Machining

What is machining?

Machining is a manufacturing process where material is removed from a workpiece, most often by milling or turning. Machining can be manual or computer controlled.

What does CNC machining mean?

CNC (Computer Numerical Control) refers to controlling machines using a computer program. The program contains, for instance, the machine's movements and coordinates where the tools are intended to move. The program also includes functions of the tools such as speed and feeds. CNC machines are used to manufacture complex parts very accurately and efficiently.

What are the most common machining methods?

The most common machining methods are milling, turning, and grinding. The most suitable machining method is selected based on the workpiece, the required accuracy, and the production volumes. 

Milling is a machining method where a high-speed rotary tool, or a mill, is used. When the mill rotates, its teeth cut metal in small chips, forming a specific shape or surface. The milling process has several variations, such as plane milling, groove milling, and ball milling. 

In turning, a metal piece is attached to a lathe, which rotates the piece quickly around its longitudinal axis. The lathe's blade cuts metal off from the workpiece's surface. The turning process has different variations, such as spindle turning, peeling turning, and longitudinal turning.

During cylindrical grinding, the CNC machine's grinding head cuts off a thin layer from the workpiece's surface. Cylindrical grinding is one of the most accurate machining processes and it's used when very precise dimensions and smooth surfaces are needed. It's usually the last process in the machining chain.

What's the difference between 3-, 4-, and 5-axis machining?

The number of axes refers to the number of directions, or axes, the tool or the workpiece can move in CNC machines. In 3-axis machining, the piece can be machined on the x-, y-, and z-axes. With 4- and 5-axis machines, we can machine more complex geometries, as additional axes provide more possibilities for turning and tilting the part.

>> Read more about 5-axis machining

What materials can be machined?

We can machine many different materials, such as steels, aluminum, and titanium. We can also machine technical plastics. Each material has its own characteristics, which affect the machining process.

>> Read more about materials

How long does machining take?

The duration of machining depends on several factors, such as the size of the piece and the complexity of the geometries, the chosen material, and the used machining method, as well as whether it's a single piece or a large series. Machining a small, individual piece can take just a few minutes, whereas machining a large and complex piece may take several hours or even days.

It's good to remember that before we start running the CNC machine, a program has to be created for it and the right tools need to be selected. Also, the preparation of the blank takes its own time.

How much does machining cost?

The cost of machining is composed of the time spent on setting up and actual machining, material costs, and possibly the time spent on measurements. When expert design and experienced operators are involved in the project, we can maximize the efficiency of the work and thus make the price level more affordable.

 >> Read the blog: Where do CNC machining costs come from?

I want to get the parts as cheap as possible. What should be considered in the design of the machined part?

Our long experience has shown that 80% of the cost of the machined part is determined at the design table.

In the design, it's worth considering manufacturability-related issues, such as settings and tools used in CNC machines, tightness of tolerances and determining the surface roughness of different surfaces of the part. Also, the features of holes and threads, as well as the dimensions of shapes milled into the blank, affect the time spent on the settings and thus the price.

>> Download our free guide, where we provide practical tips related to the above-mentioned issues

How is the quality of the machined part ensured?

The machine operator's task is to ensure the dimensional accuracy of the part, i.e., to measure that the part corresponds to the dimensions and tolerances defined in the drawing. The most precise tolerances are verified with a coordinate measuring machine.

The guide for the measurement is the product specification provided by the customer as well as product-specific measurement, testing, and inspection instructions. We also perform quality assurance based on Mectalent's own processes.

>> Read the blog about quality assurance for machined parts

What does tolerance in a machined part mean?

Tolerance refers to allowable deviations in the dimensions of a part. In machining, the aim is to achieve tolerances as precisely as possible. Tolerances are a critical factor related to both the quality of manufactured machined parts and their functional quality.

If a part does not meet tolerance requirements, it can cause problems when the part is used in assembly. If the tolerances are not correctly defined or if they do not match, the parts may not fit together or they can cause quality problems, such as excessive wear, friction, or vibration.

What does post-treatment of a machined part mean?

Post-treatment of a machined part refers to processes used for finishing metal parts after machining. These processes can improve the appearance of the part, enhance its physical properties, protect it from corrosion, or prepare it for subsequent production stages.

At Mectalent, all machined parts are washed before they are sent to the customer. In addition, we perform various blasting and burring removal by tumbling. Through our extensive subcontracting network, we can offer a wide variety of surface treatments.

>> Read more about post- and surface treatments