Electronic Substrates
Anonymized application scenario: 95% alumina insulating bushing for high-voltage vacuum interrupters
Representative 95% alumina insulating bushing concept for high-voltage vacuum interrupters, covering deep internal threads, thin-wall distortion and micro-cracking.
Anonymized application scenario: This representative engineering case is based on typical design, material and machining requirements. It does not represent a specific customer project. Values below are engineering targets, not measured customer results.
Application overview
This representative scenario discusses machining and inspection approaches for alumina insulating bushings with thin walls, internal threads and vacuum sealing requirements.
Engineering scope
This page does not claim customer-specific pass rates, certifications or lead times; the values shown are design targets.
Challenge
A representative high-voltage bushing requires deep internal threads and thin-wall steps. Prior machining approaches can produce thread micro-cracks and sintering distortion. Typical requirements include wall sections down to 1.2 mm, M12×1.25 internal threads, and coaxiality ≤0.015 mm across internal and external steps.
Solution
The representative approach uses DFM to adjust the internal thread root radius and distribute stress during green machining and firing. Diamond-coated taps and ultrasonic-assisted CNC drilling reduce chipping risk. Hermeticity testing can use vacuum helium leak detection as required by the project.
Process
Drawing/DFM review → 95% alumina blank → green machining → sintering → diamond finishing/internal threads → cleaning → helium leak/dimensional/visual inspection → packaging.
Inspection & compliance approach
- CMM dimensional inspection per drawing; report available on request.
- Surface roughness measured with a profilometer; Ra targets are project-specific.
- Lot-specific material certificate; material grade confirmed against the drawing.
- Life validation is application-specific; the test protocol is agreed per project.
- RoHS/REACH declarations are reviewed per material lot where required; no blanket certificate is implied.
Engineering targets
Minimum wall target
1.2mm
Engineering target, project-specific
Coaxiality target
≤0.015mm
Engineering target, project-specific
Internal thread
M12×1.25
Engineering requirement
Related products
NDA & Confidentiality
This case is published as an anonymized application scenario. Customer names, logos and proprietary drawings are not disclosed. Values are engineering targets, not measured customer results.
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