Machining refers to a series of processes, also known as controlled removal, through which raw materials are turned into desired shapes and sizes. The controlled part of the process usually means the use of machine tools such as computer numerical control (CNC).
Though the process mainly involves the subtractive method, occasionally it can also make use of additive manufacturing methods. That is a process of material addition. Machining can involve several processes of cutting, material addition, boring, or drilling. Metal is the main material used in this process although other materials such as plastic, wood, ceramic, and composites can also be worked on.
What is Custom Machining?
Custom machining is a more precise approach to the process in which the machining meets specific or unique requirements. It is used in place of other forms of manufacturing including casting and molding. With custom manufacturing, it is possible to do complex designs and detailing whenever such a piece is desired.
Different techniques are available when it comes to custom machining. These can include milling, turning, grinding, drilling, and so on. The technique that may be more efficient to use is most often dependent on what is required.
Custom machining can be used in a variety of industries including steel washing, automobile, jewelry, and so on. Whatever your needs, an efficient custom machining company will be able to answer any question you may have and also guide you on what the right solutions are to whatever you require.
What is Milling?
This is one of the many techniques of machining and in fact one of the most common. You can find out more about other types in this article.
Milling uses rotary cutters for the removal of materials to create varying features on a material. This is done by advancing a cutter into the workpiece. The process requires a milling machine, a fixture, a workpiece, and a cutter.
The workpiece, a pre-shaped material, is fastened to the fixture that is already attached to the machine. The cutter, which is a cutting tool that has sharp teeth and is also attached to the machine, rotates at a very high speed. When the workpiece is fed into the rotating cutter, the material is removed from it in small chips and this creates the required shape.
Milling most times is used for producing parts that have several features like holes, pockets, slots as well as three-dimensional contour surfaces that are not axially symmetrical. It can be used for fabricating tools which can also be used for other processes and for prototypes. Milling can also be used to add to or refine features on parts that were manufactured by another process. It offers high tolerance levels and surface finishes that make it ideal for the addition of precision features to a piece whose basic shape is already formed.
There are two ways of milling, computer-aided via a CNC machine and manual milling. In CNC milling, the machine feeds the workpiece in the same direction as the rotation of the cutting tool. In the manual milling, it is the other way round as the workpiece is fed in the opposite direction to the rotation of the cutting tool.
The Milling Process Cycle
The duration of time required for producing a given number of parts includes the setup time as well as the cycle time for every one of the parts. The setup time involves the time required to set up the machine, plan the movement of tools as well as install the fixture into it.
The cycle time on the other hand is the time required for the completion of one cycle of the manufacturing process. That is the time required to make a single part (some processes can allow the production of several parts in a cycle). The process can be divided into:
- Load/Unload time
- Cut time
- Idle time
- Tool replacement time.
Modern technologies now allow for a quick and rapid turnaround time that will allow any protoptype machine shop produce high-precision parts in as little time as possible using state-of-the-art software.
Typically, there is no post-processing required after the milling process cycle. However, to improve the surface finish, secondary processes may be used but this is most times not needed.
During a given process cycle, there are a variety of operations that may be performed in cutting the workpiece into the desired shape. This is usually defined by the type of cutter as well as the path used by the cutter to remove materials from the piece. This can include:
This makes slot or peripheral cuts that are determined by the step-over distance. Specific features like pocket, slots, profile, or a complex surface contour can be machined across the workpiece. The required depth may be milled in a single pass or in multiple passes.
This involves machining a flat surface of a workpiece to get a smooth finish. The depth of the face which is typically small can either be done by a single pass or done at small axial depths with multiple passes.
This is used to make a peripheral cut along the edge of a workpiece. It can as well be used to make a feature that creates an angled surface referred to as chamfer. The chamfer typically has an angle of 45 degrees and can be machined either on the interior or exterior of a workpiece.
In this operation, a drill is used axially to cut a hole that is equal in diameter to that of the tool used. It can be used to produce a through-hole or a blind hole. A through-hole extends completely through the piece and when you look inside, you can see through while a blind hole extends to some depth inside the workpiece.
This is when a reamer is used axially to enlarge an already existing hole to the size of the diameter of the tool used. It is used to remove a minimal amount of material and typically performed after drilling so that an accurate diameter as well as a smoother finish can be obtained.
Other types of milling operations that can be done on a workpiece includes boring, counterboring, countersinking, and tapping.
As can be seen from the above, custom machining allows you to get your shapes and parts made to precise requirements. There are several custom machining techniques that can be used one of which is milling.
When requiring parts to be done in a specific and unique way, it is crucial that you work with experts because they will know the best techniques to use in order to achieve the best result.