Ceratizit, the precision tool manufacturer, has deliberately positioned the additive manufacturing system for its production facilities right at the heart of its centre of excellence for PCD and CBN tools. The special tools and mechatronic tool systems for large-scale production are developed and produced here in Besigheim, and can draw on the enormous benefits of 3D-printing. The tool specialists rely on the systems and expertise of Renishaw.
“Our Besigheim site specialises in customised tool solutions for batch production, an area where additive manufacturing fits the bill perfectly”, reports Andy Staiger, Head of Segment Automotive, Team Cutting Tools in the Ceratizit Group. Unsurprisingly, this requirements profile means that the site is heavily oriented towards the automotive sector. “However, it’s been some time since we focussed solely on the automotive segment”, explains Staiger. “Increasingly, our customers will also be found in the aerospace or heavy machining sectors.“
Even the automotive sector is undergoing radical change: “We're currently experiencing a dramatic upheaval”, notes Staiger. “In the future we’ll have to cope with an even wider range of models and lower volumes.” A consequence of this is that there will be a constant flow of new components that need machining. Even now, the lightweight e-mobility components often make their presence felt due to their tight tolerances. “The combination of precise machining and lightweight components is particularly challenging, as their thin walls often cause lightweight components to oscillate”, explains Staiger.
In addition to the machining challenges, product life cycles are also becoming shorter, meaning that new model ranges are appearing more frequently.
The manufacturer of precision tools has already reacted to this trend. For example, some special tools are now no longer completely designed from scratch - the design team can access a building block of already existing solutions. “At the end of the day we adapt every special tool solution to the individual requirements of the customer. Our building block system enables us to define the basic structure of the tool much quicker than before”, observes Patrick Schreiber, Head of Global Project Engineering, Team Cutting Tools of the Ceratizit Group. This also means that the customer takes delivery of its tool much sooner.
The advantages of additive manufacturing – such as a high degree of design freedom, simpler implementation of lightweight structures and the faster production of customised components – dovetail seamlessly into the modular tools concept. “Using additive manufacturing enables us, for example, to print individual tool heads onto existing base holders”, says Staiger. However, additive manufacturing is only employed when the printed tool offers real added value for the customer.
“We were totally blown away by the quality of the printed tools. They’re on a par with conventional manufactured tools, in terms of tool life for instance, in every way”, stresses Staiger. It’s when we look at performance, or more specifically cutting speed and potential feed, that tools produced using additive manufacturing really come to the fore. Their much greater capability is often aided by an optimised flow of coolant directly to the cutting edge. This is achieved by positioning the coolant holes more or less anywhere in the tool. This has a positive impact on chip removal as well as tool life.
For their additive manufacturing facilities, the Ceratizit tool specialists rely on the systems and expertise of Renishaw. “Initially, we had our components printed at Renishaw”, recalls Staiger. “Over time, we realised that we needed our own in-house additive manufacturing system so that we could react more flexibly.” A RenAM 500Q system was consequently purchased. Several points spoke in favour of the Renishaw system: the tool specialists were particularly impressed by the very high productivity of the multi-laser system, the high level of functional integration in the machine and, last but not least, its low gas consumption.
The RenAM 500Q is equipped with four powerful 500 W lasers. It also features an optical system developed by Renishaw themselves. “The laser beams are guided via four separate channels into the optical system and directed onto the assembly platform. Each of the four laser beams can reach each and every point on the assembly platform, providing us with greater flexibility in our melting strategy”, explains Lars Markus, Head of Application Technology and Service Additive Manufacturing at Renishaw.
The system also has an integrated powder handling system. “Excess powder is cleaned using an ultrasonic screen and returned to the main container so it can be used again”, notes Markus.
Also included in the Renishaw offering is the QuantAM software package, a special data preparation tool for all Renishaw additive manufacturing systems. The software processes CAD data in various formats and enables users to prepare their models for the AM process. QuantAM can also be used to support the Design for Additive Manufacturing (DfAM) process.
The close proximity of Renishaw was also ideal with regard to service and support. “We specified fixed service intervals for our systems”, comments Markus. “So, our systems are calibrated regularly and we also carry out preventive maintenance on them. That way, we can ensure productivity and quality remain at a consistently high level.”
One of the first market-ready projects at Ceratizit featured a PCD screw-in cutter whose additive manufactured base body was equipped with PCD cutting edges and screwed onto a tool holder. As hoped, the additive process enabled significantly more PCD cutting edges to be added to the tool. This was done by modifying the position of the cutting edges and creating a much larger axis angle. For example, the number of grooves and cutting edges on a 32 mm threaded adapter increased from six to ten. The tool also increased the feed speed by the same ratio.
Besides high-end tool solutions such as these, the tool specialists also employ additive manufacturing for less conspicuous applications. For example, 3D-printing was recently used to produce counterboring tools with PCD cutting edges. “We normally mill the pockets for the PCD cutting edges into a steel base body”, explains Staiger. “The uncoated PCD is then brazed in place and subsequently precision-machined using a laser.” The difficulties arose when reconditioning the tools, since the brazed PCD cutting edges had to be removed thermally and the input of heat into the base body caused the service life of the tools to be reduced a little every time.
The cartridges for the PCD cutting edges are now produced on a 3D-printer and can be screwed to the base body. This solution enables the tools to be reconditioned in a much simpler and faster manner without having any impact at all on the base body. The 3D-printed solution also allows the coolant supply to be positioned in such a way that the chips are efficiently flushed from the hole. “We can print around 200 cartridges in one job”, states Markus. “This means that 3D-printing is not a significant cost factor in this case.“
“From our perspective, these two examples show a possible way forward”, summarises Staiger. “On the one hand we can offer high-end solutions that allow us to expand the physical machining boundaries. On the other are the low-scale solutions that will enable us to use smart ideas to improve the productivity of our tools.” Previously, the innovative spirit required to also look at the high-end solutions was sometimes lacking: “The conventional approach is still often the one that dominates in the world of machining. Unfortunately, not enough consideration is being given to the additive alternative”, is how Andy Staiger sums up his experiences.
The tool specialists were also able to demonstrate their mastery of additive manufacturing in very demanding machining situations on a recent project with the GreenTeam from Stuttgart University. GreenTeam is a racing team in Formula Student Electric. What's unusual in this case is that a completely new racing car has to be designed each season. When confronted by tricky components, the students can draw on the knowledge of various companies (sponsors). Renishaw and Ceratizit have been supporting the GreenTeam for many years.
As the leading team in Formula Student Electric, the students frequently place the emphasis on innovative ideas. In the drive train for example, where the wheel hub motors have been integrated directly into the crossmembers. Lars Markus describes the situation as follows, “All things considered, the overall construction process was so complicated that the only viable solution was to manufacture the parts using a 3D printer, which we were eventually able to do here in Pliezhausen.”
The machining of the printed housing subsequently proved to be just as demanding, as the topology-optimised component contains some very delicate structures. “However, we were able to come up with a solution using 3D printing”, Patrick Schreiber is pleased to report. “We used the printer to create an attachment tool for a mechatronic U-axis system from tool steel.“ When designing the tool, the Project Engineering specialists used Finite Element Analysis to tease out the best design. The resulting tool, which performs the internal and external machining in a single operation, is so far removed from a standard solution that conventional manufacturing would have been completely out of the question here as well.
The machining results reproduced the theoretical design at the very first attempt. “This example clearly demonstrates what we can achieve with our engineering services”, stresses Schreiber. “The additional expense incurred during the construction phase is more than offset by the capability of our special tools. After all, they frequently deliver an optimal machining outcome at the very first attempt.”