Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D5342-97 – Standard Test Method Technical Guide
ASTM D5342 – 97 (Reapproved 2007) defines a standard procedure for measuring the resistance to bending of paper and paperboard using a Taber-Type Tester in its basic configuration. This test method determines the bending moment required to deflect the free end of a vertically clamped specimen through a specified angle, providing a critical parameter for material characterization and quality control.
📐 Specimen Geometry and Testing Configuration
The test method specifies a specimen width of 38 mm (1.5 in.). The vertically clamped specimen is loaded 50 mm (1.97 in.) away from the clamp, and the bending moment is recorded when the free end is deflected 15° from its center line.
Some instruments may be equipped with ultrasensitive attachments or modified for shorter specimen lengths. For papers that are low in grammage or highly flexible, Test Method D5650 provides a modified configuration specific to the 0 to 10 Taber stiffness range. However, results from D5650 can differ by as much as 40 % from this test method, and such modifications must not be used when D5342 is explicitly specified.
⚠️ Critical Compliance: Modifications of the basic Taber-type instrument, such as those detailed in Test Method D5650, can yield results up to 40% different from the standard D5342 procedure. It is imperative to use the standard configuration when this test method is referenced.
⚙️ Test Procedure and Instrument Considerations
The fundamental instrument has been utilized for nearly fifty years. Historically a manually operated (crank-driven) device, modern improvements include replacing the manual drive with a constant speed motor, the addition of automatic data determination, and fully automated instrument (motor sequencing) operation. Regardless of the drive system, the principle of bending a defined specimen through a specific angle to measure the bending moment remains unchanged.
Adherence to standardized sampling and conditioning practices is mandatory. This standard references Practice D585 for sampling methodology and Practice D685 for conditioning paper and paper products. Terminology specific to the testing of paper and paper products is based on Terminology D1968.
| 🟦 Parameter | 📏 Specification |
|---|---|
| Specimen Width | 38 mm (1.5 in.) |
| Deflection Angle | 15° from center line |
| Load Distance from Clamp | 50 mm (1.97 in.) |
| Low Stiffness Range (D5650) | 0 to 10 Taber Stiffness Units |
💡 Tip for Instrument Operators: While motor-driven instruments improve reproducibility, users must ensure their equipment is correctly calibrated for the 15° deflection and 50 mm load distance to maintain compliance with the core method.
📊 Key Measured Properties and Applications
The test method directly measures the bending moment required to achieve the specified deflection. The resistance to bending is then calculated from this moment. The bending resistance of paper relates directly to performance in wrapping, printing, copy machine operation, and high-speed mechanical document handling.
| 🎯 Application | ⚡ Relevance of Bending Resistance |
|---|---|
| Wrapping & Packaging | Maintains shape and resists creasing under load during transport and storage. |
| Printing & Converting | Directly affects sheet feeding, registration accuracy, and overall stack handling on printing presses. |
| Copy Machine Performance | Critical for reliable jogging, stapling, and the mechanical finishing of documents. |
| High-Speed Document Handling | Ensures durability and minimizes jams during sorting, mailing, and archival processing. |
❓ Frequently Asked Questions
🔍 What is the primary scope of ASTM D5342?
This test method outlines a procedure to measure the resistance to bending of paper and paperboard using a Taber-Type Tester in its basic configuration. The bending moment required to deflect a 38 mm wide specimen 15° at a load distance of 50 mm is determined.
💡 What are the exact test specimen dimensions and geometry?
The standard requires a specimen width of 38 mm (1.5 in.). The specimen is clamped vertically, the load is applied 50 mm (1.97 in.) from the clamp, and the bending moment is measured as the free end is deflected 15° from its center line.
⚡ How does ASTM D5342 differ from ASTM D5650?
ASTM D5650 describes a significant modification of the Taber instrument for measuring highly flexible or low grammage papers (0 to 10 Taber stiffness range). Results from D5650 can vary by up to 40% from D5342, and its use is restricted when D5342 is specified.
📌 Which standards are referenced for sampling and conditioning?
Proper implementation requires adherence to Practice D585 for sampling a single lot of paper or paperboard, and Practice D685 for standard conditioning of paper and paper products prior to testing.