CNC Technology So Precise You Can Set Your Watch by It
Swiss machine builders deliver high-precision machining of small parts for Swiss timepieces using PC-based control and TwinCAT CNC from Beckhoff
Manufacturing tiny parts with high precision is no small feat, especially when the clock is ticking. It’s a challenge that the horologists of Switzerland’s Watch Valley, the region between Basel and Geneva, know well. Over centuries, this industry has worked to optimize how it produces the smallest components, such as gears and screws for the watch industry or contact pins for connectors, with micrometer-level accuracy and in large quantities.
In this environment, the machine builders Esco SA in Les Geneveys-sur-Coffrane and Affolter Group SA in Malleray deliver critical manufacturing solutions. Their CNC machines produce the smallest gears, screws, shafts and other components at maximum precision. Using the latest automation technology, the machine builders ensure that Swiss watches live up to their global reputation for precision timekeeping.
Esco specializes in lathes to produce parts with high accuracy and impeccable quality in medium and large quantities. Beyond the main process of turning, the Esco systems offer additional machining functions. This enables production of complex parts on the compact machines.
Unique lathe principle helps production beat the clock
Unlike conventional automatic lathes, Esco machines harness a unique operating principle: stationary material, rotating tools. This allows the machines to process ring or bar material in a fully automated process without interruptions. The spindle, which rotates at up to 12,000 rpm, balances the high precision with fast throughput.
“The proximity of the tools to the workpiece offers advantages in terms of production rate and surface quality,” says Vincent Fankhauser, sales manager at Esco.
Esco has relied on PC-based control, in particular TwinCAT 3 automation software from Beckhoff, to automate its machines since the beginning of 2020. “The control and drive technology from our previous suppliers were at the end of their life cycle and we needed future-proof CNC technology that could be easily configured for our different series,” Fankhauser says.
This is where Affolter, a Beckhoff Solution Provider, comes into play. The company manufactures gear hobbing machines itself and, as a contract manufacturer, produces intricate parts for the watch industry and other sectors on around 350 machines, according to Managing Director Vincent Affolter: “We were always proud of our own machine control solution, which we developed ourselves and then had the electronics manufactured.”
The central component of the control system was an FPGA that calculated all setpoints for all axes in parallel within microseconds. But when the electronic components became unavailable, Affolter was no longer able to maintain its control system, let alone develop it further and integrate additional requirements such as IT connectivity. Fortunately for Affolter, the performance of industrial control technologies was increasing rapidly.
An open control platform saves time
“When analyzing possible control system suppliers in 2016, we quickly found what we were looking for in Beckhoff and started initial tests with PC-based control,” says Affolter.
A key priority for the company was to retain the flexibility for in-house innovations without the company having to develop hardware again itself. “This is provided by the open control platform from Beckhoff,” adds Philippe Abt, Business Development Manager – CNC at Beckhoff Switzerland.
PC-based control and TwinCAT CNC now form the basis for a control platform that Affolter uses in its own CNC machines and makes available to machine builders such as Esco as a Beckhoff Solution Provider.
When adapting the CNC solution to the Esco machines, the flexibility of PC-based control became apparent. Due to the required machine cycle, there was no time to waste when processing the CNC tasks. So any functions that were not required were removed to reduce the computing times for the tasks that remained.
“Due to the modular system architecture of TwinCAT CNC, it was possible to achieve the short cycle times required by Esco by configuring it accordingly,” recalls Abt.
PC-based control for round-the-clock production
The control concept relies on TwinCAT 3 and a C6920 control cabinet Industrial PC. This solution works in all Esco machine series and forms the basis for the long-term and safe migration of all CNC machines to PC-based control.
In total, Esco has already delivered around 150 machines with TwinCAT CNC-based control technology since 2020. This demands serious scalability from the control platform. An Escomatic D6 Twin, for example, requires control of 12 servo axes and calculation of three CNC channels.
“We are now much more flexible and can put together exactly the computing power and drive configuration we need from the entire portfolio, including safety,” Fankhauser says.
Drive technology with One Cable Technology (OCT), including AX5000 Servo Drives and AM8000 servomotors, saves space in the control cabinet and in the machine. Now only one, thinner motor cable needs to be routed for power and EtherCAT communication. The switch to OCT also eliminated issues with signal interference in the feedback systems that Esco previously struggled to resolve.
Affolter and Esco are currently working on integrating tool monitoring and inline quality control. The roadmap also includes CNC machine connectivity to MES and ERP systems via umati (universal machine technology interface) and OPC UA. With Beckhoff PC-based control as an open and modular control system with inherent OPC UA compatibility, this is set to be another success.
As in previous upgrades, close collaboration with the automation experts at Beckhoff will continue to help the machine builders save time while delivering an optimal solution. “The crucial thing for us is that we have always received support in this from the very beginning,” Affolter explains. “So we have always found and implemented solutions together with Beckhoff.”
Ready to get your time back with powerful, efficient and precise CNC and industrial automation tech? Contact your local Beckhoff sales engineer today.
Paxton Shantz is the Digital Manufacturing Industry Manager at Beckhoff Automation LLC