Prototyping and small-batch production are typical application areas of 3D printing. If the physical properties of injection-moulded parts are needed, however, 3D-printed moulds may be a viable solution. Depending on the requirements, plastic or metal 3D printing makes sense.
Especially in prototype construction and the increasingly individual designs of the components, more flexible and cost-efficient solutions are required instead of the complex construction of expensive steel moulds. If only small batch sizes of a plastic part are required or if the component is still in the development phase, modern 3D technology can help to save mould costs.
However, direct part production from the 3D printer differs significantly from an injection-moulded part. Thus, for example, the physical properties of a 3D-printed component differ considerably from injection-moulded parts. The solution is 3D-printed mould inserts. With these inserts, the plastic parts can be manufactured very cost-effectively in a cassette mould.
Based on the CAD data of the plastic part, the print data of the mould inserts can be processed accordingly and 3D printers create the mould. Depending on the size of the components, this can be done within minutes, while longer processing times are required for larger designs. Nevertheless, these mould inserts are designed much faster and more cost-effectively than their “steel competitors”.
3D-printed mould inserts revolutionise mould manufacturing
Low mould costs thanks to 3D-printed mould inserts as well as the fast implementation of modifications are the decisive advantages for the users. A “drop of bitterness” is, however, the lifetime of these moulds. High temperatures of the materials and large injection pressures affect the mould inserts more significantly and thus the operating times of the 3D-printed moulds dwindle. As a result of this, the service life of plastic moulds is very limited.
Especially in the case of small batches and average quantities, many users are looking for a more reliable solution. This solution is offered by the use of 3D-printed metal mould inserts. Higher stability and the possibility of a partly required mould temperature control/cooling are provided with these metal mould inserts and thus they represent the next upgrade level of additive production.
However, the layer-by-layer print of the plastic or metal mould inserts is clearly different in terms of preparation and planning. In the case of the metal mould inserts, a large number of additional elements has also to be taken into consideration in advance.
Proper preparation is the be-all and end-all
For the complex and highly 3D-dimensional parts, temperature control channels and their connections must be provided during the planning stage of the mould inserts.
In the case of the metal-printed moulds, the parting line still has to be processed, since the structure of the surface of the moulding part comes from the printing process. For the achievement of a defined and desired surface, this additional processing step is necessary.
The fact that the technological and monetary expenditure for 3D-printed mould inserts is manageable and much more efficient for small quantities than conventional steel moulds is not fully applicable for metal mould inserts, depending on their design and complexity. The decision on a metal mould insert or a conventional aluminium or steel mould should be made is in the design phase of the moulds or metal mould inserts. The engineer should be familiar with the capabilities of 3D technology and be able to find a good and affordable mould in light of the additional possibilities.
This article was first published on ETMM online.