Authorised HEIDENHAIN distributors

ACC Systems Ltd

Industrial Automation

STEM drill controllers and power supplies


ACC Systems design and manufacture STEM drill control systems and power supplies. Previous designs have included both CNC and PLC based control and positioning systems.

Our customer base includes both machine tool OEMs and aerospace manufacturers.

Stem drilling machine

Typical STEM drill setup showing tooling and fixtures for simultaneous drilling of 4 components on a single head.

Stem drill tooling

Detail of the tooling, showing the STEM tube guide.

Control system benefits:

  • Control systems from major CNC and PLC manufacturers, assuring world wide support and long term spares availability
  • Full control of machining parameters such as voltage, feed, and acid
  • Ability to program turbulated cooling holes
  • PLC based controllers provide a simple data table approach to programming, removing the requirement for NC programming knowledge
  • CNC based controllers offer a fully flexible programming solution, permitting advanced turbulation patterns and machining techniques
  • Controllers offer true INDEPENDANT multi-head control from a single PLC or CNC, allowing simultaneous machining on multiple heads
  • Multi-head machines are able to share a single acid pack providing lower capital cost
  • Digitally coupled servo drives provide superior slow speed control over traditional analog systems
  • Optional remote monitoring, allowing controller screen to be viewed on a PC via Ethernet

Power supply systems

  • Typically up to 1000A at 20V for the main machining supply, with a smaller 50A supply for electrode de-plating.
  • High reliability MOSFET switching systems are used to control the supply to the machining process
  • Switching systems are designed for 100% duty well within the capabilities of the individual devices


Stem drilling power supply

Power supplies, featuring 15V 500A main supply and 12V 70A de-plating supply.

Stem drill power supply and MOSFET

Simple yet robust interconnection between power supplies and MOSFET switching module.

Stem drill power supply and MOSFET

STEM drill controller based on HEIDENHAIN iTNC530.

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