The Danish Technological Institute has partnered with coffee supplier Bentax to showcase the use of Additive Manufacturing in the replacement part sector. In a MADE Material Demonstration project, the company replaced the previous, expensive milk pumps with additively manufactured spare parts, reducing production waste and expense.
“These milk pumps are the root of all evil in a coffee machine, because if they don’t work optimally, there are many other expensive parts around the pump that suffer,” stated Anders Myrup, Technical Project Manager, Bentax. “This requires many trips to the clients and means that the individual technician cannot handle as many customers, so it requires more employees, more service vehicles, etc. So to stop the vicious spiral, it is important that the pump works optimally.”
In the project, Bentax looked specifically at the 10% of the milk pump that typically wears out. It involves some gears and a small housing for these. A common issue is that the gears cut into the housing over time and leave tracks which mean that the pump cannot deliver the desired result.
In the project, the entire pump was scanned and measured at the Danish Technological Institute in order to produce an identical digital copy. The housing was then additively manufactured in stainless steel and post-processed down to the desired tolerances, which are very fine. AM was also tested for the gears themselves, but wasn’t deemed suitable.
Along the way, there have been disagreements between Bentax and the Danish Technological Institute, and this has led to three different design versions, which have been tested. At the end of the project, Bentax is not far from the goal in terms of achieving the desired result from the pump. The additively manufactured housing is completely in place, but some very fine adjustments still need to be made to the gears.
In the long term, the components must be surface treated with chromium nitride so that the surface does not break when the gears work against it, and the expectation is that this will increase durability.
“Initially, the aim is to pump some life into the broken pumps so that we can recycle them,” Myrup explained. “In the long term, we would like to be able to make spare parts rather than buying new pumps from the supplier, and we would also like to achieve a longer durability and a lower price compared to a new pump.”
“The results we have seen are beyond all expectations, and when we held the parts in our hand, no one really believed that they were 3D printed. It was far beyond what we thought was possible, so we clearly did not have enough insight into the technology,” he continued. “Here and now it is a huge success, and we are very satisfied with where it is in terms of price, so we are ready for the next round with 3D printing, and it is also a fantastic story for us to be able to tell our customers.”
While the MADE Material project is now finished, Bentax is still working on the final gear alignment. After this, the entire set must be machined so that the output can be verified before it is installed in a customer’s machine. From there, Bentax will monitor the gears over a fifteen-month period.
Bentax has already started mapping other components that could be suitable for Additive Manufacturing for future projects, such as adapted holders or hooks for work tables. As the company develops its inventory and digitises it further, it anticipates that Additive Manufacturing will form the basis of this growth.
“We don’t stop here, even though the project is over and we don’t yet have all the answers, because the project has shown that 3D printing makes sense. Here and now it’s a huge success, and we’re quite satisfied with where it is in terms of price, so we’re ready for the next round with 3D printing – and then it’s a fantastic story for us to be able to tell our customers,” Myrup concluded.