Auxiliary machine
DATE：2022/8/15 8:47:10 / READ： / SOURCE：This station
Auxiliary machine
The plastic is melted and plasticized by the extruder, extruded in the mold for forming the pipe, and the pipe blank is formed. After cooling, shaping, traction and cutting, the pipe blank becomes a plastic pipe; Due to the need of installation and connection, the diameter of some pipes needs to be expanded with a flaring machine at the pipe end. These devices used in the production process of pipe blanks are auxiliary machines for plastic extrusion forming pipes.5.1.2.1 cooling water tank
The structural form of the cooling water tank is shown in Fig. 5-12, which is a cooling water tank structure commonly used for extruding small-diameter plastic pipes. The water tank is made of welded steel plates and connected with steel pipes to form water supply and drainage. Cooling water is introduced into the tank, and the whole cooling water tank can move back and forth along the pipe running center line. This facilitates the installation and disassembly of the forming die and the operation and adjustment of the wall thickness of the tube blank. (1) The function of the water tank: after the setting sleeve, the water tank is mainly used to immerse the formed pipe extruded by the setting sleeve into the water to further cool and solidify the pipe. The water tank structure in Fig. 5-12 is suitable for application when the pipe diameter is less than 100mm. For the cooling when the pipe diameter is large, the buoyancy in the water is large, and the cooling of the pipe is uneven and easy to bend. Therefore, the cooling of such large-diameter pipes should adopt the spray method, spraying cooling water on the circumference of the pipes at the same time, so that the pipes can be evenly cooled. (2) Precautions for use of cooling water tank ① the circulating cooling water in the water tank shall enter from the water outlet end of the pipe and be discharged from the water inlet end of the pipe, so as to gradually reduce the temperature of the pipe blank from high temperature to low temperature, and prevent the sudden temperature drop of the pipe from causing great stress on the product and affecting the quality of the pipe. ② Pay attention to adjust the center line of the inlet and outlet pipe holes on the water tank and the center line of the mold on the same horizontal center line to prevent the pipe from bending. ③ Drain the cooling water in the water tank when the production is stopped.
5.1.2.2 tractor
The structure of the tractor is usually roller type and crawler type. The structure of these two types of tractors is shown in Fig. 5-13 and Fig. 5-14. When the roller tractor works, the center distance of the upper and lower pressure rollers is adjusted by the distance adjusting screw according to the diameter of the pulled pipe. When the upper roller moves down to compress the pipe, the traction speed of the driving roller as the lower roller shall match the extrusion speed of the pipe from the die mouth (according to the requirements of the pipe traction ratio, the traction speed of the pipe is generally slightly faster than the extrusion speed of the pipe blank from the die mouth), and the pipe shall be smoothly pulled and transported to the cutting machine. Precautions for use of tractor are as follows. ① Before the production and start-up of the tractor, it is necessary to adjust the running center line of the pipe clamped by the driving wheel and the driven wheel to be on the same horizontal center line as the center line of the forming die. ② The running speed of the tractor shall be adjustable at any time, and the speed of the running speed shall be adjusted smoothly so as to meet the technological requirements of the tractor for the speed ratio of the tube billet. ③ The traction pressure of the traction roller (belt) on the pipe shall not be too large, and it shall be subject to the smooth operation of the traction pipe without slipping. ④ The operation speed of the tractor is relatively slow, and the lubrication of the transmission reduction gearbox in the equipment is easily ignored. It is required to check whether the lubricating oil is sufficient once a quarter, and open the box once a year to maintain the transmission parts. 51.2.3 the cutting machine extrusion molding pipe has a fixed length specified in the standard. The cutting machine on the pipe extrusion production line is mainly used to cut the pipe according to the required length. There are several methods for cutting pipes. When the diameter of the produced pipe is small (less than 50mm), it is usually cut manually with a saw. Large diameter pipes are cut with a cutter. The cutter on the cutting machine can be cut with a circular saw blade or a circular grinding wheel. The saw blade or grinding wheel is directly driven by the motor and V-belt to rotate at high speed. When the extruding pipe reaches the required length, the clamping device on the cutting machine clamps the pipe, and the saw blade starts to cut the pipe. At this time, the whole clamping and cutting mechanism slides forward on the rail of the cutting machine with the extrusion traction force of the pipe moving forward. When the pipe is cut, the saw blade stops rotating, the clamping device opens, and the cutting clamping device returns to the original position along the original forward track to prepare for the next cutting action. When producing large diameter pipes, planetary automatic cutting machine shall be selected for pipe cutting. The cutting blade of the planetary automatic cutting machine is composed of a plurality of small-diameter saw blades, which form a circle around the pipe to be cut. When the pipe needs to be cut, these small-diameter saw blades can not only rotate at high speed but also revolve around the outer circle of the pipe. Using this method to cut large diameter pipes, the cutting speed is fast and the end face of the cutting mouth is flat. Precautions for use of cutting machine are as follows. ① The center line of the pipe after the clamping device is adjusted and the center line of the upper pipe of the tractor is on the same horizontal center line; The running track of the clamping and cutting device is parallel to the running center line of the pipe. ② Before each cutting and start-up production, check whether the clamping of all working parts is firm, and tighten the loose fastening screws. ③ Note that the high-speed rotating saw blade is not allowed to swing when working; The center distance of V-belt drive shall be adjusted frequently, and the belt shall not slip during operation.
5.1.2.4 flare device for pipe end flare
For the installation and connection of plastic pipes, small-diameter pipes are generally connected by pipe fittings (tees, elbows and joints), and large-diameter pipes are usually connected by expanding their ends. When connecting, the two pieces shall be fixed and glued with adhesive at the joint. There are two forms of pipe end flaring: one is flat flaring, and the other is flaring the pipe end with a sealing rubber ring. When the pipe end is flared, first heat the rotating pipe end evenly with hot air or resistance heater to make it reach the softening degree required by the flared process, then configure the flared die according to the required flared shape. The flared die moves toward the pipe end under the pneumatic or screw rod, enters the pipe end for flared, and finally cools the pipe end through the die through air or cold water.
Author：admin