Skiving machine
Encyclopedia
Skiving or scarfing machines cut material off moving strips, usually metal
, but also leather
or laminates, to leave a desired edge shape or cross section
. The process is used instead of rolling
the material to shape when the material must not be work hardened
, or must not shed minute slivers of metal later which is common in cold rolling processes.
The process involves moving the strip past precision-profiled slotted tool
s made to an exact shape, or past plain cutting tool
s. The tools are all usually made of tungsten carbide
-based compounds. In early machine
s, it was necessary to precisely position the strip relative to the cutting tools, but newer machines use a floating suspension technology which enables tools to locate by material contact. This allows mutual initial positioning differences up to approximately 12 mm (0.47244094488189 in) followed by resilient automatic engagement. Products using this technology directly are automotive seatbelt springs
, large power transformer winding strip, rotagravure plates, cable and hose clamp
s, gas tank straps, and window counterbalance springs. Products using the process indirectly are tubes and pipe
mills where the edge of the strip is accurately bevelled prior to being folded into tubular form and seam welded. The finished edges enable pinhole free welds.
For lines which use low speed welding processes, such as laser welding, the skiving tools cannot normally cut - for example at speeds below metal planing
speeds or about 10 meters/minute (33 feet/minute). In these cases the tools can be vibrated at high frequency to artificially increase the relative speed between the tools and strip.
s for PC cooling products. A PC cooler created with the use of skiving has the benefit that the heat sink base and the heat sink fins are created from one piece of material (copper or aluminum). This provides optimal dissipation and transfer of the heat from the base to the fins. Additionally, the skiving process also increases the roughness of the heat-sink's fins. Unlike the underside of a heat-sink which needs to be smooth for maximum surface area contact with the heat-source that it cools, the fins benefit from this roughness because it increases the fins' surface area which serves to provide more area on which to release heat into the ambient environment.
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
, but also leather
Leather
Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...
or laminates, to leave a desired edge shape or cross section
Cross section (geometry)
In geometry, a cross-section is the intersection of a figure in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc...
. The process is used instead of rolling
Rolling (metalworking)
In metalworking, rolling is a metal forming process in which metal stock is passed through a pair of rolls. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is termed as hot rolling...
the material to shape when the material must not be work hardened
Work hardening
Work hardening, also known as strain hardening or cold working, is the strengthening of a metal by plastic deformation. This strengthening occurs because of dislocation movements within the crystal structure of the material. Any material with a reasonably high melting point such as metals and...
, or must not shed minute slivers of metal later which is common in cold rolling processes.
The process involves moving the strip past precision-profiled slotted tool
Tool
A tool is a device that can be used to produce an item or achieve a task, but that is not consumed in the process. Informally the word is also used to describe a procedure or process with a specific purpose. Tools that are used in particular fields or activities may have different designations such...
s made to an exact shape, or past plain cutting tool
Cutting tool
In the context of machining, a cutting tool is any tool that is used to remove material from the workpiece by means of shear deformation. Cutting may be accomplished by single-point or multipoint tools. Single-point tools are used in turning, shaping, plaining and similar operations, and remove...
s. The tools are all usually made of tungsten carbide
Tungsten carbide
Tungsten carbide is an inorganic chemical compound containing equal parts of tungsten and carbon atoms. Colloquially, tungsten carbide is often simply called carbide. In its most basic form, it is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery,...
-based compounds. In early machine
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
s, it was necessary to precisely position the strip relative to the cutting tools, but newer machines use a floating suspension technology which enables tools to locate by material contact. This allows mutual initial positioning differences up to approximately 12 mm (0.47244094488189 in) followed by resilient automatic engagement. Products using this technology directly are automotive seatbelt springs
Spring (device)
A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...
, large power transformer winding strip, rotagravure plates, cable and hose clamp
Hose clamp
A hose clamp or hose clip is a device used to attach and seal a hose onto a fitting such as a barb or nipple.- Screw/band clamps :...
s, gas tank straps, and window counterbalance springs. Products using the process indirectly are tubes and pipe
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...
mills where the edge of the strip is accurately bevelled prior to being folded into tubular form and seam welded. The finished edges enable pinhole free welds.
For lines which use low speed welding processes, such as laser welding, the skiving tools cannot normally cut - for example at speeds below metal planing
Planing (shaping)
Planing is a manufacturing process of material removal in which the workpiece reciprocates against a stationary single-point cutting tool producing a plane or sculpted surface. Planing is analogous to shaping. The main difference between these two processes is that in shaping the tool...
speeds or about 10 meters/minute (33 feet/minute). In these cases the tools can be vibrated at high frequency to artificially increase the relative speed between the tools and strip.
Heat sinks
Skiving or Skivetek is also used for the manufacturing of heat sinkHeat sink
A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat sinks are the heat exchangers used in refrigeration and air conditioning systems and the radiator in a car...
s for PC cooling products. A PC cooler created with the use of skiving has the benefit that the heat sink base and the heat sink fins are created from one piece of material (copper or aluminum). This provides optimal dissipation and transfer of the heat from the base to the fins. Additionally, the skiving process also increases the roughness of the heat-sink's fins. Unlike the underside of a heat-sink which needs to be smooth for maximum surface area contact with the heat-source that it cools, the fins benefit from this roughness because it increases the fins' surface area which serves to provide more area on which to release heat into the ambient environment.