Friedrichshafen, Germany — Since 2018, Marinha Grande, Portugal-based Moldwelt Moldes e Comércio has been expanding its activities to include 3D printing and injection molding.
The company is a small mold maker with 22 employees, established 40 years ago in an area known for its strong tooling sector. Its core mold making activity involves tools weighing up to 6 metric tons.
Operations Manager Pedro Rosa said at Fakuma 2021 in Friedrichshafen that Moldwelt now offers all services within the company. This starts with initial rough outline part design, then proceeding to structural engineering simulation (since 2020) and injection simulation, prior to cutting raw mold steel.
Rosa says this approach ensures molds are not unnecessarily too thick, heavy and expensive to produce and operate, while not compromising the application, so that the first parts produced can survive the conditions under which they are used.
The company uses CADmould software from Würselen, Germany-based Simcon kunststofftechnische Software GmbH. Rosa explained that Moldwelt chose this software due to its widespread use in Germany and the importance of the German market for Moldwelt.
He illustrated this with the main exhibit at its booth, a FootClean product for application of disinfectant. Patients stand on the molded polypropylene part to activate and release disinfectant spray on shoes or feet.
This required simulation to ensure the overall part can withstand a load of 450 kilograms. Integrated bosses restricting downward movement of the attached elements, which are fitted with 3D printed nozzles with a spiral channel and activate the spray. This ensures protection of the nozzles, as they can withstand only a maximum 2 kg load.
The FootClean nozzles are printed by stereolithography, but Moldwelt also 3D prints with the fused deposition melting process.
When Moldwelt needs mold inserts with fine close contour conformal cooling channels, these are produced for Moldwelt by SLS by Lüdenscheid, Germany-based iQtemp GmbH, a member of the Bendern, Liechtenstein-based Listemann Group, a specialist in thermal material optimization solutions.
He is proud of the FootClean development, as the project took less than six months from outline design to molding the product, something rather important with the urgency for more disinfectant solutions increased by the COVID-19 pandemic. It is a typical example of Moldwelt's philosophy of operating with all facilities and competence in-house enabling finding and applying final solutions very quickly, Rosa said.
Moldwelt has produced several molds for the water-assist injection molding technology since 2018. Aside from well-known advantage of gas-assist molding of smoother internal walls, faster molding cycle times through more effective cooling, Rosa favors water as the assist fluid medium, as it is not compressible, so has more power to push the melt when forming the hollow core of parts somewhat further than with gas assist. And water is reusable, whereas gas cannot be re-used due to nitrogen contamination, he adds.
Moldwelt uses water-assist equipment from the Ettenheim, Germany-based PME Fluidtec GmbH. Rosa is particularly impressed by the technical ability of PME founder Freidrich Westphal.
The company has a Bole injection molding machine with 350 tonnes of clamping force, and will likely buy a second, with 120 tonnes, from the same supplier.
Scouting in the market for a suitable machine resulting in the Bole choice, "as it provides good support in Portugal and we have known its distributor for years," Rosa said.
As with the first machine, the second machine "would certainly be equipped" with a control system from Linz, Austria-based Keba Group AG, Rosa said.