Everything you need to know about machining processes, cutting tools, CNC machines and cutting parameters, to make metal parts accurately, efficiently and at a competitive cost.

What is machining?

Machining (Metal Cutting / Machining) is a process in which material is removed from a raw workpiece with cutting tools until the required shape, dimensions and surface finish are reached. It is one of the oldest and most central manufacturing processes in industry, and it keeps developing as new technologies arrive.

Unlike processes such as casting or forging, here the material is removed layer by layer and chips are formed. Control of the process, from choosing the cutting tool to setting the cutting parameters, is what separates a reasonable result from a precise, cost-effective one.

The main processes

What rotates and what moves: the basic difference between the three processes.

Turning (Turning)

In turning, the workpiece rotates while the cutting tool moves along it. The process is mainly suited to making round, symmetrical parts, and is done on CNC lathes.

Milling (Milling)

In milling, it is the cutting tool that rotates and removes material from the workpiece. Milling makes it possible to machine complex shapes, pockets, slots and 3D surfaces. Modern machining centers work on 3 to 5 axes simultaneously.

Drilling (Drilling) and tapping (Tapping)

Drilling to make holes and tapping to make internal threads. It sounds simple, but at high accuracy levels and in hard materials it takes precise tools and parameters.

Cutting tools

Indexable inserts (Indexable Inserts) are the component in direct contact with the material. Inserts come in different shapes, coatings and chipbreakers, and the right match directly affects tool life, surface finish and production rate.
Milling heads, drills and toolholders complete the system. The right choice of holder (HSK, BT, Capto and others) affects stability, runout accuracy and the ability to achieve better results.

End mills, a drill and a tap standing in a tool rack — Right: end mills, a drill and a tap. Left: a milling head with indexable inserts.

A milling head with indexable inserts, surrounded by chips — Right: end mills, a drill and a tap. Left: a milling head with indexable inserts.

The leading cutting tool manufacturers include Sandvik Coromant, Iscar (an Israeli company!), Kennametal, Seco, Walter, Mitsubishi and Kyocera. Each manufacturer specializes in different areas, and the right choice depends on the combination of material, process, machine and quality requirements.

CNC machines

CNC (Computer Numerical Control) machines are the backbone of every machining shop. The machines perform the cutting movements automatically according to a G-code program, and provide repeatable accuracy, high speed and consistency that cannot be achieved with manual machining.

A CNC machining center on a shop floor — CNC machining centers on a shop floor.

Leading machine manufacturers: DMG Mori (Germany/Japan), Mazak (Japan), Okuma, Haas (USA), Makino and Doosan. Each manufacturer has different strengths in areas such as speed, thermal stability, control systems and cost-effectiveness.

Optimizing the cutting parameters

Four critical parameters determine the success of the process:

VcCutting speedMeasured in meters per minute, and set according to the part material and the tool material.
f / fzFeedThe rate at which the tool advances, mm per revolution or mm per tooth.
apDepth of cutHow much material is removed in each pass.
aeWidth of cutRelevant mainly in milling.

In milling: the depth of cut (ap) is how deep the tool cuts, and the width of cut (ae) is how much of the tool's width is in the material. The arrow shows the feed direction.

CAM software

CAM (Computer Aided Manufacturing) software is the bridge between the 3D model and the G-code program that runs on the machine. Good software allows advanced machining strategies, precise parameters and optimal toolpaths that save time and extend tool life.

3D modelThe drawing of the part
CAM softwareStrategies and toolpaths
G-codeThrough a post-processor
The machineThe part is cut

Leading software in the field: ESPRIT CAM (Hexagon) for 2-5 axis programming with factory-certified post-processors, NCSIMUL for G-code simulation and verification, Robotmaster for industrial robot programming, as well as Mastercam, Siemens NX, hyperMILL and others.

Today's challenges

The machining industry faces several prominent challenges:

Materials that are harder to machineTitanium alloys, Inconel, hardened steels.
Rising accuracy requirementsTighter tolerances on every part.
Pressure to cut costsThe same part, in less time and for less money.
A shortage of skilled workersFewer experienced programmers and operators.

Meeting these challenges takes the right combination of advanced cutting tools, suitable CNC machines, smart CAM software and, above all, practical knowledge and experience that make it possible to take the right decisions on the shop floor.

Need professional advice on machining?

At ZF Engineering we bring more than 50 years of experience in machining consulting, cutting tool selection, CNC programming and CAM software integration. We do not just sell tools; we are engineers who understand your challenges and deliver tailored solutions.

What is machining? An introduction to metal cutting