Friction drilling is a method of making holes in metal in which the material is pushed out of the way with the aid of heat from friction. The process is also called thermal drilling, flow drilling, form drilling, or friction stir drilling.[1]
The basic steps in the friction drilling process: A. Applying pressure. B. Tool heats target and melts through it. C. Screw thread tapping.
In 1923, the Frenchman Jean Claude de Valière tried making a tool that could make holes in metal by friction heat, instead of by machining. It was only a moderate success, because at that time the right materials were not yet available. Moreover, he hadn't yet discovered the right shape for this kind of tool.
It was not until the 1980s that a useful tool could be produced.[citation needed]
Principleedit
Friction drilling uses a conical bit made of very heat-resistant material such as cemented carbide. This device is pressed against a target material with both high rotational speed and high pressure. That way, there is a high local production of heat which softens the object, making it plastic. The tool then "sinks" through the object, making a hole in it. Lubricants help prevent work-material from adhering to the bit. Unlike drilling, material that is flowed is not lost but it forms a sleeve around the hole. The length of that sleeve is up to 3 times the original thickness of the material. The presence of this metal lip around hole edges makes connections stronger.
Several options are available with this technology. Bits may include a cutting device that removes the typical "collar" of plastified material that flows upwards, so that an even top surface is the result. Drilled starter holes may be used to reduce the required axial force and to leave a smooth finish in the bushing’s lower edge. Internal screw threads may be cut with taps or rolled with dies.
The process reshapes all material so that no material is lost. The excess material forms a sleeve that is about 3 times longer than the original thickness of the target material, which makes it possible to make very strong bolt joints in thin material.
It is a clean process because no litter (particles) is produced.
No access needed to back of workpiece, as with press-in or self-clinching hardware.
More reliable and faster than rivet nuts (an alternative that also does not require access to back of workpiece).
Friction drilling is not possible in massive material since displaced metal must be able to flow somewhere. Maximum material thickness is typically half of the hole diameter[4] with bit manufacturers providing specific guidance.[5]
The target material must be able to withstand the added heat. Materials that have been painted, plastic coated, galvanized, or heat treated are often unsuitable for this process.
Requires higher motor capacity and rotational speed than conventional drills.[2]
Referencesedit
^Scott F. Miller; Albert J. Shih; Peter J. Blau (October 2005). (PDF). Journal of Materials Engineering and Performance. 14 (5): 647–653. Bibcode:2005JMEP...14..647M. doi:10.1361/105994905x64558. S2CID 53559794. Archived from the original (PDF) on 2013-05-04. Retrieved 2013-03-12.
^ ab"Thermal Drilling". Machine Design. 23 October 2008.
^. Archived from the original on 2013-05-11. Retrieved 2013-07-12.
^Criste, Erin (February 2013). "Steel Interchange" (PDF). Modern Steel Construction.
^. Archived from the original on 2013-05-11. Retrieved 2013-07-12.
External linksedit
Video of the flow drill process
May 08, 2024
friction, drilling, method, making, holes, metal, which, material, pushed, with, heat, from, friction, process, also, called, thermal, drilling, flow, drilling, form, drilling, friction, stir, drilling, basic, steps, friction, drilling, process, applying, pres. Friction drilling is a method of making holes in metal in which the material is pushed out of the way with the aid of heat from friction The process is also called thermal drilling flow drilling form drilling or friction stir drilling 1 The basic steps in the friction drilling process A Applying pressure B Tool heats target and melts through it C Screw thread tapping Friction drilling is commonly used on bicycle frames heat exchangers and to create holes for mounting bearings Contents 1 History 2 Principle 3 Advantages 4 Disadvantages 5 References 6 External linksHistory editIn 1923 the Frenchman Jean Claude de Valiere tried making a tool that could make holes in metal by friction heat instead of by machining It was only a moderate success because at that time the right materials were not yet available Moreover he hadn t yet discovered the right shape for this kind of tool It was not until the 1980s that a useful tool could be produced citation needed Principle editFriction drilling uses a conical bit made of very heat resistant material such as cemented carbide This device is pressed against a target material with both high rotational speed and high pressure That way there is a high local production of heat which softens the object making it plastic The tool then sinks through the object making a hole in it Lubricants help prevent work material from adhering to the bit Unlike drilling material that is flowed is not lost but it forms a sleeve around the hole The length of that sleeve is up to 3 times the original thickness of the material The presence of this metal lip around hole edges makes connections stronger Several options are available with this technology Bits may include a cutting device that removes the typical collar of plastified material that flows upwards so that an even top surface is the result Drilled starter holes may be used to reduce the required axial force and to leave a smooth finish in the bushing s lower edge Internal screw threads may be cut with taps or rolled with dies Advantages editVery quick process 2 to 6 seconds 2 The process reshapes all material so that no material is lost The excess material forms a sleeve that is about 3 times longer than the original thickness of the target material which makes it possible to make very strong bolt joints in thin material It is a clean process because no litter particles is produced No access needed to back of workpiece as with press in or self clinching hardware More reliable and faster than rivet nuts an alternative that also does not require access to back of workpiece Works in almost all kinds of metal 3 Disadvantages editFriction drilling is not possible in massive material since displaced metal must be able to flow somewhere Maximum material thickness is typically half of the hole diameter 4 with bit manufacturers providing specific guidance 5 The target material must be able to withstand the added heat Materials that have been painted plastic coated galvanized or heat treated are often unsuitable for this process Requires higher motor capacity and rotational speed than conventional drills 2 References edit Scott F Miller Albert J Shih Peter J Blau October 2005 Microstructural alterations associated with friction drilling of steel aluminum and titanium PDF Journal of Materials Engineering and Performance 14 5 647 653 Bibcode 2005JMEP 14 647M doi 10 1361 105994905x64558 S2CID 53559794 Archived from the original PDF on 2013 05 04 Retrieved 2013 03 12 a b Thermal Drilling Machine Design 23 October 2008 Materials Centerdrill Archived from the original on 2013 05 11 Retrieved 2013 07 12 Criste Erin February 2013 Steel Interchange PDF Modern Steel Construction Maximum Wall Thickness Archived from the original on 2013 05 11 Retrieved 2013 07 12 External links editVideo of the flow drill process Retrieved from https en wikipedia org w index php title Friction drilling amp oldid 1222348305, wikipedia, wiki, book, books, library,
