Gear Manufacturing Operations – Form Milling, Broaching…

Gears are very important parts of machinery. We use them in lots of kinds of applications. So, the production rate of them is very high in the world. There is a separate business to produce gears. Here, we talk about the general gear manufacturing processes and operations. You can find this information here;

  • What are the gears? What are their general types of them?
  • What are their manufacturing processes of them?
  • Finishing operations.
  • FAQs

What are Gears and Types of Them?

Gear manufacturing.

The gear manufacturing market is developing day by day. And this market is very big. This is also because of the different types of gears. Firstly, we need to understand the general types of gears in the market.

Gears are the machine elements where that transfer torque and power between the rotating shafts. At the circumference of them, some teeth structures meshed between themselves. This teeth structure is very important to transmit power.

The main advantage of the teeth structure, they transmit torques in a very smooth and frictionless way. So, there is very little power loss in the gear systems.

The most important applications of gears, transmission systems, and reducers. They are very common in power transmissions from engines to other rotating components of machines.

The Types of Gears

Also, there are different types of gear in the industry. The first and the most common one is a spur gear. Spur gears are the types of gears where the orientations of gear teeth are straight. So, in the gear manufacturing businesses, they are the most common ones.

The second type of gear is a helical gear. The only difference between the helical gears is the orientation of the teeth. So with this orientation, they create a more smooth drive.

Another type of gear is bevel gear. We use bevel gears in the transmission of the power between perpendicular shafts.

Rack and pinions are also very common types of gears. In these systems, there is a rack which is a straight bar that has gear teeth on one of its sides, And it has meshed with normal gear. When the gear rotates, the rack makes reciprocating motions right and left.

Gear Manufacturing Processes

So, up to this point, we know about gears and their different types. Because of these different types, there are different gear manufacturing processes and techniques. Around these techniques;

Gear Casting Processes for Gear Manufacturing

In casting operations, molten material is cast into the molds to obtain the net shapes of the products. So, we can produce the gears with these methods.

Casting processes are very common in the gear production market. These methods can make a serial production of them in different industries. Around the casting processes, investment casting and die casting operations are the most common ones.

In the casting operations, we can obtain very smooth surfaces and surface textures, and exact shapes without any post-processing. So, casting is a very common gear manufacturing process.

Plastic Injection Processes

Plastic injection.
Image Source: Wikimedia.

In plastic injection processes, there is a screw plunge mechanism that injects the molten material inside the molds. So, we obtain the net shape of the system. Extra injection pressure results in better shapes and surface characteristics.

Plastic injection processes are also very common in gear manufacturing. In the manufacturing of plastic gears, we use injection machines. Because polymer materials are also very common in this sector.

Also, we can produce metal gears in plastic injection processes. And the biggest advantage of these gear manufacturing processes is, that we can obtain net shapes of gears.

Powder Metallurgy Techniques on Gear Manufacturing

Powder metallurgy in gear manufacturing.
Powder metallurgy(Image Source: Wikimedia).

In powder metallurgy techniques, the material comes in powder form. And we spill this powder inside a mold or negative-shaped system. And we press this metal inside the mold and heat it. With this heat and pressing application, the material gets sintered. So, we obtain the whole part.

You know that powder metallurgy techniques are also very common in the production of different complex shapes. So, in the production of gear shapes, these processes are very common also. With sintering operations, we can obtain very smooth and complex gear shapes from metals.

But the most important drawback of these techniques, they are very time-consuming processes. It is hard to obtain serial production of gears.

Additive Manufacturing

Additive manufacturing.
Additive manufacturing)Image Source: ABB).

In additive manufacturing techniques, the production of parts takes place in the layer by layer manner. So, in the general application, we can produce nearly all kinds of shapes.

Additive manufacturing or rapid prototyping techniques are also very common in gear manufacturing. There are different types of additive manufacturing that we can use of them. In different materials, we can use different additive manufacturing techniques to produce gears.

Also, it is possible to obtain very good surface characteristics with very good mechanical strengths. But also, the serial production manner is a problematic issue in additive manufacturing techniques. The general process times are high to manufacture the gears in large quantities.

Gear Rolling Processes

Gear rolling processes.
Cold rolling of gears(Image

In gear rolling processes, the gear teeth are produced by the rotating gear cutting tools with one pass.

Production of different kinds of gears is a very big market in the industry. There are various kinds of processes are devised to produce gears. One of these processes is the gear rolling process. 

In the gear rolling process, a round gear blank is attached to a piece of machinery. This machinery is pretty similar to the thread rolling processes. But in gear rolling, the teeth geometry is obtained instead of threads. Different kinds of teeth geometries can be obtained such as helical gears. 

The most important advantage of the gear rolling process is the ability the produce gears at very high rates. This is a very important feature for the industries like automotive. If you think about other alternative processes to produce gears(such as machining processes), the gear rolling process is very advantageous in terms of serial production. 

Less material waste and higher fatigue strength are other important merits of the gear rolling processes. 

Gear rolling processes are also very common in gear manufacturing. So, we can produce very high quantities of gears in a short time if we compare it with other techniques. And the gears are in the standard sizes directly with the rolling processes.

Sheet Metal Stamping in the Gear Manufacturing

In these techniques, very small gears for clockwork mechanisms or other kinds of small mechanisms there is a stamping mechanism that produces these gears from sheet metals. So, the general manufacturing of the gears is very simple with this technique.

We can produce the exact shapes of gears with very high production rates with sheet metal stamping techniques.

Form Milling in Gear Manufacturing

In milling operations, a cutting tool produces the intended shapes on the blank materials. So, we use the milling operations in gear manufacturing. And form milling is one of these milling operations.

In form milling operations, there is a cutting tool that the cutters are in the shape of the spaces between the gear teeth. Once the cutter rotates around the blank material, the gear teeth are obtained.

But the most important drawback of the form milling operations, the production rates are very slow. And it is proper for the production of gears in low quantities. And one advantage is, that the tooling is quite cheap.

Gear Hobbing

Gear hobbing process.

Gear hobbing applications are very common in the gear manufacturing business. And şn gear hobbing, the production rates of gears are much higher than the form milling operations.

The tooling is special in gear hobbing processes. If we take a look at the tooling, there is a special tool that we call hob. And there are little teeth on this hob to manufacture multiple teeth in one pass.

Hob rotates around itself and blank material comes to contact with the hob. So, the primary motion is the rotation of the hob, and the secondary motion is the feed motion of the blank material.

And the machinery is special for this gear manufacturing technique. And also, the shapes of hobs are for the production of gears.

Gear Shaping Operations

Gear shapers and gear shaping operations are very common in the manufacturing industry. The main feature of these operations, these machines are using the reciprocating motion of the cutting tool. So, there is a cutting tool that has the shape of the gear teeth. And makes a reciprocating motion to obtain the complete shape of the gear teeth.

Also, there is another common application of gear manufacturing. In this gear shaping application, the shape of the cutter is like the gear. So, this makes a reciprocating motion to obtain the total shape of the gear. And also they make a respective indexing motion to change the gear teeth.

The production rates are low in gear shaping operations. But they use these processes in the production of large gear systems.

Gear Broaching Processes in Gear Manufacturing

Gear broaching techniques are also very common in the gear manufacturing business. In these systems, we obtain the gear teeth by linear motion of the broach cutting tool.

The gear broaching operations are very common in the serial production of the gears. Also, the tooling to produce the shapes lie gears is complex. Because of this, the tooling is very expensive in broaching processes.

Gear broaching is only useful in the production of gears on high scales.

Finishing Operations of Gear Manufacturing

Surface quality is a very important parameter that we need to consider. We need to obtain specific qualities of surfaces to obtain specific working conditions. So, this is also valid for gear manufacturing.

After the main manufacturing techniques, there are some heat treatment applications on the gear teeth to obtain better wear resistances and mechanical strengths. So, these heat treatment applications can lead to warpages on gear teeth. And we can require to apply some additional finishing operations.

The general finishing operations of them;

  • Shaving
  • Burnishing
  • Grinding

Gear Shaving Operations

These operations are the most common finishing operations in this industry. In these processes, there is a tool that has the same shape as the manufactured gear. And this tool makes a reciprocating motion to remove small chips from the teeth surfaces. So, we obtain the desired surface quality and properties with shaving operations.

Gear Burnishing

This is a finishing application on the gear teeth where there is a hard die that has the same shape as the gear. And, this dies pressed againts the gear teeth and rotated around it. And the surfaces of the teeth hardened and the surface characteristics of gears increased.

Gear Grinding

It is also a very common gear surface finish operation. The only difference from the conventional ones, the grinding tool has the same shape as the gear material. So, we can obtain very good surface characteristics.

Honing and Lapping Operations

Gear honing and gear lapping operations are also very common operations for gear finishing. So, with these finishing operations, we can create very good surface finishes after the gear manufacturing techniques.

Conclusion on Gear Manufacturing

As you understand above, gear manufacturing and gears are very common in the manufacturing industry. Because there are different types of common applications that we use gears extensively. And to provide enough amounts of gear to this market, people developed different gear manufacturing methods.

Around these methods, there are forming and machining operations. Also, there are special machining operations that are only for gear manufacturing. This proves the level of the manufacturing of these systems.

And also, the finishing operations are very important. We apply finishing operations which are special for gears to obtain the required surface characteristics.

Finally, do not forget to leave your comments and questions below about the gear manufacturing processes.

Your precious feedbacks are very important to us.

FAQs About Gear Manufacturing

What is the gear manufacturing process?

There are different processes to use in the manufacturing of gear systems. Around these processes, forming operations such as casting and plastic injection molding. And also we use machining operations to produce gears such as form milling, hobbing, and shaping operations. All of them are the gear manufacturing processes.

What material is gear manufacturing?

They use different types of material in the production of these systems. Because, in different applications, we use different types of materials. Among these materials; metals and polymer materials are very common in the market.

Which machine is used for gear manufacturing?

If we think about the machining of the gears, the general machines are the form milling machines, gear hobbing, and gear shaping machines. These are the special machines that they use in these systems.

How do you manufacture the gear teeth?

There are different methods to obtain gear teeth structures. The most common ones are gear hobbing and gear shaping machines. In these machines, the tools have the same shape as the gears. And also with the reciprocating motion, they produce the shapes of the teeth.

Which is the fastest gear manufacturing method?

The fastest gear manufacturing method is gear broaching. Because we require very less passes to obtain the general shape of the gears. But the main drawback is, that the prices of the tooling are very high if we compare it with the other systems.


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