Using rotary cutters and perpendicular motion, CNC milling removes material from the face of a workpiece, while CNC drilling allows engineers to drill holes and shapes into a blank with precise diameters and lengths. CNC milling and drilling are both examples of precision manufacturing. CNC machining, also known as computer numerical control (CNC) machining, is a traditional manufacturing method that produces parts by removing material from a solid block, referred to as the workpiece or blank. To be more precise, the term "CNC machining" can refer to a number of different processes, each of which employs a different set of tools and machines to shape and finish the desired part. Many cnc services processes involve the application of spinning cutting tools to a fixed workpiece, but CNC turning is a machining method that works in the opposite direction of this principle. This process, which revolves the blank rather than the tool, allows for the efficient production of a wide range of cylindrical or oblong parts. Here are some things that engineers and product teams should keep in mind.
When should CNC turning be considered in lieu of CNC milling Even though CNC turning is extremely efficient for producing parts with revolved profiles — such as bolts, ball bearings, and washers — it is not ideal for producing pieces that are not axisymmetric in nature. Combined with CNC turning, CNC milling can be used to create design features such as flat faces that would otherwise be impossible to achieve. CNC milling is commonly used in automotive, aerospace, and furniture manufacturing applications, as well as the production of robots and industrial-grade machinery.
Turning parts with a CNC machine is generally accomplished by moving a cutting tool along the external surface of a rapidly spinning workpiece. This process results in a helical toolpath and highly axisymmetric parts as a result of helical toolpath. When this same cutting action is applied to a blank's internal surfaces, it is referred to as "boring." Together, turning and boring form a larger subset of CNC processes known as cnc lathing, which includes both turning and boring. Lathe turning is similar to other CNC manufacturing processes in that manufacturing engineers use digital CAD files to assist in programming the machine, which results in the cutting implements moving in a controlled manner. Because the process has few material restrictions, it can be used to create parts from a variety of materials, including metal, plastic, and even wood. While some of the smaller details differ from model to model and manufacturer to manufacturer, the majority of CNC turning machines contain a similar set of components. The ones that are most relevant to production are as follows: The chuck or collet is comprised of the following parts:The chuck grips the workpiece and secures it in place with a firm grip. Chucks are available with either a hard or a soft jaw. Collets are typically used for smaller blanks, such as pens and pencils. The spindle is composed of the following parts:The spindle is the rotating axis of the CNC turning machine, and it receives instructions from the CAM file regarding the appropriate rotational speed. The cutting instruments are as follows:Each of the various cutting tools required for production is contained within a tool turret, which allows the machine to change tools as needed. As part of the manufacturing process, the workpiece is inserted into the chuck, the spindle is turned on, and the cutting tools are applied to the piece's surface in order to shape the part geometry. The most important considerations when fabricating parts with CNC lathes Contrary to conventional lathe machines, which typically only allow for tooling along two axes (although turning centers will almost certainly have some Y-axis capabilities), CNC turning machines allow for cutting operations to take place along three, four, or five axes, depending on the machine's configuration. Among these additional operations are the following: Using straight or cylindrical turning, you can make uniform cuts into the diameter of the workpiece, as well as remove large amounts of material from the workpiece. A cylindrical shape with smooth decreases in diameter (similar to an hourglass shape) is produced by taper turning techniques. Grooving is a process in which a shaped tool is used to create narrow cavities in a workpiece. In this technique, straight, angled, or crossed lines are cut into the workpiece to create a serrated pattern, which provides the part with additional grip. Threading: This produces the threads seen on nuts and screws, which allow objects to be fastened together. It can be applied to geometries of varying sizes, from relatively large to relatively small. Parting: Parting is the process of separating the finished part from the original workpiece. CNC turning is generally considered to be a good choice for prototyping and small-scale production. But when determining which method of manufacturing a part will be more economical in the long run, one factor that must be considered is the outer diameter (OD) of the piece being manufactured. This is due to the fact that CNC turning machines have a maximum outside diameter (OD) for bar-feed capable part production, and any part with an OD greater than the set limit will need to be chucked individually, which can increase both production time and production costs significantly. Workpieces for CNC turning are typically long and cylindrical in shape, but they can also be square or hexagonal in shape depending on the design of the part. Hex brass ball valves, for example, start out as hexagonal bars that are then lathed on either side of the nut to create threads on either side of the nut.
An additional factor to consider is the CNC tools themselves. Many of these are cylindrically shaped and have a limited cutting edge, which inherently limits the types of cuts that can be made to the workpiece in question. This also implies that design elements such as internal corners will have a radius, regardless of how fine or small the cutting tool's size is. Creating undercuts (also known as neck grooves or relief grooves) with CNC turning is a simple and straightforward process. Circular turned parts frequently have these types of features, which would be extremely difficult to manufacture on a CNC milling machine. If specialized cutting tools are required, it is important to remember that these come with their own set of difficulties. When using long-shaft tools to reach deeper areas of workpiece cavities, for example, the risk of vibration, less-accurate cuts, and poor surface finish increases.