The challenges of plastics machining in the production of precision components and how to overcome them

CNC plastic machining is a rapidly growing sector in the production of precision components for a wide range of industries. Although polymers offer many advantages, including low weight, chemical resistance and ease of moulding, their physical and thermal properties present a challenge for manufacturers. At RADMOT, we have been supplying precision plastic components for years, ensuring the highest quality thanks to our advanced CNC machinery and the specialist knowledge of our experts. Below, we discuss the key challenges in plastics machining and strategies for overcoming them.

The most common problems encountered when machining plastics

The machining of engineering plastics differs significantly from working with metals. Due to their low rigidity, lower thermal conductivity and higher coefficient of thermal expansion, a different technological approach is required here. The most common problems include:

• material melting – resulting from the low softening temperature of polymers and incorrect plastic machining parameters,
• difficulties in maintaining dimensions – polymers deform easily under the influence of heat and cutting forces,
• plastic deburring – the softness and ductility of the material increase the risk of unwanted edges forming,
• problems with the removal of plastic chips – chips often stick to the tools or the workpiece, which affects surface quality.

As a RADMOT expert explains, machining plastics is an art of precision – not only are the process parameters crucial, but so too are experience and the right choice of tools.

How can material melting during machining be prevented?

Polymer melting during machining is one of the most common problems. It results from low thermal conductivity and the incorrect selection of cutting conditions. How can this be counteracted?

• Reducing the cutting speed – excessive speed generates too much heat.
• Use of air cooling or non-emulsifying oil – cooling minimises the risk of the cutting zone overheating.
• Selection of the appropriate tool geometry – sharp tools reduce friction.
• Avoiding interruptions in cutting – continuous machining allows for better heat dissipation.

At RADMOT, we employ optimal strategies to prevent workpiece melting – in both single-unit and high-volume production. Professional CNC milling – explore our services in plastics machining.

Dimensional tolerance control for polymers

Precision plastic components must meet stringent tolerance requirements, particularly in the automotive and electrical engineering sectors. However, controlling plastic tolerances is significantly more difficult than with metals. Key factors include:

• thermal expansion – a temperature change of just a few degrees can affect the part’s dimensions,
• post-processing stabilisation time – plastic components should be measured after a specified period, once they have reached thermal equilibrium,
• minimisation of internal stresses – appropriate machining strategies and preparation of the semi-finished product help to limit deformation.

RADMOT has one of the largest measurement facilities in Poland, enabling precise inspection of components. This allows us to guarantee our customers high repeatability and compliance with standard requirements – even in such demanding sectors as mechanical engineering and automation.

Selecting tools for precision machining of plastics

Professional CNC milling and precision turning of plastics require the use of appropriately designed tools. Their geometry, material and coating have a direct impact on the quality of the workpiece and the efficiency of the process.

Key features of plastics machining tools:

• sharpness – minimises friction and the risk of melting,
• small rake angle – improves control over the machining of soft materials,
• smooth chip surfaces – improve chip evacuation,
• no hard coatings – some coatings can increase friction when machining plastics.

By using high-quality tools and tailored plastic machining parameters, our operators achieve excellent results, even on demanding projects for the consumer products or machine building sectors.

Strategies to minimise burrs and improve surface quality

Plastic burrs are one of the greatest challenges in mass production. Burrs generated during plastic milling not only affect aesthetics but also the functionality of the component (e.g. tightness, fit).

In industrial practice, including in such precision-oriented sectors as electrical engineering, a range of proven methods are employed, e.g.:

• tool path optimisation – appropriate cutting paths help to minimise burr formation,
• use of dedicated finishing tools – special geometries enable a smooth, burr-free surface,
• pre-machining and finishing – performing two cutting passes helps reduce stresses and improve cut quality,
• mechanical or thermal deburring – finishing processes such as brushing, flame treatment or ultrasonic cleaning effectively remove residues.

By combining these strategies appropriately, excellent results can be achieved in terms of both the aesthetics and functionality of the finished component, which is particularly important in sectors such as the automotive, medical and consumer products industries.

Discover our state-of-the-art CNC machine park – at RADMOT, we have over 80 modern CNC machines, enabling us to carry out large-scale production and machine highly complex parts. Combined with advanced measurement facilities, this allows us to manufacture components with up to Class 6 accuracy.

Precision CNC turning – see what we offer. Whatever the scale of your project – we’ll help you choose the optimal technology, guaranteeing quality, repeatability and on-time delivery. Request a free quote today!