XHX Precision Industry-Metal Parts Solutions
Turning operations are operations that rotate the workpiece as the primary method of moving metal against the cutting tool. Lathes are the principal machine tool used in turning.
Milling operations are operations in which the cutting tool rotates to bring cutting edges to bear against the workpiece. Milling machines are the principal machine tool used in milling.
Drilling operations are operations in which holes are produced or refined by bringing a rotating cutter with cutting edges at the lower extremity into contact with the workpiece. Drilling operations are done primarily in drill presses but sometimes on lathes or mills.
Miscellaneous operations are operations that strictly speaking may not be machining operations in that they may not be swarf/shavings producing operations but these operations are performed at a typical machine tool. Burnishing is an example of a miscellaneous operation. Burnishing produces no swarf but can be performed at a lathe, mill, or drill press.
Machining is a term used to describe processes in which a cutting tool removes unwanted material from a workpiece to produce the desired shape or part. The workpiece is typically a cast or forged component or a piece of raw material or machined from bar stock.
Parts that are machined from a pre-shaped workpiece are typically cubic or cylindrical in their overall shape, but their individual features may be quite complex. Machining can be used to create a variety of features including holes, slots, pockets, flat surfaces, and even complex surface contours. While machined parts are typically metal, almost all materials can be machined which is why machining is often considered the most common and versatile of all manufacturing processes.
As a material removal process, machining is inherently not the most economical choice for a primary manufacturing process on larger parts that can easily be cast or forged. The material, which has been paid for, is cut away and discarded to achieve the final part. It is recommended that if more than 40% of the weight of the part is cut away, an alternative method of manufacture should be considered. Also, despite the low setup and tooling costs, long machining times may be required and therefore may be cost prohibitive for large quantities of larger parts. As a result, machining is most often used for limited quantities as in the fabrication of prototypes or custom tooling for other manufacturing processes. However, for big volume small parts that are easily machined out of bar stock, tend to be machined in high-speed screw machines at very low costs. Machining is also very commonly used as a secondary process, where minimal material is removed and the cycle time is short. Due to the high tolerance and surface finishes that machining offers, it is often used to add or refine precision features to an existing part or smooth a surface to a fine finish.
As mentioned above, machining includes a variety of processes in which each removes material from a workpiece or part. The most common material removal processes, referred to as conventional or traditional machining, are those that mechanically cut away small chips of material using a sharp tool. Non-conventional machining processes may use chemical or thermal means of removing material. Conventional machining processes are often placed in three categories - single point cutting, multi-point cutting, and abrasive machining. Each process in these categories is uniquely defined by the type of cutting tool used and the general motion of that tool and the workpiece. However, within a given process a variety of operations can be performed, each utilizing a specific type of tool and cutting motion. The machining of a part will typically require a variety of operations that are performed in a carefully planned sequence to create the desired features.
