Machining ceramics, a material extensively used in daily things ranging from clocks and knives to bricks and pottery, can be a terrific method for a company to increase its materials range. Machining them may be a valuable activity that offers your machine shop a distinct marketing advantage. Still, they are typically manufactured utilizing a kiln as the manufacturing method.
Ceramics are classified as a material type that can be machined into many different shapes but may be challenging. However, they have a one-of-a-kind appearance and texture and a high level of compressive endurance (albeit a lower level of tensile force endurance). They may serve as an adequate foundation for a variety of goods. In addition, they are pretty durable.
Ceramic Materials Being Processed Via Machining
Ceramics previously sintered might be a hurdle when subjected to CNC machining. These treated and hardened ceramics may provide quite a bit of difficulty since bits and debris will fly everywhere when they are broken. Machining ceramic components before the stage of final sintering may be done most successfully when the parts are either in their “green” (non-sintered powder) compact condition or in their “bisque” (pre-sintered) form.
Machining techniques such as milling, drilling, and turning may, in most cases, be used on ceramic components when they are in pre-sintered condition. Machining pre-sintered ceramics often involves using high-speed steel tools coated with titanium nitride (TiN), tungsten carbide tools, and polycrystalline diamond (PCD) tools. The MRR that may be achieved by a machine tool can be comparable to that of tool and die steels when the material is in the bisque stage.
Grinding is the machining procedure used most often when dealing with materials in the sintered form. The equipment can achieve a surface finish that is polished with the assistance of the abrasive wheel. When grinding ceramics, a fluid coolant that lubricates the ground area is recommended for optimal results. When working with sintered ceramics, it is recommended that you utilize resin-bonded wheels. These wheels use synthetic or natural diamonds of varying grit sizes that have been compressed at different concentrations in polymer resin.
Ceramics come in a highly diverse range of varieties, each of which has its distinguishing qualities. These are only some guidelines to follow. However, the actual procedures may differ.
Different Types of Ceramics
So, here we discuss some of the numerous types of ceramics.
Corning Inc. owns the machinable glass ceramic known as Macor and produces it. The material finds use in various fields, including aviation, medicine, and the manufacture of semiconductors. When lower-volume quantities have to be manufactured but high-priced tooling expenses are not an option, using machinable glass-ceramics is an economical approach to save costs while still meeting production needs. The temperature at which Macor is used continuously is 800 degrees Celsius, and its peak temperature is 1,000 degrees Celsius. It has a thermal expansion that is comparable to that of the majority of metals and sealing glasses. Macor is indeed non-wetting, has zero porosity, and, in contrast to ductile materials, it will not deform when heated. In addition, it functions well as an insulator when subjected to high voltages, different frequencies, and high temperatures. In vacuum conditions, it will not release any gases either.
Alumina can be used in diverse contexts thanks to its favorable mechanical and electrical qualities. It can be manufactured in various purities by combining it with additions intended to improve its properties. Plus, it may be machined or molded to generate an extensive range of different sizes and forms. It can be made using several procedures for processing ceramics. Besides, it may be easily attached to metals or various ceramics by using processes like metalizing and brazing.
Because it is possible to metalize aluminum nitride and has a lower thermal expansion than alumina, aluminum nitride is an excellent material for semiconductors applications. Aluminum nitride very nearly matches the expansion of silicon wafers.
Alumina Silicate (Lava)
Alumina silicate or Lava refers to a machinable ceramic material. In addition to having significant thermal and electrical insulating characteristics, it can withstand high temperatures during usage.
Boron nitride may be machined with standard carbide drills without any problems. BN is chemically inert, has a low thermal expansion, a robust electrical resistance, and an excellent resistance to thermal shock. It also has a reduced dielectric constant and loss tangent. Because of these characteristics, BN is a suitable material for vacuum systems, a wide variety of electrical components, and applications involving nuclear technology.
Many different kinds of glass are used in various applications, particularly those that demand good optical quality, thermal shock resistance, and insulating qualities.
Depending on its polymerization stage, the carbon-based ceramic substance known as graphite may have several densities. Graphite is an excellent material for molds, plating anodes, furnace boats, and brazing fittings due to its strong resistance to thermal stress and chemical attacks.
Because of its outstanding thermal stability, creep resistance, and strength, mullite is a suitable material for use in the construction of structures. It also has a solid electrical insulating capacity and a low dielectric constant. Kiln Furniture, the central tube of a furnace, heat exchange components, heat insulation parts, rollers, and other typical applications are all possible uses. Even though it can be machined, mullite is a better candidate for laser cutting.
Mycalex is an outstanding machinable ceramic insulator material manufactured into complicated pieces. It is available in many grades, each of which varies in strength and temperature performance. It is frequently utilized for producing small parts for use in industrial equipment.
Quartz is often used in lighting and semiconductors since it has exceptional thermal, chemical, and optical qualities. Diamond tools, grinding, or water jetting are the most effective ways to do these tasks. The abrasive methods are far more beneficial than any cutting method.
The material known as silicon carbide is renowned for both its extreme hardness and its abrasion resistance. Pump seals, valve components, and parts that see a lot of wear and tear are examples of everyday uses. This material has high hardness values, but it is still somewhat brittle. The only way to process it is by using diamond grinding methods. In most cases, it is made in an Acheson graphite resistance furnace and may be made into a fine powder or a bonded mass. In either case, it must be crushed and processed before being utilized as a powder feedstock.