Valid

GB/T 7690.5-2013Reinforcements -- Test method for yarns -- Part 5: Determination of fiber diameter for glass fiber (English PDF)

增强材料纱线试验方法第5部分：玻璃纤维纤维直径的测定

Preview PDF

This is a limited preview

Buy now to download the full PDF (9 pages)

Need quotation for your management?

Get a formal quotation for GB/T 7690.5-2013 in 30 minutes.

Issued by

General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China

Level / Type

National · Recommended

Issue date

September 18, 2013

Implementation date

June 1, 2014

Scope

GB/T 7690.5-2013 is the English-translated version of 增强材料纱线试验方法第5部分：玻璃纤维纤维直径的测定.

GB/T 7690.5-2013 — This Part of GB/T 7690 specifies two test methods for the average fiber diameter (i.e., the average value of the actual diameter) in glass fiber products, namely the longitudinal method and the cross-sectional method.

This method is applicable to fixed-length fibers or continuous fibers in glass fiber products. The mean diameter must not be confused with the nominal diameter, which is used to name the yarn and its constituent materials. It is a rounded-off value related to the mean diameter.

Found what you need?

Document preview — GB/T 7690.5-2013

National Standard of the People's Republic of China

ICS: 59.100.10
Classification: Q 36

Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China

Foreword...3
1 Scope...5
2 Method A: longitudinal method...5
3 Method B: cross-sectional method...7
4 Results expression...9
5 Test report...9

Foreword

GB/T 7690 "Reinforcements - Test method for yarns" consists of 6 parts:

- Part 1: Determination of linear density;

- Part 2: Determination of twist;

- Part 3: Determination of breaking force and breaking elongation for glass fibre;

- Part 4: Determination of stiffness;

- Part 5: Determination of fiber diameter for glass fiber;

- Part 6: Determination of twist balance index.

This is Part 5 of GB/T 7690.

This document was drafted in accordance with the rules given in GB/T 1.1-2009.

This Part replaces GB/T 7690.5-2001 "Reinforcements -- Test method for yarns -- Part

5: Determination of fibre diameter for glass fibre". Compared with GB/T 7690.5-2001,

in addition to editorial modifications, the main technical changes are as follows:

- Changed the content of NOTE 1 in "Scope" to the main text (see Chapter 1 of this

Edition; NOTE 1 in Chapter 1 of Edition 2001);

- Deleted the two chapters "Normative references" and "Definitions" (see Chapter 2

and Chapter 3 of Edition 2001);

- Changed the minimum magnification of the microscope from "500 times" to "400

times" (see 2.2.1 of this Edition; 4.2.1 of Edition 2001);

- Added the method of removing the sizing from the fiber (see 2.3.1 of this Edition).

This Part uses translation method to identically adopt ISO 1888:2006 "Textile glass -

Staple fibers or filaments - Determination of average diameter". It made the following

modifications:

- Modified the standard name.

This Part was proposed by and shall be under the jurisdiction of National Technical

Committee on Fiberglass of Standardization Administration of China (SAC/TC 245).

Main drafting organizations of this Part: Nanjing Fiberglass Research and Design

Institute Co., Ltd., National Fiberglass Product Quality Supervision and Inspection

Center.

Reinforcements - Test method for yarns - Part 5:

Determination of fiber diameter for glass fiber

1 Scope

This Part of GB/T 7690 specifies two test methods for the average fiber diameter (i.e.,

the average value of the actual diameter) in glass fiber products, namely the longitudinal

method and the cross-sectional method.

This method is applicable to fixed-length fibers or continuous fibers in glass fiber

products.

The mean diameter must not be confused with the nominal diameter, which is used to

name the yarn and its constituent materials. It is a rounded-off value related to the mean

diameter.

2 Method A: longitudinal method

2.1 Principle

Fibers and monofilaments are immersed in a liquid medium with a different refractive

index. Their longitudinal profiles are observed under a microscope and their diameters

are measured.

2.2 Instruments

2.2.1 Microscope: equipped with the following:

- Eyepiece with built-in micrometer. The total magnification of the eyepiece and

objective lens shall be at least 400 times. 1000 times is preferred. The resolution

of the microscope shall be sufficient to measure values with an accuracy of at

least 0.5 µm (see NOTE);

- A stage that can be moved laterally and rotated;

- Lighting system.

NOTE: The system can be replaced or combined with a micro projector. A transparent ruler (arc

ruler is better) can be used to measure the specimen on the micro projector.

The recommended microscope is one that uses plane polarized light. It is equipped with

a Kohler light source illumination system and an Abbe condenser. A green filter can

Remove the mold. Use the saw (3.2.5) to cut a thin disc-shaped specimen (about 4 mm

thick) from the upper part of the molded body for testing under a microscope.

3.3.3 Positioning and centering of specimens

To facilitate the positioning of the specimen in the field of view, the magnification can

be lowered first, for example to 150 x. When the specimen is positioned, the

magnification can be increased and completely centered.

The end of the fiberglass will appear as a shiny disk.

Adjust the lighting to minimize the area of stray light around each bright surface, while

maintaining sufficient brightness to make the scale easy to read.

Adjust these bright disks to the micrometer scale.

3.3.4 Measurement

Move the stage so that one scale of the micrometer is tangent to a disk. Record the scale

number. Estimate the reading to the nearest half scale, which is equivalent to the

diameter of the disk.

NOTE: Elliptical surfaces may appear during measurement. These ellipses are caused by the fact

that the fibers in the sample are not all arranged in parallel and are obliquely cut during cutting. The

length of the minor axis in the ellipsoidal surface can represent the diameter of the continuous fiber.

Randomly measure 25 disks. Slightly move the stage during measurement so that one

scale of the micrometer is tangent to one disk in each measurement.

If 25 values cannot be obtained in this way, measure along another axis, avoiding

measuring the same fiber twice, until 25 measurements have been made.

4 Results expression

Calculate the arithmetic mean of the 25 measured values. Convert the arithmetic mean

into a value in micrometers (µm) based on the magnification factor of the optical system.

The result is rounded to 0.5 µm.

5 Test report

The test report shall include the following:

a) a statement of the method used in this Part and the method (A or B) chosen;

b) the necessary details to identify the yarn tested;

......

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 9 pages — is available in the English PDF.

Referenced standards

Cited by

How to Download GB/T 7690.5-2013

1
Add to cart
Click "Download PDF" on this page and choose "Buy this standard". You can add more standards before checkout.
2
Checkout
Enter your email and billing details. Payment is processed securely by Stripe (cards or bank transfer). Prefer bank details? Request a quotation (min. order $300).
3
Instant delivery (0–9 sec)
Delivery is automatic: within seconds of payment you'll receive an email with a secure download link. The link stays valid for 72 hours.
4
Invoice included
A tax invoice is attached to the confirmation email. Need a custom invoice? Contact us.