Abrasives Lesson 2: Flexing

by EMI Supply, Inc.
This article was published on Monday March 09, 2009.

Lesson 2

Flexing

Flexing is the controlled cracking or breaking, in one or more directions of the adhesive bond which holds the abrasive grain to the backing, with the aim of varying the flexibility and aggressiveness of the product.
This is accomplished by putting the abrasive web under tension and pulling it over a steel bar or using other mechanical operations.

The spacing and direction of the breaks must be controlled if the product is to meet the application requirements for which it is intended, such as:

- Conforming to workpiece contours;
- Shape control of the product in use;
- Control of grain breakdown to improve performance.


Competitive Flux Designations

Carborundum Abrasives

3M

Norton

90
45
Longitudinal (G or T)

Single Flex
Double Flex
"L"

Single Flex
Double Flex
"Q"




Three basic flexes are currently available:

1. Flex 90 - Flex lines or breaks are perpendicular to the edge of the belt or material. Provides flexibility in the lengthwise direction only.
2. Flex 45 - Flex lines are at a 45° (2-45° angle flexes) to the edge of the belt or material. Provides length-wise and crosswise flexibility.
3. Longitudinal Flex (G or T) imparts a uniform all-directional flex in the lengthwise direction.

All paper commodities – 45 flex
All cloth commodities – 90 Flex

On many operations where dulling and glazing of the abrasive occurs, increasing the amount of flex will often improve performance.
On most platen operations. better results are obtained by using more flex than normal especially on grit sizes 100 grit and coarser
Open coat products are inherently more flexible than comparable close coat products.

All flexes are not appropriate for all abrasive commodities and applications. Consult the Product Selection Guide for flexes that are available for the various products.



Questions on Lesson 2

1. A change in the flex of the belt used on a back stand operation will affect belt life:
a. Always
b. Usually
c. Never

2. The standard flex used on cloth single splice wide belts is:
a. 90
b. 45
c. Longitudinal

3. Flexing is the controlled breaking or cracking of the abrasive backing:
a. True
b. False

4. Competition is using double flex on an operation. The Carborundum Abrasives equivalent is:
a. 90
b. 45
c. Longitudinal

 

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