The idea of gears has been around for a while since they are among the oldest mechanical components still in use today. Be it the auto industry, the aerospace industry, industrial equipment, or even something as basic as a clock, gears are used everywhere.
A variety of processes can be used to manufacture gears, including casting, forging, extrusion, powder metallurgy, and blanking. As a general rule, however, machining is applied to achieve the gear's final dimensions, shape and surface finish.
Did you know? Gear dimensions and teeth are the most critical components that require the highest level of precision in the final product.
Overview of the Gear Manufacturing Industry
Gears must function under extremely poor circumstances to transmit power, which is their intended function. First and foremost, the gears must be in flawless condition. Then, they must always be trustworthy, have very low to no probability of crack propagation, and have almost no residual strain. Naturally, it is very challenging to meet all those demands in equipment manufacturing. Because of this, the fabrication of gears is a highly specialised industry with very limited scope for errors.
Gear Manufacturing Process
A gear manufacturing process involves multiple layers of work to deliver the best quality. However, the following is the generally practised gear manufacturing process in the industry:
The teeth are manufactured by machining, and blanks or cylinders for gears are often prepared through a simpler method called casting. Due to its potential for mass production and relative simplicity, it is a suitable method for producing gears for numerous purposes. However, casting is the preferred manufacturing technique for large gears. That is how huge gears are produced.
Large dimensions make machining techniques and other gear-building techniques less practical. Large gears are typically spur gears. Casting is a very wise choice because of its relative simplicity. The most popular casting techniques for making gear include shell casting, die casting, sand casting, and permanent mould casting.
Depending on your needs, this shaping technique can provide you with both blanks and ready-to-use gears. If your gears are simple, forging is a viable option. Theoretically, forging is a highly effective method of producing gears for heavy-duty applications. Heat treatment is necessary during forging, so the finished gear will have improved fatigue characteristics. However, the size and thinness of this technique are constrained by the enormous force needed for forging. Forging typically works well for gears with a diameter of 6 to 10 feet.
In form milling, the gear tooth is created by moving a cutter, known as a form cutter, axially along the length of the gear tooth at the proper depth. The cutter is removed, the gear blank is rotated, and the process is repeated to cut another tooth. The procedure is repeated until every tooth is removed.
Broaching can create gear teeth, which works particularly well for internal teeth. The procedure is quick and generates a high degree of dimensional precision and exquisite surface quality. However, this process works best for high-quality production because broaches are costly, and a different broach is needed for each gear size.
When creating a gear, the teeth flanks are created as an outline of the cutter's upcoming positions, which are shaped similarly to the mated gear in the gear pair. The two machining techniques used are milling and shaping. These procedures can be altered in several ways depending on the cutting tool used.
Gear teeth are gradually produced during gear hobbing machining using a sequence of cuts made with a spiral cutting tool. The hob and gear blank constantly rotate, like two gears meshing, throughout the whole hobbing process, until all teeth are cut.
The field of powder metallurgy has advanced significantly in recent years. These days, it's employed in a variety of manufacturing procedures, including the production of gear. It appears quite simple from the outside. But there are lots of tasks involved. Metal powder is where it all begins. The first step, to begin with, is to take all the powder and give it the final form you desire.
Extrusion and blanking are extremely similar processes, although blanking only works in two dimensions. With the aid of numerous dies, this gear-forming procedure employs sheet metal to produce the necessary shape. The best results, however, are provided by spur gears. Today, various industries use the gear blanking method for lightweight applications. Typical examples of applications with modest load needs include office equipment, hydraulics, minor medical devices, and others.
Extrusion and Cold Drawing
Another easy method of gear manufacturing is extrusion and cold drawing. Extrusion requires fewer tools, but that doesn't mean it is the most cost-effective method. Extrusion forces a heated metal profile through a more precise, smaller shape. You end up with a bar in the shape you want with a smooth, hardened exterior.
Extrusion and cold drawing are extremely similar processes. There are two variations and the blank is pulled through a die by extrusion. The temperature is the other difference where the billet isn't heated during a cold draw. Hence raising the cost while decreasing the mechanical characteristics.
The gear manufacturing process has evolved to where more sophisticated machines replace hammers. Still, the gear manufacturing process is a matter of precision, requiring the gears to be strong enough to work in extremely poor conditions. For efficient production of gears, you will be required to have efficient and accurate machining methods and components of production backed by the planned batch size. The gear manufacturing industry is highly contract-based since every client's requirement is different, so the structure, dimension, and tooth eliminate the possibility of a homogeneous product.
Follow Khatabook for the latest updates, news blogs, and articles related to micro, small and medium businesses (MSMEs), business tips, income tax, GST, salary, and accounting.