For a stator made of ZTA ceramic, an interrupted Ø18.014 ±0.001 mm through bore is being processed in a two-stage honing process. Honing is performed with DIAHON single-stone honing tools for pre-honing and finish honing on a honing machine. The targets are Ra = 0.4 µm and cylindricity < 1.5 µm. In the final optimization step, a cylindricity of 1.36 µm was achieved, meeting the form requirement.

• Component: Stator
• Material: ZTA ceramic
• Hardness: approx. 1,500-2,000 HV10 (approx. 14-20 GPa)
• Bore: Interrupted through bore
• Final size: Ø18.014 ±0.001 mm
• Surface requirement: Ra = 0.4 µm
• Form requirement: Cylindricity < 0.0015 mm (< 1.5 µm)
• Pre-machining: Internal cylindrical grinding to Ø17.920 mm
• Machine: Honing machine
• Coolant: Honing oil
• Workpiece handling: Workpiece re-clamping

Pre-machining: Internal cylindrical grinding to Ø17.920 mm, leaving sufficient stock for the two-stage honing process.

OP1 - Pre-honing: Honing with a DIAHON single-stone honing tool, tool design 1L18/210-T170/350 A1.75 KA18×35.

OP2 - Finish honing: Honing with a DIAHON single-stone honing tool, tool design 1L18/210-T182/350 A1.75 KA18×35.

Target: Stabilize size, cylindricity and surface finish in the interrupted ZTA ceramic bore.

• Cylindricity target: < 1.5 µm
• Achieved cylindricity: 1.36 µm - form requirement < 1.5 µm achieved
• Surface target: Ra = 0.4 µm
• Measured surface: No final measured roughness value is documented in the supplied project files yet.

• Bore geometry is sensitive to tool guidance, spindle runout and workholding conditions.
• Optimization of tool guidance and process conditions significantly improved the previously unstable bore geometry.
• Early honing trials showed that tool runout and workholding conditions influence bore geometry.
• During development, tapered and barrel-shaped deviations occurred initially and were reduced through process and tool optimization.
• The tool design was further developed, with guidance and cutting zones specifically adapted to the interrupted ceramic bore.
• The final measured value of 1.36 µm shows that the required cylindricity can be achieved through the coordinated interaction of the DIAHON single-stone honing tool, guidance and process parameters.

Can ZTA ceramic be precision honed?
Yes. In this application, an interrupted Ø18 mm bore in ZTA ceramic is processed in two stages using DIAHON single-stone honing tools for pre-honing and finish honing. After process optimization, a cylindricity of 1.36 µm was achieved.

What bore geometry is required?
The final size is Ø18.014 ±0.001 mm. Cylindricity must be below 1.5 µm, and tapered or barrel-shaped deviations are not permitted.

Which honing technology is used?
DIAHON single-stone honing tools are used in two operations: pre-honing and finish honing on a honing machine.

What was achieved in the final process stage?
After optimization of the honing process, a cylindricity of 1.36 µm was measured. This meets the required cylindricity of < 1.5 µm.

The project documents the successfully optimized precision honing of an interrupted Ø18 mm bore in high-hardness ZTA ceramic. The two-stage DIAHON honing process with single-stone honing tools is clearly defined. In the final optimization step, a cylindricity of 1.36 µm was achieved, meeting the requirement < 1.5 µm. The development trials show that tool guidance, spindle runout and workholding are decisive for achieving the required bore geometry.