How to process helical gear with universal knee type milling machine?
Gear is almost used in mechanical transmission system. Although the volume of gear is small, the gear should be able to withstand huge tension, huge stress and certain metal fatigue. According to the gear tooth line shape, gears can be divided into spur gears, helical gears, herringbone gears and curved gears.
If many customers want to process steel gears, they may choose gear hobbing machine (need to select gear hobbing tool) and gear shaper machine (need to use gear shaper tool). And some customers may also choose honing machine and gear grinding machine in order to improve gear accuracy. But it also increases the budget cost of customers. Why is it so troublesome to process a few small gears? A universal knee type milling machine can do it easily.
1) Before processing helical gears, we first apply the basic indexing formula to calculate and analyze the number of teeth of the helical gears to be processed. It is also necessary to accurately calculate the outer diameter of helical gear. There is no too much analysis here. If you want to process helical gears, you must understand the data of gears.
2) The worktable of the universal knee type milling machine can move longitudinally, corssly and up and down, and can also rotate about 45 degrees. When milling helical gears, the worktable must turn an angle equal to the spiral angle before milling. In addition, check and confirm in advance whether the end of the transverse feed lead screw of the worktable has the shaft diameter and keyway matching with the change gear.
Finally, select the universal dividing head that wants to be matched with the milling machine worktable. The universal dividing head must be linked with the milling machine worktable. Universal indexing head is an optional accessory of universal milling machine. It is not only used for processing helical gears, but also has various other functions and is widely used. Our professional technicians can help customers recommend suitable universal dividing heads according to the table size of the milling machine. If the input shaft end of the indexing head purchased by the customer is too short, or the shaft diameter of the lead screw is too long, when the universal dividing head is fixed on one wheel of the table, the gears in the change gear system cannot mesh with each other, so the transmission cannot be input to the universal dividing head, resulting in the inability of milling. The universal milling machines that meet these conditions produced by our company include WN736A, WN736B and WN736C universal knee type milling machines.
3) When we use a universal milling machine to mill helical gears, some customers may choose gear milling cutters with simple structure. As long as the number of teeth of gears with the same module is different, the tooth profile curve is different. Therefore, we need to prepare many forming cutters with different tooth profile curves, which is not economical. So please select a special gear milling cutter. Each milling cutter is used to process a group of gears with a certain number of teeth. Relatively economical. If the machining requirements are not high, the forming disc milling cutter or end milling cutter with the same cutting edge shape as the gear groove shape can be used.
4) Before machining, we need to confirm whether the transverse feed direction of the milling machine workbench matches the rotation direction of the helical gear.
5) Before the worktable of the milling machine rotates, the accurate position of the gear workpiece and the cutter must be adjusted. Otherwise, the tooth profile, pressure angle and tooth direction of helical gear will be affected. Before milling, the gear workpiece shall be reliably installed on the support mandrel, and then the mandrel shall be fixed between the dividing head and tailstock of the milling machine workbench.
First, check the installation direction of gear workpiece with a dial indicator. If the direction is inaccurate, need to properly adjust the position of dividing head and tailstock to make the axial direction of workpiece consistent with the transverse feed direction of worktable. Then adjust the gear workpiece at the bottom of the gear milling cutter. The direction of the rotary worktable depends on the direction of the helical gear.
6) In addition to the preparation of the above milling machine, universal dividing head and gear cutter, it is also necessary to select the appropriate cutting speed and feed rate. When milling, you can mill a complete tooth space first and then divide the next tooth space, or mill all the tooth spaces at a certain cutting depth, and then mill all the tooth spaces one by one after giving all the cutting depths. Before each indexing, please loosen the tailstock and separate the connection between the indexing crank and the indexing disc. After indexing, the tailstock must be tightened again, and the indexing crank and indexing disc must be reconnected. Finally, trial machining is required to test the correctness and fluency of each movement, direction and angle. After everything is normal, normal batch processing can be carried out.
The efficiency of universal knee type milling machine for processing helical gear is still a little slow compared with special machines. If you don’t want to buy special machines, but you need to process or repair some small gear parts occasionally, and the accuracy doesn’t need to be so high, you might as well use milling machine and try according to the methods we provide. The versatility of universal milling machine is not only this, but also more functions. We welcome technical engineers all over the world to provide valuable practical experience to discuss and study with us.
