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- Apr 27, 1999
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Since the old link was broken and we are about to lose our memory beyond the last 3 years I thought I would refresh an old topic. How do the real edge pros (the guys who make safety razors) create a million miles of slick shaving edges? Here is some info from Shick:
http://www.shaving.com/history/blade.asp
That link doesn't seem to work directly. I'll copy an extract:
A soft, stainless steel strip, containing at least 12% chromium, goes through a series of steps before being made into razor blades. Large coils, weighing up to 110 pounds (50 kg) each and containing over two miles (3.2 km) of this steel, are used at the start of the process and must meet strict tolerances for metallurgical composition, width and thickness. Most of the razor blades first travel through a press to precisely perforate the blade with a series of notches and holes. These are used for locating the position of the blade in subsequent operations and for placement in the cartridge during the final assembly process. After the strip is notched and perforated, it proceeds to the next step in the process.
PERFECT TEMPERATURES CREATE THE PERFECT BLADE
The blade strip, as it arrives from the steel manufacturer, is too soft to grind into a shaving edge and must first be hardened. Furnaces with temperatures of more than 2,000°F (1,110°C) heat the blade strip in a controlled atmosphere to prevent oxidation. Both the time and temperature under which the strip is heated are critical to the final product. If the time is too short or the temperature is too low, a soft strip will be produced. If the time is too lengthy or the temperatures too high, the strip will be undesirable for grinding. The strip is then subjected to temperatures below –100°F (–70°C) in a deep-freeze chamber to complete the hardening process. It is then heated again to only a few hundred degrees in order to temper it. Tempering gives some ductility or flexibility back to the hard but brittle strip of steel. A great deal of control is required at each step of heat treatment. And, if any one of the steps is compromised, the resultant steel will not be suitable for a high-quality blade edge. Only highly skilled manufacturers are capable of producing hardened steel that meets the physical characteristics needed for grinding a superior razor blade edge.
Next, the hardened and tempered coil of steel is sent to the grinding area to have a sharp edge formed on the strip. Unlike the commonly held belief that a razor blade is simply a sharpened piece of steel, the blade edge is actually composed of three distinct facets, each working together to form a strong edge that is both sharp and durable. The blade strip is fed through a series of progressively finer grinding wheels. Coarse grinding wheels remove material to approximate the desired profile. Finer grit wheels shape the edge more precisely, and extremely fine grit wheels finish forming the blade tip profile. High-speed leather-like strops provide the shape and smoothness to the ultimate tip of the blade.
The thickness of the blade profile must be tightly controlled. If a blade is too blunt, it will give an uncomfortable shave. If it is too sharp, the edge will break down more quickly. The grinding equipment used to form the edge is developed by highly skilled, in-house designers and engineers. This is necessary to protect the proprietary nature of the equipment. High precision is required in equipment design to obtain the proper edge profile and to ensure the consistency of the millions of blades processed each day. After grinding, the strip is cut into individual blades and stacked on long pins, called bayonets, so they can be finished and assembled into shaving products
COATED BLADES FOR A SAFER SHAVE
Although a properly formed blade is quite sturdy, additional durability is generally obtained by depositing a layer of hard metal directly onto the edge in a sputtering process. After all impurities are removed from the blade edges, bayonets of blades are placed inside high-vacuum chambers in which an inert ionized gas is present. High-energy ions bombard a chromium target and eject chromium atoms, depositing them on the razor blade edges.
In spite of the finely shaped blade apex, if an uncoated stainless steel blade is used to cut the hair, the friction between the cut surfaces of the hair and the steel would cause pulling and discomfort. In order to reduce this friction, the blade edges are sprayed with a coating of Vydax, a low molecular weight polymer of polytetrafluoroethylene (PTFE) with low-friction qualities similar to Teflon. The film is then melted on the blade edges and cured at temperatures over 500°F (276°C). After the first few strokes with a Vydax coated blade, the excess Vydax is peeled back from the apex of the blade and a thin layer is left on the surface to reduce friction and improve comfort. All Shaving Products Group razor blades meet high specifications for quality. Some systems may have slightly different coating characteristics or steel composition, but all are designed to enhance the shaving performance of the systems.
PLASTIC MOLDINGS KEEP BLADE SAFE
While blades are a critical aspect of a good shave, the plastic cartridge in which bonded blades are housed is critical in controlling the action of the blades in terms of cartridge geometry. Through a process called injection molding, plastic cartridge components are molded by melting plastic pellets at 400° to 500°F (221° to 276°C) and then injecting the molten plastic into multi-cavity precision molds. Once cooled, the parts are ejected and the automated cycle continues. The parts are made with strict tolerances so they can be assembled with razor blades in the optimum position for the best shave. Caps, seats and some spacers are molded out of various plastic materials, including polystyrene and polypropylene, to meet each shaving system's requirements. A new technology has been developed and patented by the Shaving Products Group—a process called “insert molding.” This complex process molds the plastic around the blades in a single operation, eliminating the need for assembly and reducing cartridge variation. This sophisticated technological process results in a more consistent, dimensionally stable product for the consumer.
SMART CARTRIDGE GEOMETRY CONTROLS THE SHAVE
A typical twin-bonded blade shaving cartridge is composed of five components that interact with one another. The lowest member of the cartridge "sandwich" is the SEAT or PLATFORM, comprising the foundation on which the other members rest and which contains the guard bar. The SEAT or LEADING BLADE sits on top of the SEAT underneath a SPACER. The CAP or TRAILING BLADE is placed above the SPACER and the CAP rests on top of the entire package. Although the blade edge is a critical contributor to a good shave, the cartridge geometry (i.e., the relationship of the blades to the guard bar and cap) controls the closeness of the shave and the dynamics of the cutting action itself. How a razor blade behaves during a shave is similar to that of a wood plane in which the protrusion of the blade and its angle to the surface control the cutting action. In a twin-blade shaving system the relationships are more complicated than in a single-blade system.
Manipulating the variables affecting geometry can greatly alter the characteristics of a shave. The Shaving Products Group spends considerable effort determining and controlling the factors affecting cartridge geometry to produce an optimum blend, resulting in shaves that are both safe and close. A great deal of process control is required to ensure a safe razor. The blade must be the correct width, the blade perforations that locate the blade in a cartridge must be precisely located, the dimensions of the plastic components (i.e., seat and cap) must be exact, and the assembly of the parts must be carried out in a reliable manner. The sharpness of the blade, the relationships among all the geometric variables, and the needs of the consumer are taken into account when designing the best geometry for a given razor system.
Comfort Strips
Many razor systems produced by the Shaving Products Group have a comfort or lubricating strip located on the cap above the blades. Warner-Lambert was the first company in the world to patent this novel improvement to the daily shave. These strips, some of which contain aloe, are made from a water-soluble polymer called polyethylene oxide (Polyox). When activated by water they provide lubrication that makes the shave more comfortable.
Another approach to the same end is used on many products, in which an Aquaglide strip (polyvinyl pyrolidone or PVP) is positioned on the cartridge cap. When wet, the strip becomes extremely slippery and reduces friction between skin and blade. These innovative materials are both safe to the consumer and effective in improving shaving comfort. Many of the Shaving Products Group shaving systems use this technology to enhance their performance
Wire-Wrapped Blades
In an effort to develop an extremely safe shaving system, the twin blades in some products are wrapped with very thin wire. Patented Microfine Wire Wraps help guide the blades evenly over the skin, protecting it from nicks, cuts and irritation while providing the closeness the shaver needs. This significant step forward in safety has proven to be a successful advancement in the science of shaving.
http://www.shaving.com/history/blade.asp
That link doesn't seem to work directly. I'll copy an extract:
A soft, stainless steel strip, containing at least 12% chromium, goes through a series of steps before being made into razor blades. Large coils, weighing up to 110 pounds (50 kg) each and containing over two miles (3.2 km) of this steel, are used at the start of the process and must meet strict tolerances for metallurgical composition, width and thickness. Most of the razor blades first travel through a press to precisely perforate the blade with a series of notches and holes. These are used for locating the position of the blade in subsequent operations and for placement in the cartridge during the final assembly process. After the strip is notched and perforated, it proceeds to the next step in the process.
PERFECT TEMPERATURES CREATE THE PERFECT BLADE
The blade strip, as it arrives from the steel manufacturer, is too soft to grind into a shaving edge and must first be hardened. Furnaces with temperatures of more than 2,000°F (1,110°C) heat the blade strip in a controlled atmosphere to prevent oxidation. Both the time and temperature under which the strip is heated are critical to the final product. If the time is too short or the temperature is too low, a soft strip will be produced. If the time is too lengthy or the temperatures too high, the strip will be undesirable for grinding. The strip is then subjected to temperatures below –100°F (–70°C) in a deep-freeze chamber to complete the hardening process. It is then heated again to only a few hundred degrees in order to temper it. Tempering gives some ductility or flexibility back to the hard but brittle strip of steel. A great deal of control is required at each step of heat treatment. And, if any one of the steps is compromised, the resultant steel will not be suitable for a high-quality blade edge. Only highly skilled manufacturers are capable of producing hardened steel that meets the physical characteristics needed for grinding a superior razor blade edge.
Next, the hardened and tempered coil of steel is sent to the grinding area to have a sharp edge formed on the strip. Unlike the commonly held belief that a razor blade is simply a sharpened piece of steel, the blade edge is actually composed of three distinct facets, each working together to form a strong edge that is both sharp and durable. The blade strip is fed through a series of progressively finer grinding wheels. Coarse grinding wheels remove material to approximate the desired profile. Finer grit wheels shape the edge more precisely, and extremely fine grit wheels finish forming the blade tip profile. High-speed leather-like strops provide the shape and smoothness to the ultimate tip of the blade.
The thickness of the blade profile must be tightly controlled. If a blade is too blunt, it will give an uncomfortable shave. If it is too sharp, the edge will break down more quickly. The grinding equipment used to form the edge is developed by highly skilled, in-house designers and engineers. This is necessary to protect the proprietary nature of the equipment. High precision is required in equipment design to obtain the proper edge profile and to ensure the consistency of the millions of blades processed each day. After grinding, the strip is cut into individual blades and stacked on long pins, called bayonets, so they can be finished and assembled into shaving products
COATED BLADES FOR A SAFER SHAVE
Although a properly formed blade is quite sturdy, additional durability is generally obtained by depositing a layer of hard metal directly onto the edge in a sputtering process. After all impurities are removed from the blade edges, bayonets of blades are placed inside high-vacuum chambers in which an inert ionized gas is present. High-energy ions bombard a chromium target and eject chromium atoms, depositing them on the razor blade edges.
In spite of the finely shaped blade apex, if an uncoated stainless steel blade is used to cut the hair, the friction between the cut surfaces of the hair and the steel would cause pulling and discomfort. In order to reduce this friction, the blade edges are sprayed with a coating of Vydax, a low molecular weight polymer of polytetrafluoroethylene (PTFE) with low-friction qualities similar to Teflon. The film is then melted on the blade edges and cured at temperatures over 500°F (276°C). After the first few strokes with a Vydax coated blade, the excess Vydax is peeled back from the apex of the blade and a thin layer is left on the surface to reduce friction and improve comfort. All Shaving Products Group razor blades meet high specifications for quality. Some systems may have slightly different coating characteristics or steel composition, but all are designed to enhance the shaving performance of the systems.
PLASTIC MOLDINGS KEEP BLADE SAFE
While blades are a critical aspect of a good shave, the plastic cartridge in which bonded blades are housed is critical in controlling the action of the blades in terms of cartridge geometry. Through a process called injection molding, plastic cartridge components are molded by melting plastic pellets at 400° to 500°F (221° to 276°C) and then injecting the molten plastic into multi-cavity precision molds. Once cooled, the parts are ejected and the automated cycle continues. The parts are made with strict tolerances so they can be assembled with razor blades in the optimum position for the best shave. Caps, seats and some spacers are molded out of various plastic materials, including polystyrene and polypropylene, to meet each shaving system's requirements. A new technology has been developed and patented by the Shaving Products Group—a process called “insert molding.” This complex process molds the plastic around the blades in a single operation, eliminating the need for assembly and reducing cartridge variation. This sophisticated technological process results in a more consistent, dimensionally stable product for the consumer.
SMART CARTRIDGE GEOMETRY CONTROLS THE SHAVE
A typical twin-bonded blade shaving cartridge is composed of five components that interact with one another. The lowest member of the cartridge "sandwich" is the SEAT or PLATFORM, comprising the foundation on which the other members rest and which contains the guard bar. The SEAT or LEADING BLADE sits on top of the SEAT underneath a SPACER. The CAP or TRAILING BLADE is placed above the SPACER and the CAP rests on top of the entire package. Although the blade edge is a critical contributor to a good shave, the cartridge geometry (i.e., the relationship of the blades to the guard bar and cap) controls the closeness of the shave and the dynamics of the cutting action itself. How a razor blade behaves during a shave is similar to that of a wood plane in which the protrusion of the blade and its angle to the surface control the cutting action. In a twin-blade shaving system the relationships are more complicated than in a single-blade system.
Manipulating the variables affecting geometry can greatly alter the characteristics of a shave. The Shaving Products Group spends considerable effort determining and controlling the factors affecting cartridge geometry to produce an optimum blend, resulting in shaves that are both safe and close. A great deal of process control is required to ensure a safe razor. The blade must be the correct width, the blade perforations that locate the blade in a cartridge must be precisely located, the dimensions of the plastic components (i.e., seat and cap) must be exact, and the assembly of the parts must be carried out in a reliable manner. The sharpness of the blade, the relationships among all the geometric variables, and the needs of the consumer are taken into account when designing the best geometry for a given razor system.
Comfort Strips
Many razor systems produced by the Shaving Products Group have a comfort or lubricating strip located on the cap above the blades. Warner-Lambert was the first company in the world to patent this novel improvement to the daily shave. These strips, some of which contain aloe, are made from a water-soluble polymer called polyethylene oxide (Polyox). When activated by water they provide lubrication that makes the shave more comfortable.
Another approach to the same end is used on many products, in which an Aquaglide strip (polyvinyl pyrolidone or PVP) is positioned on the cartridge cap. When wet, the strip becomes extremely slippery and reduces friction between skin and blade. These innovative materials are both safe to the consumer and effective in improving shaving comfort. Many of the Shaving Products Group shaving systems use this technology to enhance their performance
Wire-Wrapped Blades
In an effort to develop an extremely safe shaving system, the twin blades in some products are wrapped with very thin wire. Patented Microfine Wire Wraps help guide the blades evenly over the skin, protecting it from nicks, cuts and irritation while providing the closeness the shaver needs. This significant step forward in safety has proven to be a successful advancement in the science of shaving.