Choosing a spindle: People & Companies

There are three kinds of machine tool spindles: belt driven, coupled motor and integral motor. What’s right for your shop?

It may surprise some people but “belt-driven spindles provide the ‘best bang for the buck’ in regards to spindle drive designs,” said Jeff Clark, vice president of sales and marketing for Setco Sales Co., Cincinnati.

That’s why they are so common in standard machining operations. But belt-driven technology is also suitable for specialty machining. This is not just because of the ease in sizing belts but also because of positive tooth designs and the use of materials like Kevlar that extend belt life, Clark noted.

Last year, Colonial Tool Group Inc., Taylor, Mich., saw a significant increase in dedicated transfer machine sales compared to CNC technology, noted Paul Thrasher, company president. “Therefore, the belt- and gear-driven spindles increased significantly,” he added. The machinery in a dedicated transfer line typically uses a custom belt-driven system for spindles.

The belt-driven technology is still the most popular spindle design and also offers the lowest maintenance cost.

Nor are belt-driven spindles only for low-end machines. “There are high-end, belt-driven machines,” said John Easley, vice president sales and marketing, Fischer Precise USA, Racine, Wis. “Spindle technology is more tied to rpm than low- or high-end machine tools.”

Another option, coupled-motor spindles, have grown in popularity over the past few years because they are now able to achieve higher speed capabilities, according to Clark. Many machine builders promote coupled-motor spindles because of their low noise and vibration levels.

As for motorized spindles, their use is growing as the industry further develops high-speed machinery. Additionally, 5-axis machines with a swivel head require a motorized spindle because of the machine’s mechanical design, according to Hurco Cos. Inc., Indianapolis.

Motorized spindles provide “wide adaptability in terms of allowable speed ranges, features and ease of maintenance. So depending on the application requirements, this spindle type is helpful as a self-contained package,” Easley said.