Equipment conditions Plastic bridge forming technologist manual
DATE：2022/11/4 8:40:24 / READ： / SOURCE：This station
Equipment conditions Plastic bridge forming technologist manual
The diameter is selected according to the data in Table 7-2. The screw structure is of equidistant gradual change type, with L/D>20:1 and compression ratio of 3. Generally, branch pipe type or screw distributed T-shaped mold is adopted for the selection of mold structure.Forming process
① See Chapter 4 for mixing process parameters and requirements of raw materials.
② Extrusion plasticizing raw material barrel temperature.
a. The feeding section of hard board (sheet) is 120~130 ℃, the plasticizing section is 130~150 ℃, and the homogenizing section is 160~180 ℃.
b. The feeding section of soft board (sheet) is 100~120 ℃, the plasticizing section is 130~140 ℃, and the homogenizing section is 150~160 ℃.
③ Forming mold temperature
A. The middle part of the hard board (sheet) is 155~165 ℃, and the two ends are 170~180 ℃.
b. The middle part of the soft plate (sheet) is 145~155 ℃, and the two ends are 160~170 ℃.
④ Three roller calender roller temperature
a. 70~80 ℃ above, 80~90 ℃ in the middle and 60~70 ℃ below the hard board (sheet).
b. 60~70 ℃ on the soft board (sheet), 70~80 ℃ in the middle, and 50~60 ℃ in the lower.
Quality requirements The quality requirements of PVC sheets (sheets) shall comply with the provisions of GB/T 4454-1996. See Table 7-8 for the dimensions of plates (sheets). See Table 7-9 for the appearance quality requirements of plates (sheets).
Table 7-8 Dimensions of PVC sheets (sheets) (excerpted from GB/T4454-1996)
Nominal size of the project/mm Limit deviation/% Limit deviation/mm Variable thickness d 2 ≤ d ≤ 20 10 ≤ d<50
Width 6 ≥ 700
Length L ≥ 1600+15 ± 15 rolls
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