Diamond Blade Select » Diamond Segment

Sandwich Diamond Segments of Diamond Blades

Hanjiang Wang — Tue, 08 Dec 2009 09:19:21 +0000

Earlier diamond segments of diamond circular blades were all designed to be even cuboids. Later, people found that, after a period of sawing, the two sides of the segments are easier to be worn than the middle, and the segments become a convex shape. The convex-shape diamond segments have a larger contact area with the material being cut, therefore the diamonds on them are easier to be ground blunt and then need dressing. In addition, as the sawing force will also increase, the core of the diamond blade tends to be distorted and be deformed for vibrations. This can influence the cutting precision, and reduce the blade core’s service life. Sandwich diamond segments, which have higher side layers and lower middle layers, however, can solve this problem to a great extent.

A Kind of Sandwich Diamond Blade

Sandwich diamond segments can be made via the following methods:

The diamond concentration in side layers is higher than the one in middle layers.
The bond material in side layers is more wearable than the one in middle layers.
The diamond’s grade in side layers is higher than the one in middle layers.
Make the working length of middle layers shorter than the one of side layers via structural designing.
Add non-working layers into the multi-layer structure, and adjust the width ratio of working layers and non-working layers.

Why Diamond Segments Have Different Shapes

Hanjiang Wang — Thu, 03 Dec 2009 04:08:45 +0000

The shape of diamond segments is an important factor influencing the performance of diamond saw blades. The different shapes are directly related to cutting efficiency and the ratio of the diamonds’ non-normal failure.

Currently, there are many kinds of shape diamond segments, for example, convex segments, layered sandwich concave segments, L-shape segments, step-shape segments, segmented segments and side-slotted segments.

Various Shapes of Diamond Segments

The designing for the shape and structure of diamond segments mainly has two purposes. The first is to increase the diamond blade’s capabilities of containing and discharging sawdust, and improve the cooling and lubricating conditions. The second is to reduce the friction between the segments and the material being cut as well as the sawdust, improve the blade’s cutting capability, and thus save energy and improve the blade’s performance.

As there are slots on the rim of diamond blades, the length of diamond segments also influences the blade’ performance. In sawing, the diamonds on the front of the segment, which enter the cutting arc earlier, bear more loads than the diamonds on the back of the segment. Therefore we can segment the diamond segments properly, so that the performance of the front end and the back end of a diamond segment matches the loads they bear.

Bond Materials Used In the Transition Layer of Diamond Segments

Hanjiang Wang — Tue, 24 Nov 2009 10:35:08 +0000

A diamond blade consists of a steel core and some diamond segments. In many cases, a diamond segment (especially for those diamond segments for laser welding) includes not only a working layer (containing diamonds for cutting), but also a transition layer. The transition layer has no diamonds, and is a pure bond layer which connects the working layer to the steel core of a diamond blade.

The transition layer should have good weldability. For if not, the diamond segment will fall from the steel core when receiving high alternating forces in cutting, and this may cause safety issues.

The bond materials used in the transition layer normally do not contain low melting-point metals, for example, Sn and Zn, for under high temperatures, these metals tend to be evaporated and gasified, and then produce air-holes. The transition layer often adopts Cu, Ni and some other alloy materials.

WC (tungsten carbide) can improve the wear resistance of the weld and the transition layer, but if its content is too high, welding defects such as holes and slag will be caused, and when this is serious, the transition layer may break. To solve this problem, a few Mn and Cr can be added. This will not only generate solid-solution-strengthening and increase wear resistance, but also reduce air-holes.

The compositions of the working layer and the transition layer should not be very different. Otherwise, the junction of the two layers will tend to break because of uneven heat and forces they receive when the diamond blade is sawing.

Some Knowledge of Diamond Segments

Hanjiang Wang — Tue, 17 Nov 2009 08:19:08 +0000

The valid working parts of metal-bonded diamond tools (e.g., the teeth of the common diamond blades) are normally called diamond segment, which is the sintered mixture of diamond grains and metal bond materials. Generally, diamond segments are made via the procedures of mixing diamond grains with bond materials, hot pressing and sintering, and arc grinding. They can be arc-shaped or rectangular.

Diamond segments have two basic functions. One is holding diamond grains; the other is wearing along with the diamonds’ wearing to let the new sharp diamonds be exposed properly. Besides having a certain hardness and wear resistance, the diamond segment’s bond should also be tough.

Diamond segments for laser welded diamond tools consist of a working layer and a transition layer. The working layer contains diamond grains for cutting or grinding, while the transition layer has no diamonds. It just consists of bond materials, and is used to connect (via welding) the working layer to the body of the diamond tool.