There is still no substitute for the dependability and efficiency of CNC machining, even if there are numerous new and developing industrial technologies. This technology is used to make millions of precise parts in a variety of substrates each day. In order to produce high-quality rapid prototypes and production parts, we'll examine the seven most commonly used methods in the industry.
Turning is probably the earliest known mechanical function, involving nothing more complicated than securing a workpiece to a revolving plate or mandrel. A fixture mounted on a rotating slide holds the cutting tool against the workpiece while it rotates. The slide can be moved up and down the workpiece's length, as well as closer and farther away from the workpiece's center line. It's easy to remove vast volumes of material using these basic methods. Tailstock drills can also be used to make precise holes along the workpiece's centerline, making it easier to remove and replace components.
Round parts can be turned into concentric shapes using lathes. Turned features such as slots, ring groove, step shoulders, threads, cylinders and shafts are all possible on the lathe. They also have the ability to achieve smooth and uniform surface finishes that are hallmark of their work.
Because the cutting tool is mounted on a spindle, milling is fundamentally different from turning in that the workpiece is kept stationary during the process. Workpieces are often held horizontally in a machine vise, which is attached to a moving table that can move in both directions. The spindle can carry a variety of cutting tools and can move in the X, Y, and Z axes.
Despite its drilling and boring capabilities, a mill's real strength lies in the removal of stock from more complicated and asymmetrical components. Mills are used to create square/flat faces, notches, chamfers, channels, profiles, keyways, and other features that need accurate cutting angles. Combined, milling and turning account for the majority of CNC machine tool operations.
Cutting fluid is used in all metal machining operations to cool the workpiece and the cutting tool, to lubricate and to flush away metal particles.
Preparation of the Workpiece for Grinding
For many purposes, it is critical to have a perfectly flat metal surface, and the grinder is the best tool for the job. In order to grind, a spherical abrasive grit must be applied to a rotating disk. On some machines, the abrasive wheel is rotated while an object mounted on a table is slid back and forth beneath it. Please keep in mind that this procedure can only be employed on faces that are free of surface protrusions.
Different abrasives are employed depending on the substance being ground. Care must be made to control tool speed and temperature as grinding heats and mechanically stresses the work piece.
Electron Diffraction Micromachining
It is necessary to submerge the electrode in dielectric fluid so that it can be used near the workpiece. For the feature it is cutting, the electrode has a shape that is perfectly matched. Metal particles are ejected from the workpiece when the electrode is discharged. Although the electrode itself does not come into direct contact with the workpiece, it is sacrificial and may need to be replaced more regularly.
EDM can be used to create pockets, holes, and square features inside hardened tool steels that would be difficult, if not impossible, to create any other way. Rarely is it used on the finished product itself, although it is commonly used on plastic injection and pressure die casting molds. Using EDM, mold tools can have textured or debossed (recessed) writing and logos.
An electric charge at a high voltage is sent over a copper wire when using Wire EDM. A spool of fresh wire is continuously fed into the cutting operation as the conductor is gradually corroded. In order to employ this method, you must pass through the hole.
Wire EDM is used on hardened tool steel to create circular or semi-circular features that would be impossible to achieve with traditional cutting tools.
Grinding and turning are combined here. In most cases, the workpiece is kept still while a circular or cylindrical grinding wheel is spun against its surface. Cylindrical grinders can be used on both inside and outside diameters, along the entire length of the part, or at partial depths.
Tolerances are exceedingly exact and accurate, and the surface texture is extremely smooth, making this method ideal for producing high-quality products.