CNC machining is a general term used for a variety of machining applications. “CNC” stands for Computer Numerical Controlled and refers to the programmable feature of the machine, allowing the machine to perform many functions with minimal human control. CNC machining is the fabrication of a component using a CNC controlled machine. The term describes a range of subtractive manufacturing processes where material is removed from a stock workpiece, or bar, to produce a finished component part. There are 5 common types of CNC machining performed by 5 different types of CNC machines.
These processes are used in many applications across a spectrum of industries including medical, aerospace, industrial, oil and gas, hydraulics, firearms, etc. A variety of materials can be CNC machined including metal, plastics, glass, composites and wood.
CNC machining offers many benefits over machining without CNC programmable capabilities. Significantly reduced cycle times, improved finishes and multiple features can be completed at the same time and can improve quality and consistency. It is conducive to medium and high volume requirements where accuracy and complexity are required.
#1 – CNC Lathes and Turning Machines
CNC lathes and turning machines are characterized by their ability to rotate (turn) materials during the machining operation. The cutting tools for these machines are fed in a linear motion along the rotating bar stock; removing material around the circumference until the desired diameter (and feature) is achieved.
A subset of CNC lathes are CNC Swiss lathes (which are the type of machines Pioneer Service operates). With CNC Swiss lathes, the bar of material rotates and slides axially through a guide bushing (a holding mechanism) into the machine. This provides much better support for the material as the tooling machines the part features (resulting in better/tighter tolerances).
CNC lathes and turning machines can create internal and external features on the component: drilled holes, bores, broaches, reamed holes, slots, tapping, tapers and threads. Components made on CNC lathes and turning centers include screws, bolts, shafts, poppets, etc.
#2 – CNC Milling Machines
CNC milling machines are characterized by their ability to rotate cutting tools while holding the material workpiece/block stationary. They can produce a wide range of shapes including face-milled features (shallow, flat surfaces and cavities in the workpiece) and peripheral milled features (deep cavities such as slots and threads).
Components produced on CNC milling machines are typically square or rectangular shapes with a variety of features.
#3 – CNC Laser Machines
CNC laser machines have a pointed router with a highly focused laser beam that is used to precisely cut, slice or engrave materials. The laser heats the material and causes it to melt or vaporize, creating a cut in the material. Typically, the material is in a sheet format and the laser beam moves back and forth over the material to create a precise cut.
This process can produce a wider range of designs than conventional cutting machines (lathes, turning centers, mills), and often produce cuts and/or edges that do not require additional finishing processes.
CNC laser engravers are often used for part marking (and decoration) of machined components. For example, it can be difficult to machine a logo and company name into a CNC turned or CNC milled component. However, laser engraving can be used to add this to the component even after the machining operations are complete.
#4 – CNC Electrical Discharge Machines (EDM)
A CNC electric discharge machine (EDM) uses highly controlled electrical sparks to manipulate materials into a desired shape. It can also be called spark eroding, die sinking, spark machining or wire burning.
A component is placed under the electrode wire, and the machine is programmed to emit an electrical discharge from the wire which produces intense heat (up to 21,000 degrees Fahrenheit). The material is melted or flushed away with liquid to create the desired shape or feature.
EDM is most often used for creating precise micro holes, slots, tapered or angled features and a variety of other more-complicated features in a component or workpiece. It is typically used for very hard metals that would be difficult to machine to the desire shape or feature. A great example of this is the typical gear.
#5 – CNC Plasma Cutting Machines
CNC plasma-cutting machines are also used to cut materials. However, they perform this operation using a high-powered plasma (electronically-ionized gas) torch that is controlled by a computer. Similar in function to a handheld, gas-powered torch used for welding (up to 10,000 degrees Fahrenheit), plasma torches achieve up to 50,000 degrees Fahrenheit. The plasma torch melts through the workpiece to create a cut in the material.
As a requirement, anytime CNC plasma cutting is employed, the material being cut must be electrically conductive. Typical materials are steel, stainless steel, aluminum, brass and copper.
Precision CNC machining provides a wide range of production capabilities for components and finishing in the manufacturing environment. Depending the environment of use, material needed, lead time, volume, budget and features required, there is usually an optimum method for delivering the desired result.
Post time: Dec-14-2021