Carbide saw is a machine tool for cutting. The sawtooth is made of cemented carbide, so the hard material can be cut.
Video Carbide saw
Histori
In 1926, Krupp, a German company, developed carbides, a very hard mixture of sintered carbides of various heavy metals, especially tungsten carbides, used for cutting edges and dies. This new material revolutionized metal transfer or "chip cutting" in manufacturing. In 1950, carbides were used in all machining processes except for sawing. In 1942, German scientists developed carbides into a mirror. After World War II, American universities developed this material further and began marketing it as a cutting material for machine tools under the brand name Cermet. Sawing non-ferrous materials, such as aluminum, brass, plastics and wood with circular saw blades began in the 1930s. However, attempts to cut the iron with the carbide end fail because the existing saws do not have the speed, stiffness, and innovation required to transfer high strength with low vibration. All these attributes are needed for sawing carbides. Also, the existing dental geometry with positive cutting angle leads to a harder cracking of the carbide end and, consequently, is more fragile than a high-speed steel round knife (HSS).
The name of the visible carbide comes from the tool, a circular saw blade, with the tip of the soldered silver carbide. It competes with and about replaced, solid or Segmental HSS blades, because the carbide is much harder than HSS. Before the HSS saws are developed, abrasive, friction or hot saws are used and still manufactured for specific applications. These processes create heat and are therefore called hot saws. However, the HSS blades use cooling and the cut surface does not become hot, so it is called chainsaw. With the unique geometry of circular sawtooth of carbide, the heat, developed by the cutting process is transferred to the chip and taken away with the chip. The cut surface remains cool. Therefore, carbide saws are also called chainsaws. Other names include cold cut saws, cold circular saws, cold cutting saws or circular chainsaws.
In 1963, the American Company, Ingersoll Milling Machine Co. in Rockford, Illinois, developed the first carbide saw used for cutting steel plates with circular carbide-tipped saw blades. Positive cutting angle minimizes tool life. Between 1963 and 1969, Professor Pahlitzsch and engineers Arno Willemeit and Horst Doepcke at the University of Braunschweig, developed a new carbide edge geometry with negative cutting angles and a pair of teeth that divided the chip into three parts. With this development in tip geometry, it becomes economical to look at steel alloy billets. In 1969, Advanced Machines & amp; Engineering Co. (AME) of Rockford, Illinois developed the first Billet Saw that used a lead carbide saw that incorporates "Braunschweig geometry". AME started building these machines for Metalcut Inc., another Rockford-based company. The machine was sold in the global market under the name Metalcut 12 and exhibited at trade shows in Milan, Italy and Chicago. The cutting efficiency is eight times faster than the band saw and four times faster than the circular HSS circular saws and revolutionized the sawing market.
In 1970 the US government's defense department learned about the development of a new chainsaw concept. Chamberlain Manufacturing Corporation, contracted by Frankford Arsenal (), has evaluated Goellner carbide billet saws. Chamberlain issued a comprehensive technical report on May 29, 1970. The report concludes that the new sawmill concept is superior to conventional saws, cold saws and other boundary methods in various purposes. Benefits include faster cutting speeds, longer lifetime blades and improved cutoff interface quality.
From 1972 to 1976 for his dissertation, Horst Doepcke, a scientific assistant at the Institute of Machine Tools and Manufacturing Techniques at Braunschweig University, developed a special carbide cutting geometry for the tubes that each tooth splits each piece in half. In 1984, Speedcut Inc. from Rockford, Illinois developed another type of geometric dental carbide with the name, "Notch Grind". This is used for steel billets and it will split the chips with one staggered groove per gear. With the incorporation of this Notch Grind technology, chainsaws are significantly faster than Braunschweig's geometry. Over the next few years, various companies have developed carbide saw blades with the tip of the carbide exchange. This saw blade, so far, has not proven economical to cut steel.
Maps Carbide saw
Type
Chainsaw with horizontal slide
The horizontal shear saw is probably the most common type of carbide saw. With this design the saw blade is mounted on the spindle gearbox, where it slid horizontally and enters horizontally into the billet.
In 1969, the first horizontal billet billet was developed by AME and built for Metalcut Inc. For the first time, Hennig's telescopic steel enclosures and steel aprons were used to protect the vital components of chainsaws from high-speed flying chips. control.
Saw with vertical slide
The saw blades for this type of saws enter vertically into the material. This saw is often used as a saw layer, where many tubes, profiles, or bars can be simultaneously cut horizontally.
In 1974, the first carbide saw with a vertical slide developed by Arno Willemeit, co-inventor of Braunschweig dental geometry. It was produced by the Ohler company in Remscheid, Germany. Framag, an Austrian company then took over the production of this type of machine and also built it as a saw layer. Ohler had previously built a vertical HSS saws by double-turn and then converted it into a chainsaw carbide.
Carbide saw in an oblique manner
This is more expensive than conventional horizontal shear saws. They are most effectively used for cutting the rail, as the saw blades enter optimally into the rail profile.
Pivot chainsaw
Pivot saws were originally used as HSS saws to cut profiles and small tubes. In the late 1970s these saws began to be used for larger steel profiles on construction projects (Kaltenbach).
In 1973, Metalcut developed the first high efficiency pivot carbide saw for a 75 mm (3 inch) rod, in which a gearbox rotation center was fitted to the floor plate. The saw cuts both sides of the pivot axis, one each, and is more productive as a result.
In 1976, Carbide Cutoff Inc. (CCI) in Rockford, IL developed a larger carbide production of this type in order to compete with the horizontal shear saws of Metalcut Inc. This machine successfully cut billets up to 8 inches (200 mm) in diameter.
The pivot type saw is also used by Metalcut Inc., either as a layer saw or billet that cuts billet diameter up to 600 mm (24 inches). The pivot is located on the base of the machine and the saw blade is vertically in a form of arches into the material, but does not have a closed-loop style.
In 1994, AME developed a cost-effective pivot view under the AMSAW 200 brand name for the US market. In 2011, AME of Rockford, IL, developed a high efficiency saw carbide where the shaft axis of the gearbox remained at the bottom end of the engine bed, to cut the 350 mm (14 inches) billets. This style is contained in a close loop and the engine is very stiff. In this machine the chip flow is also improved, because the chip is thrown directly into the conveyor chip.
Custom models
Sawdle
In 1963, Ingersoll Milling Machine Co. Rockford, Illinois developed a saw that cuts plates made of high strength carbon steel using a saw blade carbide. The horizontal way is mounted on the beam above the plate.
Then, Oliver Machinery Co. from Detroit, Michigan developed a plate saw in which the gearbox slid under the plate on the engine bed and cut the plate from the bottom.
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In 1973, Metalcut developed the first carbide rail saws that were later produced by other companies including Wagner. In 1997, AME developed an economical rail saw with the AMSAW 300-R trademark, which is still widely used throughout the US. In 1999, AME built a special model of chainsaw carbide to cut railroads for frogs and switches. In 2011, AME developed a special model that is integrated as a double saw in a railroad car and used for railroad repair work in the US. This replaces the previously used abrasive saws. This abrasive saw is guilty of causing forest fires due to hot chips and sparks. As a result, these dangerous machines are replaced with cold chainsaws AMSAW.
Sawdle
In 1974, Metalcut developed two layers of saws that cut the tip to six "C" profiles. The profile approaches the saw in horizontal, layered. The first saw cuts the front end, the second back, where the latter moves on the track and therefore cuts the different lengths. These machines are built as pivot saws and cut from bottom to top through profiles.
In 1976, pivot saw is also used to cut the tubes in layers.
Later, Wagner and Framag made chainsaws similar to vertical designs.
Carbide heat chains
In 2008, AME developed carbide hot saws that cut off the ends of the hot-rolled shaft for the railway industry.
Carbide sail ring
The thick-walled rings are hot-rolled and often have to be cut in slices. MFL Liezen, from Austria, developed a saw that cuts these rings from inside diameters. AME Rockford, IL also offers such chainsaws; However it cuts the ring from the outside.
General design
Carbide saws in ways (horizontal, vertical or oblique slide arrangements) consist of a weld base made of a fairly grooved solid steel plate and often filled with vibration damping materials. This base absorbs the force that occurs and dampens the vibration. The hardened ways are locked at the bottom of the slide gearbox.
This slide is guided by a gibs taper with a minimum game, or a hydraulically operated gibs that can be loaded to eliminate the game, to obtain the required stiffness. Recently, preloading linear methods have also been used. Experts are still debating, if the way boxes are loaded with a low friction plastic layer is a better vibration damper than preloading, a hardened linear way with a hardened ball or roller.
Feed system
The feed system consists of a hydraulic cylinder or ball screw and a damper, powered by a servo motor.
Gearbox
Most of the time, low case-hardened backlash gears mounted in ball-or-taper-roller bearings are used. Depending on the size of the saw blade, a maximum of five sets of teeth with 40: 1 tooth reduction can be used. Variable speed motor up to 150 KW drives the gearbox directly or via timing or belt "V". Many saws have blade mounting flanges integrated in the spindle. It's cheaper, but requires expensive maintenance when the surface of the blade is worn. However, some of the more innovative saws have removable hub drives that are rigidly mounted, and can be easily replaced. Some saws also use flywheels on the input shaft of the gearbox to smooth the torque fluctuations.
Schedule
Usually consists of two hydraulic clamping cylinders that clamp the material on both sides of the saw blade in a horizontal, vertical, or angular manner. To improve the life of a saw blade, the material is separated from the blades on both sides before the saw blade is pulled from the piece.
View blade installation
The saw blades must be fitted firmly to the driveshaft to deliver large amounts of torque without vibration. The larger blade blade usually reduces blade vibration, but requires a larger blade diameter. To reduce the cost of blades, some manufacturers use smaller flanges in combination with a blade stabilizer and thus can reduce the cost of the chisel.
Blade stabilizer
Because the carbides see circular blades, they are radically the most powerful element of the power train in the feed direction, but they are very unstable perpendicular to the direction of the feed. Because of the thin blade body, the blades must be stabilized to minimize the amplitude of the side vibration. When the first experiments with a saw carbide were made, engineers developed Advanced Machines & amp; The technique at Rockford stabilizes the blades by using a broom that is pushed into a vibrating blade, minimizing vibration. From this experience, the blade stabilizer was developed using two plastic coated ball bearing mounted on the eccentric shaft and supported by a bracket welded to the gearbox. Horst Doepcke, who saw this method during the experiments performed by Metalcut, also described them in his dissertation "SÃÆ'¤gen von Rohren mit hartmetallbestÃÆ'¼ckten KreissÃÆ'¤geblÃÆ'¤ttern". The further development of Amsaw causes segment stabilizers, where on both sides of the adjustable plastic-plated plate blade minimizes blade vibration (AME). Other manufacturers then use the same slide element as "vibration dampers". This error-labeled vibration damper does not damp the oscillations, but only minimizes the amplitude. Mr. Doepke explains this function in detail in his dissertation. Recently Advanced Machines & amp; The Engineering Company has developed a pair of front stabilizers for an AMSAW engine that is set close to the point at which the blade enters the material. This stabilizer extends hydraulically, when the carbide gear has moved past the tip of the stabilizer before cutting and stabilizing the blade which also helps direct the blade into pieces to improve the accuracy. Other forms of stabilizers are listed in German at Verlag VDI No. 1999 by Dipl.-Ing. Rainer Liebrecht. This report primarily addresses the effects of vibration on chainsaws.
Measuring device
In general, there are two different types of measurement systems:
1. Measurements with gripper clamps: The billet is clamped with a gripper clip that is slid by means and operated by a combination of servo-screw motor.
2. Measurements with stop measuring: Bills are pushed through the conveyor roller to the adjustable stop. This stop can be positioned accurately by the screw ball servo mechanism and usually combines the shock absorbers to dampen the impact. This method is used for longer pieces.
Control
Automatic saws are mostly operated by PLCs.
Blade diameter
Small diamond saw blades are cheaper and require less torque to drive. A thinner saw blade discards less material and requires less energy to spin. Therefore, it is desirable to use small diameter drive hubs for blade and thin blades to see larger diameter materials with smaller diameter saws. This criterion somehow weakens the lateral stiffness of the blade and the blade may vibrate more due to the ratio of the thickness of the diameter/large knife.
Gear kicks
Gear kicks, especially spindle gear sets, are also important. The ratio between blade diameter of 1800 mm (70 ") and pitch diameter of approximately 250 mm (10") spindle teeth is about 7/1. Thus, the 0.025 mm (0.001 ") tooth play produced 0.18 mm (0.007") loss of movement in the tooth gear.
The large amount of lost movement is added to the torsional windup of the gear gear, when the tooth gets into the wound and relaxes when it exits, inducing torsional vibration and should be minimized by using anti-backlash mechanism or by grinding the set of gears to the absolute minimum game.
Machine rigidity
When a carbide-tipped saw blade curves in or out of the material, only one tooth is cut. Fluctuations in load, when the teeth enter and exit the wound, cause vibration and require very stiff boxes and gear machines.
A pivot view has the highest stiffness, because the forces are arranged in a closed loop (figure 1). If we assume that the base of the saw is very rigid, the force will flow from the gearbox shaft to the ball screw feeding system in a closed loop, where the cutting force moves in the middle, approximately, between the rotation point and the ball screw. This arrangement substantially reduces the lost motion and compliance in the feed system. Furthermore, the drive screw ball that forces the blade into the cut darts into the frame fixture which is again clipped onto the billet and gives this setting additional rigidity.
Saws with horizontal or slanted slides have an open loop style flow (fig. 2) and maintain any lost motion and feed system compliance.
Summary
The closed loop of the vertical slide saw is the heaviest, but also the most expensive machine. They require less space than horizontal shear or angle saws, but also more difficult to control the flow of horizontal chips. They are also more expensive and harder to serve.
Horizontal and angle type saws should be built heavier to maintain the same stiffness as a vertical saw or axle. The chip flows down and is therefore better to control than a vertical saw.
The horizontal cutting pivot saw is the most cost-effective machine. They require less parts and floor space and have a profitable downward chip control. The closed loop system reduces compliance and hence can be built lighter, while maintaining high stiffness.
External links
- Goellner bar-cutoff Saw Abstract
- Metalcut XII Saw Abstract
References
Source of the article : Wikipedia
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