High RPM Spindles: 5 Advantages for 5-axis CNC Machines

Five-axis CNC machines can produce intricate components and surface details in a single setup and enable the production of complex parts. These CNC machines produce complex components and surface details in a single setup and enable the production of complex parts. However, milling intricate 5-axis part geometries often necessitates small cutting tools that require high RPMs to achieve optimal speeds and feeds. Unfortunately, most five-axis CNC machines are not equipped with high-speed spindles.

Fortunately, there are ways around this. Five-axis technology combined with high-speed air spindles offer a variety of advantages, such as increased precision, rapid production rates, improved surface finish and enhanced drilling techniques.

How Do High-Speed Spindles on 5-Axis Machines Benefit Your Business?

Air Turbine Spindles® easily and inexpensively integrate into 5-axis machines with the power necessary to deliver consistent high speed milling in cut. These powerful spindles maintain their high speed throughout the tool path, even in corners and hard material.

Retrofitting five-axis CNC machines with governed Air Turbine Spindles® makes it possible to achieve high-speed milling on any five-axis machine. These spindles provide a variety of benefits, including increased production speed, enhanced surface quality and increased profitability. They can operate 24/7 at 25,000- to 90,000-RPM with power to 1.4 horsepower.

Let’s look at five ways the integration of this type of high-speed CNC spindle on a five-axis machine can be beneficial to your shop:

1. Increased Productivity and Efficiency

Milling at speeds of 25,000 to 90,000 RPM can reduce cycle time by 6-to-10 times compared to the standard CNC spindle speeds of 8,000 or 16,000 RPM. With shorter cycle times come accelerated production rates, reduced cost per part and improved profitability. Of course, increasing throughput also increases machine availability, enabling the shop to take on more work.

2. Improved Reach for 5-Axis Machining

When milling sophisticated geometries which cannot be machined on conventional three-axis CNC machines, cutting tools need to be able to reach into deep holes and approach from difficult-to-access angles to meet part specs. Larger spindles can limit the access of the tooling, but deep holes and challenging angles are not an issue for Air Turbine Spindles®. A variety of long-body spindle options are available to meet your needs. These extended-body spindle heads enable the cutting tool to mill hard-to-reach surfaces without losing rigidity as long tools that extend far from the collet do.

The 625HSK-L100 spindle can be observed in the video below milling at 50,000 RPM inside a deep hole on a Hermle CNC machine.

3. Improved Product Quality

Five-axis machines are equipped with two additional axes in addition to the conventional three linear axes, allowing for the tilting and rotation of cutting tools or parts. This makes it possible to machine complex, high-quality parts. With Air Turbine Spindles® parts need no secondary finishing, as the high speed of the spindle enables the machine tool to achieve precise finishes.

Furthermore, high RPM is essential for optimal tool performance when using small cutting tools on complex features and finishing operations. Most CNC machines don’t have the high spindle RPM required to match the milling speeds and feeds recommended for micro end mills, but Air Turbine Spindles® easily integrate into a five-axis machining center, enabling machinists to use the optimum high speed and feed required for small cutting tools to avoid breakages.

With both roughing and detail work done on one five-axis machine, parts can come off the machine in a single setup, saving the user a great deal of costly labor.

With both roughing and detail work done on one 5-axis machine, parts can come off the machine in a single setup, saving the user a great deal of costly labor.

4. Reliable High-Speed Machining

Machinists may consider the use of a traditional spindle speeder or electric spindle to increase the speed of their CNC machine spindle. These nominal high-speed spindles often are not able to maintain high RPMs over prolonged periods. They heat up, resulting in limited duty cycle, burn-out and negative thermal effects. Likewise, coolant spindles often have insufficient power to maintain high speeds in-cut, and are ineffective except with tiny micro tools in a light pass.

A key difference between patented Air Turbine Spindles® compared to speeders or electric spindles is that there are no gears, high-frequency brushes or vanes to thermally expand or burn out. Air Turbine Spindles and Tools® avoid these issues as their technology has only two moving parts: their proprietary governed turbines and air-cooled grease-packed ceramic bearings.

This direct drive eliminates heat and duty cycle while increasing durability. The key difference is that the patented governor control increases air flow CFM to match cutting tool load and maintain high speed in the cut. The rated and speed does not drop materially on the tool path – and that same governed control of air flow keeps consumption to a minimum. This means these CNC spindles last longer and maintain continuous quality.

5. Easy Set Up and Auto Tool Change

One of the significant advantages of five-axis capability lies in the fact that it enables the user to process five sides of a component in a single setup, saving the machine operator’s time. Five-axis machines can be programmed to perform all roughing operations with the lower RPM main spindle, bring in a high-RPM air spindle via the CNC tool changer, and complete the detail work and finish processes in one setup.

Air Turbine Spindles® can be installed on any CNC machine with an automatic tool changer, including but not limited to Chiron, Hermle, Grob, Haas, Mazak, Hurco, DMG Mori, Okuma, Mazak, DN Solutions and Brother. All that is required is to connect 90 PSI compressed air at the required CFM air via the integrated shank, side inlet or Tool changer Mounting Assembly (TMA). Learn more about how to retrofit your milling machine here.

Spindle Selection Guide

Selecting the appropriate CNC spindle for your application is essential. The guide below will provide you with information to help you make an informed decision but in any event Air Turbine Spindles’ team are specialists in high-speed machining and available to consult with you.

625L Series

For extended reach into angles and cavities the 625L Series with 50mm or 100mm barrel extensions are ideal for small end mills operating at governed constant high speeds under load – 30,000 to 65,000 rpm, < 0.55 hp (0.41 kW). This reliable multi-purpose spindle is available in two extended body lengths both with 25mm outside diameter. Due to its small cutter capacity, it can reach into deep pockets suitable for mold manufacturing, detail, MEP, milling, and finishing applications. This CNC spindle is designed to operate 24 hours a day, seven days a week, with ultra-low vibration, no heat and no duty cycle.

The high RPM achievable by the 650L Series is ideal for heavy-duty applications, as well as for milling hard materials in corners and pockets.

650L Series

The long body 650L (100mm) CNC Spindle Series delivers governed constant high speed and power under load – 25,000 to 40,000 rpm, < 0.88 hp (0.66 kW). The 650L (100mm) Series is ideal for use in heavier-duty applications and milling hard materials in corners and pockets. The governor-controlled turbine maintains rated high speed, optimizing tool performance and life. Effective in all materials, including tool steel, titanium and ceramics. With ultra-low vibration, no heat and no duty cycle, this CNC spindle can be operated 24 hours per day, seven days per week.

650XL Series

The option of a double turbine “X” version of the 650 is available with 1.4 HP for harder materials or deeper cuts, if needed. The powerful 650XL (100mm) with the reach for deep pockets is suitable for, robotic face or edge milling and finishing operations with power up to 1.40 hp / 1.04 kW at 25,000, 30,000 or 40,000 rpm. Maximal power increases the number of inches per minute cut. Maintain high cutting speeds at the edge of your CNC end mill/burr using the unique governed performance of the 650 to achieve reduced cycle time, clean the finished surface and increase your CNC throughput. This CNC spindle features ultra-low vibration and no heat, allowing it to be operated 24 hours a day, seven days a week.

The utilization of five-axis machining in the manufacturing industry is becoming increasingly popular due to its numerous benefits. U.S. manufactured Air Turbine Spindles® are a solution which has proven capabilities to maximize five-axis machining processes. Governed high speed delivers tool optimization and enhanced quality so retrofitting an Air Turbine Spindle® into a five-axis CNC machine tool can be an effective way to speed up and enhance production while simultaneously increasing profitability.

To learn more about Air Turbine Tools® spindles, motors, live tools and hand tools, click here.