Owing to our rapid growth and increased demands for our services, we are in the process of moving to larger premises whereby all our respective services are now under one roof. Our company grew organically into several unconnected units, but demand is such that we are now streamlining our activities to be in one place. (CNC Milling and Machining, Steel and Aluminium Fabrication Spiral welding and pipework installation.)
Our new address is:
Direct Engineering & Site Services Ltd
Foxwood Industrial Park
This is only around 100 meters away from where we have been operating up to now.
An Introduction to CNC Machining
1. CNC stands for ‘Computer Numerical Control’
CNC machining is a process used in a wide range of manufacturing applications, but what exactly is it and how does it work? CNC stands for ‘Computer Numerical Control’ and refers to the use of a computer to control the action of a machine tool such as a lathe, mill or router. CNC machining can be used to machine parts from many different materials such as a wide range of metals and plastics.
2. CNC machines are programmed with a language called G-Code.
CNC machining uses special CNC software and a programming language called G-Code in order to control every aspect of the machine tool’s movement in order to manufacture an object. G-Code instructions control the speed and positioning of the cutting tool in relation to the work-piece, the feed rate of material into the tool and many other factors.
3. It all starts with CAD
The process generally starts with either a 2D CAD (Computer Aided Design) drawing or a 3D CAD model. The G-Code is then derived from this and a trial run is performed to test the program. This is known as “cutting air” and is very important in order to avoid any mistakes which could result in a damaged work-piece or cutting tool. If the test is satisfactory then the program can be run to machine the real part.
4. CNC offers precision and repetition
CNC machining can be used to make complex 3-dimensional shapes as a single piece. It allows greater precision than manual machining, and most importantly, it is repeatable. The same CNC program can be used again and again to manufacture multiples of the same part.
5. With CNC you can manufacture any part you can imagine
CNC machines are typically capable of moving the cutting tool and/or the work-piece in several different axes of motion. A 3-Axis CNC machine has movement in the X, Y and Z axes to produce 3 dimensional shapes and is the basic model. More advanced 4-Axis CNC machines introduce a 4th rotational axis of motion parallel to the X axis to enable production of even more complex objects. 5-Axis and even 6-Axis machines are also available, which make it possible to manufacture almost any shape which can be imagined.
CNC machining offers some important benefits over more traditional manual machining. CNC gives a level of precision, control and consistency that would be virtually impossible to achieve with a human operator machining by hand.
With manual machining, the machinist must manipulate the cutting tool and/or work-piece by hand in order to produce the desired result. This takes great skill, but it also takes a lot of time and intense concentration. A machinist can only work on one piece at a time and the work can only proceed as fast as they are able to cope with it. A momentary lapse in concentration could result in an error which may require a damaged work-piece to be discarded.
With CNC machining, the operator’s involvement in the actual machining process is minimal. The machine can be left largely unattended once the work-piece is inserted and the program has started running. A CNC operator could potentially supervise several CNC machines running in parallel, giving obvious benefits in terms of efficiency.
Perhaps the greatest benefit of CNC machining over manual machining is consistency. A CNC machine will follow the steps of a program exactly, and a program can be run again and again. This means it is possible to create multiple identical components, confident that each will have exactly the same measurements and finish as all the others. It’s simply not possible for a human machinist, even a highly skilled one, to produce the kind of consistent accuracy needed for many precision engineering applications.
Because of the programmable nature of CNC machines it is relatively easy to change from producing one work-piece to another one. It’ is simply a case of loading a different program. Making modifications to a component requires only that you modify the program, and the program itself can be stored and re-used at a later date. This enables fast turnaround between different products, and also makes just-in-time production viable. If a replacement piece is needed, the program can be loaded and a new object machined, negating the need for a large stock of machined components.
As can be seen there are considerable benefits to CNC machining, especially where multiple identical copies of an object need to be produced.