Chapter 1Introduction1Chapter 1 IntroductionWith the rapid development of China's economic construction, construction also has been rapid development. The reinforcement material as an important construction projects, the demand is growing dramatically, which effectively pulling the market demand for steel automatic cutting machines. And in recent years, high strength, good ductility and excellent performance, quick been widely used in the national construction of its new steel grade III. It also put forward higher requirements for buildings with steel automatic cutting machine [1]. For this reason, many companies have invested a lot of money, competing development, development for high-speed, large-diameter steel reinforcement required by the new class III under the automatic feeder.China's introduction in 1958, the Soviet Union's bedroom steel automatic cutting machine drawing, began to produce the country's first steel automatic cutting machine, the production of GQ40A type steel automatic cutting machine is its improved. 40A cutting machine is fully open architecture, all of the transmission gear all exposed. Thus, the dust-poor performance, easy to wear, cutting the number of 28 beats / min, and no clutch control, safe operation, quality, volumes are larger. More than 20 cutting machine manufacturer, from 1966 to 1985 has been the model for leading products. 1982 Taiyuan Heavy Machinery Institute machinery plant design GQ40BII type steel automatic cutting machine at the crankshaft gear mounted on a rigid turn key clutch pedal steering mechanism controlled by cutting, while retaining material and fitted with feeding device. The models for safe operation, accurate cutting length, reduce labor intensity. Currently under GB50B series steel feeder on the market with a fully enclosed, lubrication systems, Flying Wheels, Huff cabinet structure, and therefore, easy maintenance, safety and reliability, high efficiency, light weight, energy section. Other types of steel automatic cutting machine, such as the GT series automatic steel cutting machine is mainly used for straightening, cutting length of cold-rolled ribbed steel, hot-rolled and cold-rolled steel grade III round bars. This series of high degree of automation, equipment failure rate for continuous duty mode. Low energy consumption, without prejudice to the ribs, without even cutting, low noise, vibration light and equipped with safety devices, automatic stopping device count, there are efficient and reliable operation of the trial [2]. In addition, there are many on the market reinforced hydraulic automatic cutting machine, such as DYJ-32-Hebei United University School of Continuing Educationand YQJ-32 type automatic hydraulic steel cutting machines, cutting machines both have adopted a piston pump driven by the main cut to the structure, convenient operation, but processing difficulties, difficult to ensure accuracy, can not achieve rapid return, low efficiency. Compared with the international advanced products, the overall level of China's steel automatic cutting machine is still relatively backward. Main features: small-scale enterprises, low-tech products, low productivity, high level of automation level is not rough appearance quality [2]. Most of the products and the modulation speed is low, not high straightness reinforced, scratch the surface of the heavierThe face of an increasingly competitive Chinese construction machinery market, investments in technology, emphasis on new technology, new product research and development, improve product quality, so that the company's products continue to meet the needs of customers, to shorten the gap with foreign companies forward as soon as possible [1], is China's steel automatic cutting machine reached the international advanced level, is undoubtedly China's vast steel automatic cutting machine manufacturer only way to survival and development1.1 steel automatic cutting machine applications, status and prospectsApplication of (1) in the next feederSteel automatic cutting machine is a tool used by the shear reinforcement. Generally have automatic and semi-automatic steel cutting machine steel cutting machine of the points. It is one of the essential steel processing equipment, it is mainly used for building construction, bridges, tunnels, power plants, large-scale water conservancy projects for steel and Cutting. Compared with other steel cutting machine cutting equipment, light weight, low energy consumption, reliable operation, high efficiency, and therefore is widely used in recent years gradually machining and small rolling mills, etc., in all areas of the national economy played an important effect. Steel automatic cutting machine, there are two types of automatic cutting machine called the electric off, the motor is converted into kinetic energy by controlling the cutter cuts to achieve the effect of shear reinforcement. The semi-automatic is manual control incision, thereby shear reinforcement operation. At present, more is should belong hydraulic steel cutter cutting machine, hydraulic steel cutting machine and portable rechargeable divided into two categories.Chapter 1Introduction3Due to cost and efficiency factors, more small businesses to choose a manual hydraulic cutting machine cutting, length and efficiency to control by the workers, the efficiency is not high accuracy, and are often not able to meet production needs, so the design is automatically cutting machine, pressing rollers carried by the feed, and two pairs of rollers for straightening, when it reaches a predetermined length, by electrically controlling the hydraulic cylinders push the knife for cutting, and is to ensure that each simultaneously cutting a plurality of when the length of the same size, at the same time, but also to ensure high efficiency in medium and large enterprises has been widely used, which greatly improves the efficiency of cutting steel.Development Status (2) cutting machinesForeign cutter eccentric shaft eccentric distance is large, such as Japan, vertical cutting machine eccentricity 24mm, while the domestic is usually 17mm. Seemingly and material, some small gear structure, but give users the trouble, is not easy to manage. Because when you expect from the big cut cut small material, not the tool change is to change the blade pad, and sometimes need to convert angles.Rack cutter are foreign steel plate welded structure, parts machining accuracy, especially in the heat treatment process roughness excellent, the cutting machine to put too load, fatigue failure, worn over other aspects of domestic machines.Domestic cutter blade design is unreasonable, single bolt, blade thickness thin enough, 40-and 50-type blade thickness are 17mm; while abroad are double-bolted, 25 ~ 27mm thick, so the foreign forces and blade life, etc. comprehensive performance are excellent over the country.Domestic cutter cut fewer times per minute. China is generally 28 to 31 times higher abroad 15 to 20 times, 30 times higher than the highest high efficiency.Foreign models generally use a semi-open structure, gears, bearings with grease lubrication, crank shaft, connecting rod bearing, red knife, twist added by hand at oil lubrication. Domestic model structure fully open, fully closed, half open, half closed three kinds, have centralized lubrication oil lubrication and splash lubrication of two kinds.Domestic cutter appearance quality, overall performance unsatisfactory; shown in Figure 1-1; foreign manufacturers are generally scale production, willing to invest in technology and equipment, high level of automation, the formation of a comprehensive quality assurance process systems. In particular, the appearance Hebei United University School of Continuing Educationquality is better, cover one-time stamping, paint by spraying paint color with scientific and reasonable, there is not much the outside welds, burrs, sharp corners, the overall smooth appearance. Some domestic manufacturers although Figure 1-1 domestic rebar cutter cutting machine commonly used in the overall figureProduction history is long, but no one scale, coupled with aging equipment, processing physical fight, experience, production processes consistent system for decades, so the rough appearance of quality, perception is poor.(3) under development prospects steel automatic feederDomestic use from the current situation, hammer, reinforced mechanical structure of the automatic length cutting machine dominates. This is mainly because of high precision mechanical length of the length, suitable for the production of prestressed reinforced concrete, reinforced this structure under the automatic feeder reinforced its forward speed is generally 0.5 ~ 0.8m / s . The length of reinforced user less precision, reliability is a major requirement, the failure rate should be as low as possible, the output should be as high as possible [8]. For this reason, the use of hydraulic cutting machine mechanism is simple, reliable performance and shorten its cut time and improve productivity in the future development direction of steel straightening and cutting machines.But the automatic hydraulic cutting machine steel shear rate than slower. If hydraulic cutting machine 0.5S need to complete a cut, while the forward speed steel is 0.5m / s, the shearing process requires hydraulic shear reinforcement ahead with 0.25m, so you need to slide under the hydraulic steel feeder long as the forward speed is greater than the steel 0.5m / s, the guide rails and the forward speed increases with longer [9]. This shows that a key factor in the lower steel automatic cutting machine Chapter 1Introduction5Straightening speed lies in the cutting cycle is too long, which greatly limits the cutting machine efficiency.Domestic auto cutting machine shearing time generally in 80 ~ 120ms, which can only lead to straighten speed hovered between 50 ~ 70m/min. The rate of foreign Straightening Straightening Machine reason are generally able to reach 120m/min, the main reason is to be able to cut the time down to less than 20ms. So, when asked how to shorten the automatic feeder shear is an important task to improve steel automatic cutting machines. Steel automatic cutting machine cut to length required to achieve not only high-precision control, while required to have a relatively high production efficiency. So, how to use the following features of hydraulic steel automatic feeder, make steel electro-hydraulic automatic cutting machine to achieve a high degree of integration, give full play to their respective advantages, will be the main direction of future research.1.2 Classification and Features automatic cutting machineCurrently, the production and sale of steel on the market many types of automatic cutting machine, according to the characteristics of facilities and working bodies, can be classified according to the following six ways: by length mode, press blanking mode, press control, press a material way, by the way, and by cutting off straightening way. Here are several ways on this introduction Mechanical and electromechanical: length mode (1) Length way steel cutting machine generally exists in two ways.Mechanical length error is small, easy to control, but noisy, short life. Length of error requirement applies to the higher speed is not critical.Electromechanical length error is slightly larger, less noise, and long life. For the lower tolerance requirements for length, straightening speed requirements of the occasion.Cut to length signals emitted roughly three forms: Telecommunications No. mechanical signals, electrical limit switch (contact or contactless) issued photoelectric encoder issued.Generally, the accuracy depends on the length of time the signal issued from the error response to the cutter. High precision mechanical signals, the error in plus or minus 1mm, because it is directly associated with the cutter, short response time, the time error is small. Other forms of length error of plus or minus 5 ~ 30mm.Hebei United University School of Continuing Education(2) the way blanking blanking main methods of supporting pillar, turn plate, withdrawal plate and open type four.support pillar structure is simple, small job noise. Suitable for small diameter round bar and rebar straightening high degree occasions.turn plate structure is more complex, larger work noise. For large, medium diameter steel.withdrawal plate structure is more complex, larger work noise. For large, medium diameter steel.Simple open structure, a smaller working noise. For large, medium diameter steel bars, and high bar straightening of the occasion.(3) Control Control of ordinary electrical control and PLC control.Normal electrical control circuit complexity, higher requirements for maintenance personnel. Low control accuracy, ease of failure, the initial commissioning of trouble.PLC control circuit is simple, do not ask for maintenance personnel. High control precision, stable operation, the initial commissioning simple.(4) In a material way the way to separate the material and non-unwinding roll style.complex unwinding devices, actinomycetes speed steel twist is not particularly suitable for high speed operation.non-open-book-style single device, suitable for straightening speed is not too high in the workplace. When actinomycetes reinforced natural twist.(5) Straightening way reinforced mode automatically straighten the main feeder straightening mode, curve roll on and roll-to-roll straightening mode plus compound.Mode Bar Straightening Straightening effect, relatively easy to control. But straightening speed is low, the surface to be machined steel scratches, large work noise. This mode is suitable for a variety of plain bars.curve roller straightening faster, better steel straightening effect, and easy Chapter 1Introduction7to control. But scratch the surface to be machined steel heavy work noise as well. For a variety of light round steel and reinforced surface scratches less demanding situations.on roll straightening speed steel surface to be machined with a slight scratches, small working noise. Steel straightening effect in general, higher control requirements. For a variety of steel, especially for cold-rolled ribbed steel bars.straighten mode plus composite roller straightening effect is better, easier to control. Straightening roll faster than the curve below on roll. Processed steel surface scratches, working noise is relatively small. For a variety of reinforcement.(6)Different ways of cutting off the way, largely affects the performance of cutting machine, the following will cut a variety of ways described in detail, to analyze its working principle and characteristics. By cutting moves the cutter can be divided into: Rotary Cut, cut and down up and down the mobile shearing three [5], it works shown in Figure 1-2.Hebei United University School of Continuing EducationFigure 1-2 off three kinds of waysWhen working around the rotating frame of steel in the continuous rotation of the traction wheel and frame straightening roller straightening the joint action, from the knife through the middle, into the Order of the rack. After adjusting reinforced when the tip touches the straight length device signal generator, a signal generator, actuator cutting tool to cut off the steel tool returns to the starting position next time.Rotary cutting system consists Cheng rack, fixed-length switches, solenoids, jaw, active gear, cut gears, brakes and other components. When reinforced through two slits cut into the Order of the intermediate gear rack and fixed-length touch switch, driven by an electromagnet so fly jaw clutch shaft and drive gear shaft, pinion gear rotation drive gear rotates third week off while cutting steel. On three pairs of uniform cut gear teeth and take turns working to extend tool life.Cut down mobile rack system consists Cheng, fixed-length switches, solenoids, turn key clutch, crank and connecting rod, pan-style units under the knife, swinging the cutting blades, brakes and other components. When reinforced by entering the Order of the rack and pan-style touches length under the knife switch, turn key clutch solenoid drive shaft and the crank shaft so fly connection, connecting rod crank role in promoting pan-type knife table in the next four-bar linkage under forward. Cut one end of the swing blade fixed to the frame, the other end of the blade close to the edge of the pan-style units under the knife, when the pan cutter station along the arc trajectory, the relative movement of the two blade edge, cut steel, knife sets reset crank so wait for the next cut.Form down shearing systems are more driven by the form of the tool can be divided into: swing, hammer, hydraulic.Swing off mode: This device is similar institutions a guillotine shear, when reinforced by fixed fixed knife into the Order of the holes on the rack and rack touches length switch, clutch friction plate with cam shaft rotation, so that the cam swing arm with the cutter, a cutting operation to complete. Currently imported automatic cutting machine shearing mechanism mostly adopt this approach.Hammer off by: Most domestic ribbed steel plants and precast plant to use automatic cutting machines are used in such institutions. The device is driven by the motor rotates a crankshaft, a high-speed hammer kept moving up and down under the action of the crankshaft, the position of the hammer on the back of a sliding knife sets, knife cut off the platform with a steel cutter. When reinforced advance to a Chapter 1Introduction9predetermined length, length steel plate and slide the knife touched the tip attached units, cut to length plate knife sets driven forward. When the station moved the knife up and down movement of the high-speed hammer, the hammer blow of the knife blade platform, the cutter on the steel cutting knife, cut rebar falls within the Order of the rack, and slide the compression spring knife sets quickly pushed back to the original location, to avoid being the second hammer blow. Hammer cutting mechanism, has long been in existence even cut problem called chronic problem industries. With the development and application of “zero even cutting device stamping and cutting equipment hammer“ patent technology, not only solve the problem even cut off body hammer and straighten good, the length of error is small. Hydraulic cutting method: by cutting into the steel edge Cheng rack touches length signal, which can control the operation of the hydraulic cylinder, the hydraulic cylinder piston rod end is provided with a cutter to cut steel rod downward. This way depending on the cut, length accuracy length bodies are different.Despite hydraulic steel cutting machine cutting machine is later than mechanical , but it has unparalleled technical superiority and high economic efficiency. Its technical superiority roughly in the following areas :( 1 ) has a higher performance because the higher hydraulic pressure can be used , and thus automatic cutting function reinforced high impact force to cut .( 2 ) has a lower operating noise out of the gears and other mechanical drive , straight drive directly implemented by the cylinder, thus a simple structure , low noise .( 3 ) has a better ability to adapt the work can be achieved in a 6mm diameter steel processing between ~ 16mm of . At the same time , but also a multi-purpose machine , using different working head can be a variety of work , such as bending , perforation.( 4 ) having a higher reliability for all the clutch means is omitted , since the clutch device does not produce reliable and even cut , easy to automate production . Meanwhile, the control system is introduced , cut to length can be achieved , and to ensure the cut surface quality steel .( 5 ) easy to carry when the output power or output torque is the same, the weight of the hydraulic working head is much smaller than electric or pneumatic tools. In