High Speed Spindle
High Speed Spindles - Why We Need Them: With a trend towards miniaturization in manufacturing, work piece sizes are decreasing and part versions are increasing. So, the use of micro tools is becoming more and more prevalent. However, efficient and cost-effective use of these small tools requires high speed spindles or high frequency spindles. This is primarily due to the fact that the spindles on conventional CNC equipment cannot achieve the higher RPM speeds required for small diameter tools. Even if they can, it puts undue stress on the equipment by constantly red-lining their spindles. As an example, a conventional CNC machining center running tools smaller than ½” in diameter at 10,000 RPM or less will result in unfavorable feed rates and costly tool breakage.
Often this tool breakage is blamed on operator error, incorrect machining parameters, or worse yet, simply the nature of small tools. The reality is that it’s due to the force of a conventional machine’s heavy spindle and its inability to reach the high RPM speeds required to effectively evacuate chips from the cutting channel.
The smaller the tools, more you need a high speed spindle to efficiently machine quality parts and avoid tool breakage. High frequency spindles with speed ranges up to 60,000 RPM are ideal for milling, drilling, thread milling and engraving using micro tools.
High speed spindles use high RPM rates, taking a smaller stepover, but with significantly increased feed rates. Move your hand through the flame of a burning candle. If you move too slowly, there’s enough time for the flame to cause damage. But if you sweep your hand swiftly through the flame, there’s insufficient time for the fire to damage your skin. The same principle applies to high-speed machining with micro-tooling. Move fast, and there’s insufficient time for heat to feed back into the part and cause issues.
During the machining process, the tool continually carves a chip out of the work piece. The generated heat develops approximately 40% from friction on each side of the tool, and 20% from the deformation (bending) of the chip. Therefore, about 60% of the heat is inside of the chip. High speed spindles evacuate the bulk of the heat with the chip, providing for a cleaner cut. The better machining quality is based on cooler tooling, lower machining forces, and therefore less vibration.
The high frequency spindle reduces the chip load to less than 0.005”. Such a low chip load significantly reduces the forces between the tool and the material. High speed spindles and high speed machining yield less heat, reduceing tool deflection, and allowing for machining of thinner walled work pieces. This all results in cooler machining, superior surface and edge quality, better accuracy and, as a by-product (of low force), easier workholding — since modular vacuum tables can be employed for quick set up and job changeover (particularly with thin flat substrates).
High Speed Spindle Showcase (Sample Photos):