3DTEC s.r.o.: Use of 3D Measurement in Mold Optimization

Injection mould – the foundation of plastics manufacturing

Injection moulds are a fundamental element of manufacturing processes in the plastics industry. Their precise design and high-quality construction are key to producing plastic parts with high dimensional and geometric accuracy. Mould quality is directly reflected in the final product and affects both production efficiency and costs. In this context, 3D measurement and scanning play an indispensable role in mould design, inspection and optimisation.

Choosing the right 3D scanner

If only a moulded plastic part is available initially, for which a mould needs to be reverse-engineered, 3D scanning can significantly streamline the design process. The first step is to choose a suitable type of scanner, which depends on the size of the part and the required measurement accuracy. In practice, structured-light optical scanners or laser scanners are most commonly used. Laser scanners can handle even shiny or dark surfaces without the need for matting sprays or photogrammetric markers. Camera-based scanners, on the other hand, provide a higher level of detail but require surface preparation before scanning.

Laser scanning generates a digital model in the form of a point cloud that accurately captures the surface geometry. These data are then converted into a 3D mesh, with noise removal, surface smoothing and data volume optimisation. Missing sections of the scan can also be filled in if necessary. The mesh prepared in this way then serves as the basis for creating a solid 3D model using reverse engineering methods.

Fig. 1 Point cloud	Fig. 2 Polygon model	Fig. 3 Solid model

How to manufacture a reliable injection mould using 3D measurement

A prototype is usually created before production of the final mould begins. Its accuracy can be verified by comparing a 3D scan with the CAD model, allowing dimensional or geometric deviations to be identified and eliminated at an early stage. This significantly increases the likelihood that the final mould will function correctly from the outset. Manufacture of the mould itself then proceeds on the basis of the optimised 3D model and simulation analyses, with the choice of technology – CNC machining, electrical discharge machining or 3D printing – depending on the complexity of the mould and the materials used.

Fig. 4 Mould machining

Mould manufacturing is usually an iterative process. At each stage, 3D measurement can be used to verify dimensional accuracy and compare the actual condition with the design data. Moulds are generally manufactured with a machining allowance – whether this is sufficient can be assessed precisely using a 3D scanner. Obtaining information on the actual allowances enables machining parameters to be optimised, reducing the production of defective parts, lowering material consumption and increasing production efficiency.

Once the mould is completed, a final 3D scan is performed for geometry inspection and calibration. This step verifies whether the finished mould matches the original design and meets the specified tolerances. If deviations are detected, they can be corrected quickly and precisely on the basis of accurate 3D data, significantly reducing the time needed for final fine-tuning.

Fig. 5 A “positive” deviation that can still be corrected. It is most often caused by operator error, for example when the operator incorrectly sets up the tool being used. Fig. 6 A “negative” deviation caused by programming errors. It can be corrected by using inserts or remanufacturing the entire mould.

The digital model of the finished mould is then used not only for archiving but also for predictive maintenance. It enables mould wear to be monitored during operation, its service life – in other words, the number of production cycles – to be estimated more accurately, and maintenance or replacement to be planned efficiently. This helps reduce scrap rates, limit unplanned downtime and ensure greater production stability.

A practical example: the automotive industry uses 3D scanning to reconstruct moulds

Automotive industry – reverse engineering a headlight cover: An automotive parts manufacturer needed to create a new mould based on an older moulded plastic headlight cover for which technical documentation no longer existed. The moulded part was scanned using a 3D scanner, then converted into a CAD model and further modified to reflect current production requirements. Thanks to the accuracy of the scanning, there was no need to create a physical prototype – the mould could be manufactured directly and subsequently put into production successfully.

Why 3D measurement is an integral part of modern injection mould manufacturing

Today, 3D measurement is not just an inspection tool but an active element of optimisation and the decision-making process. It enables not only the precise manufacture of new moulds but also modifications to existing ones, maintenance planning and the minimisation of production risks. In the era of digitalisation and Industry 4.0, it is thus becoming a key partner for efficient, high-quality and predictive production.

Would you like to make injection mould manufacturing more efficient using 3D technologies? Do not hesitate to contact us – we will be happy to help you find the optimal solution.