The Technology: A new machining process that reduces the number of components, saves production time and cost, and at the same time is environmentally friendly? Sounds unlikely, however, that is exactly what FDRILL friction drilling accomplishes.
The ideas of rubbing two materials together to produce heat is as old as the Indians fire making process; however applying the principle to drilling holes in metal is a more recent development. Most of us who have worked in machine shops have at one time or another tried to drill a hole with a very dull bit. The result, a lot of smoke, heat and frustration. Jan Claude de Valliere, working on a little farm in the south of France some seventy-five years ago encountered the same problem. He recognized that if he could generate enough heat he could melt form a hole through the metal. With that thought in mind he set about to develop a special drill designed to increase friction. After many trials he found a shape that worked. He had achieved technical success, however hand shaping of the tool was very costly and the tool life short. Jan Claude de Valliere's invention was not at the time commercially viable.
In the early 1980's the idea of thermal drilling was re-examined. With the availability of hard metals like tungsten carbide and computer controlled diamond grinding equipment capable of producing complicated profiles the process seemed feasible. After an extensive design and experimentation program the FDRILL was born.
The modern FDRILL extrudes a precision hole through the work piece with eighty percent of the molten displaced material flowing down and twenty percent up. This forms a boss approximately three times the thickness of the original material. A boss that is ideally suited for tapping, use as a bearing surface or positioning a tube for brazing.
The FDRILL bit can be used in any conventional drilling machine with adequate horsepower and RPM. It is suitable for use with mild steel, stainless steel, most aluminum, copper, and brass. Holes from 1/64 inch to 2 inches can be formed in material from 1/16 inch to 1/2 inch thick.
Today's four lobed FDRILL provides the designer with an exciting new manufacturing process. A process that opens new possibilities in the fabrication of tube and sheet metal parts. It provides a lower cost alternative to insert nuts, weld nuts, bushings, and fasteners; thus reducing the number of parts required, production time and assembly equipment.
In addition to lowering manufacturing costs, the thermal drilling process has an added benefit; it is environmentally friendly. It is a dry process, no cutting or cooling lubricants are required and there are no chips to dispose of or clean from the finished parts.
A PROCESS FOR THE NEW MILLENNIA.
The long Fdrill has a long parallel body designed to produce a hole that is cylindrical for the entire bush length. Material that is backward extruded is rolled into a rim by the Flowdrill collar, ( L = LONG )*
The short Fdrills have a shorter parallel body. This design produces a bush that is conical and provides great strength when formed into a thread, ( S = SHORT )*
On the flat Fdrills, the collar is ground into a cutter. This removes the rim formed around the top surface of a Flowdrilled hole, leaving the surface flat, ( M = FLAT )*
On the fluted Fdrill there are two small cutting flutes at the tip. This style is useful for coated materials such as galvanized steel, ( F = FLUTED )*