It is well known that for parts such as hardened gears, pinions and worms with a modulus range of 0.3 to 3 mm and an accuracy of 6 to 7 DIN, the traditional domestic finishing processes are mainly grinding and hardened surface scraping (ie Scraping) Both. However, due to the limitations of the hob material, the scraping is usually not used. In recent years, with the continuous improvement of machine tool structure, the rigidity of machine tools and workpiece fixtures has improved, the advancement of tool materials, especially the development of coating technology, has made the processing quality and stability of the scraping teeth increasingly improved, and gradually become a small modulus quenching. The mature technology popular in hard gear finishing, many foreign companies have gradually adopted scraping teeth instead of grinding teeth as a finishing method. 1. Finishing of hardened gears and pinions Using the scraping process to finish small modulus gears, the accuracy can reach DIN standard 6-7, the surface roughness quality is high, and the stability is also very high. On the basis of ensuring the quality of the product, the advantages of the scraping process are as follows compared to the grinding: 1) High efficiency For the hard tooth surface machining of small modulus gears, if the grinding machine technology is adopted, the grinding machine is greatly limited in the diameter of the grinding wheel due to the small workpiece and limited space of the machining part (usually the diameter of the grinding wheel is more than 150mm). ), the gear can be machined one by one only with a shaped grinding wheel (60 mm in diameter), so the processing cycle is slow and the efficiency is very low. The scraping process is carried out on a hobbing machine. Due to the use of a smaller outer diameter hob (such as a 24 mm diameter, 32 mm hob), the processing cycle is fast and efficient. In general, the processing cycle is only one-fourth to one-half of the tooth-grinding beat of the formed piece grinding wheel, that is, the production efficiency is usually 2 to 4 times higher than that of the toothed grinding using the molded piece grinding wheel. 2) low cost Take Koepfer's gear hobbing machine as an example, with the tools, fixtures and accessories required for the workpiece scraping process, for a total price of only 35 to 450,000 euros; and with the same grinding wheels, clamps and accessories, the imported gear grinding machine The price is usually around 1 million euros. If the processing efficiency factor is added, the capacity that can be achieved by using a squeegeeing process for one hobbing machine may require two or three grinding machines to be realized, so the investment cost required for the two different processes is different. ~ 6 times. In addition, considering the factors such as floor space, energy consumption, required operators, equipment maintenance and spare parts preparation, the cost of the scraping process is small compared to the grinding process. A lot lower. 3) High equipment versatility Generally, the processing of high-precision gears generally involves two processes: pre-rolling (ie, soft rolling before quenching) and finishing (scraping or grinding after quenching). For companies with small production batches, it is possible to use soft rolling and scraping on the same gear hobbing machine without the need for a separate gear grinding machine; in the case of mass production, pre-rolling and scraping may need to be separately Processing on different machine tools. However, in the selection of equipment, it can be considered to use the same type of hobbing machine for soft rolling and scraping. In this way, it can be used for machine maintenance, spare parts and consumable parts. When the soft and scraper hobs need to be sharpened again, the same hob sharpening machine can also be used for grinding. Of course, two Hobs can be recoated at Balzers. 2. Finishing of hardened worm Prior to this, worm machining with a modulus between 0.3 and 3 mm was not able to complete all contour shapes on the same hobbing machine. However, Koepfer has successfully combined soft milling (axial, radial and tangential milling) and hard machining on a hobbing machine with the newly developed hobbing head and corresponding software, and has improved the machining quality several times. Three years ago, Koepfer was equipped with the latest universal offset roll milling head for machining worms on a reliable and technically hobbing machine, which enabled the hobbing machine to machine the worm and perform hard scraping. This versatile offset hobbing head is powerful and compact, designed for the hobbing of cylindrical gears and the milling of single and multi-head worms. Due to its compact size, the hobbing head can swing to the contour of the worm under the tailstock. It can be said that Kopefer has created a new application field for gear hobbing machines, which greatly expands the application range of hobbing machines. Kopefer's new drive technology creates the ultimate in precision and superior quality that was previously only possible through grinding. It is well known that worm drive mechanisms with cross-shafts have been produced by impregnation. Although the worm can be machined using a conventional gear hobbing machine, it cannot satisfy high precision. Parts in the aerospace industry, such as those used to adjust the landing flaps of aircraft, must meet the accuracy requirements of DIN 6-7. Thanks to the high precision of Kopefer's hobbing machine and the ability to achieve tangential milling, special tools can be configured. Finally, software developed specifically for this purpose meets the above requirements. When machining a worm with a Koepfer gear hobbing machine, the worm can be soft-milled first, then hard-toothed in the same machine, or even hard hobbing to eliminate the grinding process. This means that the workpiece is hardened to HRC54 and then hard scraped to achieve the best quality. 3. Features and advantages of Koepfer gear hobbing machine Kopfer's gear hobbing machine, as always, uses a closed frame structure and uses technology to perfect the proven bed made of high-grade polyester material (commonly known as artificial marble). The machine is equipped with at least eight CNC axes (one for each) For the overhead robot). Unlike the "U"-shaped vertical machine, this closed-type forced structure avoids the bending of the power tailstock spindle when the clamping force and cutting force are maximized. The BWO control system of the machine tool configuration may sound strange, but it is highly recognized and respected by experts. The control system has a touch control screen and has a built-in program memory of 1 megabyte. The software developed by Koepfer uses a conversational programming interface that is easy to operate, and even the average technician can quickly master programming skills. The main advantages of the Koepfer gear hobbing machine are as follows: - The machine is equipped with a universal offset rolling head for a wide range of applications. - Powerful to perform machining of different contours and different processes: tangential roll/milling, radial roll/milling, soft roughing, soft finishing and hard finishing (scraping or hard rolling). - High processing precision and high processing quality stability - The machine is flexible and can be equipped with automatic workpiece delivery system according to user needs. - Can be easily integrated into the production unit (eg hobbing, cleaning, measuring, and then placing the workpiece without damage). Next page Pharmaceutical Dyes, Antibiotic Pharmaceutical Dyes Dynasty Chemicals (NingBo) Co., Ltd. , http://www.dychemco.com