Lumbered D Bars
These are typical specifications for single crystal cultured quartz material grown on a Z-plate seed and lumbered so as to simplify the cutting of wafers for the family of doubly rotated crystals operating in the thickness shear mode. The additional rotation is about the Z-axis and is designed to reduce the effects of stress on resonant frequency.
Lumbered D Bars are manufactured such that doubly rotated blanks are easily obtained when the D-bar is wafered using procedures similar to those used to fabricate AT-cut blanks. The φ - rotation (i.e. the first, or X to X´, rotation), nominal values of which are typically around 22° for bars used to make SC-cut blanks and 19° for IT-cuts, is provided as shown. The θ - rotation (i.e. the second, or Z to Z´, rotation) is delivered when the bar is wafered, the primary difference between AT wafering and this θ - rotation being a slight reduction in the cutting angle.
Typical Specifications
Mechanical Characteristics
| Description | Units | Typical Values | Tolerance |
|---|---|---|---|
| X-height x Z-width | mm | 13.3x12.7 | ± 0.13 |
| 16.5x15.2 | ± 0.13 | ||
| 17.8x16.5 | ± 0.13 | ||
| Y´-Iength | mm | 63.5 | + 2.5, -0 |
| Orientation of X´-surface @ Z-axis | degrees | 0 | ± 15 minutes |
| Orientation of Z-surface @ X´-axis | degrees | 0 | ± 15 minutes |
| @Y´-axis | degrees | 0 | ± 15 minutes |
| Flatness of -X´ lumbered surface | mm | Flat | ± 0.1 |
| Surface finish of -X´ lumbered surface, Ra | µm | 4.0 | maximum |
| Dimensions above are standard. Other dimensions are available to meet customer specific requirements. | |||
Material Characteristics
| Handedness | Right | ||||
|---|---|---|---|---|---|
| Infrared α (3500 cm-1) | α - units | Grade B: 0.045 | maximum | ||
| Grade ll | Grade l | ||||
| Inclusions (diameter) | 25 - 75 µm | cm³ | 5 | 4 | maximum |
| 75 - 100µm | cm³ | 4 | 2 | maximum | |
| >100µm | cm³ | 3 | 2 | maximum | |
| Etch Channels | cm² | Grade 4 : 300 | maximum | ||
| Twins and Cracks in Useful Volume | Count | None | |||
Seed Characteristics
- Pure - Z, seed free material
Marking and Packaging
- Supplier logo, grind lot number, part number and "Minus X" are marked on the minus-X surface of each bar. Reference Z-surface is marked "Z reference".
- Bars are shrink-wrapped to cardboard backing and stacked within double walled cardboard boxes.
- Total piece count, net weight, gross weight and part number are marked on the exterior of the carton.
References
International Electrotechnical Commission Standard, CEI/IEC 758, Second edition, 1993-04.
Institute of Electrical and Electronic Engineers Standard on Piezoelectricity, ANSI/IEEE Std. 176-1987.