ASD-H25 Ultra Precision Air Bearing Tool Spindles from Levicron

Levicron’s ASD-H25 ultra precision air bearing tool spindles are designed for the ultra-precision machining market and for micro and precision metal cutting applications.

They are capable of moderate chip load and high level accuracy. ASD-H25’s optimization targets on favorable load capacity and robustness with a slotted permanent magnet motor that is more powerful than Levicron’s ASD-Cx.

This is the first time an air bearing spindle such as the ASD-H25 has been fitted with an automatic HSK (tapered) tool clamping units.

The modified HSK-E25 tooling system is not built with any springs, thus guaranteeing excellent spindle dynamics. It can be adapted to work with automatic tool loaders. The uniform steel body measures 100 mm in diameter and works well together with the spindle to enable usage of traditional metal cutting such as grinding and milling. It can also be applied for any other application where spindle power and high accuracy are needed. This spindle can come with an iron-less motor. The high-torque motor offers several advantages for CNC-machining with respect to chip-to-chip time and acceleration/deceleration

The ultra precision air bearing tool spindles are offered in three versions:

  1. ASD060H25(A) – 60,000 rpm, HSK-E25, with radial (or axial) spindle connector option
  2. ASD080H25(A) – 80,000 rpm, HSK-E25, with radial (or axial) spindle connector option
  3. ASD090H25(A) – 90,000 rpm, HSK-E25, with radial (or axial) spindle connector option

Key Features

The main features of the ultra precision air bearing tool spindles include:

  • dynamic run-out
  • Stiffness
  • load-capacity
  • HSK25 tooling system
  • error-motion

Measurement Data

The measurement data for ASD060H25 are outlined below:

  • Radial stiffness at spindle nose: > 40N/µm
  • Ultimate radial load capacity at spindle nose: > 350N
  • Static TIR at tool, 70 mm overhang: < 1µm
  • Power losses at nominal speed, idle running: < 800W
  • Vibration speeds: < 0.5mm/s
  • Axial stiffness: > 60N/µm
  • Ultimate axial load capacity: > 550N
  • Acceleration: up to 60.000rpm/s
  • Air consumption at 6 bar: < 50 NL/min
  • Coolant flow: 5-10 L/min @ 3-5 bar
  • Shaft taper run-out: < 50 nm (in-production pre-measurement video of < 30 nm)
  • Error in motion: < 30 nm

Retro-Fit Kit

Based on high demand, Levicron has built a ready-to-use and retro-fit kit for ultra-precision machining centers which enables users to upgrade their machine tool or substitute existing spindles with Levicron ultra-precision spindles. The retro-fit kits are offered to customers because most times end-customers don't know how to integrate spindles into a machine.

The existing control lines of the machine control can be used without re-programming. As an alternative, a stand-alone kit can be used on a number of machines together with a handheld device or a PC/laptop.


In the case of CNC machine tools, drive units are mostly combined with the machine control, and so the motor and encoder features will have to be altered, programmed and tested separately. A custom spindle flange is mostly required due to the complex and frequently closed Z-stock designs.

Levicron has designed several spindle integration kits with tailored flange designs and encoder adjustments to suit all major machine control types, thereby ensuring a secure and quick integration of Levicron’s spindles with the user’s machine.

Typical Applications and Recommendations

The basic applications and recommendations for the ultra precision air bearing tool spindles include:

  • Micro, HSC, form and optical surface milling with tools of a diameter > 2 mm for hardened steel and > 4 mm for aluminum
  • Applications/operations with more than 50% at < 60 krpm
  • Applications with an automated tool change for HSK-25 tool holders
  • Coordinate and form grinding of work piece made from hardened steel, ceramics, carbide metal, and other brittle materials with tools of a diameter < 15 mm and speeds < 60 krpm

ASD-H25 Ultra Precision Air Bearing Tool Spindles from Levicron

ASD080H25A - Air bearing tooling spindle with HSK25 industrial tooling
Ultra-Precision Machining Kit

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