30N High Precision Planar Voice Coil Actuator for Micro Machine Tool Z Axis

The VCAP0030-0200-00A is a medium-force model in the flat voice coil series: it has a peak thrust of 30 N, a continuous thrust of 12.3 N at 25°C, a total stroke of 20 mm, a maximum voltage of 24.3 V, and a back-EMF constant of 10.5 V/m/s. Its 80 × 74 × 25 mm housing is compact enough to be mounted beneath a small spindle or inside a tool holder, whilst the 20 mm stroke is sufficient to meet the working depth requirements for most micro-drilling and press-fit operations. As the coil is the only moving part, this axis has no wear-prone lead screws, no couplings prone to misalignment, and requires no regular lubrication or maintenance.

In micro-machining, cutting tools must not only reach a specified position but must also arrive at that position with a predetermined force. Screw-driven axes can only provide the force generated by the motor when the nut is locked, which is far removed from the force actually exerted on the cutting edge of the tool. A voice-coil actuator acts as a force source: the current determines the thrust, the thrust determines the contact force, and the control loop can directly regulate either of these parameters. This enables a constant feed force, ensuring that whether a 0.5-millimetre drill bit or a carbide micro-end mill is used, a stable cutting load is maintained when engaging the workpiece; furthermore, the feed rate automatically ceases to increase as the cutting tool becomes blunt. This characteristic is equally applicable to press-fit and riveting operations, where the target force curve is far more significant than the target depth. As the coil is rigidly coupled and lightweight, the spindle can reach the commanded force value within a few milliseconds, thereby supporting short drilling cycles, rapid tool retraction in the event of overload, and in-process force monitoring without the need for additional sensors. The 25-millimetre height also allows the actuator to be mounted on a vertical slide behind the spindle, rather than on top of it, thereby shortening the structural path and improving rigidity.

Z axes on micro milling and micro drilling machines, PCB and ceramic substrate drilling, electrode feed on small EDM units, press fit and staking of pins and bearings, spring and contact force testing, micro dispensing needle positioning, and short stroke tool compensation axes on optical grinding equipment.

Q: Can this actuator replace a pneumatic cylinder in a press fit station?
A: Yes, and it usually gives a better result. Instead of one fixed air pressure, the coil follows a programmed force ramp, so insertion force can be monitored and the cycle stopped the moment it exceeds a limit, which protects both pin and board.

Q: How much force can it hold at standstill?
A: Continuous holding force is limited by coil heating, which is 12.3 N at 25°C with natural convection. With a heat sink the sustainable level rises, while the 30 N peak is reserved for short acceleration phases.

Q: Does the 20 mm stroke mean 20 mm of usable tool travel?
A: The figure is the total mechanical travel. Practical working travel is normally set slightly smaller to keep a safety margin at both ends and to avoid hitting the magnetic end stops.

Q: What happens if the tool jams?
A: Current rises as the coil pushes against the obstruction, so a current limit or force threshold in the drive stops the motion immediately. Because the moving mass is small, the reaction on the machine frame stays minor.

Q: Is a vertical mounting orientation supported?
A: Yes. When the axis is mounted vertically the coil weight has to be balanced by a counterweight or a light spring, otherwise gravity will pull the axis down whenever the drive is disabled.

Actuator, cable set and mounting screws are supplied as standard. Optional linear guide stages, force sensors and matched servo drives can be quoted as a complete Z axis kit.