PVC sheet
DATE：2022/11/5 8:35:08 / READ： / SOURCE：This station
PVC sheet
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
Key points of process operation
Timely fine lines
① At the beginning of the section, the temperature at the joint of the barrel and the forming die increases gradually.
② The mold temperature is slightly higher than the barrel temperature. The higher temperature shall be controlled at 5~10 ℃. The temperature at both ends of the mold is slightly higher than the temperature in the middle of the mold, and the higher temperature is controlled at 5~10 ℃.
③ As shown in Figure 6-3, the upper roll surface of the intermediate roll of the three rolls should be on the same horizontal plane with the lower plane of the die lip; The lip end face is parallel to the center line of the intermediate roll, with a distance of 50~100mm.
④ The clearance between die lips shall be slightly less than or equal to the thickness of plate products, and the clearance between die lips shall be slightly less than the clearance between end die lips on both sides.
⑤ Note that the roughness R of the three roll working surface shall not be greater than 0.2 μ m。 When cleaning the roll surface, it is not allowed to scratch the roll surface with a hard steel knife. Instead, a copper knife should be used to clean the residue on the roll surface.
⑥ The roll surface shall have some middle height; The clearance between the three rolls shall be equal to or slightly greater than the thickness of the plate.
⑦ The temperature control of the forming die shall be stable. When the temperature is high, the molten material flows faster in the mold; When the temperature is low, the molten material flows slowly in the mold. Unstable melt flow rate will cause large longitudinal thickness error of plate (sheet) products.
⑧ Pay attention to controlling the working surface temperature of the three rollers. The temperature of the sheet feeding roller should be slightly higher and the temperature of the sheet discharging roller should be slightly lower. The roller surface temperature is too high, the slab is not easy to roll off, and the product surface is easy to produce transverse lines; The temperature is low, and the surface of the product is dull. According to this phenomenon, the roller surface temperature control should be adjusted in time.
⑨ The running speed of the three rollers should be slightly higher than the extrusion speed of the slab from the die mouth. Generally, the speed difference should not exceed 10%. The three working degrees should be controlled stably. Too fast or too slow running speed has a great impact on the thickness error of the slab.
The forming of PVC corrugated plate is very simple. During production, just heat and soften the PVC hard plate, roll it with a group of arc shaped convex and concave steel rollers to form corrugated plate, and then cool it to shape and cut it to form corrugated plate products.
Author：admin