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Three Important Facts About CNC Milling!

CNC milling is one of the CNC services that is available. This is a subtractive production method since you will use this process to develop a product with the help of a special machine, this will remove parts from a block material. The machine will, of course, use specific tools to cut away parts of the material. This is thus entirely different from a 3D printing service, because with this process you will create an object with a 3D printer. CNC milling is thus different, but it is used quite a lot. Below you will find three important facts to know.


NOT ALL CNC IS MILLING OR MACHINING

Not all CNC machines are machining, which might be confusing. However, CNC refers to a technology, so not a specific process. This technology is called Computer Numerical Control, or abbreviated thus CNC. It can be applied to mills and lathes in order to use a traditional machining process. However, CNC could also be used with 3D printers, waterjet cutters, Electronic Discharge Machines (ECMs), and many other machines. If someone uses the term CNC machining, it is smart to ask them what they exactly mean with that. They could possibly mean a CNC milling machine, but that is not always the case.


ALL MILLING IS MACHINING

So not all CNC is milling, but all milling is in fact machining. What is this? Machining is a subtractive, mechanical process. This is the case since it removes material from a piece through physical ways. The most common ways to do this is with the help of lathes and mills. These differ a bit. Mills use a rotating tool to cut or drill away material. This cutter will spin rapidly while the piece is fixed in place. Lathes switch these around. The piece will thus rotate in a rapid fashion, while the cutter will slowly move through it to remove material.


Vertical or horizontal

There are multiple types of mills, however the two common ones are vertical and horizontal mills. This refers to the axis of movement from the cutter. Both mills may appear to be quite similar, but if you inspect them a bit closer you can easily see some differences. Each kind of milling machine has its own set of advantages and disadvantages. Usually the vertical mills are not only cheaper, but also smaller and slightly easier to use than the horizontal ones.


THE KEY DIFFERENCES BETWEEN CNC MILLING AND CNC TURNING

Custom CNC machining can be done in multiple ways. Two of the most common CNC machining services are CNC milling and CNC turning. These are both everyday processes in a machine shop. Both methods use a cutting tool in order to remove material from a solid workpiece. This will be done to create 3D products, which can also be done with online 3D printing. CNC milling and CNC turning are both seen as subtractive manufacturing methods. This is the case since they both remove material. There are some key differences between the two processes, as you can read down below.


CNC TURNING

The term turning refers to the part since it rotates about a central axis. The cutting tool will thus remain stationary and will not rotate. However, it will move. It namely moves in and out of the piece in order to create cuts. Turning is employed to create cylindrical items and derivatives of cylinders. Examples of these parts are shafts and balusters, but even baseball bats can be created with the help of CNC turning. The workpiece will be held centered on a rotating spindle by a chuck. At the same time, a base secures the cutting tool so it is able to move along the axis and in or out radially. The rate of rotation of the piece will influence the feeds and speeds, just like the radial depth of the cut and the rate the tool moves along the axis.


CNC MILLING

CNC milling differs from CNC turning quite a bit. In milling operations, the cutting tool will rotate. The workpiece will be secured to the worktable and will thus not move at all essentially. The tool can move in the X, Y, or Z direction. Typically CNC milling is able to create more complex shapes than what is possible with the help of CNC turning. It could produce cylindrical products, but many other shapes are possible as well. In a CNC milling machine a chuck will be used to hold the tool in a rotating spindle. The cutting tool will be moved to create patterns on the surface of the workpiece. Milling does have a major limitation. This is about whether or not the tool can access a cutting surface. Access can be improved by using thinner and longer tools, but these can deflect which could lead to a poor product.


THIS ARTICLE WAS ORIGINALLY PUBLISHED ON TECHNEWS BY EMILY FORBES ON OCTOBER 4, 2020.