Advanced Precision Machining

Swiss CNC Machining; An Introduction to Precision Turning with Swiss-Type CNC Lathes

[7/8/2020] The precision manufacturing techniques utilized by today’s machine shops are the result of an industry that’s dynamic and constantly evolving, allowing for the design and production of machined parts that are astonishingly more complex, accurate, and versatile now more than ever. Recent advances in milling and machining technology mean that shop floors similar to Advanced Precision Machining (APM) in Colorado are almost unrecognizable compared to what they once were in terms of specialized equipment and current capabilities. More traditional means of removing material to machine a part relied on a system of cams, mechanical linkages, and some sweat equity, but these historic methods eventually gave rise to what we see today; highly sophisticated, computer-driven machining centers, lathes, and drill presses. Even newer technology introduces electricity, photo chemicals, ultrasound, and 3D printing into the machining arsenal. Add in the progression of computerized numerical control (CNC), CAD/CAM software, and robotics to assist with automating certain tasks, and our industry has truly experienced a revolution.

Now, some nostalgic food for thought. Given all of this cutting edge technology presently in hands of CNC machinists everywhere, are we truly experiencing an improvement over some older ways of milling and machining a part? In almost every case, the short answer is a resounding yes! Surprisingly though, a machining concept introduced over a hundred years ago is having a renaissance of sorts today. Swiss-type lathes, pioneered in Switzerland for the watchmaking industry, are seeing their popularity flourish in recent years and are being increasingly utilized in machine shops running conventional CNC turning machines. Unlike their counterparts from yesterday, state-of-the-art Swiss-type lathes now rely on CNC and automation, and they’re a go-to machine for many high-precision, high-production applications that require accuracy. They’re more powerful than ever, generate faster cycle times, and have much greater flexibility and sophisticated controls that help streamline the machining process. Once seen merely as a specialty tool for one-off custom jobs, many machine shops are realizing the benefits and values Swiss-type lathes bring to the table and are installing this variety of turning technology for the first time. This is due in part to the increased demand for small, complex, low-volume machined parts from the defense, automotive, electronic, and medical parts manufacturing sectors. Machine shop owners the advantages they have over conventional lathes for turning small, intricate and fragile parts, especially those that are long, narrow diameter and cylindrical in nature. In short, CNC machinists are manufacturing parts today that would’ve been unthinkable 5 or 10 years ago on traditional lathes. 

What truly sets Swiss-type lathes apart, resulting in reduced setup times, secondary operations and work in process adjustments, is their specific design allowing for extreme accuracy and ultra-high tolerances. They differ from other lathes where the part is stationary and the cutting tool moves. Instead, Swiss turning lets a part move vertically while the tool remains stationary. The key to this operation is a “sliding headstock” style and a “guide bushing”. To explain, bar stock is held firmly in the machine with a “collet” and advanced, or slid vertically through the guide bushing closely past a stationary, single-point lathe turning tool. Only the portion being machined is exposed from the guide bushing to the cutting tool. This results in great rigidity during the CNC turning process minimizing deflection and vibration while maximizing accuracy and efficiency. In fact, the entire machining process can be completed in a single operation with one setup, reducing the number of times a part is touched during production. The use of live tooling and sub-spindles even allows for overlapping operations. Simply put, with a wide range of capabilities, Swiss-type machining is the most precise and efficient machining method for manufacturing the accurate and critical components customers demand. 

Of course, there are a few drawbacks. As expected, price is a common obstacle causing shops to stop short of adding a Swiss-type lathe to the mix with an average cost running significantly higher than traditional machines There are also some nuances to be learned for a CNC machinist new to the technology, and Swiss-type CNC turning certainly requires deft operation to ensure the demands of tight tolerances are adhered to. The learning curve is steep and requires different thinking regarding axis motion. Most of these machines use oil as the cutting fluid rather than water, so this is a concern when it comes to fire suppression. But, the advantages far outweigh the shortlist of disadvantages! What began with Swiss watchmakers, then on to screw manufacturers, has now become mainstream. The bottom line is that more and more machine shops have discovered the value of these machines as demand for ever-smaller CNC machine parts has grown. The future for Swiss-type machines will only expand, and machine shops that seek to adopt the technology can distinguish themselves with more high-end work and gain a competitive advantage; What every operation needs in these challenging times.

Would you like to learn more about Swiss-type machining? The discussion above only scratches the surface of this once traditional, but now revolutionary technology. For more thorough information on the benefits of turning with Swiss-type lathes, or if you have questions about your next precision machining project, contact the expert CNC machinists at APM's Colorado machine shop today.

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About the Author

Gerry Dillon is a co-founder, current owner, and certified CNC machinist at Advanced Precision Machining (APM), a full-service machine shop located in Longmont, Colorado. Before making his home in the United States in 2000, Gerry was born and raised on the emerald isle of Ireland and took an interest in milling and machining from an early age, ranking #1 in the Irish National Apprenticeship Program. In 2005, he and a partner began what’s grown into a leading Colorado machine shop. Gerry brings over 30 years of machining experience to the shop floor and is certified in all aspects of geometric dimensioning and tolerancing.

 

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