Cutting disc (tool)
A cutting disc is a circular flat disc made of special material, which is usually used as a component of a cut-off or angle grinder for workpiece machining. In contrast to the planar removal of the similarly designed grinding wheel by fine chip removal , the considerably thinner cutting wheel is mostly used for cutting material removal along a line, preferably for separating material sections. Cutting discs are not suitable for roughing . Cutting discs are available for a wide variety of materials, such as metal , natural stone , asphalt , concrete , etc. Cutting discs are divided into two main groups: synthetic resin- bonded cutting discs and diamond cutting discs.
Resin-bonded cutting discs
In the case of synthetic resin-bonded cutting discs, a mass is mixed from various raw materials such as normal corundum ( aluminum oxide ) or special corundum for metal cutting discs , silicon carbide for stone cutting discs, as well as fillers, powder resin and liquid resin, which are then pressed in special machines into cutting discs of various thicknesses and diameters. In order to withstand the enormous centrifugal forces, fiberglass fabrics are embedded in the actual abrasive . Because this layer of fabric is typically on the outer surface, cutting disks cannot be used as grinding disks either, since the early wear of the fabric would then no longer provide sufficient stability.
Dimensions of synthetic resin-bonded cutting discs: The most common diameters are 115, 125, 180 (178), 230, 300 and 350 mm. However, there are also smaller and larger discs in a wide variety of dimensions. Discs 115-230 mm in diameter have a 22.23 mm (7/8 ") diameter hole. The thicknesses vary from 0.75 mm (only up to 125 mm diameter) to "thin" slices with 1–1.6 mm (up to a maximum of 178 mm) for fast, light, burr-free cuts up to the usual, more resilient 3 mm thick Discs.
Due to the strong centrifugal forces, the manufacturer must comply with various safety standards that are regulated in the standards EN 12413 and EN 13236.
Cutting discs are also available specially for stainless steel, INOX & metal, steel. This means that you no longer need 2 different cutting discs for steel and stainless steel, but only one cutting disc.
Diamond cutting discs
With diamond cutting discs (exclusively for use in natural stone, concrete, asphalt, but not in metal - except for a few special types), diamond segments are applied to steel stems by sintering , soldering or laser welding :
- Sintering: The segments are sintered in a single operation using high pressure and temperature (heated to just before the melting point) and connected to the core blade.
- Soldering / hard soldering: Application of the diamond segments with silver solder. Soldered diamond discs can only be used for wet cutting, since without water cooling the solder can melt and the segments would peel off.
- Laser welding: The best connection between the diamond segment and the blade, as the segment is welded directly to the blade. A segment loss is practically impossible with this method.
To produce the diamond segments, various metal powders are mixed with (mostly) industrial diamonds and sintered in special press molds at great heat and high pressure. The metal powders melt and combine with the diamonds. The segments are then deburred and then applied to the stem blades. The type of metal powder, the diamond content and the diamond quality, as well as the type of connection between the segment and the blade, determine the quality, the cutting ability and the service life of a diamond cutting disc. In order for diamond cutting discs to withstand centrifugal forces and loads, the manufacturer must adhere to the safety standard that is regulated in the EN 13236 standard.
Shapes of diamond cutting discs
There are different types of diamond cutting discs:
- with closed, smooth edge (full edge) for fine and clean cuts in tiles and ceramics
- with closed, fluted edge (turbo edge) for quick cuts in old concrete, marble , clinker , sandstone , granite and other materials
- with segmented edge, d. H. with either smooth or corrugated segments on the side (the latter are also called turbo segments), for quick cuts in concrete and generally hard or abrasive (e.g. screed) construction site materials
- a special form is used for high-precision cutting of inner holes . Here the abrasive grain is applied galvanically.
Structure of a diamond cutting disc
So-called segments with embedded industrial diamonds are connected to the metal body (so-called main blade) of the diamond cutting disc , which enable a higher cutting performance than conventional cutting discs. In the case of high-quality panes, this connection is welded with the laser ; there are also brazed or sintered panes.
An arrow indicating the direction of rotation is affixed to the cutting discs, indicating the direction in which the discs are rotating. If the cutting disc is installed in the opposite direction of rotation, the diamonds in the metallic binders are quickly ground free and can fall out. The cutting effect is lost. The diamonds in new diamond cutting discs are i. d. Usually sharpened before delivery, this enables ideal cutting performance immediately.
Working with diamond cutting discs
With conventional diamond cutting discs in the lower and middle quality segment, a cooling break must be observed. This required cooling time is indicated on these products. In professional use, special cutting discs that do not require a cooling break are more often used. Certain aggregates in the metallic bond as well as a special laser weld seam that connects the segment with the master blade enable a more efficient way of working.
A high-quality diamond cutting disc is not only characterized by its cutting performance (ease of cutting, efficiency and service life). Fatigue-free work and reduced noise development are essential in daily use. The noise pollution is reduced by using perforated master blades. Nevertheless, it is advisable to use soundproofing equipment and respiratory protection measures when dust is generated.
Dimensions of diamond cutting discs
The diamond cutting discs are from 60 mm to 5000 mm outer diameter available (for angle grinders , joint cutter , table saws , multi-blade saws or wall saws ). The inner bore is i. d. R. 22.23 mm for angle grinders and 20 mm, 25.4 or 30 mm for table saws and floor saws. For professional applications in the natural stone industry, larger mounting holes, e.g. B. 60 mm and 100 mm common.
Recording, connections
Miniature cutting disks with a diameter of about 30 mm have a hole for an M3 screw with which the disks are screwed on the front side to a mandrel for mounting in a three-jaw chuck.
100 mm washers usually have a 16 mm bore (5/8 ″ = 15.875 mm) and are clamped onto the flange with an M10 clamping nut.
With cordless machines for 100 mm, there is the SDS PRO or “Bosch hub” attachment on which disks with triple riveted sheet metal hubs with 3 slots around and 3 grooves in the 22.23 mm hole fit. The cranked sheet metal hub with an outer diameter of 58 mm enables tool-free assembly / disassembly.
Cutting disks for stonemasons can often be clamped (as well as cranked grinding discs) without protruding parts on the outside, so that protrusions can be cut off flush even from larger surfaces.