high tensile stress value exceeds the breaking strength of materials.
The hydrophilic high sensitivity after emulsification fluorescence penetrant flaw detection method can effectively detect the whole cemented carbide cutter grinding cracks;recommend the method widely used in the whole cemented carbide tools technical field of quality assurance.
By improving and optimizing the grinding process and the grinding parameters of the solid carbide tools, it can effectively prevent the grinding cracks and grinding burn.
February 27, 2017
According to the actual situation of Chinese cemented carbide tool material development and application,focus on technical upgrades to cemented carbide bars of existing products, accelerate the development of a new generation of high strength lightweight cemented carbide bar products with high efficiency and low cost, with independent intellectual property rights, to be in the cold spiral alloy, light alloy materials leader, this it is very important.
Research on the key technology of powder metallurgy for preparing high strength and light weight cemented carbide.The rapid development of metal processing requirements tool has the characteristics of high cutting speed,high feed rate, high precision and long life,and the traditional cemented carbide cutting tool, although it has a certain hardness and wear resistance, but poor toughness and hardness, has been unable to meet the requirements.
According to the cutting of stainless steel at high speed for a long time in the process of dry cutting, red hardness and toughening of the poor, to adjust the powder composition and the sintering process and other measures,independent research and development of powder metallurgy high strength lightweight cemented carbide bars, improve the current stainless steel stem cutting tool materials during the service cycle.
High strength lightweight cemented carbide bars can effectively reduce the temperature of cutter machining process, mechanical debris removal process,improve the quality of the machined surface, improve processing efficiency, prolong the service life of cutting tool. Foreign enterprises are strictly confidential to the process from the equipment,Chinese domestic for the product market demand is huge, preparation technology of high strength lightweight cemented carbide is difficult China powder metallurgy industry eager to break through.
The project's characteristics and innovations, put forward the new sintering process high strength lightweight cemented carbide raw materials and sophisticated processing equipment and processing method,preparation of high strength lightweight cemented carbide,high strength lightweight cemented carbide bars are developed,with cemented carbide drill, milling cutter, alloy steel, titanium alloy processing requirements reached the foreign advanced level, and to fill the domestic blank.
February 24, 2017
Because the titanium alloy casting molding will be formed after the uneven skin is hard and brittle, easily cause chipping phenomenon,which has become one of the most difficult removal of crusts in titanium alloy processing process. Recommend appropriate to increase the depth of rough machining first took the knife (2mm-4mm), to control the tip under the surface of the workpiece is Appropriate,to prevent direct contact with the tip and crusty chipping phenomenon.
The tool life can be improved by changing the geometric parameters of the cutting tool,After the study on the cutting edge of cemented carbide scrap parts found defects in cutting edge part of the design of new tools, namely the lack of transition and transition edge. This is the result of the main cutting edge strength is not enough, which leads to rapid tool wear, easy to appear the main reason why "tipping" phenomenon.
With the grinding out of plane arc transition in arc transition edge add cutting edges, to enhance the strength of the tip, which can solve the cutting edge is easy to wear, easy to chipping of the problem, but also improve the workpiece surface roughness and milling efficiency. At the same time reducing the knife at the tip of the cutting thickness for cemented carbide cutter, the formation of the machined surface the cutting thickness is small,which is conducive to the improvement of the surface roughness of the milling surface. In addition, also can grind out repair light cutter, and make it parallel to the surface, to fix the light surface effect, improve the quality of the machined surface.
The tool after repeated chipping and grinding, cutting and grinding will be exhausted only handle part; or because of improper operation caused in the process of using the tool directly from the hilt fracture. In this case, the effective length of the warp can use the remaining knife cutting, grinding, heat treatment and other processing methods the single pole forming, can be safe and effective in the clamping range, we can use the plane milling, groove cutting, chamfering, and can be used for boring the re using scrap cutter.
In order to increase the cemented carbide cutter rigidity and strength, heat treatment and surface coating of the corresponding parts, and special treatment of the cutting edge part. Using this approach, in order to make better use of the damaged cutter shank portion (YG hard alloy) into a single, through the heat treatment quenching will increase the cutting edge the hardness of 54-57HRC, so as to improve the service life of the cutter.
February 23, 2017
Wire drawing die in the process of long-term use, the mold wall by metal wire intense friction and flushing action, would inevitably produce wear phenomenon, the most common is the workspace wire into LJ site in the annular groove tank (dent) pull mode ring groove, exacerbating the die wear and tear, because the ring groove on the peeling off by loose small particles by metal wire core materials into the die workspace and sizing area, abrasive role, while the wire into the die like grinding needle die wear.If not timely repair switch, then the ring groove will continue to accelerate expansion, increase the repair is difficult, even in the depth of the annular groove is, the avalanche crushed scrap wire drawing die completely.
Learn from experience, develop a set of standards, strengthen the daily maintenance, often for maintenance of wire drawing die is very economical. When diamond die is present any slight wear and tear, in a timely manner polishing, diamond die polishing to restore to the original state is spent time is shorter, and wire drawing die pass, no obvious change.
After decades of development, has the appearance of many new type wire drawing diesmaterials. According to the material types, drawing diescan be divided into alloy steel, cemented carbide die, natural diamond die, polycrystalline diamond die, CVD diamond mould and ceramic mould, etc. In recent years the development of new materials greatly enrich the application range of wire drawing die and improve the service life of drawing die.
(1) alloy die early wire drawing die manufacturing materials. Used in the manufacture of alloy steel mould materials are mainly carbon tool steel and alloy tool steel. But as a result of the alloy steel hardness and poor wear resistance and short service life, can not adapt to the need of modern production, so the carbide diessoon be eliminated, in the present production and processing has hardly see alloy steel.
(2)cemented carbidedies aremade from cemented carbide. Tungsten carbide belongs to cobalt alloy, its main composition is tungsten carbide and cobalt.Tungsten alloy is "skeleton", the main hard wear-resisting effect; Cobalt is bonding metal, is the source of metal toughness. Therefore, cemented carbide die compared with alloy steel mould has the following characteristics: high wear resistance, good polishing, small adhesion, low friction coefficient, low energy consumption, high corrosion resistance, these features make a wide variety of cemented carbide drawing die processing adaptability, become today's most used wire drawing die.
(3) natural diamond is carbon with straight body, use it to make the mold has the characteristic such as high hardness, good wear resistance. But the brittleness of natural diamond is bigger, more difficult to machining, commonly used in the manufacture of diameter of 1.2 mm below the drawing die. In addition, natural diamond is expensive, supply shortage, so the natural diamond die is not ultimately seeks both economic and practical tool for drawing.
February 20, 2017
In the past, when the wholetungsten carbidebit was introduced hole processing, in order to reduce the load and prevent the cutting edge chipping, users have to reduce the feed per revolution (compared with high-speed steel drill). However, the hard alloy bit can be used in cutting speed faster. With cutting grades and drill design progress of hard alloy drilling, cutting edge chipping possibility is greatly reduced, so that the actual feed the whole hard alloy bit rate increase.
Tungsten carbidetap, conduction only by the thread, thread number and cutting edge slope to control chip load, tapping the environmental conditions difficult to further reduce effect to tap on the cutting edge of the load. However, in order to avoid tipping, improve the overall carbide drill in the design (which can obtain higher feed rate) also can be applied to solid carbide taps. These improvements include new cutter type KC7542, this brand will be devoted to the development of high strength cemented carbide taps and nano TiAlN coating for the new development of the hard alloy bit perfectly together.
Machine tool control system, tool chuck, hard alloy and tap design improvement greatly expand the scope of the workpiece material can achieve efficient tapping,which includes not only short chip materials (such as aluminum and iron),but also for the first time included long chip materials (such as carbon steel and alloy steel).
In addition,mounted by the heat in the CNC machine can realize synchronous tapping on hydraulic sleeve type TGHP or precision tool clamping when tapping, carbide taps new can be processed to 5 times faster than the speed of high-speed steel cone, which can greatly improve the production rate of tapping.
However, we must pay attention to in tapping on the blind hole, not all of the CNC CNC machine tool has the same ability. The synchronous tapping processing to the blind hole bottom tap and spindle must slow down and exit, reversal may occur when the tap lead error, resulting in lateral thrust tap, and cause the thread when detecting the size difference. In addition, the tap speed, reverse and re acceleration still and the workpiece are bonded together, therefore, the blind hole tapping speed should be about 40% lower than the through hole tapping recommended speed.
February 17, 2017
In the drawing of metal products industry, wire drawing die is very important. Consumable tool drawing die material selection of drawing die quality plays a key role.The physical and chemical characteristics of drawing die must satisfy high hardness, impact resistance, wear resistance, low friction coefficient, which directly affect the quality of wire rod the quality of life of dies to the influence of the length of wire drawing production and production efficiency. Therefore to improve the quality of wire drawing die prolong the life, is the domestic and foreign scholars continue to study. The quality and life of die and material, pass design, manufacturing process, tooling equipment and testing instrument and so on.
Currently on the market are mainly cemented carbide drawing die mold,mold and die. Polycrystalline CVD diamond carbide drawing die life is lower than the norm and CVD polycrystalline diamond die,but its cost is relatively low, so it is widely used in the wire drawing dies,especially suitable for drawing with larger diameter (more than 8mm) of the wire or section.
Carbide drawing die mold core is generally made from tungsten carbide as raw materials, with a certain amount of cobalt binder for sintering.The tensile strength and hardness of the cobalt binder are very low, so, in the production of wire drawing, wire and die in the air on the contact surface of adhesive wear and abrasive wear to affect the service life of drawing die the easy to produce.
It is worth noting that the drawing die in the use process is easy to produce ring groove wear, wear marks, weld damage, different shaft wear, grinding and violent mode.
In recent years, with the chemical vapor deposition of diamond thin film technology, considering the cost of the mold and the use effect, a more reasonable approach is in the cemented carbide drawing die hole surface coated with a layer of uniform and adhesion of diamond films can meet the use requirements. There is also research workers from the structural change of drawing die. In order to improve the drawing die noodles, such as rotary drawing die, detachable assembly mode.
In general,drawing die material selection should consider drawing die material and the drawing material goods,to ensure that the goods have been based more on the surface gloss,the best to ensure the life of drawing die; and the wear resistance of the two is not particularly big difference, so you can avoid the excessive wear the product,or make the effectiveness of drawing die damaged or scrapped; at the same time we also should consider economic factors, in ensuring the normal production of the premise, so to maximize the interests and make the lowest cost.
February 16, 2017
Cemented carbide is a valuable tool material, due to its brittleness is big, easy to crack, when handling so want to put light. Collapsed area not exorbitant, avoid collisions, fall edge Angle, affect the use.
The brand and model of cemented carbide, if it was improperly secured, easily mixed together, in distinguish between carbide insert number of cases, the available method to identify as follows:
Firstly,with clear brand mark on the insert: can according to the brand mark on the insert area to stop.
Secondly,according to the color difference on the insert:if no brand mark on the insert,or are painted a variety of color,which can according to the color to distinguish.
Thirdly, mercury identification method: to see not clear brand mark,and no color mark insert, available mercury identification. Because the proportion of mercury is 13.6, the proportion of YG alloy in 14 or more commonly, the highest proportion of YT alloy but 13,so everything in mercury can sink is 1 G alloys. Float on the surface of mercury is not sinking is YT alloy.As for the different type of alloys, such as YT15, YT 5 how to distinguish, can use the known brand of alloy in mercury, according to its determination of the speed of sinking and floating to compare.YG alloy can also be based on what it float on the surface of the mercury to reveal part to measure.Y T30 the lightest, revealing the mercury surface parts is big, YT15 show less, YT least 5 dew in the above section. But this approach is not very accurate, more practice, to master.
Toxic mercury to identify,because mercury,the hand is not to be exposed to mercury, available perturbation clamping inserts were determined.Price of mercury is very expensive,to avoid falls, should be put in vessels containing mercury below a large tray.Larger alloy insert,had better be put vertical mercury inside,because the flat,because the relationship between the surface tension, sometimes even the YG alloy can not sink.To identify accurate,available stick first pressed the insert to the mercury, to see if it can float.
Fourthly,chemical identification method:use a concentration of 50% hydrochloric acid and hydrogen peroxide drops on clean insert (1-2 drops), then different insert can form different color and bubbles.
February 14, 2017
the domestic cemented carbide rod production in China have been growing in recent years, but with the growing demand, market supply situation, the demand for quality inspection is also facing difficulties.The detection of cemented carbide rod generally adopts the artificial method, human consumption is more, the test results are not stable, automation testing equipment gradually by the manufacturers of all ages.
According to relevant data, cemented carbide rod with high hardness, high wear resistance, high strength, anti bending, long tool life and a series of excellent performance. cemented carbide rod are blank making bits and cutters, mainly by extruding process of powder. Now widely used in the production of automotive tool, drill, printed circuit board the whole engine tool, milling cutter, cutter, reamer overall, carving knife and so on, but also can make the punch, mandrel, and the top punch tool.
With the market demand soared, ultra-fine grain cemented carbide rods has been more and more widely adopted. In the high-speed cutting field, because the reliability of tool safety, high standard of durability, quality requirements of the whole hard alloy tools and inner surface are more strict. And with the cemented carbide rod especially the intrinsic quality of ultrafine cemented carbide the material continues to improve, the whole surface of hard alloy cutter quality more and more attention.
It is reported that some domestic Chinese companies provide a large number of solid carbide cutting tools (such as milling, drilling, carving knife, gauge, gauge) withcemented carbide rod, there are a variety of materials available, the highest hardness can reach 94.5 (HRA) processing of titanium alloy machining various kinds of material. At the same time provide a variety of needle, punch with cemented carbide rod. It can be seen that the use of cemented carbide rod quite widely, the market prospect is very considerable. cemented carbide rod face demand increased year by year, traditional methods cannot achieve fast, accurate and effective detection, so many manufacturers demand for automatic test equipment is more and more urgent.
With the soaring production of cemented carbide rod, automatic test equipment comes in. Just imagine,the concept of leading custom detection state apparatus has been advocated the manufacturing industry is widely accepted In recent years,It is expected that the next few years, non-standard customized automatic detection device is bound to replace the traditional detection mode, so as to create more value for the manufacturers of cemented carbide rod.
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