The acugrind-C is a centerless grinding machine designed to achieve, besides tight diameter tolerances, high concentricity accuracy (ID to OD). Parts typically ground on the machine are bushings or tubes. Prerequisite is an already existing accurate bore through where a high precision wire is pulled. The parts threaded onto this guiding wire form a processing chain of parts up to 1000 mm in length. The wire is mounted onto the oscillating axis of the machine. The special process is used with hard material workpieces as ruby or sapphire bearings, ceramic connectors for fiberglass (ferrules), carbide guide bushings or stainless steel medical tubes, waterjet cutting orifices, permanent magnets for micro drives and injection nozzles.

Part OD

0.500 – 12.000 mm

Bore size (guiding wire)

0.100 – 6.000 mm

Maximum part or chain length

1000 mm

Grinding wheel dimensions

1A1 175 x 20-70 x 45mm (other dimensions are available upon request)

Process control

Siemens SIMATIC S7

Electrical specification

voltage 110VAC – 240VAC
frequency 50Hz – 60Hz

Dimensions (length x width x depth)

2700 x 800 x 1900 mm


Carbide tubes
Workpiece specifications
Inner diameter0.30 mm
Outer diameter0.59 mm
Length2.3 – 5.3 mm
Honing process data
Achieved tolerances (diameter)0 / + 0,0127 mm
Material removal0.52 mm
Number of pieces / clamping (=1 group)150 pieces (5.3 mm each)
Cycle time (group)60 minutes
Cycle time (workpiece)24 seconds
Bearing jewels

Ruby bearings are used in every mechanical watch. Together with the metal pins of the balance wheels they form a journal bearing.

Furthermore they are used in different counters.

Workpiece specifications
Inner diameter1.605 mm
Outer diameter2.653 mm
Length1,88 mm
Honing process data
Achieved tolerances (diameter)+/-0,002
Material removal0.147 mm
Number of pieces / clamping (=1 group)500
Cycle time (group)83.3 minutes
Cycle time (workpiece)10 seconds
Ceramic tubes
Workpiece specifications
MaterialZirconium oxide
Inner diameter0.90 mm
Outer diameter1.302 mm
Length10.1 mm
Honing process data
Achieved tolerances (diameter)0/+0.004 mm
Material removal0.6 mm
Number of pieces / clamping (=1 group)85
Cycle time (group)30 miutes
Cycle time (workpiece)21 seconds

Available accessories

Dressing unit to dress the grinding wheel without dismounting it from the machine
Grinding wheels
Direction wheel
Blade holder
Dressing stone
System to mount workpieces onto the honing wire: acuthread
Guiding wire, gradation: 0.001
Coolant unit