Broaching is a manufacturing process that uses a toothed tool that is sharp and hardened to remove unwanted material from the workpiece in a continuous and consistent method. The broaching process is typically used for high quantity production that requires precise, complex, and repetitive cuts. We commonly see the use of broaching in plumbing appliances, hand tools, farming equipment, or other industrial tools and applications. The cutting tool used in the process is known as a broach, it possesses different sizes of raised teeth that can cut away a certain amount of material in a precise way when it passes over the workpiece. How does it work to remove the material in the workpiece? It can be done in a few ways. Either the tool moves along the workpiece while the workpiece remains in a fixed position, or the workpiece moves while the tool stays in its original location. In certain situations, there may have a relative rotation between the workpiece and tool to perform the operation. The broaching process can also be done externally across the surface of the workpiece or internally through the center of the workpiece. The styles of internal broaching include keyway, solid, shell, concentricity, modular, and cut-and-recut. On the other hand, the styles of external/surface broaching include slot, slab, pot, contour, and straddle. We choose the broaching styles according to the portion of the workpiece that needed to be cut or broached.
Types of Broaches
The cutting tool - broach, is having a complex design that is specially made for a special task. It can be made of a variety of shapes and sizes. There are several types of broach and each relates to the type of broaching machine used to apply the force. The first one is Push Broach, which is designed to be pushed by the broaching machine. The second one is Pull Broach, which is designed to be pulled by the broaching machine. The last one is Stationary Broach, which remains fixed while a machine moves along the workpiece.
Types of Broaching Machines
Broaching machine is a simple mechanism that is used to push and pull the tool to perform the broaching operation. The machine consist of a holding fixture, broaching tool, supporting frame, and drive mechanism. It can have one or more rams depending on the applications. Most of the broaching machines are hydraulically operated to ensure a smooth and constant cutting result. There is two common types of broaching machine, which are vertical and horizontal.
Horizontal Broaching Machine
Most of the horizontal broaching machines are pull-type and commonly used for internal broaching such as keyways, slots, holes, splines, or other internal shapes. It can also be used for external or surface broaching. A horizontal broaching machine consists of a bed, a broach pilot, and a drive mechanism to pull the broach in a horizontal direction. The length of the base is slightly longer than the length of broaching stroke. It is bigger and may take up a lot of floor space than the vertical broaching machine, but it is able to handle heavy workpieces and a long broach.
Vertical Broaching Machine
The vertical broaching machine moves the broach in a vertical direction. It can be either pull or push type. But we commonly see a push type of vertical broaching machine. The vertical broaching machine can also be categorized into three types which are push down, pull up, and pull down. The design of the pull-up is the most popular one. The vertical broaching machine can be used for multiple operations as it is convenient to transfer the work from one to another machine. Hydraulic drive is most commonly used in vertical broaching machines due to its lower cost. A modern version of vertical broaches is also available in electro-mechanical drives.
Continuous Broaching Machine
The continuous broaching machine is highly productive and suitable for the mass production of small parts. During the operation, the broach is stationary and fitted in the frame of the machine. The workpiece will be loaded into a holding fixture that carried by the endless chain, and being rotated continuously, and move constantly in a horizontal direction. There are three broaches in the machine and the third broach is a finishing broach. The workpiece moves and passes under the broach. It will be unloaded after the finishing broach and the next workpiece will be loaded without stopping the rotary table.
Surface Broaching Machine
A surface broaching machine is used to remove access material from the surface of the workpiece. It can create either a flat or contoured surface on the workpiece depending on the application. With different designs of the machine, the cutting tool is attached to the ram that can move horizontally or vertically.
Advantages and Limitations of Broaching
Broaching is suitable for a large volume of production and it can achieve high accuracy with a tolerance level of ±0.0075mm. The cutting process is fast and easily repeatable which helps to save production time. It can be used for either external or internal surface finishing, and the surface finishing created by it is quality and about 0.8 microns. In most cases, the machine operator is only required to perform the task of loading and unloading the workpiece from the machine, which requires little training on the task.
However, there are some limitations on the broaching that we should consider when choosing this method. The tool is relatively expensive. In some cases where the standard tool can not be used for the application, a custom broach is needed and it is costly to make. So it requires a high production to be economically feasible for the use of broaching. In addition, the size of the workpiece cannot be too large and the amount of material to be removed by the broaching also has its limitation. As we know that, broaching will apply a great force on the workpiece, we must ensure that the material of the workpiece is rigid and able to withstand the forces generated in the broaching.
Although broaching machine is not as common as the milling or lathe machine, there are still many applications where only broaching can do the work and cut the desired pattern. MecHero Malaysia provides broaching manufacturing process for a wide range of products, hardware, and industrial tools. You can always contact us at +6011-7000 7687 or email us at my.mechero@gmail.com for an inquiry about the types of broaching in Malaysia. As a steel and online hardware store in Malaysia, we also supply a wide range of steel materials, general hardware, or mechanical components. Tell us your requirements now and we can advise you accordingly.
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