4.1 cold header, Hot rolling machine

cold header, hot upsetting, Hot-rolled bulb, The fast and efficient forming of ball blank can be realized. Z32 series has been formed

4.2 Deflashing machine

Deflashing machine process cold header, hot upsetting, Hot-rolled bulb efficiently. Ensure that the ball has a certain allowance，dimensional accuracy and surface quality. They formed the 3M49 and 3M79 series. The machine tool structure has vertical and horizontal 2 kinds.

3ML4980 vertical deflashing machine adopts the big cycle process. Main transmission mechanical transmission, Lower plate rotation, upper plate rotation, Pressure is pressurized by hydraulic pressure. spring pressure maintaining. The rotary feeding disc adopts inverter stepless speed adjustment. There is a break protection device. Automatic fault alarm system. The ball board is 800 mm in diameter. The load capacity of the ball is 400 kg. Comply with subsequent processing requirements. The precision of the ball can reach the spherical error of 20 μm. The whole batch diameter change is 40 μm. The surface roughness Ra is 6.3 μm.

80，90，95 series horizontal type of horizontal deflashing machine adopts horizontal layout. Tilting material for large cycle processing. frequency step-less governor. Hydraulic-driven pressure. Speed of main-shaft controlled by a two-speed motor. Have a “setting off” protection device. The ball board is 800-950 mm in diameter. The load capacity of the ball is 350-1000 kg. Comply with subsequent processing requirements. The precision of the ball can reach the spherical error of 20 μm. The whole batch diameter change is 40 μm. The surface roughness Ra is 6.3 μm.

4.3 Hard grinding machine

Hard grinding machine for the steel ball embryos that has been heat treatment with high efficiency process. Ensure that the ball has a certain allowance，dimensional accuracy and surface quality. They formed the 3M4680 and 3M76 series. The machine tool structure has vertical and horizontal 2 kinds.

3ML4680 vertical hard grinding machine adopts the big cycle process. Main transmission mechanical transmission, Lower plate rotation, pressure is pressurized by hydraulic pressure. spring pressure maintaining. The rotary feeding disc adopts inverter step-less speed adjustment. The grinding disc is automatically trimmed. Automatic fault alarm system. The grinding disc is 800 mm in diameter. The load capacity of the ball is 350 kg. Comply with subsequent processing requirements. The precision of the grinding balls can reach the spherical error of 3 μm. The whole batch diameter change is 6 μm. The surface roughness Ra is 0.4 μm. 3M4680C horizontal type of horizontal hard grinding machine adopts horizontal layout. The spindle adopts variable frequency control. Tilting material for large cycle processing. frequency step-less governor. hydraulic drive eccentric inflating. Normally open type hydraulic pressure station sequential oil control pressurize. The main shaft is equipped with a boring car protection. The grinding wheel is automatically trimmed. Automatic fault alarm system. The ball board is 800 mm in diameter. The load capacity of the ball is 400 kg. Comply with subsequent processing requirements. The precision of the grinding balls can reach the spherical error of 3 μm. The whole batch diameter change is 6 μm. The surface roughness Ra is 0.4 μm.

4.4 surface-strengthening equipment

The surface reinforcement is to load the steel ball into the horizontal drum machine, it has about 1 m of diameter with a lift. The lifting bucket will lift the steel ball that has been heat treatment to the top of the tube. The kinetic energy of the steel ball makes the ball collide with each other. The elastic-plastic deformation is produced on the surface. It forms a cold hardening layer and compressive stress. Thus, the hardness of the surface is improved by 1 ~ 3 HRC. Steel ball wear resistance is increased by 1.5 ~ 2 times.

4.5 Lapping machine

The lapping machine can process the steel ball after hard grinding. Ensure the precision and surface quality of finished steel ball. It is a fast growing machine tool. It is also the focus of the development of steel ball industry in recent years. Formed 3M7266, 3ML4780, 3M7770 and 3M7780 series. The machine tool structure has vertical and horizontal 2 kinds. Vertical steel ball lapping machine 3ML4780C is processed in large cycle. Main transmission mechanical transmission, lower plate rotation. hydraulic drive eccentric inflating. spring pressure maintaining. The rotary feeding disc adopts inverter stepless speed adjustment. Use water agent to grind. Automatic fault alarm system. The ball board is 800 mm in diameter. The load capacity of the ball is 250 kg. Comply with subsequent processing requirements. The precision of grinding ball can reach G5 ~ G10.

3M4680A horizontal type lapping machine adopts horizontal layout. Type L low-gravity machine body. Inflating and sliding mechanism are separate. Rolling line guide locate. The flat material large cycle processing. Main shaft and feed plate frequency stepless speed adjustment. The continuous oil supply pressure-maintain by variable displacement pump control and normally open hydraulic station. The main shaft is equipped with a boring car protection. Electrical control by PC. Automatic fault alarm system. The ball board is 800 mm in diameter. The load capacity of the ball is 250-400 kg. Comply with subsequent processing requirements. The precision of grinding ball can reach G5 ~ G10.

Resin grinding wheel grinding technology is a new process of steel ball processing developed in 1990. Ensure the uniformity of the surface quality of the steel ball and reduce the vibration of the steel ball. Implement custom manufacturing process specification for steel ball processing in on time, size and precision. To adapt the grinding process of steel ball resin grinding wheel. A series of horizontal machine tools including 3M7766, 3M7770 and 3M7780A were developed.

The machine adopts open type high – low and low – center – gravity L – type overall structure. The main shaft structure is unique. The end of the rotating disk and the radial beat are within 0.01 mm. It can even reach 0.005mm; The pressure is separated from the sliding mechanism, the fixed plate frame is completely fixed. The spindle head frame moves with a rolling linear guide with a heavy pre – tight clearance. The rear end is pressurized by an oil cylinder that is connected to it. The change of the two discs in pressure and different positions is overcome because of the positioning of the cylinder. Ensure the precision of repeatability the machine tool repeatability position. Unique rotary grinding plate and fixed grinding plate. Main shaft and feeding drive system frequency stepless speed adjustment. Also for use cast-iron plate grind or resin grinding wheel grinding different process speed selection. The goal area of the machine tool, main drive pulley, and rotate the parts are equipped with monitoring devices. Electrical control by PC. Automatic fault alarm system. Comply with subsequent processing requirements. The precision of grinding ball can reach G5.

4.6 Steel ball processing equipment joint line configuration

With the increase of bearing output in China. The demand for steel balls of the same specifications can reach up to 100 million. This provides a possibility for the configuration of the steel ball connection equipment. The configuration method is: One of high speed cold header, One of ball flashing machine, One of ball crusher, Three – six of grinding miller (Including the preliminary research and the super – intensive process) flexible connection. The production of a kind of steel ball perennial. Ensure the stability of steel ball quality. It also reduces the consumption of grinding tools considerably. Facilitate management and reduce manufacturing costs.

4.7 Main working tools for steel ball processing

The grinding tools needed for steel ball machining mainly include cast iron grinding board, special purpose wheels(resin wheel), grinding fluid, abradant, diamond dresser, cold heading die. At present, specialized production has been formed. However, there is still a large gap between the domestic and foreign countries, such as cast-iron, resin grinding wheel and resin grinding fluid. Further research is needed.

（作者：张永乾1，吴朝阳2
1. 中国轴承工业协会技术委员会 滚动体专业委员会，河南 洛阳 471039
2. 常州光洋轴承有限公司，江苏 常州 213002）
（未完待续）