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D4987-99 – Standard Test Method Technical Guide
📐 Specimen Preparation and Handling
Careful handling of test specimens is essential to avoid weakening the perforation ties. According to Section 6.1 of the standard, folding and refolding a perforation must be avoided, as this can cause damage to the ties. The specimen should only be unfolded immediately before it is placed in the tensile tester jaws.
Section 6.2 highlights the need for precise alignment to prevent uneven stress. Misalignment can result in a tearing effect rather than a true tensile measurement, affecting the accuracy of the test. As noted in Section 4.1, the specimen size may be modified based on the material characteristics.
| 🟦 Interference | 📏 Precaution |
|---|---|
| Folding and refolding | Unfold just before testing |
| Skewed placement | Align specimen carefully in jaws |
⚠️ Avoid any manipulation of the perforation before testing to ensure accurate results.
⚙️ Test Method and Apparatus
The test method is based on ASTM tensile strength procedures, as per Section 4.1. The apparatus must conform to Test Method D828, which describes constant-rate-of-elongation tensile testing. Note that D828 has been withdrawn, but its last approved version provides the necessary specifications.
Specimens should be conditioned in accordance with Practice D685 before testing. Sampling procedures should follow Practice D585, and sample size can be determined using Practice E122. Terminology is defined in D1968 and the Dictionary of Paper.
| 🟦 Standard | 📐 Description |
|---|---|
| D585 | Sampling of paper products |
| D685 | Conditioning for testing |
| D828 | Tensile apparatus (withdrawn) |
| E122 | Sample size calculation |
| D1968 | Terminology for paper |
💡 Calibrate the tensile tester per D828 to ensure reliable and repeatable results.
📊 Significance and Use of Results
The tensile breaking strength of perforations is crucial for forms performance. Section 5.1 emphasizes that minimum strength is needed to prevent premature breakage during printing and converting operations. Conversely, Section 5.2 notes that maximum strength is required for easy detachment when the parts are separated for further processing. This test method provides quality control for these properties.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D4987?
This standard covers the tensile breaking strength test for perforations in one-part continuous forms paper.
💡 How should specimens be handled?
Avoid folding and refolding; align carefully in tester jaws to prevent tear effects.
⚡ What equipment is required?
A tensile tester meeting D828 specifications, with conditioning per D685.
📌 Why are minimum and maximum strengths important?
Minimum prevents breakage during handling; maximum allows easy detachment for processing.