3D-printed metal tool inserts impose higher demands on mold design
If only small batches of a plastic part are required or if the component is still in the development phase, modern 3D-technology can help to save mold costs. Instead of the complex construction of expensive steel molds, more flexible and cost-efficient solutions are required, especially in prototype construction and in the increasingly individualized design of components.
Direct or indirect
However, a direct part production from the 3D-printer differs significantly from an injection molded part. For example, the physical properties of a 3D-printed component of injection-molded parts are sometimes significantly different. The solution is 3D-printed mold inserts (installed in a cassette mould), which can be used for a very cost-effectively production of plastic parts.
Based on the CAD data of the plastic part, the print data of the mold inserts can be prepared accordingly and 3D-printers create the mold. Depending on the size of the components, this can already be done within minutes, for larger designs longer processing times are required. Nevertheless, these mold inserts are prepared much faster and cheaper than their “steel competitors”.
From the plastic mold to the metal mold
Over the past two years, 3D-plastic mold inserts have revolutionized mold manufacturing in the plastics processing industry. Low mold costs due to 3D-printed mold inserts as well as the rapid implementation of modifications are the decisive advantages for the users. A drop of bitterness, however, is their durability. Higher temperatures of the materials and high injection pressures have a negative impact on the lifetime of the mold inserts. The operating cycles of the 3D-printed molds decrease. Especially for small series and medium quantities, many users would like to have more stable solutions. This is guaranteed by the use of 3D-printed metal mold inserts. Higher stability and the possibility of a sometimes required mold temperature control / cooling are given with these metal mold inserts and thus represent the next stage of additive manufacturing.
A good preparation is most important
However, the layered pressure of the molds made from plastic or metal differs significantly in terms of preparation and planning. In the case of metal mold inserts, a large number of marginal conditions have to be considered in advance. For example, for complex 3D-dimensional parts, tempering channels with the corresponding connections must already be provided in the planning stage of the mold inserts. In the case of the metal-printed molds the parting line still has to be finished processed, because the structure of the surface of the mold part arises from the printing process. For the achievement of a defined or desired surface this additional processing step is therefore required.
If the technological and financial expenses of 3D-printed mold inserts for small quantities are manageable and significantly more efficient than conventional steel molds, this is not the case for metal mold inserts, depending on their structure and complexity. At the beginning of the planning phase of the molds or the metal mold inserts, decision should be made to either use a metal mold insert or a conventional aluminum- or steel mold. The design engineer should therefore be familiar with the potential of 3D-technology to create to a good and cheap mold, based on the additional possibilities.