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D6261-14 – Standard Test Method Technical Guide
ASTM D6261-14 (Reapproved 2022) establishes requirements for extruded and compression molded basic shapes—plate, rod, and tubular bar—manufactured from thermoplastic polyester (TPES). This specification is designed for mechanical-grade plastic products used in fabrication of end items or parts, incorporating material, dimensional, and workmanship criteria with allowance for recycled plastics.
📐 Specimen Geometry and Conditioning
Specimens must be prepared and conditioned in accordance with ASTM D618, which defines standard conditions for temperature and humidity. Test specimens are machined from the basic shapes to conform to geometry requirements of specific test methods. For tensile testing per D638, specimens are typically dog-bone shaped; for flexural testing per D790, rectangular bars are used. Impact specimens for D256 are notched to standard specifications. Proper conditioning is critical for achieving consistent mechanical properties.
⚙️ Test Procedure and Speed Selection
Mechanical testing follows prescribed ASTM procedures. Izod impact resistance is measured using Test Methods D256 with notched specimens. Tensile properties such as strength and elongation are evaluated per Test Method D638, with testing speed selected based on material type. Flexural properties, including modulus and strength, are determined per Test Methods D790, with rate dependent on specimen geometry. Adherence to these procedures ensures reliable comparison of material performance.
📊 Key Measured Properties and Compliance
The specification outlines critical properties including tensile strength, flexural modulus, and impact resistance. These values are designated for the TPES composition, with classification according to Section 4. The standard allows incorporation of recycled plastics as defined in Guide D7209, promoting sustainable material use. Dimensional tolerances for plate, rod, and tubular bar are specified to ensure workmanship quality.
Table of Test Methods
| 🟦 Property | 📏 Test Method | 📐 Typical Units |
|---|---|---|
| Izod Impact | D256 | ft·lb/in |
| Tensile Strength | D638 | psi |
| Flexural Modulus | D790 | psi |
| Conditioning | D618 | 23°C, 50% RH |
Reference Standards for Classification
| 🟦 Standard | 📏 Purpose |
|---|---|
| D5927 | Classification for TPES based on ISO test methods |
| D4000 | General classification for plastic materials |
| D7209 | Guide for recycled polymeric materials |
💡 All property values are reported in inch-pound units per standard convention. SI units are provided in Table S-TPES for reference. Always condition specimens per D618 before testing to ensure valid results.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D6261-14? It specifies requirements for extruded and compression molded plate, rod, and tubular bar made from thermoplastic polyesters (TPES).
💡 Can recycled plastics be used? Yes, the standard allows use of recycled plastics as defined in Guide D7209 for waste reduction.
⚡ Which test methods are key for mechanical properties? Izod impact per D256, tensile per D638, and flexural per D790 are primary methods.
📌 How are materials classified? Using the classification system in Section 4, which specifies requirements for compositions and applications.