Page 22 - 3D Metal Printing Fall 2018

3D Optimization Yields Efficient Coolant Nozzles
Therefore, Grindaix enlisted Bionic Pro- duction’s help. Founded by former employ- ees of Laser Zentrum Nord GmbH, an application-oriented competence center for laser technology, Bionic aims to ramp up 3D-printing processes to an industrial scale. In addition to parts manufacturing, Bionic Production’s services include con- sulting, training, component opti- mization, and process and mate-
rial development.
“The team of experts at
Bionic Production revised and optimized our initial design to make it suit- able for 3D printing,” Friedrich explains. “We learned so much from them
that we’re now able to design 3D parts on our own.”
Matthias Schmidt-Lehr, head of sales at Bionic Production, knows the ins and outs of 3D printing. “Designers,” he says, “need to start by forgetting everything they’ve learned before and opening their minds to this new technology. Only in exceptional cases do you need straight lines and rectangular structures. 3D print- ing gives you the opportunity to create free-form surfaces, many of which would be difficult or impossible to produce using conventional CAD tools.”
Equally important is the ability to rec- ognize the limitations of the 3D-printing process and sidestep them where possible. “In 3D printing,” says Schmidt-Lehr, “we hold the part in position on the 3D-printer platform using supports, which have to be removed once the process is finished. In many cases you can avoid using sup- ports completely by designing the part in a certain way.”
Systematic Effort
The first step when designing a part for 3D printing is modeling the essential aspects. For the Grindex nozzles, these included defined lubri-coolant entry and exit points, and the space required to avoid collisions with moving machine
Coolant nozzles by Grindaix feature gentle curves made possible by 3D printing.
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parts. After modeling the essential aspects, the designer adds as much material as necessary for the part to fulfill its purpose. “Machine cost/hr. is still a key cost driver in 3D printing,” says Schmidt-Lehr. “The smaller a part’s volume, the shorter the process time required to construct it. By leaving out any unnecessary material, we make the part lighter, often a major advan- tage in its own right. But even if it doesn’t matter how heavy the part, reducing the volume still makes it cheaper to produce,”
Unlike with conventional methods, in 3D printing the designer can focus purely on optimizing how the part works. In the case of Grindaix coolant nozzles, curved channels lead to a lower drop in pressure thanks to reduced flow losses. That reduces the amount of pumping power required, so the end customer benefits either from the ability to use a smaller pump or from a higher coolant-exit velocity.
Using specifications provided by Grindaix and a Trumpf TruPrint 1000 3D metal printer, Bionic Production created the perfect model of the new nozzle in a systematic process. “Software allows you to perfectly simulate many aspects of the design, such as the direction of the coolant jet,” says Schmidt-Lehr. “But the benefit
of 3D printing is that it makes it so much easier to create prototypes, try them out, and then modify them as nec- essary.”
That enabled the team to implement every possible optimization within a rea- sonable timeframe and budget. This abil- ity to tailor nozzles for customer appli- cations delights Friedrich. “We make a huge number of different product vari- ants,” he says. “The 3D-manufacturing technique enables us to supply the perfect nozzle to virtually every customer.”
Benefits Outweight Downsides
The new nozzle demonstrates effi- ciency in many ways. Optimizing the flow of coolant reduces pressure losses by as much as 20 percent, meaning that lower pressure and less energy achieves the specified coolant-exit velocity. Curved channels and optimized jet tra- jectory deliver the coolant precisely where needed, delivering no more and no less than is required to carry out the process in an optimum manner without causing thermal damage. This reliable and automated solution for delivering coolant eliminates factors that may have previously caused hold-ups in the man- ufacturing process.
Despite his enthusiasm for 3D printing, Friedrich essentially sees this particular manufacturing method as just the icing on the cake. What really gives the nozzle its unique selling point, he says, is the clean engineering process that guarantees an accurate geometric design.
“There’s a correlation between the pres- sure of the lubri-coolant in the line upstream from the Grindaix nozzle and the velocity with which it exits the nozzle,” says Friedrich. “We calculate the exact figures for each custom-made nozzle shape. In addition, there is a correlation