The BKM9 Series from Techna-Tool Inc. is a family of digital broken tool detection controllers originally developed by BK Mikro (Germany) for CNC machining centers. Using wand-type scanners, the system verifies tool integrity after machining cycles — detecting breakage, missing tools, and position errors before they cause scrap or machine damage. Models include the BKM91 (PROFIBUS), BKM92 (standard), BKM93 (entry-level), and BKM9 I/O extension module.

How does the tool detection scanning work?

A motorized wand scanner rotates in contact with the tool tip, measuring angular position against a taught reference. The controller supports programmable clockwise and/or counter-clockwise wand rotation with adjustable scan intensity in 8 steps. Detection accuracy reaches ±0.05°, typically identifying 1–2 mm of tool breakage. The system handles tool length variations exceeding 635 mm (25 inches) between the shortest and longest tools in a magazine. Teach-in functionality allows rapid programming of scan positions via the front panel or USB-connected PC software.

How are multiple tool positions managed?

The base controller provides 3 digital inputs (Start, Teach-in, and one configurable) plus 2 relay outputs (OK and KO) configurable as N/C or N/O with momentary or latching behavior. For multi-tool magazines, the BKM9 I/O extension module adds 10 digital inputs addressing up to 512 different tool positions, with 3 rotary switches for scanner head selection and swing angle (0–360° in 24° steps), plus 8 toggle switches for monitoring parameters. All models mount on standard DIN rail in a 22.6 mm wide housing.