About Cutting

Depending on the size or shape of a piece of material, it may need to be sectioned. A plane surface, with as little deformation as possible, is required to facilitate and expedite further preparation. Consequently, the most appropriate sectioning method is abrasive wet cutting, which will introduce the least amount of damage in relation to the time needed. Note: The sample taken must represent the features of the parent piece from which it is cut.

Gatan offers a complete range of machines for cutting materialographic samples - from high-capacity cutting of very large workpieces to precision cutting of even the most delicate specimens. The program of cut-off equipment covers all material and capacity requirements, including both automatic and manual machines.

Abrasive Wet Cutting

Abrasive wet cutting employs a cut-off wheel consisting of an abrasive and a binder. Cooling liquid flushes the wheel to avoid damaging the sample with frictional heat. The coolant also removes debris from the cutting area.

Choice of Wheel

Depending on the material to be cut, wheels of different composition may be needed. The hardness and ductility of the material influence the choice of cut-off wheel. Ceramics or sintered carbides are sectioned with diamonds in either a metal or a bakelite bond. For ferrous materials, aluminum oxide (Al2O3) in a bakelite binder is typically used. Cubic boron nitride (CBN) is also increasingly used for the harder types of ferrous materials. Non-ferrous metals are cut with silicon carbide (SiC) in bakelite.

Design of Wheel

Apart from the abrasive particles, the basic difference between diamond/CBN wheels and SiC/Al2O3 wheels is the design. The diamond/CBN wheels have long-lasting performance due to the extreme hardness of the abrasive particles and the durable binders used to hold these particles in place. Only a thin layer of abrasive is placed on the circumference of a metal disc (continuous rim). These are long-term consumable wheels. The other abrasives, SiC and Al2O3, wear faster and are less expensive. Therefore, the complete body of the wheel consists of abrasive and binder. These are called consumable wheels.

Wheel Characteristics

	Long-term consumable wheels
	Diamond wheels are available in two variations, with different binders for the abrasive particles - wheels with a metal bond and wheels with a bakelite bond. Both are used for cutting extremely hard materials. The metallic bond is used for the more brittle materials, such as ceramics. The bakelite bond is used to cut materials like sintered carbides. CBN wheels are available only with a bakelite bond, and are used for cutting very hard ferrous materials, like white cast iron.
	Consumable Wheels
	The cutting characteristics of these wheels vary with the properties of the bond. Binders can be classified according to their "hardness", or their ability to retain or discard abrasive grains. "Hard" wheels retain the abrasive grains better than "soft" wheels. The "soft" wheels are used to cut hard, brittle materials because new, sharp abrasive grains are supplied continuously as the softer bond breaks down. Wheels with a harder bond should be used when cutting soft and ductile materials. In addition, wheels with a harder bond are more economical because they wear slower.

The correct choice of cut-off wheel for a specific material is highly important. Only the proper wheel ensures low deformation and a plane surface. A better surface after cutting allows you to obtain the required preparation result faster.

Cutting Products

Cutting Consumables

Selection of Cut-Off Wheels (Download)

Distributed in the U.S., Canada and China for Struers.