CNC Machining - large bed size

The A to Z guide of CNC machining technical terms: What ‘5 axis’ and ‘feed rate’ really mean.

CNC machining is full of technical terms. Here is Axiom’s A to Z guide to the most common CNC Machining technical terms in a simple language everybody can understand.

3 Axis

The direction of movement on a 3-axis machine. This is usually the X-axis (left to right), Y-axis (front to back) and the Z-axis (up and down).

5 Axis

Additional axis to the standard machine are A and B. They allow the cutting tool to have a more multidirectional approach. The additional axis are achieved by moving both the cutter and the bed. Axiom has both 3 and 5-axis machines.

Automatic Tool Changers or ATCs

This system automatically changes the tool used to cut a workpiece.


A backlash is an inaccuracy in the cutting of a piece caused by the mechanical parts of a machine needing a tiny amount of play to move over each other.  This can result in a small but measurable error in the positioning of the cutter head when changing the axis. This may be significant as the workpiece must be cut to a very tight tolerance.


The work surface of the machine. This limits the size of the workpiece that can be placed into the machine. Axiom has a bed size of up to 2 metres on our largest machine.

CAD or computer aided design

A piece of software which can be used to model a workpiece. At Axiom we use 3D CAD to design parts for our customers.

CAM or computer aided manufacturing

CNC Machines do not understand CAD software. The CAD design must be translated into a CAM program, which the CNC machine can use to manufacture the workpiece.

CNC or computer numerical control

A machine that is numerically controlled by a computer. Axiom uses CNC milling machines.

CNC milling

Using a computer controlled mill to subtract (cut away) material from a workpiece to leave a defined shape.  For more information see our Blog ‘What is CNC machining


The collar which holds a cutting tool in place


CNC machines typically use an emulsified coolant, which is a small amount of oil emulsified into a larger amount of water. This is sprayed onto the workpiece while cutting takes place.

Cutting oil

This is specialised oil specifically designed for metalworking, which is mixed with water to make a coolant – it also serves as a lubricant between the cutting head and the workpiece.

Feed rate

The speed at which a cutting tool moves over a workpiece


A piece of equipment which holds a workpiece in position while machining takes place. At Axiom we use 5-axis vice and clamp sets.

Fully simultaneous 5-axis machining

An advanced technology CNC machine where the bed holding the workpiece and the cutter move simultaneously in differing axes to ensure the cutter is in constant contact with the workpiece.  At Axiom we have a number of these machines.

Flute length

The length of the cutting portion of the cutting tool.

Home position

is the location in the X.Y,Z axis, which is the reference point on a workpiece for the machine to calculate where and when to use its cutters.


The matter from which an item is made. CNC machining can be used on several materials. At Axiom, we especially mill aluminium and model boards, but we can also mill other metals and materials, such as plastics and wood.


Positioning the workpiece within the block of material to ensure the minimum amount of wastage. Good nesting will further ensure cost-effective manufacturing and reduce the waste material produced.


User-defined point on the workpiece that the cutting tool will reference to position all its movements


An initial cut designed to remove excess material quickly, leaving a rough outline of the required workpiece.  A more accurate and usually slower cutting tool will cut a more precise shape. This technique is often used when a large amount of material needs to be removed.

Spindle speed

The speed at which the cutter rotates when cutting a workpiece. This will be set in the CAM, depending on the accuracy and finish quality required on the workpiece.

Subtractive manufacture

The removal by milling, grinding or cutting of material to produce a finished workpiece.


Levelling the surface of a workpiece.


The total amount a dimension on a workpiece may vary and is the difference between the upper (maximum) and lower (minimum) size limits.  This is specified on the CAD for a workpiece and is agreed upon with a customer before manufacturing.

Tool path

The route the cutter follows to machine any workpiece.

Contact us to discuss any CNC machining project you have.


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