**High-Speed Spindle System of CNC Gold Cutting Machine (2)** Home > Bearing Knowledge > High-speed spindle system of CNC gold cutting machine (2) *728*90 created on 2018/5/16* var cpro_id = "u3440131";

High-speed Spindle System of CNC Gold Cutting Machine (2)

---

/*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089';

Over the past few years, with the development of ceramic cylindrical hybrid bearings and the smooth application of oil-gas lubrication, the high-speed performance of cylindrical roller bearings has been significantly improved. As a result, there are now suitable options for medium-speed machining applications, where the rear bearing of an electric spindle is typically selected as a cylindrical roller bearing that allows greater relative movement between inner and outer rings and can withstand higher radial loads (Figure 4). This design ensures progressive stiffness and reduces the risk of swelling. The high-speed electric spindle produced by Step-Tec in Switzerland uses a ceramic cylindrical hybrid bearing. In addition to rolling bearings, several other types of bearings are also considered for high-speed electric spindles: **Hydrostatic Bearings**: These bearings have low rigidity and are not ideal for high-speed applications. Although they offer high precision, their load capacity is limited. Oil hydrostatic bearings can experience turbulence in the oil chamber during high-speed rotation, leading to increased liquid impact force, power loss, and heat generation. Therefore, they are rarely used in high-speed cutting machines. However, some manufacturers like IBAG do offer oil-static bearings capable of reaching up to 32,000 rpm. FISCHER is also developing a hydrostatic bearing electric spindle called Hydro-F, which can reach a maximum speed of 36,000 rpm (67 kW). **Dynamic and Static Bearings**: These bearings use fluid dynamics and hydrostatic forces to support the main shaft within an oil film. They combine the advantages of both dynamic and static bearings, offering high rigidity, precision, damping, and long service life. They are commonly used in horizontal machining centers and high-speed grinding machines. However, when the linear speed of the spindle journal exceeds 50 m/s, the oil flow transitions from laminar to turbulent, causing severe heat generation and power loss. Further increases in speed remain a challenge for this type of bearing. **Magnetic Bearings**: These high-performance bearings use electromagnetic force to suspend the main shaft in the air. Active sensors continuously monitor the spindle orientation and adjust the electromagnetic force in real time to maintain proper alignment. Due to the active conditioning system, magnetic bearings offer controllable stiffness and damping, enabling active balancing of the spindle. Their rotational accuracy can reach as high as 0.1 μm. With no physical contact, these bearings have a long lifespan and minimal wear. Their speed is primarily limited by centrifugal force, allowing rotor speeds up to 200 m/s. Magnetic bearings are ideal for high-speed, high-precision cutting machines, but they are expensive and not widely adopted in practice. Companies like German GMN and Swiss IBAG have developed maglev bearing electric spindles, with IBAG producing models reaching up to 70,000 rpm and 40,000 rpm. **Dynamic Balance and Centrifugal Force**: The dynamic balance of the high-speed spindle and the centrifugal force of the HSK shank are proportional to the square of the spindle speed. At high speeds, even small imbalances can generate large centrifugal forces, causing machine vibration and affecting machining quality. Professional electric spindle manufacturers ensure strict dynamic balance, usually meeting ISO specification G0.4 (G=ew; e is the displacement between the mass center and the axis, w is the angular velocity), meaning the maximum oscillation caused by residual imbalance at maximum speed must not exceed 0.4 mm/s. Additionally, each tool replacement affects the dynamic balance, so FISCHER provides online active balancing devices that measure and correct imbalances in real time. The Beijing Machine Tool Research Institute’s μ1000 series fine vertical machining center features a self-made electric spindle with a maximum speed of 15,000 rpm, built on a FANUC spindle motor. The spindle undergoes two precise dynamic balances during production: one after hot loading and another after all rotating parts are installed and inspected. It also includes front and rear balance rings for online dynamic balancing. The connection between the spindle and the tool greatly affects processing quality. Most electric spindle manufacturers can provide various custom tool interfaces based on user needs. Traditional 7:24 solid shanks only rely on taper surface positioning, which can cause misalignment due to centrifugal force. To address this, HSK tool holders with double-taper and face positioning have become popular in high-speed machining. Since 2001, HSK has been an international standard (ISO 12164-1:2001). The HSK shank is hollow and designed with a short 1:10 taper, allowing elastic deformation under axial tension, ensuring tight contact between the shank and the spindle. This design eliminates gaps and improves rigidity and positioning accuracy, making it ideal for high-speed operations. HSK holders come in various types, such as A, B, C, D, E, and F. Types A and E are most commonly used. HSK-A has keyways for heavy-duty cutting, while HSK-E relies on cone friction to transmit torque without keys, suitable for moderate cutting loads. **Conclusion**: While the cutting speed of machine tools still has room for development, the maximum speed of international high-speed machining spindles has entered a relatively stable phase. Medium-speed machining products range from 20,000–60,000 rpm, while large-scale spindles operate between 8,000–24,000 rpm. According to EMO2003 data, intermediate products typically reach 10,000–30,000 rpm, with the highest at 60,000 rpm. Currently, high-speed cutting machine tools mainly use electric spindle units, with rolling bearings being the most common. Their dmh value usually does not exceed 250×10⁴. Future developments may push this to 300×10⁴ or higher, allowing bearings with an inner diameter of Φ50–55 mm to reach up to 50,000 rpm. For higher speeds, magnetic bearings are needed, but cost reduction and addressing issues like heat and magnetic flux leakage remain challenges. Other areas, such as integrated sensor monitoring, compact high-output motors, and lightweight designs, are also under discussion. Although domestic electric spindle manufacturing is still limited, China has made progress in research and talent development. Government support for domestic CNC machine tool components is crucial. We should seize the opportunity and accelerate the development of high-speed electric spindles domestically.

---

**Recommended Articles** - What is the outer dimension of the bearing? - Metallurgical defects in bearing steel - Preloading intent and criteria for NSK bearings - Causes of wear failure in NTN bearings - New skills in NTN bearing inspection and repair This article links to http:// Please indicate China Bearing Network http:// Previous: Production characteristics of rolling bearing parts Next: The analysis of the application method of SKF bearing

RADIATA PINE BOARD

Our radiation pine board has a smooth surface and clear texture. Strong load-bearing capacity, manufacturers have an advantage in direct selling prices.

RADIATA PINE BOARD for closets,Maple Fancy Furniture Plywood,9mm Marine Fancy Plywood,Wardrobe Fancy Plywood

Linyi Lanshan Weipu Rubber Factory , https://www.weipuwood.com