Rawlplug’s 3D Printing Lab. Injection mould designing and conformal cooling
It’s already happening. Making the most of the capabilities of the latest 3D printers, we can design optimised plastic cooling systems, which effectively shortens the parts production cycle by up to 40 per cent.
Several months ago, we announced process changes that would not have been possible without investing in new 3D printers, including innovative equipment which allows us to print in sintered steel. One of the priorities of the 3D Printing Lab, set up at that time, and now operating in the R&D area, was developing conformal cooling systems. They were assumed to help us significantly shorten the parts production cycle, where the traditional plastic cooling methods previously used devoured up to 70–80 per cent of the time. Do you think we have been successful?
Traditional cooling systems
But first things first. Let’s start from basics:
- every injection mould uses a cooling system;
- without it, even though it would be possible to cool down plastic to 80–90 degrees Celsius, being previously heated to temperatures which can exceed 200 degrees, it would also be very time-consuming and problematic, especially in large-scale production;
- in order to enable and, at the same time, accelerate this process, different types of cooling systems are used, and they are most typically based on traditional drilled channels filled with water flowing through a steel injection mould, however...
“That’s where problems start” says Sebastian Szymczyszyn, Leader of the Construction Area at Rawlplug’s R&D Department. “In the traditional model, we almost always prepare the cooling channels using a drill or a milling machine, since we simply lack alternative tools and methods. However, when using a drill, you can’t make any turns you need. This makes the preparation of complex channels very difficult, expensive, and often simply impossible.”
Solution: printed injection moulds
With the new equipment, Rawlplug’s 3D Printing Lab can surmount (and with a significant margin) the above obstacles and streamline the entire process of workpiece production in injection moulding machines.
Sebastian Szymczyszyn
lider Obszaru Konstrukcji
How is that possible? Here’s how, step by step:
- step I – running a series of high-precision digital simulations to analyse the potential for introducing conformal cooling against Rawlplug’s specific products;
- step II – selecting the products where conformal cooling will guarantee improvements in the manufacturing process of specific workpieces;
- step III – running injection moulding simulations with a detailed analysis of the length of individual cooling periods and potential process errors;
- step IV – designing conformal cooling channels optimised for a specific workpiece;
- step V – printing injection moulds with cooling channels dedicated to specific workpieces;
- step VI – processing print-outs at the Tool Shop and refining the rough surfaces typical of 3D printing.
Why conformal coling?
“It mainly serves to make the cycle shorter and more stable,” Sebastian Szymczyszyn explains. “Not everyone realises how great the values we are talking about are. In a workpiece production cycle, i.e. from the moment the mould is closed and the injection commences until the moment the mould is opened and the workpiece is pushed out, cooling can consume up to 70 per cent of the process time. Having developed the cooling channels by 3D printing, with bends made at points where it would be impossible using conventional production methods, just a few millimetres away from the mould cavity, we can reduce the entire process by 20–30 per cent on average, and in extreme cases – even by 60 per cent, simply because, precisely thanks to conformal cooling, water flows right next to the workpiece and in places where – as we can find out through simulation – cooling is most needed.”
Optimised cooling of moulding inserts is not all...
Both the 3D Printing Lab and the Tool Shop along with the injection moulding line at Rawlplug are currently running tests of the cooling systems printed in steel (the photographs show the insert and the cavity printed in this way), necessary before the new moulds are put into mass production. We will keep you posted on the test results soon. We also promise to take a peek behind the scenes of the Lab to report about the capabilities of the new resin printers which have already proved their worth at the R&D Department in prototyping. So stay tuned!
About an author
Michał Raińczuk
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