CNC Milling: A-Z About It

Introduction

First, A CNC machine is programmed to transform the computer code into numerical coordinates use those to convert the raw materials into a finished part. Milling and drilling are almost similar processes. In milling, the machine can cut the piece at several different angles along different axes. Formally, there are an infinite number of axes along which the milling machine can machine apart. But frequently, there are milling machines with 3-axis, 4-axis and 5-axis. In CNC milling, a computerized code and a milling machine are linked to each other, such that the machine reads the code and cuts the part according to it. However, CNC milling machines don’t come at a cheap price, and hence, there are different services such as get it made, which can offer you high-quality milling works.

Understanding the process of CNC Milling

The CNC milling process is similar to any other CNC machining process. The steps involved in CNC milling are:-

  1.            
                Designing        the par in a CAD software:-


CAD stands for Computer-aided-design. CAD is the process to design a part in a computer software according to the dimensions and projections by using the software. There are different types of CAD software such as Solidworks, AutoCAD, Creo and Catia.

  •            
                Converting      CAD files in Numerical Code


Mainly, CAD-CAM software automatically converts the CAD design into numerical code used by milling machines. Moreover, these programs also check the design for errors, ensuring that the milling machine is not instructed to create any impossible features.

  •            
                How to set up the Milling Machine


CNC milling machines cut and finishes the parts automatically. However, some processes need to be done manually. These processes are to place the workpiece on the workbench and install the milling tool to the spindle.

  •            
                Manufacturing Parts


For manufacturing parts, the milling machine uses a rotating tool that comes in contact with the surface of the part and renders the material according to the specification.

Appropriate Materials for CNC milling

CNC milling is a highly versatile process and can be done on various materials. However, the material which needs to undergo milling needs to be decided according to the project requirements. Moreover, milling cannot only be done on metals. It can also be performed on different plastics such as Nylon, PEEK, HDPE, Teflon, ABS, etc.

Some of the metals suitable for milling are

  • Aluminium.
               
  • Brass
               
  • Tool steel
               
  • Mild Steel
               
  • Stainless steel.


Pros and Cons of milling.

Like any other CNC machining process, CNC milling offers different kinds of benefits such as precision, enhanced productivity, low labour costs, replicability, etc. However, milling does have some severe drawbacks as well. One of them is undoubtedly the cost of the milling machine. The milling machine comes at a very high price. Therefore for a firm, there are two options. The first one is straightforward, where the manufacturer buys the milling machine while the second option is to outsource the milling work. The second profound disadvantage of milling machine is that it requires trained staff to successfully complete the milling work.

Importance of CNC Milling Machine for Customers and Machinists?

The main purpose of modern CNC millingis to turn resources like metal castings into completed, functional products. That goal can only be achieved with the use of ultra-precise CNC milling machines.

A CNC (Computer Numerical Control) milling machine’s brain is computer software, which controls the machine and automates production to boost throughput while maintaining consistent quality. CNC machining is so efficient and beneficial to both clients and machinists because of its repeatability.

However, you might still question

CNC milling machine: What exactly does it do?

The main work of a CNC machinist is to transform a casting into a part that can be used in the larger product. These parts do require high tolerances, which certain unfinished castings don’t give. Following are certain structures which CNC milling machine tries to work upon

Flat Surfaces – CNC face milling creates flat surfaces on a piece of metal. Face milling produces a completed sealing surface that is so flat that leaks are virtually eliminated.

Drilled Holes — Drilling makes a hole, while tapping adds threads to it. The most frequent method of joining pieces is through and tapped holes. Drilling concentrates on the hole’s diameter and depth.

Bored Holes – A precise interior cavity within a workpiece is formed by enlarging an existing hole using a drill and a stiff, boring bar with a single-point cutting tool. Boring permits pieces to be assembled properly and firmly (with very tight diameter tolerances) or valves to control the flow of air, oil, or gas reliably.

Now let us understand

How does a CNC Milling Machine Work?

Range of motion is an important component of CNC milling since it determines what the mill’s tooling can do. This comprises 2-, 3-, 4-, and full 5-axis possibilities in CNC milling machines.

2-Axis Machine — Used to manufacture manual fixtures; movement is limited to the x and y axes; lacks repeatability.

3-Axis Machine – A vertical milling machine with movement on the x, y, and z axes.

4-Axis Machine — The most popular CNC mill; movement on the x, y, and z axes with an additional b axis to allow the table to spin, providing access all around a workpiece; normally limited to horizontal machines, however advanced shops use 4-axis vertical machines as well (normal vertical is three-axis)

5-Axis Machine – Specialty milling machines with movement on the x, y, z, and b axes, as well as an extra a-axis; not suitable for high-volume production parts.

Generally, CNC machines are of two types.

In CNC milling machines, there are two major spindle orientations. The spindle axis, often known as the z-axis, is oriented vertically in vertical CNC machines. The spindle rotates in this direction in a c-column setup, while the table that supports the workpiece moves in both x and y horizontal directions. Vertical milling machines are ideal for high-volume, fast-paced applications such as covers and brackets, which are machined from one side. The spindle z-axis in horizontal CNC machines is horizontal and runs parallel to the machine’s length. The spindle moves horizontally on the x-axis and vertically on the y-axis.