Diamond tools: types, purpose and operating rules

Recommendation points

• A Precious Tool: How It Works
• Types, purpose and scope of use
• Use with hand tools
• Diamond cutting on stationary equipment
• Processing modes
• Restoration of diamond edges

In terms of the efficiency of processing hard materials, synthetic diamonds have practically no competitors. In our review, we will talk about the types of diamond tools, the features of the choice, and most importantly, the processing modes and the rules for maintaining the edges in a fit for work condition..

A Precious Tool: How It Works

Physicomechanical processes accompanying the processing of various materials have one general tendency: the cutting body must have a hardness higher than that of the material being processed and move relative to it at a certain speed. When it comes to the processing of metals, wood and plastics, high-alloy steel or common abrasives such as silicon carbide or carborundum can be used as the processing material. However, when dealing with very hard materials such as granite or concrete, preference is given to substances with an unprecedented hardness – synthetic diamonds..

Like other types of abrasive tools, diamond has a scattering of microparticles with sharp edges, which are fixed in a layer of binder. As a rule, metal alloys with a high softening point are used as a binder. In the process of work, the tool loses part of the diamond chips, while the upper layer of the bond is melted and erased on the treated surface, exposing new particles with sharp edges.

There are a fairly large number of variations of diamond tools designed for cutting, grinding, milling and drilling. In this case, the spraying is located exclusively on the edges of the working edges. At these locations, the maximum cutting speed is achieved, which is an essential requirement for the correct operation of the diamond tool. This is associated with a specific drawback of this processing method – a high temperature in the contact zone, therefore, usually such work is performed with the supply of coolant.

Types, purpose and scope of use

Diamond tools have gained popularity due to the high efficiency of processing hard materials, the cleanliness of the processed surfaces, high accuracy and the ability to work with fragile products. Another feature is the variety of types of tools for performing highly specialized tasks.

The most widespread are diamond cutting discs for cutting stone and concrete. These consumables come in two form factors: split (segmented) lip and ribbed bezel. It is believed that a wheel with a split edge is better suited for dry machining due to the fact that the removal of dust from the cutting area by air flow through the slots is more efficient, while the presence of spiral tracks on a disc with a stepped rim is better for accelerating the coolant flow.

For grinding surfaces, diamond cups are used, on the working side of which there are protrusions, the surfaces of which lie in the same plane. On the one hand, this configuration reduces the contact area and, accordingly, reduces frictional heating. On the other hand, the air gaps between the segments facilitate effective removal of the removed material particles. There are several configurations of cup segments that do not have a fundamental difference, but differ in the efficiency of removing various waste material from the grinding zone.

As a rule, the base of the cups is rigid, but the so-called turtles are also quite common, in which numerous segments are fixed on a flexible base. There are a very large number of varieties of such a tool, differing in the composition of the bond, the size of the diamond grain and the configuration of the segments, and each individual type of turtles is designed to work with a certain type of stone with a strict limitation of processing modes.

Drill bits are the third widespread type of diamond tools designed for the production of bore holes in hard masses by the non-impact method. In the spraying zone, the bit has an effective diameter that is several millimeters larger than the outer dimensions of the nozzle, which creates a gap for dust removal and core extraction. The edge of the crowns can be segmented by analogy with cutting discs, which allows you to increase the speed of rotation of the tool and increase the productivity of drilling with an equal feed force.

Use with hand tools

The most important applied value of diamond tools is considered to be their use for processing stone products, dismantling concrete structures and manufacturing technological channels. For these purposes, it is optimal to use a hand-held power tool, taking advantage of high mobility at the expense of processing accuracy..

Not all hand-held grinding tools are suitable for diamond cutting tooling. Of the whole range of design requirements, there are two most important: the ability to adjust the spindle speed and the availability of devices for gripping with both hands. So, ordinary grinders cannot be used for grinding work, only special angle grinders with a developed front handle and speed control, in some cases a standard coolant supply device may be required. Cutting with grinders can be carried out, however, you should select segmented diamond discs in exact accordance with the speed of the tool. The fastening for all diamond consumables for hand tools is standardized: a 22.2 mm hole for discs and a 14 mm thread for cups.

For drilling, heavy hammerless drills or hammer drills are used, which have a mechanism for disabling the percussion mechanism. The power of the tool is selected in accordance with the diameter of the crowns, however, as a rule, at least 1.5 kW. Almost all diamond drilling equipment has a round or faceted shank with a thickness of at least 8 mm for clamping in a three-jaw chuck. When drilling, it is allowed to use abundant liquid cooling of the working area due to the considerable remoteness of the electric drive from it, however, the fluid must be supplied by the gravity method..

Diamond cutting on stationary equipment

The most technologically advanced method of using diamond tools is as machine tooling. This includes both heavy grinding and cutting machines and special installations with limited mobility. An example of the latter are road cutters designed for cutting asphalt concrete with discs over 400 mm in diameter and jigs for diamond drilling.

The main advantages of stationary equipment are high accuracy, which is provided by a rigid bed and an automatic feed mechanism, as well as the possibility of unlimited use of coolant. Thanks to these two circumstances, the service life of the edges and the cleanliness of the treated surfaces are significantly increased. It is impossible not to mention the increased convenience and safety: the operator of the machine is less tired due to the fact that there is no need to firmly hold the tool with both hands.

Stationary grinding machines can use diamond stones with a metal, ceramic and elastic polymer bond. As a rule, such a tooling is used for finishing the edges of a cutting tool or for fine processing of edges on products made of valuable rocks. In such cases, the hardness of the diamond grain is especially beneficial, because the removal of particles of tool steel or natural stone occurs without overheating the workpiece, and therefore without irreversible loss of its properties by the material..

Processing modes

Diamond tools are very demanding on the observance of processing modes: cutting speed, applied force, the presence of coolant in the processing area. Failure to comply with these requirements is practically guaranteed damage to the tool itself or the workpiece. However, it is not so difficult to learn the rules of work, for this you need to take into account only two circumstances.

The first is the need to ensure uniform wear of the edges, during which there is a gradual destruction of the bond and exposure of “fresh” diamond grains. If the required processing speed is not observed, the binder will melt, clogging the pores on the surface of the edges, this phenomenon is called salting. The edges can be renewed by evenly grinding them against a solid, hard material with an abrasive component, for example, ceramic bricks or a worn grinding wheel.

Another rule follows from the first one: any grinding or cutting tool is designed to process a certain list of materials in compliance with the modes and sequence of this processing. So, for discs and crowns, the manufacturer strictly regulates the rotation speed and feed force, and for cups and flexible stones – the number of steps for reducing the grain size, the presence of coolant supply, the ability to work on flat surfaces or edges. Therefore, only compliance with the rules regulated by the manufacturer guarantees the longest possible operation of diamond tools and high quality of products..

Restoration of diamond edges

As a result, it should be emphasized that diamond tooling can be both a consumable material (AGShK, plates) and calculated for long-term operation, as is the case with crowns and saw wheels. The composition of the binder and the fraction of diamond dust in some cases can be selected with the expectation of accelerated, but systematic shedding, that is, the work is performed not only by the grain fixed at the edge, but also by the crumbling fragments. In such cases, diamond tools are not very expensive and the only way to restore them is to eliminate salting using the method described above..

However, there is another class of equipment, which is characterized by increased strength, density and hardness of the bond material, as well as a specially selected fraction of diamond grain. As a rule, this applies to large cutting discs and crowns that experience significant operational loads. This tool is quite expensive and its complete replacement as it wears out is absolutely irrational. Instead, only the contact surfaces can be refurbished or replaced by specialized organizations. This is the optimal solution for professional wall sawing craftsmen, reducing depreciation costs by 2–3 times.