Industrial diamond tools – the origin, significance in industry and the latest types available today
Origin of diamond cutting tools
Diamond is the most sought gem in the world and is widely used in jewelry. However, it is also the hardest known substance to man on earth. Made purely of carbon element, the tetrahedron structure of it makes it highly resistant to wear and tear and thus makes it suitable for the industrial cutting and grinding purposes.
The earliest use of diamonds in cutting and grinding around the world –
The use of diamonds in the cutting, grinding and polishing applications started much before and there are evidences to the same from different parts of the world. The earliest mention of diamond comes from Indian sub continent where the Sanskrit texts speak of the same as ‘vajra’. 4th century BCE offers evidences gathered through the archaeological findings and these talk of vajra as a valued material!
In the famous compilation – ‘Arthashastra’that belongs to the Mauryan times in India, Kautilya, its writer has described a diamond as ‘a big and heavy symmetrical substance that is capable of scratching the surface and shines brilliantly.’
Chinese chronicles from past have also described diamonds for cutting and engraving purposes. Their references ‘kun wu’ or ‘kin kang’ relate to diamonds as tools for cutting jade (a semi precious stone) and for drilling the holes or grooves in beads.
Pliny has offered evidences of diamond use in Europe as early as 100 CE. He has talked of diamonds as substance with greatest value among all human possessions while ‘adamas’ (diamond) is also much demanded by the engravers due to its hardness characteristics.
Such references point to the applications of diamonds in the industrial ambiences where artisans and skillsmen learned the use of it towards the desirable cutting and grinding purposes. This is analogous to the diamond grinding wheels and other diamond cutting tools of age. Thus it can be said that the cutting/grinding attributes of diamond on account of its extreme hardness was well known and diamonds were not merely used as gems. The modern industry today has adopted more refined forms of diamond tools and grinders for whole range of purposes. In many instances, the tasks could be economically accomplished through diamond tools alone because the other variants like corundum and silicon carbide prove to be much inferior along multiple dimensions of high relevance.
Diamond being the hardest substance on earth is capable of cutting and grinding other surfaces with high efficiency. Such use has continued since the earliest times, the evidences of which are discussed above. The modern industrial uses of diamond have been accomplished through the high quality and dedicated cutters and grinders whose functional parts are studded with the diamonds in order to improve the efficiency. The advantages of such diamond tools are actually derived from the attributes of diamond. Here are the notable characteristics of diamond that make it the preferred choice in industrial cutting tools.
- High cutting and grinding efficiency
Extreme hardness of diamond delivers high grinding efficiency. The tool surface that is studded with diamonds is able to cut and grind the surfaces effectively and with high precision because diamond offers stiff resistance against the substrate surface that is being worked upon by the tool. The diamond tool surface bears the force of grinding effectively for longer times and delivers sharp cutting and grinding in the surfaces of diversity. A practical corollary of diamond’s hardness is also that the substrate surface suffers clean, sharper and well maneuvered cutting/grinding, thus delivering finesse in results.
- Low force of cutting and grinding
Low grinding force is required during cutting or grinding with the diamond tools. This is again derived from the extreme hardness of the diamond which is a symmetrical tetrahedron crystal. The hard diamond impacts the substrate surface through its symmetrical structure which is highly wear resistant. This ensures that cutting and grinding is achieved precisely with less force of impact. Through the diamond cutting tools, the task is achieved with less number of impacts also.
- Low friction coefficient
The force of friction that is produced between the diamond tool surface and the substrate surface is much less as compared to other tool options like silicon carbide and corundum. There is much significance of this low friction coefficient in industrial applications. High friction also means the generation of too much of heat which is considered undesirable; because excess heat can alter the characteristics of the work piece that is being worked upon. The alignment of atoms in metal surfaces gets changed and this changes the strength and brittleness also! In non metal surfaces, excess heat can lead to the burn out of the external surface and thus destroy the shape and superficial attributes of the workpiece. In some cases such undesirable effects can also lead to the work piece getting useless!
- High durability
Diamonds being super hard substance are highly wear resistant and does not loose dimensions or suffer any kind of chipping in surface even after prolonged use at the surface of cutting and grinding tools. This attribute makes diamond tools highly durable as compared to the corundum and silicon carbide tools where the surface suffers easy damage and needs to be replaced after some time. Diamond surface tool can be used for very long time without replacement.
- Low cost of production (of workpiece)
The workpiece or the part that is being worked through diamond cutting and grinding does not require frequent replacement of the tool blade which is highly wear resistant. This reduces the cost of production per piece and hence ensures the much sought factor of economy in industrial ambiences.
4 most important uses of diamond tools
Cutting with diamond tools is very common now because these allow working on whole range of surfaces and achieve fine cutting with high precision and sharpness. The extreme hardness characteristic of the diamond makes the tool surface very effective for impacting other surfaces. Cutting tools are generally developed as rotating diamond wheels that are driven through high speed electric motors. The diamond wheel has a sharp edge that cut through the surface without suffering any wear or tear. Single point diamond dressers are also used for programmed cutting operations in industry applications. The high hardness and the tetrahedron structure allow the diamond to deliver high level impact and thus cut through the surface easily. Saw cutters are also available in market that perform as high speed bands that rotate through the electric motors.
Diamond tools manufacturers add the maneuvering functionalities to allow high level of customization and precision in the result. Thus the diamond blades and saws can be manipulated for different and desirable angles and planes as per the requirement of the task.
Grinding is yet another important application of diamond tools. These tools grind various surfaces to generate desirable shape and dimensional attributes. The ability to grind any surface is a result of the hardness of the diamonds that impact the edges and deliver clean and precise removal of the material. Multipoint diamond dressers and Diamond grinding wheels are available that allow fine shaping and material removal. The bonding material is also a significant determinant in the development of grinding and polishing applications because the rate at which the new diamonds surface is available is actually determined by this material.
Polishing is a refined task that is well accomplished by diamond tools. These tools are developed as abrasives which rub against the substrate surface and remove the inconsistencies in the plane. As the size of the diamonds used in the tool decreases a better polish is achieved. Highest level of polishing delivers quality shine to the surface like the marble and granite floor finish.
Drilling task is also being done with diamond tools that are developed in a dedicated manner suiting the particular requirement. The drilling bits are loaded with diamonds at the frontal surface which make the linear movement easy as the drill cuts through the surface. Diamond drilling is being done in high intensity applications only where the ordinary drilling proves ineffective or expensive.
Industries where diamond tools are used
Diamond tools are being used in large numbers of industries around the world. In fact, the entire manufacturing sector relies on the diamond cutting, grinding, polishing and drilling tools in one or the other manner. The industries that work upon metals are the major users of the diamond tools. The last few decades have seen the manufacturing processes making transitions to the diamond loaded precision looms and the advantages that drive the industries for such transition have been discussed above. These benefits have been further strengthened through the high level of customization that the diamond machines offer. Most such tools and machines are custom made towards a specific purpose in the manufacturing line. Here are the prominent industries that utilize the diamond tools –
- Aerospace–in aerospace sector, diamond tools are being used upon composites like honeycomb composites as also the reinforced plastics. Titanium and molly are also worked through these tools.
- Automotive–the diamond tools manufacture engine, body parts and suspension apart from brake, rubber tires and steering.
- Electronics–these tools make semiconductor based PCB, ceramics and glass substrates and ferrites, magnetic and quartz crystal
- Medical–high precision surgical implements, customized dentures and dental implants and prosthesis are made from diamond tools
- Construction and allied materials sector–cutting and grinding tasks are being done while marble and granite polishing is being also done.
- Gems–precious and semi precious stones are being cut, ground and polished with the high quality diamond tools
- Reinforced plastics –for thermoset resin materials, corrosion resistant materials, cultured marble types
- Fiberglass–fiberglass reinforced plastics and composites
- Ceramics–carbon and graphite products, lavatory, glass and ceramics products
- Tool parts –carbide tools, molding dyes, bearing, pneumatic and hydraulic valves, jigs
- Food processing equipments –for making super fine and high precision knife blades and scissors
Different types of diamond tools
Diamond tools are generally made by fixing the diamonds (natural or synthetic) at the surface of moving tools so that viable applicative concept is developed that could be utilized in different orientations of manufacturing and other industries. The method of developing the diamond tools may differ due to many factors and one among them is the bonding material that fixes the diamond grains onto the tool surface. The surface area covered by the diamond grains is also a factor. Diamond tools manufacturers offer the following types –
The metal bonded tools– these include sintering the even mixture of metal powder and diamond grains on to the tool surface. Powder metallurgy methods are used to achieve this.
The resin bonded tools– these diamond tools are manufactured by mixing the diamond grains and resin powder and then pressing (hot or cold) on the tool surface and then doing mechanical processing.
Diamond plated tools–by making use of electroplating or the CVD (chemical vapor deposition), the tool surface is coated with one or several layers of the mixture that evenly contains metal powder and diamond grains.
Ceramic bonded tools–diamond grains mixed with glass or ceramic powder are pressed on the surface and then sintered and mechanically processed.
Poly crystalline diamond or PCD–numerous micro sized diamond grains are sintered individually in a disordered way on the surface through application of high temperature and pressure.
Poly crystalline diamond composite or compacts–cemented carbide is used to combine various layers of PCD through high temperature and pressure.
High temperature brazed diamond tools– a layer of diamond grains is brazed through soldering process at temperature as high as 900 degrees Celsius.