Zone: Screw Machines - Swiss-Type

OVERVIEW: Designed to efficiently process long slender parts for the watch industry, the Swiss-type screw machine has evolved well beyond its original application niche. When equipped with CNC, 11 or more axes of motion--in the form of driven tools, sub-spindles, compound slides, thread whirling and rotary broaching attachments as well as polygon turning--can be brought to bear for single handling (done-in-one) production. Today this class of machine is found in medical, aerospace, automotive, electronics and general metalworking as well as the watch industry—anywhere complex, precision parts with a length to diameter ratio that is subject to deflection in the turning process. The differentiating feature of the Swiss-type machine tool configuration is use of a sliding headstock to produce its Z-axis feed. This feature sets the design apart from conventional turning centers. Swiss-types use a guide bushing, usually carbide lined and mounted as the spindle nose, to support the blank stock within the work zone of the machine. As the sliding headstock moves in X-plus or minus, the work “slides” through the close coupled bushing allowing movement and as well as support. To provide X-axis feed, numerous cutting tools on independent slides or gang tool plates are arrayed around the periphery of the spindle and cross feed perpendicularly to the workpiece. These tools are close coupled to the guide bushing support so deflection from cutting forces is mitigated. The cutting action comes from interpolated motion of the Z-axis headstock as it moves the work axially across the X-axis cross-slides. Use of pick-off or sub spindles allows backworking operations to complete the workpiece on the machine. As the CNC Swiss-type has grown in its application breadth, many parts that are being run on these machines are actually not “Swiss” parts. In order to gain access to the multi-tasking and high precision advantages offered by the sliding headstock design, many shops are running parts that because of their low length to diameter don’t require the support of the guide bushing. In response, most CNC Swiss builders offer a “bushless” Swiss machine. It eliminates the need to adjust the guide bushing, speeding setup, and allows the machine to use bar stock that doesn’t require as tight size tolerances to fit the guide bushing. In other words, the stock need not be ground. Swiss-Type Screw Machine Trends: Bushless or fixed headstock Swiss turning Quick change tooling schemes In-process tool breakage detection Off-line tool setting Synchronous main and sub-spindle Thread whirling attachments Rotary broaching attachments High pressure coolant application

Featured Zone Content

Adding Swiss Machining to the Production Mix

In business since 1946, this Michigan shop has survived and thrived, and it is building up a CNC Swiss machining department to augment its banks of multi-spindle automatics. ...MORE

Marubeni Citizen-Cincom L20 Type XII Swiss-type lathe

Swiss-Type Lathe Adds B Axis

The L20 Type XII Swiss-type lathe from Marubeni Citizen-Cincom features B-axis controllable rotary tools for simultaneous complex machining. ...MORE

Nexturn’s P series SA 38PY Swiss-type lathe (available from Absolute Machine Tools) offers eight axes and 38-mm front and rear bar capacity. The lathe’s guide bushing can be removed to enable the use of less-expensive cold-drawn barstock and minimize the size of bar remnants left after machining.

April 2014 Product Spotlight: Turning

Click through this month’s product slideshow featuring lathes and turning centers. ...MORE

Absolute Nexturn S model Swiss-turn lathe

Swiss-Type Lathes Offer Guide Bushing Options

Available from Absolute Machine Tools, the Nexturn S-model range of Swiss-type lathes include “e” and “P” series, each consisting of four models capable of handling 20-, 26-, 32- or 36-mm barstock. ...MORE

L20XII Swiss-Type Lathe Offers B Axis and Removable Guide Bushing

The L20 Type XII, part of Marubeni Citizen-Cincom’s L Series Innovation lineup, contains B-axis controllable rotary tools. ...MORE


Shop Opts for Choice in Swiss Machines

Precision CNC (Lancaster, Ohio) is a traditional machine shop that has moved into Swiss machining. From the beginning of its Swiss operation, it has used “combination” machines in its stable of Swiss-types, which offer machining capability with or without a guide bushing. Here’s how and why it uses them. ...MORE

Loading the player ...