Introduction
When manufacturing gears, there are various ways to achieve accurate and precise results. Two methods that are frequently used are Gear Hobbing and Gear Shaping. In this blog post, we will take a closer look at both and compare them objectively to understand their differences.
What is Gear Hobbing?
Gear Hobbing is a machining process that produces teeth by cutting and removing metal in a cylindrical shape. The process uses a special tool called a hob, which has a series of cutting ridges along its length. The hob is rotated while the gear blank is held stationary. The ridges on the hob cut into the blank, forming the teeth.
Gear Hobbing offers a high degree of accuracy and can produce multiple gears at the same time. It also has a fast production rate, making it a popular choice for high-volume manufacturing.
What is Gear Shaping?
Gear Shaping is also a machining process that produces teeth but uses a different method to cut them. The process uses a cutter called a shaper cutter, which moves vertically, cutting the gear teeth into the blank. The shaper cutter is mounted on a reciprocating ram, which moves back and forth, generating the tooth profile.
Gear Shaping is ideal for producing complex gear shapes, including internal gears. It offers high accuracy and can achieve very tight tolerances. However, the process is slower than Gear Hobbing and usually only produces one gear at a time.
Comparison
To compare these two manufacturing methods, we will look at different factors that determine their performance.
Speed and Production Rate
Gear Hobbing has a higher production rate since it can produce multiple gears at the same time. The process is also faster because there is no need to move the cutter vertically or horizontally. A typical production rate for Gear Hobbing ranges from 30 to 200 pieces per hour.
In contrast, Gear Shaping is a slower process since it only produces one gear at a time. The cutter also moves vertically and horizontally, slowing down the overall production rate. A typical production rate for Gear Shaping ranges from 10 to 30 pieces per hour.
Accuracy and Tolerance
Both methods offer high accuracy and can achieve tight tolerances. However, the accuracy of Gear Shaping is slightly higher due to the nature of its cutting process. Since the cutter moves vertically and horizontally, it can generate more complex shapes accurately. Gear Hobbing can achieve tolerances of up to 0.025mm, while Gear Shaping can achieve tolerances of up to 0.013mm.
Cost
Gear Hobbing equipment is usually less expensive than Gear Shaping equipment. The cost difference comes from the complexity of the cutting process and the precision required. Gear Hobbing equipment can cost between $50,000 and $150,000, while Gear Shaping equipment can cost between $100,000 and $250,000.
Conclusion
Both Gear Hobbing and Gear Shaping have their advantages and disadvantages. Gear Hobbing is faster and cheaper, making it ideal for high-volume manufacturing, while Gear Shaping is slower but more accurate and can handle more complex shapes.
Ultimately, the choice between Gear Hobbing and Gear Shaping depends on factors such as the required production rate, complexity of the gear shape, and cost considerations.