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D3787-16 – Standard Test Method Technical Guide
📐 Scope and Referenced Documents
This standard, designated D3787 – 16 (Reapproved 2020), specifically covers the measurement of bursting strength for textiles and garments that exhibit a high degree of ultimate elongation using a Constant-Rate-of-Traverse (CRT) ball burst strength tester. Values are provided in SI units and inch-pound units, which must be regarded separately and used independently.
This method is closely related to other burst testing standards within the ASTM D13 committee. Understanding the landscape of these standards is essential:
| 🟦 Designation | 📏 Title | 📐 Relevance |
|---|---|---|
| D76 | Specification for Tensile Testing Machines for Textiles | Machine calibration & construction |
| D123 | Terminology Relating to Textiles | General textile terms |
| D1776 | Practice for Conditioning and Testing Textiles | Standard conditioning procedures |
| D3786 | Diaphragm Bursting Strength Tester Method | Alternative hydraulic method |
| D4850 | Terminology Relating to Fabrics and Fabric Test Methods | Fabric-specific terminology |
| D6797 | Constant-Rate-of-Extension (CRE) Ball Burst Test | Alternative CRE method |
⚙️ Apparatus and Test Method Summary
The specific apparatus configuration for D3787 utilizes a CRT tensile testing machine fitted with a specialized ball burst attachment. The standard provides precise specifications for the setup and execution of the test.
| 🟦 Component | 🎯 Key Specification |
|---|---|
| Machine Principle | Constant-Rate-of-Traverse (CRT) |
| Specimen Clamping | Grooved, circular plates |
| Plate Mounting Location | Pulling (movable) jaw |
| Specimen Tension at Mounting | Clamped securely without tension |
| Bursting Member | Polished, hardened steel ball |
| Ball Mounting Location | Pendulum-actuating (fixed) clamp |
| Test Action | Force exerted by the ball against the specimen until rupture |
💡 Tip: The standard explicitly states the specimen must be clamped without tension. Introducing tension during clamping can alter the force distribution on the fabric and lead to premature failure or inaccurate bursting strength readings.
The procedure involves driving the pulling jaw at a constant traverse rate, forcing the clamped specimen against the polished steel ball mounted on the pendulum-actuating clamp. The force required to rupture the fabric is recorded as the bursting strength.
📊 Significance and Industry Use
The primary property measured is the bursting strength of a textile fabric. This method is widely utilized in the textile industry for evaluating a variety of fabric types, particularly those with high stretch such as knits and nonwovens. According to the standard, this test method is considered satisfactory for acceptance testing of commercial shipments, given its extensive use in the trade for this purpose.
⚠️ Important Distinction: CRT vs. CRE
Constant Rate of Traverse (CRT) machines and Constant Rate of Extension (CRE) machines have been shown to provide different results. When using a CRE device, users must strictly refer to Test Method D6797 rather than this standard.
❓ Frequently Asked Questions
🔍 What types of textiles are best suited for this test?
This test method is specifically designed for textiles or garments that exhibit a high degree of ultimate elongation, such as knitted fabrics, nonwovens, and certain stretch-woven materials.
💡 How does the CRT Ball Burst Test differ from the Diaphragm Bursting Strength Tester Method (D3786)?
Test Method D3787 (CRT Ball Burst) uses a polished steel ball attached to a pendulum-actuating fixed clamp on a constant-rate-of-traverse machine. Test Method D3786 (Diaphragm Method) uses a hydraulic diaphragm to apply force against a larger area of the fabric, utilizing a completely different expansion principle.
⚡ Is this test method suitable for acceptance testing?
Yes, Test Method D3787 is specifically described as satisfactory for acceptance testing of commercial shipments of textile fabrics for bursting strength, as it has been extensively used in the trade for this purpose.
📌 Can I use a Constant-Rate-of-Extension (CRE) machine for D3787?
No. The standard explicitly notes that CRT and CRE machines provide different results. When a CRE machine is used, the user must follow Test Method D6797, which is the specific companion standard for CRE ball burst testing.