Wuhan Handern die structure
DATE：2021/1/29 8:48:33 / READ： / SOURCE：This station
Wuhan Handern die structure
① Compression ratio, extrusion die compression ratio, is the ratio of the maximum cross-sectional area flowing into the cavity to the cross-sectional area of the daily calibration annular slit. It is suitable for low station materials and high viscosity materials. Casting film equipment www.handern.com② For low viscosity materials, the selection of R and θ is related to the material characteristics. For high viscosity materials, try to control 0. =30 ~ 60 ° range. The size of the shuttle is generally less than 2.5mm, and the material will be stagnated in the production area.
③ The transition compression angle θ and compression angle 6 of the mandrel and die directly affect the finish of the pipe. If 0 is too large, the surface of the pipe is rough obviously, and the compression transition section is (0.8 ~ 1.5) l; the compression angle must be adjusted through the transition section to make 0 = 14 ~ 50 °. For high sugar materials, the lower limit of the compression angle and transition section should be taken.
④ Draw ratio I tube grain elongation ratio refers to the ratio of annular gap area of die setting section to tube area.
There are two methods of tube extrusion setting: inner diameter setting and outer diameter setting.
(1) The sizing sleeve (or plate) of the inner diameter sizing method is usually used for the right angle die, which is connected with the outlet floor blue die, and the cooling water is circulated in the setting sleeve (or plate): the semi melted pipe is also directly sheathed on the Dingdeng Road (plate) from the die, so that the pipe products with a certain inner diameter and better roundness can be obtained. This sizing method is suitable for PE, PPPA and other plastic pipes, and it is easy to guarantee the inner diameter tolerance of pipes. The setting sleeve of the inner diameter setting method should be designed as the key degree, the taper is 0.6 ~ 1%, and the general length is 80 ~ 300 mm. When the outer diameter of the setting sleeve is 2-4% larger than the inner diameter of the pipe, it is helpful to control the tolerance of the inner diameter of the setting sleeve, which can make the inner diameter of the pipe stick to the outer diameter of the setting sleeve, and ensure the smoothness of the inner wall of the pipe. Casting film equipment www.handern.com
(2) Setting sleeve of outer diameter setting method
① This kind of setting sleeve is suitable for the production of hard PVC pipe material by ejection method. The pipe is pushed to the outlet die and setting sleeve by the screw of extruder without traction device.
② Vacuum adsorption setting sleeve vacuum adsorption setting is to make the outer wall of the pipe close to the inner wall of the setting sleeve with the help of vacuum adsorption force. At the same time, cooling water is put into the setting sleeve, and the pipe is cooled and hardened through the vacuum adsorption process, and the pipe that conforms to the inner diameter shape and size of the setting sleeve will be obtained. The vacuum degree generally requires 0.053 ~ 0.067MPa (400 ~ 500mmhg). The diameter of the vacuum hole is generally in the range of 1.6 ~ 1.2 mm, and its size depends on the wall thickness of the pipe and the material characteristics. The structure of vacuum setting sleeve is shown in Fig. 9-15ii. There should be a distance of 20 ~ 100 mm between the vacuum setting sleeve and the die mouth of the machine head. Casting film equipment www.handern.com
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