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Thread Machining

Thread processing is used to process internal and external threads in the workpiece, and there are two kinds of cutting and rolling processing.

Brief history: the application of thread principle can be traced to the spiral water tool created by the Greek scholar Archimedes in 220 BC. In the 4th century, the Mediterranean countries began to apply bolts and nuts on the pressure machine of wine making. The external threads were then threaded into a cylindrical bar with a rope, which was then carved into it. The internal threads are usually hammered by hammers on the outer threads of soft materials. In about 1500, Italian leonardo Da Vinci's drawings of thread processing devices have been conceived of using the female screw and the exchange gear to process different screw threads. Since then, the method of mechanical cutting thread has developed in European clock manufacturing industry. In 1760, the British, j. Wyatt and w. Wyatt, were granted a patent for cutting wood screws with specialized devices. In 1778, British j. ramsden made a thread cutting device with worm gear, which could produce long, high precision threads. In 1797, British h. morzley laid down the basic method of cutting threads by using the female screw and the exchange gear to cut the metal threads of different pitch. In the 1820s, mozley produced the first taps and dies for processing threads.

The beginning of the 20th century, the development of the automobile industry to further promote the standardization of screw thread and the development of all kinds of precision, efficient thread processing methods, automatic open die head and automatic contraction tap invention, thread milling to start the application. In the early 1930s, thread grinding occurred. Thread rolling technology is at the beginning of the 19th century had a patent, but due to mould manufacturing difficulties, development is slow, until the second world war (1942 ~ 1945), due to the needs of the production of the arms and thread grinding technology development can solve the problem of the precision of mould manufacturing, to obtain rapid development. Thread cutting generally refers to the method of thread cutting, milling, tapping, threading, grinding, grinding and cyclone cutting. When turning, milling, and grinding threads, each turn of the workpiece, the drive chain of the machine ensures that the tool, milling cutter or grinding wheel will move a guide smoothly and evenly along the workpiece axis. During tapping or silk, the cutter (tap or die) is rotated relative to the workpiece and leads the cutter (or workpiece) to the axial movement by a threaded groove formed first.

Thread cutting, turning thread on lathe can use forming tool or thread comb knife (see thread processing tool). It is a common method to produce thread workpiece by single and small batch because of the simplicity of tool structure. It is used to cut thread with thread and high efficiency, but the tool structure is complex, and it is only suitable for the short thread parts of the cutting teeth in medium and mass production. The accuracy of screw pitch of the cutting trapezoidal thread of ordinary lathe can only reach the level of 8 ~ 9 (jb28886-81); Machining threads on a specialized threaded lathe can significantly improve productivity or accuracy. Thread milling (FIG. 2) is milling with disk milling cutter or comb milling cutter on thread milling machine. The disk type milling cutter is mainly used for the trapezoidal external threads on workpieces such as milling screw and worm. Comb milling cutter for milling of internal and external common thread and taper thread, because it is with multiple milling cutter milling, the working part of the length is greater than the length of the thread processed, so the artifacts only need to rotate turn to be able to be finished processing of 1.25 ~ 1.5, the productivity is high. The pitch accuracy of thread milling is generally 8 ~ 9, and the surface roughness is Ra5 ~ 0.63 micron. This method can be applied to the machining of threaded workpieces or grinding before grinding.

Thread grinding is mainly used to process the precision thread of hardened workpiece in thread grinding machine (figure 3). The grinding wheel is divided into two kinds of grinding wheel and multi-wire grinding wheel according to the shape of grinding wheel section. Single - wire grinding wheel grinding can achieve the pitch accuracy of 5 ~ 6, the surface roughness is Ra1.25 ~ 0.08 micron, the grinding wheel dressing is more convenient. This method is suitable for grinding precision screw, thread gauge, worm, small batch screw thread and blade grinding precision hob. The grinding of multi-wire grinding wheel is divided into grinding and cutting. The grinding wheel width of the longitudinal grinding method is less than the length of the grinding thread, and the grinding wheel is moved vertically or several times to grind the thread to the final dimension. Cut grinding wheel width is greater than be ground thread length, radial cut into the workpiece surface grinding wheel and workpiece about can grind good 1.25 turns, the productivity is high, but slightly lower precision, grinding wheel dressing is more complex. It is suitable for grinding and grinding some fastening threads. Thread grinding Made from soft material such as cast iron type nut or screw thread tool and the workpiece is processing on the part of the screw pitch error exists to carry on the positive and negative to the rotating grinding, in order to improve the accuracy of pitch. Hardened internal threads are usually ground to eliminate deformation and improve precision. Tapping and sleeve tapping (FIG. 4) is used to process internal threads in the bottom hole of the workpiece pre-drilled with a certain torsion distance. The sleeve (FIG. 5) is used to cut out the external threads on the workpiece of the rod (or pipe). The machining accuracy of tapping or sleeve is determined by the accuracy of tap or die. There are many methods for machining internal and external threads, but small diameter internal threads can only be machined by tap. The tapping and wire can be operated by hand, and can also be used for lathe, drilling machine, tapping machine and silk machine. Thread rolling is used to make the workpiece produce plastic deformation to obtain thread processing method. Thread rolling is generally used in thread rolling machine. The thread rolling machine or the automatic lathe that is attached to the rolling head of the automatic rolling thread is applicable to the outer thread of the mass production standard fastener and other threaded joints. The outer diameter of rolled thread is not more than 25 mm, the length is not greater than 100mm, the thread precision can reach level 2 (gb197-63), the diameter of the blank pieces is roughly equal to the diameter of the processed thread. The rolling pressure generally cannot process internal threads, but the soft parts of the material can be used without slotted squeeze tap, the maximum diameter can reach about 30mm, working principle is similar to tapping. The torque is about 1 times greater than that of tapping, and the machining accuracy and surface quality are slightly higher than that of tapping.

The advantage of thread rolling is that the surface roughness is less than the turning, milling and grinding. When the surface of the thread after rolling is hardened by cold, it can improve the strength and hardness. High utilization rate of materials; The productivity ratio is more than the cutting process and is easy to be automated. The rolling die has a long life. But the rolling thread requires the workpiece material to be no more than HRC40. High precision of blank size; The precision and hardness of the rolling die are high, making it difficult to make moulds. It is not suitable for roller - shaped asymmetric thread. According to the different rolling mould, thread rolling can be divided into two types. The thread of thread and thread of two threads of thread is staggered by the half pitch, the static plate is fixed, and the movable plate is parallel to the back and forth motion of the static plate. When the workpiece is fed into two plates, the moving plate moves forward to press the workpiece, making its surface plastic deformation into threads (figure 6). The roller has three kinds of rolling thread, cutting roller and rolling thread. Radial rolling: (1) 2 (or 3) with the thread profile rolling wheel axis parallel to each other in the installation, the workpiece on the bearing between the two wheels, two rounds of synthetic constant speed rotation (figure 7), the radial feed movement round the same time. The workpiece rotates with the spinning wheel, and the surface is subjected to the radial extrusion to form the thread. A similar method can be used for the screw forming of a screw with less precision. Cutting to the wire: also known as planetary rolling, the rolling tool consists of a rotating center roller and three fixed arc wire plates (FIG. 8). When rolling, the workpiece can be continuously sent in, so the productivity is higher than the thread rolling and the radial roller. Rolling thread: on automatic lathes, usually used for cutting short threads on the workpiece. Three or four of the rolling heads are rolled in the outer ring of the workpiece (FIG. 9). When rolling, the workpiece rotates, rolling the head shaft to feed, rolling the workpiece out of the thread.

The China tungsten industry development report and the six sessions of the China tungsten industry association have been held in Beijing

On December 22, the China tungsten industry development report and the six sessions of the China tungsten industry association were held in Beijing. Chairman of China nonferrous metals industry association, chairman of the China tungsten industry association, Chen quanxun attended the meeting and spoke. Shi Tang king of non-metallic researcher at the ministry of land and resources and mineral resources development and management, the ministry of commerce, foreign trade department, deputy director of the energy resources product trade place sviri ge, China's economic research institute of land and resources mining right management division, deputy director of the Shi Dengfeng, Chinese academy of engineering, Beijing university of technology, vice President of zuo-ren nie, China nonferrous metals industry association relevant departments of the leadership and other guests attended the meeting.

Chen Quanxun President in his speech, in combination with the report spirit of study and implement the nineteenth, emphatically analyzes the non-ferrous metals industry in China is facing a situation, the industry development and society service puts forward the requirements and hope. He pointed out that the non-ferrous industry, study and implement the party's tungsten industry 19 big spirit, learning to understand have a good grasp of old-age fluctuation kongfu, to grasp the new achievement, new era, new ideas, new strategies, new target, the new project. To deeply understand and grasp new era xi thought the rich connotation of socialism with Chinese characteristics and historical status, more consciously with the party central committee with comrade xi as the core to keep highly consistent, through learning fluctuation kongfu, work hard in practice, in the development of fluctuation kongfu, in the implementation of the fluctuation kongfu, jinping the ideas of socialism with Chinese characteristics in new era is over, will be the party central committee's strategic deployment, into our industry development and the vivid practice of association work, promote the building of non-ferrous metal power. Must firm development direction, he notes, keep the development of concentration, as the guidance, in the spirit of 19 large unequivocally about politics, unswervingly in the work to carry out the new development concept, to speed up the optimization and upgrading of industries to develop new kinetic energy and the innovation, coordination, the concept of green, open, sharing, comprehensive into conscious action in terms of industry, promoting tungsten power construction, and earnestly pays special attention to the reform and development of tungsten association. He stressed that the first is to unswervingly accelerate the pace of high-quality development, and persist in the fight for production capacity. Second, we must unswervingly adhere to the guidance of innovation and make innovations in all areas the real productivity. Third, we must unswervingly adhere to the green development, so that "green water and green mountains" truly become the "golden hill" of the future generations. Four is to firmly to foster globally competitive world first-class enterprise, promote the collaborative development ability, promoting scientific and technological innovation and management ability, improve risk control ability, strengthen the talent base. He hoped that China's wolfram should forge ahead and strive to improve service capacity and level, and give full play to the characteristics and advantages of industry organizations. We should focus on improving the influence of the association and improving the voice of the industry. We should strengthen our own construction and strengthen the development of the association. At present, the decoupling reform of the association's chamber of commerce is deepening. Under the new circumstances, the association of tungsten and tungsten will adapt to change and take on the role of transformation. On the organization structure, to strengthen and improve the modern corporate governance structure of the association, will really do democracy, democratic management and democratic decision-making, promote the association to standardization, marketization and internationalization. On talent training, to strengthen the association of leading group construction, establishing and perfecting incentive mechanism, improve the association team of professional quality and ability to work, promote the contingent of professional, younger, professional association. In operations management, must set up market-oriented concept, innovative service mode, strengthen international cooperation, broaden the sources of funds, adhere to the high-value, constantly inspire association internal vitality and development.

The council heard and considered the report of the six sessions of the six sessions of the six sessions of the council, entitled "taking the spirit of the party's nineteenth spirit as the guide and striving to create a new situation of tungsten coordination". Meeting that the council work report work comprehensively and objectively summarized the association in 2017, confirmed the association in-depth industry research, both at home and abroad to carry out the research, reflect the appeal, make recommendations and coordinated industry development the fruitful work done, the 2018 association of key work arrangements and measures are put forward is feasible. To hear and consider the budget for 2017 and the budget for 2018. According to the meeting, the budget report for 2017 objectively and truthfully reflects the financial situation of the association, and the proposed budget for 2018 is in line with the actual situation.

The council elected and passed the leadership of the sixth council of China's tungsten association. According to the outcome of the vote, xue-quan ding elected President of the 6th council of China tungsten association, jiangxi tungsten industry holding group co., LTD., deputy general manager YanYangHua elected vice President, Liu Liangxian was elected vice President and secretary general. Mr. Chen no longer holds the post of China tungsten association, and Mr. Zhang no longer holds the post of executive vice President, and Mr. Zhong is no longer vice President.

During the meeting, China nonferrous metals industry association, vice President of long, the new China tungsten association xue-quan ding made warm remarks, he thanked the China nonferrous metals industry association, China tungsten industry association and other organizations at all levels to recommend him as China tungsten industry association; Thank you for the trust and support of all the governing units and the China tungsten secretariat. Thank you to President Chen, zhang chunming, vice President of zhang chunming, and vice President zhong xiaoyun for their contribution to the development of tungsten industry. He said that as President of the newly elected China tungsten industry association, he will work with new and old leaders to forge ahead and take responsibility. We should do our best and conscientiousness, and do our best to serve the government, the enterprise and the industry. To actively listen to the views of member units, under the leadership of China nonferrous metals industry association, make full use of the overall functional advantages and better serve the development of the tungsten industry. He stressed that "a new era, new ideas, new as" the context of tungsten enterprises to comprehensively implement the 19 big spirit, will continue to adhere to innovation and development, continue to adhere to the coordinated development, continue to adhere to the green development, tungsten enterprises should pay close attention to and earnestly implement the new "environmental law". He hoped that the tungsten enterprises and the tungsten industry would achieve greater progress and development, and made new efforts and contributions to the construction of non-ferrous metal industrial powers and the tungsten industry.

The council also adopted the draft resolution on the membership and membership of development members, the replacement of directors and the directors of the chapter. During the meeting also held six sessions thirteen times meetings of the presidium, pushing China Tungsten and Hightech electronic Materials Co., ltd. executives liao university for the six council the fifth executive chairman of the presidium.

According to the agenda of the meeting, China tungsten association held a report on the development of China's tungsten industry on the afternoon of the 22nd. Macroeconomic research department under the state council development research center, deputy inspector, zhang liqun, a researcher at the Chinese academy of geological sciences, deputy director of global mineral resources area along the center Chen Jishen, carbide Zhang Zhongjian, director of the state key laboratory of central south university, vice President of the institute of metallurgy and environment zhong-wei zhao, mining software technology co., LTD., Beijing, Hong Kong and chairman Gerry, and China tungsten association vice-chairman concurrently secretary general Liu Liangxian has made a special report.

Method for making thread rolling machine of steel bar

To the steel threaded connection is to connect two root reinforcement end work out a certain size and precision of the connection thread, then connect the two stay bar screwing in both ends are respectively corresponding internal thread connecting sleeve or connection thread hole on the assembly, will cooperate with thread lock, and put two steel bar together.

In many steel bar thread connection technology, the new development in recent years, the steel rolling straight thread connection method with high efficiency, strong joints and reinforcement and was welcomed by more and more construction units. There are three kinds of steel roller direct thread processing methods applied in the current project, which mainly include the following three kinds of steel screw thread rolling machine to roll the thread directly on the end surface of the steel bar without any processing. Its advantages are simple processing, the joint can reach the strength of steel and so on. Defect is in the ribbed steel bar rolling, affected by the transverse, longitudinal ribs, processing thread quality is low, such as complete tooth type screw tooth discontinuity, some screw teeth metal oxide skin ACTS as the screw tooth ontology such as metals, reduces the bearing capacity of the thread. In general, the quality of the joints is low, and the quality of the steel and steel shall be effectively supervised and controlled to ensure the quality of the joints.

2. Two parts of the equipment of stripping rib machine and thread rolling machine are used to process the screw thread on the reinforcing bar. Firstly, the surface of the rebar is peeled or extruded by a ribbed machine or a extruder, so that the surface of the rebar is as close to the cylinder as possible. Then the thread rolling machine is used to roll the thread. After the surface processing of the steel bar, the quality of the rolling thread can reach a high level, and the steel joint can reach and exceed the steel strength. The advantages of this thread machining method are high thread quality and high joint performance. The disadvantage is that the production of two equipment, the investment, the large area, the operation personnel, from the input equipment and personnel, the production efficiency is low.

Three, use compound stripping rib rolling straight thread processing equipment section, step by step to peel rib, processing thread screw rolling methods, such as using Numbers for ZL99243669.9 China patent mentioned "ribbed steel bar intensity stripping rib rolling straight thread processing equipment such as" processing steel thread. The advantage is that the stripping and rolling equipment are combined to improve production efficiency. Faults is stripping rib, thread rolling part of equipment is the two institutions in series, the roller screw rolling body repair or replacement, due to the volume, weight, high labor intensity, takes up more than human, long working hours, to calculate the production efficiency is low.

Is the purpose of the utility model provides a kind of steel straight thread screw rolling machine, the device by which has the function of rolling ribbed plastic and extrusion thread compound rolling wheel directly at the end of steel rolled threads, thread accuracy than the existing straight thread screw rolling machine, easy to use and the production efficiency is better than that of stripping rib rolling straight thread processing equipment, the strength of threaded joints more than reinforced body strength.

planetary thread rolling dies of btcarbide

Tungsten raw material supply cost to lead tungsten price is easy to rise and hard to fall

In terms of supply, policy and seasonality, the production cost of smelting enterprises is constantly increasing, and the supply of raw materials remains tense. On the one hand, the new environmental protection tax levy cause certain cost pressure to small and medium-sized manufacturing enterprises, have relevant personage points out, along with the advancement of reform of the supply side, upstream environmental protection equipment industry sales up sharply in the second half of 2017; Dry season, on the other hand, local businesses with issues such as discharges, exposure, under high pressure environmental policies, most of the inhibition of small and medium-sized mining enterprises production, superposition of mine production of repair work before and after the Spring Festival gradually developed, and the tungsten raw material supply will remain tight.

Demand side, the raw material prices continue to rise on the downstream procurement enthusiasm, and low end products orders of extruded alloys and products enterprise profit, superposition money problems before the Spring Festival, the downstream market for raw materials consumption ability weak, although there are still just need to bid to clinch a deal, but there is no a lot of stock in the short term the middlemen and wishes.

Together, opened in 2018, tungsten market stalemate between supply and demand situation continues, the tungsten raw material supply side and cost dominates, short-term price of tungsten still show up to down, the price for the new institutions and big companies is expected to have to rise, but eased.