Kollmorgen’s backlash-free direct drive solution helps MEquadrat AG
Kollmorgen’s backlash-free direct drive solution allows exact synchronicity and concentricity with maximum precision up to 2 µm, and is more cost-effective
MEquadrat AG is a start-up that has been providing highly specialized solutions for four years as a mechatronics service provider, particularly in the laboratory and medical areas. Interdisciplinary thinking plays a fundamental role in this company’s product development activities. Original ideas related to implementation, efficient development and customized support also characterize the collaboration they had with drive specialist Kollmorgen on their new production module for the medical sector. Kollmorgen’s backlash-free direct drive solution allows exact synchronicity and concentricity with maximum precision up to 2 µm, and is more cost-effective
Nyffenegger emphasizes: “With the KBM kit motor solution from Kollmorgen we have found the perfect solution for us, and the overall drive concept really was customized to our needs.”
Zimmermann: “The team from MEquadrat knew exactly what they wanted. We were able to make concrete proposals based on their input in order to get there. This allowed us to develop the best solution together.”
Networked thinking
One of the founding concepts of the service company MEquadrat AG, situated in the municipality of Root in Lucerne, is networked thinking and the creation of new machines and systems that meet its customers’ needs through consistency in the software used, the sophisticated mechanical and electronic components, and the associated increase in the degree of automation. One thing is clear for Stefan Nyffenegger, a member of the executive management team at MEquadrat AG: “The interlock between the mechanics, electronics, and software is the key to innovative products and higher productivity. We also break new ground with our unconventional approach, as can be seen with the current project for a machine module that is designed for processing thin-walled material in the medical sector”.
Precise clamping despite high levels of rotation
The two-sided and torsion-free clamping of highly sensitive glass and aluminum tubes is a particular challenge for the production module developed and constructed in Root. The product diameter ranges from between around one millimeter to 20 mm, with very thin wall thicknesses of around one-tenth of a millimeter. Cutting and joining processes are carried out on the sensitive hollow rod material. The high speed for the material clamped on both sides in the process requires absolute precision in terms of the synchronicity.
Developing the overall module in such a compact manner in accordance with the customer’s strict specifications required a highly meticulous and extremely precise drive system for the spindles in the workpiece feeder mechanism and for the relevant process steps with the clamped product. Stefan Nyffenegger highlights: “With the KBM kit motor solution from Kollmorgen we have found the perfect solution for our needs, as the product can be guided through the drive in a fluid process thanks to the large hollow shaft.”
Collaboration on an equal footing
The engineers at MEquadrat already had the idea of selecting a direct drive as they were designing the drive system. Their intention was to use an existing modular design in order to meet the precision requirements and to guarantee implementation on a time and cost-efficient basis.
But it became apparent that a rotor and a stator with the full functionality of a servo drive should be used as a result of the compact packing density and complexity of this assembly. In the end, the company decided the best solution was from Kollmorgen. The experts at the drive manufacturer were ready for any special requests. Decisions at the implementation stage for this project were made very quickly, as the experts from both companies collaborated with each other on an equal footing. The synchronicity however remained a problem. But a few ideas were developed for this and the product selection was narrowed down during some initial telephone discussions.
The Key Account Manager at Kollmorgen, Martin Zimmermann, and his colleagues providd their full support: “When MEquadrat only requested the rotor and the stator for the feeder unit in this project, we knew that a mechatronics engineer would need to focus on the motor in greater detail. You have to have confidence when trying new things like in this project, which requires mutual and absolute trust”. Aside from the time pressure and the extreme requirements related to precision in the functional specifications, there was another additional crucial challenge related to the medical technology: “The drive solution must be free from abrasion and lubricant, and we weren’t able to carry out any experiments at the implementation and commissioning stages for the mechanics and software”, says Nyffenegger. All of the components provided in this machine module therefore had to be tested and shown to be absolutely reliable.
The interaction of the direct drive with AKD Drives and the controllers from National Instruments (NI) enables extremely precise positioning. The cycle times in the current regulator are around 670 ns, and are just 62.5 µs in the speed regulator. Nyffenegger stresses: “This allows us to achieve optimum synchronicity in line with these high dynamic requirements. As such this drive combination represents the optimum price-performance ratio.”
Precise positioning with plug-and-play solutions
The crucial thing here that the two synchronized axes achieve extremely precise concentricity of 2 µm. Nyffenegger adds: “We’re talking about accuracy ranges that are otherwise only seen in spindle axes in large production plants.” The high speed was another of the major challenges in this project. There are systems on the market that “can indeed clamp sensitive products such as these at the required level of accuracy, but they often lose their clamping force from 500 rotations per minute. I haven’t seen any comparable product on the market that maintains its full clamping force at 3000 rpm!”, highlights Nyffenegger.
The “AKM” drive with single-cable solution and SFD feedback were selected for the linear axis in the machine design. The components now just needed to be put together and everything fitted perfectly. The resolver method as a single-cable solution is one of the drive expert’s specialties aimed at making optimum use of the robustness of the resolver. Nyffenegger stresses: “The wiring required in the AKM motor is also minimal here as a result. Highly compact cable carriers can also be used which really are sensational for tight spaces.”
Benefits
- High flexibility of the coordinated components
- Integrated hollow shaft for special application predestines integration of a clamping system which maintains its clamping force even at 3000 rpm
- Direct drive without any play or redundant mechanical parts allows exact synchronization and concentricity with the utmost precision up to 2 µm and is thereby hard-wearing
- Excellent, comprehensive support from Kollmorgen from design through execution to commissioning
- Easy conversion to different diameters
For more information
Web: www.kollmorgen.in
