What Is Broaching?
Broaching uses a specific broach to cut a thin layer of metal from the workpiece to attain high precision and have a low roughness. Broaching is a high-efficiency process technique. Broaching can process components that require a combination of gear hobbing machines, gear shaping machines, and a milling machine, all in a short duration.
When broaching, the device allows the machined surface to move simultaneously, which means that the broaching machine is the primary movement without feed. The chips produced by broaching are small, while the cutting process is smooth, offering more precision in machining and lower surface structure.
This method of processing is used extensively in automobile manufacturing. Broaching is also utilized for high-precision cutting of complex materials, like turbine disks, generating generators, and manufacturing aircraft engines.
Several broaching machine manufacturers have introduced innovative designs and advanced technology to meet the growing demands of the industry. The most critical aspects of broaching are the following:
- Production efficiency is high. Broachs are a multi-tooth tool. The number of teeth used in the process is enormous simultaneously, which can increase the overall cutting width. Additionally, the roughing, semi-finishing, and finishing process can be completed within a single stroke of the broach, reducing the process itself and the extra time drastically reduced, and the productivity of broaching is greater.
- The range of processing is broad. Broaching is not limited to processing flat surfaces and free exterior surfaces. Still, it also processes through holes of different forms, meaning that the broaching processing spectrum is extensive.
- The high machining precision and a low roughness on the surface. Broaching has a calibration element that measures the machine’s size and cuts any light. Furthermore, the speed of cutting broaching is typically deficient (<18 milliseconds), and the cutting depth of each tooth that is cut is minimal. It is stable, and the detrimental impact of the edge of the pseudo-hip is essentially eliminated. This means broaching can be achieved with the highest precision and lower surface roughness. Generally, the dimensional accuracy broaching tolerance is IT7IT8, while the surface roughness is 0.4~0.8mm.
- The design of broaching machines is straightforward. Broaching is the only motion. It is a linear motion of the broach, and the feed movement is triggered by the fact that the final teeth of the broach are more significant than before. The tooth’s height is referred to as the tooth lift. Therefore, the broach has a straightforward structure and easy operation.
- The life span of the machine is lengthy. When surfacing, the cutting rate is minimal, wear on the tool is minimal after the sharpening process is completed, various workpieces may be processed, and a broach may be used multiple times; therefore, the tool’s life span is lengthy.
While broaching has the above advantages, as the tool’s structure is more complex than the typical hole machining tool, fabrication is more complicated, and the price is high, making the tool ideal for mass and batch production. Small-batch or single-piece production broaching can be employed to form surfaces with high precision requirements and forms that are hard to achieve using other methods. The blind hole, the deep hole step holes, and blocked exterior surfaces can’t be fabricated using broaching.