CNC Machining

Source Credit: https://www.hubs.com/guides/cnc-machining/#basics-of-cnc

The Basics

What is CNC machining? What are the different types of CNC machines? How do they work?

In this section, we answer all these questions and we compare CNC machining to other manufacturing technologies to help you find the best solution for your application.

What is CNC machining?

CNC (Computer Numerical Control) machining is a subtractive manufacturing technology: parts are created by removing material from a solid block (called the blank or the workpiece) using a variety of cutting tools.

This is a fundamentally different way of manufacturing compared to additive (3D printing) or formative (Injection Molding) technologies. The material removal mechanisms have significant implications on the benefits, limitations and design restrictions of CNC. More on this below.

CNC machining is a digital manufacturing technology: it produces high-accuracy parts with excellent physical properties directly from a CAD file. Due to the high level of automation, CNC is price-competitive for both one-off custom parts and medium-volume productions.

Almost every material can be CNC machined. The most common examples include metals (aluminum and steel alloys, brass etc) and plastics (ABS, Delrin, Nylon etc). Foam, composites and wood can also be machined.

The basic CNC process can be broken down into 3 steps. The engineer first designs the CAD model of the part. The machinist then turns the CAD file into a CNC program (G-code) and sets up the machine. Finally, the CNC system executes all machining operations with little supervision, removing material and creating the part.

A brief history of CNC machining

• The earliest machined object ever discovered was a bowl found in Italy and made in 700 B.C. using a lathe.

• Attempts to automate machining started in the 18th century. These machines were purely mechanical and powered by steam.

• The first programmable machine was developed in the late 40’s in MIT. It used punched cards to encode each movement.

• The proliferation of computers in the 50’s and 60’s added the “C” in CNC and radically changed the manufacturing industry.

• Today, CNC machines are advanced robotic systems with multi-axis and multi-tooling capabilities.

Types of CNC machines

In this guide, we will focus on CNC machines that remove material using cutting tools. These are the most common and have the widest range of applications. Other CNC machines include laser cutters, plasma cutters and EDM machines.