Appendix D: Ceramic dimensional specifications
The following table gives ceramic dimensional specifications from various manufacturers.
| Table D1. Mechanical tolerances for PZT ceramics |
|
TYPE III
DOD-STD-1376A |
Branson Ultrasonics |
CeramTec
Catalogue (SP8) |
Morgan Electro
Ceramics
Ruabon
(PZT8) |
Vernitron |
TAMURA
SA |
| Thickness |
±0.13mm |
±0.05mm (without
plating) |
Standard —
±0.05mm
(without plating) |
±0.05mm (without
plating) |
Standard —
-0/+0.05mm,
High cost —
-0/+0.005mm,
(without plating) |
| Outer diameter |
±0.38mm |
±0.1mm
to ±0.3mm |
Standard —
±0.15mm |
±0.15mm |
±0.4mm |
| Inner Diameter |
±0.38mm |
±0.1mm
to ±0.3mm |
Standard —
±0.15mm |
±0.15mm |
±0.4mm |
Parallelism —
top and bottom
surface |
0.0254mm
until 0.0127mm |
from ≤0.02mm
to ≤0.002mm |
Standard —
within 0.012mm
Lapped, silver plated —
within 0.007mm |
≤0.012mm |
≤0.01mm |
| Concentricity |
? |
≤0.1mm |
0.2mm T.I.R. |
0.2mm T.I.R. |
? |
| Surface flatness |
0.0254mm
until 0.0127mm |
4 μm |
Standard —
≤12 μm
Lapped, silver plated —
Within 2 μm
to 5 light bands |
From 12 μm
to 5 light bands |
≤10 μm |
Squareness
(edge to face) |
? |
No specification |
≤0.5° |
≤0.5° |
? |
| Surface finish |
0.9 μm
(35 micro‑inches) |
Standard, Polished
K-Schliff |
Standard —
≤3 μm
Lapped silver —
≤0.5 μm |
From 3 μm until 0.3 μm |
Standard —
polished (#800)
High cost —
polished (#2,000)
(before silver electrodes are
printed) |
| Roughness |
? |
≤1.6 μm (Ra – value) |
? |
|
? |
|
Notes:
- Data is mainly from Prokic, pp. 6‑9, 6.1‑1.
- TIR = total indicator reading
- 1 light band = 0.000294 mm = 0.294 μm with a sodium light source
- K-Schliff = technical grinding that creates only a flat surface without consideration of the visual appearance (AUTANIA GRINDING TECHNOLOGIES)
- Ra = Roughness, average
- #2,000 = zzz
- zzz See Prokic comments p. 6-10; my notes p. 6-16