Diamond drilling, manufacturing of niches and openings

Recommendation points

• Diamond drilling technology
• Tools and fixtures
• Selection of diamond core bits and accessories
• Technique and methods of work, tasks performed

A number of specific tasks in construction can be solved only with the use of advanced technologies. In this article we will talk about the technology of diamond drilling, consider the basic drilling techniques by hand and with the use of a boom frame guide.

Diamond drilling technology

Many people know firsthand about the problems that arise with drilling or drilling reinforced concrete walls. State-of-the-art tools offer a complete alternative to impact punching, eliminating noise, dust and vibration.

Diamond wall drilling technology involves the use of hollow core bits with a cutting edge containing particles of synthetic superhard carbon. The crown is driven by an electric or hydraulic motor. Manual execution of the drive device is possible, but a guide bed is used much more often.

The main application of diamond drilling is the manufacture of cylindrical holes for laying all kinds of communications. The compactness of the drilling rigs allows them to be used in small rooms and with a high architectural complexity of supporting structures. Hard mineral inclusions and reinforcement in concrete do not impede drilling.

Tools and fixtures

For manual diamond drilling, special electric drills are used. Their cost starts at $ 500, the simplest and most inexpensive models, such as the Eibenstock END 1300 P, are designed for crowns up to 41 mm. They have a number of special functions for diamond drilling: water supply to the spindle, soft start and speed control up to 2000–2600 rpm. The more expensive tool has a higher power and therefore a larger drilling diameter. The main disadvantage of the manual method is that it is impossible to accurately start drilling without a centering device or to make a hole at an angle. Of the distinctive features of these drills, one can single out special cartridges for core drills, which are unified by many manufacturers. For example, the Bosch GDB-1600 diamond drill uses the SDS-DI chuck, which is practically not found anywhere else..

Drills can be used as part of a professional drilling rig. They are attached to a bed with a smooth feed device or used as a power unit in a vertical drilling machine. The simplest beds have a cost of $ 300, more expensive options are designed for drilling holes at an angle and automated longitudinal feed.

A separate segment of the market is occupied by diamond drilling rigs, which are used to conduct work on an industrial scale. High power motors, including asynchronous three-phase and even hydraulic motors, cope well with high loads when drilling holes up to 500–600 mm deep. Most installations have a built-in adjustable level, graduated tilt scale, dosed water supply to the working body. The cost of cars of this kind starts from $ 1000 and above.

On sale, you can often find diamond drilling rigs and drills that have already been used. Often this is the best purchase option: such a tool cannot cope with production volumes and rates, but they are suitable for domestic use.

Selection of diamond core bits and accessories

The two main varieties of core drills are wet and dry. The main difference lies in the way the carbon abrasive is soldered, so using the crowns for other purposes will almost certainly disable them..

It is better to buy a bit from the manufacturer of the drilling rig so that the shank matches the type of chuck. Although it is possible to use all kinds of adapters, this can significantly reduce the quality of drilling and cause some difficulties..

When choosing, it is important to pay attention to the material of the crown body. It should be high quality alloy steel that has passed ultrasonic and X-ray flaw detection. Feel free to ask the seller about this: a poor quality case will deform after just a few load applications. Or check it yourself: hang the crown on a thread and hit it briefly with a metal object – the ringing should be heard for 3-4 seconds with uniform attenuation.

The working edge of the bit is called a matrix; it looks like teeth made of a metal polymer, including a scattering of small diamonds. Depending on the type of material to be processed, a distinction is made between hard and soft matrices. Solid is used for drilling low-strength materials: brick, foam block, cement screed. When drilling concrete or marble, diamonds quickly dull, so they use a soft matrix, the surface of which is just as quickly renewed.

Cold galvanization is often used to connect the matrix to the housing. This is the cheapest method and is common among Chinese manufacturers. But matrices with such a connection wear out faster and poorly withstand high loads. Higher quality and more expensive drills have a matrix-to-body connection by laser welding or silver soldering.

You can also purchase accessories: extension rods, centering devices and replacement modules for restoring crowns.

Technique and methods of work, tasks performed

Crowns of small diameters (8–22 mm) are mainly used for drilling fastening holes in conditions where the use of impact perforation is impossible. Bits with a diameter of 40, 60 and 80 mm are actively used for the manufacture of socket niches, where the high drilling accuracy justifies the wear of an expensive tool. The described methods are performed mainly by manual drilling without water supply.

Diamond drilling solve the problem of the passage of communications through thick layers of monolithic materials. This technique requires the use of a frame guide, which is anchored directly to the wall near the drilling site. By adjusting the guides, the desired position of the crown and the angle of inclination are set, and the longitudinal feed handwheel allows the crown to be smoothly deepened at a speed of 2 cm / min. This ensures minimal wear of the dies and high precision of the holes made..

For the manufacture of niches and openings, diamond cutting of concrete is used, although in the absence of this, diamond bits of large diameters can be used. The presence of a guide bed allows drilling holes even with an overlap. Diamond drilling is considered the most productive way of extracting material in monolithic structures. After drilling, the core is easily cleaved and removed, if necessary, diamond wall cutters are used to make the hole rectangular.

The drilling technique itself is quite simple: a slowly rotating bit is smoothly fed to the material until the first engagement, then in several stages the penetration depth is gradually increased until an annular notch is formed of 2-3 mm. Then the centering rod is removed and the hole is drilled at the speed and feed recommended for the bit.

It is noteworthy that after diamond drilling of holes of even very large diameters, the structural strength of structures is not violated, therefore this method is indispensable for working on load-bearing walls or foundations.