15 April 2019
A fully mastered machining process for the watchmaking sector
Focus on two solutions particularly suited to watchmaking applications: the 701S, for extraordinary movement parts, and the 308S2 5-axis machining center which, as soon as it was released, offered Willemin-Macodel's renowned quality at a bargain price. Explanations from Janique Kohler, Communications Manager, Denis Jeannerat, Technology Director and Patrick Haegeli, Member of the General Management.
When it arrived on the market in 2014, the 701S, equipped with parallel kinematics and delta architecture, worked using interpolation with sub-micron precision. Receiving a lot of attention upon its launch, it offered a comprehensive and robust solution for the watchmaking world which caused quite a buzz. Its exceptional results in machining movement parts, plates and bridges, have impressed and continue to surprise even today.
As for the 308S2, this machine was unveiled for the first time in Switzerland at Baselworld 2017. Evolved from the “dental” 308 machine, this new version now offers the best of Willemin-Macodel in ultra-compact format to manufacture polyhedral watchmaking parts as well as casing parts. But not exclusively.
All the potential of the 701S
The top level in double-sided mode
For three years preceding the marketing of this revolutionary solution, we worked hand in hand with our top customers and tooling suppliers, particularly to optimize the tool-material pairing and machining possibilities. Denis Jeannerat reminisces: “We deliberately sold the first machines on the local market, which meant that we could rationalize the development of custom solutions for the watchmaking field”.
Result: the machine is equipped with a turning unit to facilitate double-sided machining of main plates and bridges with a repositioning accuracy of around one micron! A support device via the rear and a vacuum device enables small, famously very difficult, workpieces to be machined and die-trimmed, by clamping areas which do not belong to the finished part. It also offers the possibility of performing edge machining operations. “All parts related to the watchmaking movement, such as main plates and bridges, can be produced using the same blank”, states Patrick Haegeli.
Innovation is achieved in stages, and tooling is a key area to enable users to take full advantage of all of the capacities of the 701S. Several tool manufacturers have collaborated with our specialists to maximize the advantages of delta kinematics on the dynamic control and unrivalled trajectory tracking of the 701S.
Today, these partners offer tools which are perfectly suited to the intrinsic performance levels of the 701S. When questioned about the potential fragility of certain tools, the Technology Director emphasizes: “We have worked with tools which are just 2 tenths of a millimeter in diameter under extreme conditions. We never broke any of them”. And this goes even further as wear on new tools made from materials that are difficult to machine has been reduced considerably, in comparison to that of standard tools, even though the quality and productivity have improved!
Deep-rooted habits have been shaken up
Since it was released, with its inverted design and machining by interpolation, the 701S machine has shaken up the traditional production management and manufacturing methods. Its unrivalled flexibility enables parts to be manufactured in very small runs to give the best response to each demand. Mr. Jeannerat explains: “The basic machine comprises a magazine of blanks on 12 to 14 posts. But we also offer the option to install a robotized solution for medium and large production runs, for example, with a sizeable work list, as well as presetting, deburring, cleaning or inspection stations”.
Then comes the question: as the precision of the machining center is higher than standard industrial metrology solutions on the market, how can the parts be rationally measured? “The 701S enables the entire production chain to be questioned and new solutions to be offered. And believe me, this corresponds to a real market need”, responds the Technology Director.
The new 308S2, small but…
Huge performance levels in little more than 1m2
Despite a width of 800 millimeters and a reduced footprint, the 308S2 surprises with its sizeable working volume and access to the machining area. “The operator has excellent visibility, right next to the working area”, adds Mr. Jeannerat.
Equipped with the new signature design from Willemin-Macodel, the machine incorporates all the necessary peripherals within its housing. “The new design allows us to improve the customer’s experience in terms of machining, but also in terms of ergonomics, accessibility and maintenance”, explains Ms. Kohler. By integrating the design right from the very beginning, the company has been able to simultaneously rationalize and lower costs.
A stratospheric quality at a price that remains low
This new version of the 308S had to be perfectly in line with the demands of the watchmaking world. Our engineers therefore radically changed their design, and the machine presented today is genuinely brand new. Equipped with measuring scales, direct motors, a new 60,000 rpm spindle and a very large B axis, this five axis machine offers machining capacities and precision usually only available on machines which are considerably more expensive.
Mr. Haegeli confirms: “We have made no concessions during development”. We have incorporated cutting-edge technological solutions, of which we have a perfect understanding, in a coherent assembly, aimed at serving the needs of the watchmaking market with micron accuracy”. Although not considered to be “revolutionary” in the sense you would expect for the 701S, this new little gem has raised the standard level to a new degree of excellence, thanks to a re-evaluation process which continued throughout the development and industrialisation stages. An optimum solution both in terms of performance levels as well as price.
A state-of-the-art “spindle-divider” pairing
During the design process, engineers ensured that the tip of the tool is located as close as possible to the rotation axis to minimize the following movements and ensure maximum precision. The B axis offers considerable angular amplitude which, combined with rotation of the C axis, confers greater flexibility of use. “To ensure the overall performance of the machine, we have developed a new 60,000 rpm spindle.
Equipped with an HSK 32 interface, it enables all the operations required to manufacture watchmaking, movement and casing parts, and, for example, prepare for crimping. We have successfully integrated all turning functions on the C axis, up to 4000 rpm, to maximize the number of operations
in the same clamping fixture”, concludes Mr. Haegeli.
Inspired by the field
Although these two solutions are very different, they have been developed by and for the needs of the market. On this matter, the managers unanimously declare: “The shape of the parts to be produced dictates the design of the machines”. And this thinking goes even further. Rationalisation of the production processes prompts manufacturers to collaborate more closely with solution suppliers both upstream and downstream of the production chain.
“We are increasingly less manufacturers of machines, and increasingly more integrators of solutions”, concludes the director. Knowledge of the watchmaking market coupled with extensive experience therefore enables Willemin-Macodel to offer real “turnkey” solutions: designed to respond to all requirements.