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16-04-2020
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The mould trial from A to Z

A mould trial is a process by which a new mould is optimised to produce the desired products as efficiently as possible. This makes it one of the most important aspects of injection moulding.
The moulds Rompa uses for its injection moulding are made in our in-house tool shop in Boxtel. Before the moulds are transported to one of Rompa Group’s production sites, mould trials are conducted. It is important to make sure that this process is conducted in the same manner everywhere. We leave nothing to chance. How does the mould trial process work, exactly? Before the start of the mould trial process, we work on the mould design. Together we discuss the mould constructions and technical solutions. We do this to avoid unnecessary mistakes in the mould and make sure that the first phase of the mould trial (first out of tool) already provides us with a good product. Most of the time a standard mould trial process consists of three test phases. Sometimes, we conduct several mould trials during a single phase. If necessary we keep testing and optimising until the product meets the customer’s and our exact requirements and wishes.

The three phases of a mould trial

Phase 1: first out of tool The first phase is called “first out of tool” (FOT). This is the first time we inject molten plastic into the mould. We test whether the mould closes perfectly, whether there is sufficient cooling, whether the product comes out neatly and whether there are any flashes, airtraps or deformations. We draw up a report with our findings, in which we specify the modifications that have to be made. The toolmaker then proceeds to optimise the mould and samples are sent to the customer to provide a first impression. Phase 2: feedback from the customer Once any imperfections have been resolved, we conduct a new mould trial with the optimised mould. We present the resulting product to the customer. Together, we go over the cosmetic aspects and the cycle time. Did we produce an appealing and functional product, are the dimensions correct, can we manufacture it within the calculated cycle time and does it meet the customer’s other requirements and wishes? The part is then released for testing and the customer is given ample opportunity to test the product. We send the toolmaker another report, which includes the customer’s feedback this time. A second round of optimisation follows. Phase 3: the finishing touch Finally, we conduct a third mould trial with the fully optimised mould. During this phase, it is all about the finishing touch. Think of e.g. choosing between a matt or glossy texture. Once the product has been perfected and every detail checks out, we run a long trial. After this run the mould is transported to one of our production sites. We will always conduct a final on-site mould trial, because certain conditions, e.g. the temperature of the cooling water, are not the same everywhere. Once we are convinced that there is no more room for error and the part is released by the customer, mass-production process can begin!