Glass drilling

Drilling fluids Drilling glass Drilling mud additives Drillingmuds... 

Drilling. Glass is drilled with carbide or bonded-diamond drills under a suitable coolant such as water or kerosene. Other drilling processes include a metal tube rotating about its axis (core drilling), an ultrasonic tool in combination with an abrasive slurry, or an electron beam. Tolerances less than 0.1 mm are readily obtained with diamond-core drilling and, if required, holes smaller than 25 Jlm-dia can be made with the electron-beam method. 

In some cases, drilled holes are created on the same plate where the channels are etched. To achieve this, the holes were drilled either on the channel plate, or on a plain plate with subsequent channel etching [13,134]. In the latter case, the photoresist can only be sprayed, rather than spin-coated on the drilled glass plate [134],... 

The harder grades of glass may be drilled with metal drills that have been super-tempered by bringing them to a red heat and plunging them into a solution of salt water that has been previously boiled. A three-cornered file can be broken off and used to drill glass when it is placed in a chuck. The end of the file should be ground to a point on a grinding wheel. 

Abrao, A.M., Rubio, J.C., Faria, RE. and Davim, J.R (2008) The effect of cutting tool geometry on thrust force and delamination when drilling glass fiber reinforced plastic composite. Mater Des, 29 508-13. 

Caprino, G. and Tagliaferri, V. (1995) Damage development in drilling glass fiber reinforced plastics, Int J Mach Tools Manuf, 35 817-29. 

Fig. 2. Multilayer printed circuit board composite. Constmction is multiple layers of epoxy—glass and foil copper. Foil copper outermost layer and drilled through-holes are sequentially plated with electroless copper, electrolytic copper, electroless nickel, and electroless gold.

Cobalt ores are often found in association with copper(II) sulfide. Cobalt is a silver-gray metal and is used mainly for alloying with iron. Alnico steel, an alloy of iron, nickel, cobalt, and aluminum, is used to make permanent magnets such as those in loudspeakers. Cobalt steels are hard enough to be used as surgical steels, drill bits, and lathe tools. The color of cobalt glass is due to a blue pigment that forms when cobalt(II) oxide is heated with silica and alumina. 

The glass polyalkenoate cement uniquely combines translucency with the ability to bond to untreated tooth material and bone. Indeed, the only other cement to possess translucency is the dental silicate cement, while the zinc polycarboxylate cement is the only other adhesive cement. It is also an agent for the sustained release of fluoride. For these reasons the glass polyalkenoate cement has many applications in dentistry as well as being a candidate bone cement. Its translucency makes it a favoured material both for the restoration of front teeth and to cement translucent porcelain teeth and veneers. Its adhesive quality reduces and sometimes eliminates the need for the use of the dental drill. The release of fluoride from this cement protects neighbouring tooth material from the ravages of dental decay. New clinical techniques have been devised to exploit the unique characteristics of the material (McLean Wilson, 1977a,b,c Wilson McLean, 1988 Mount, 1990). 

Microfabrication is achieved by photolithography and isotropic etching of glass using HF [4—13]. Thermal bonding serves for interconnection. Holes are drilled in the top plate for connection to the fluidic peripherals. 

Glass surfaces which must fit closely are usually ground to shape. The most common example is the cone-and-socket joint the surfaces are first worked to an approximate fit with fairly coarse carborundum (about 100 mesh) which is put between them and wetted. The cone is rotated by hand or in a lathe or drill chuck, or by a special machine, until the smfaces meet closely—the carborundum must be kept moist all the time. The coarse abrasive is then washed off, and the grinding continued a number of times with progressively finer abrasive. Various possible abrasives are mentioned on p. 39. 

Many variations of the shape of steel drills for glass have been described— from Faraday who used the ground end of a triangular file to C. V. Boys who designed a special drill of tool steel—while other workers (B. Brown, 1927 N. G. Heatley, 1938) advocate the use of a normal twist drill. These drills are used in conjunction with some lubricant—usually the traditional camphor in turpentine, although pure turpentine or other mobile liquid seems to be as good, while Heatley states that dilute sulphuric acid is effective. To avoid splintering, the hole should be drilled from both sides. 

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