Common Problems and Solutions of Pvc Wood Plastic Wallboard
PVC wallboard is a kind of PVC products rising rapidly in recent years; products with environmental protection, beautiful, moisture-proof, convenient installation and other advantages quickly win customers love. In the process of PVC wallboard extrusion, the common abnormal state is mainly: the wall board is not straight, the wall board is uneven, the surface is not smooth, density, wave lines, toughness is not good, etc., encountered these problems we should how to solve it?
Panel is not straight
First of all, check whether the mold and the mouth mold are right. In general, the wall panel is bent upward probably because the mold mouth and mouth mold are not right, and the position is on the high side. The wall panel is bent down because the mold mouth appears low.
In the case that the mold mouth and mouth die have been aligned, then check whether the water cooling tank, traction and saw table are aligned with the mold.
After these reasons are excluded, there are two possible causes of indirectness:
(1) The cooling degree of PVC wall products is not enough, followed by the water cooling tank after the temperature is still relatively high, in the case of external force and distortion, specific adjustment method to increase the cooling water and water cooling groove mold or to reduce the cooling water temperature, no more directly reduce the speed of production;
(2) The discharging speed on both sides is inconsistent, the adjustment method: adjust the temperature on both sides of the mold to the same observation for half an hour, if there is no change to see which side of the discharging speed is slow, which side of the temperature increase a few degrees, or which side of the discharging fast temperature to reduce a few degrees.
PVC wallboard local uneven
General wall panel local convex and concave mainly in the mold of the vacuum forming section. If vacuum degrees is not enough, or finalize the design mode cooling water is not enough, the adjustment method is to increase the local cooling water, through water seal to improve vacuum degree, to speed up the cooling speed of wallboard products. If the local water is not equal to the maximum, then the mold will be removed to clean its true air path.
The overall surface of the wall panels is not smooth
The reason is that the overall temperature of the mold is too high or the vacuum pump of the extruder is not working properly. Adjustment method: reduce the overall temperature of the mold by several degrees or clean the vacuum pump of the extruder.
Wall crack reinforcement
See if there is damage to the wall panel water situation. Or the content of lubricant in the formula is on the high side, especially the amount of external lubrication. Or the use of inferior stabilizer, internal and external lubrication amount is more, less stable components.
Too much density, bad foaming
First of all, see whether the lubrication is balanced, lubrication is too much, causing the melt strength to decline, the bubble hole becomes larger, the density will increase. Again, the dosage of foaming agent can be appropriately reduced or the dosage of regulator can be increased to see whether there is an effect, and the situation can be adjusted according to the feedback.
The main reason is caused by uneven discharge, resulting in uneven discharge of the reasons are: excessive plasticizing melt too soft; Uneven material flow; Traction and extrusion mismatch; Melt strength is too high and rebound
We can solve this problem from the following aspects:
1) Reduce the production speed, such as screw speed, feeding speed, etc., and adjust the traction speed appropriately; sometimes in production the wavy lines disappear by adjusting them this way.
2) Reduce the extrusion temperature, especially the temperature of the plasticized section in the third and fourth zones. The clapboard that itself produces now a lot of enterprises use small tube maester, model steel maester or foamed sheet maester to undertake production, these maester belong to two times process maester, plasticize is extremely fast, reduce plasticize appropriately to produce and product stability have certain advantage.
1. Adjust the gap of the screw, reduce shear appropriately, and slow down plasticizing;
2. Clean the die head and polish it, especially at both ends of the die, so that the molten material flows smoothly.
3. Check the mold has a problem, such as forgetting to install the positioning pin, or whether there is a problem with the screw, such as different heart, which will cause the material flow bias, generally only in the side of the material wave pattern, and it is difficult to eliminate by adjusting the formula.
1. Appropriately increase the amount of external lubrication, reduce the amount of internal lubrication, but not too much adjustment
2. Do not affect the premise of foaming, foaming regulator can be appropriate to reduce or choose the foaming regulator with small melt strength, this situation is only limited to the case of melt strength is too large, to prevent the material out of the die due to melt strength is too large rebound, the formation of wave lines.
Toughness is bad
The first is to use too much plastic steel material, small tube material and other secondary materials. Secondly, consider whether the amount of external lubrication is too much, especially the use of cheap stabilizer, in order not to paste, the amount will increase, will lead to the overall formula of external lubrication amount is too much. Again consider whether PVC material plasticization is in place, poor plasticization or over plasticization will make products brittle. Finally, if these problems are eliminated or the toughness is not enough, the toughening modifier CPE-135A can be appropriately added.
In the production process of PVC wallboard, attention should be paid to the state of equipment, surrounding health and discipline. The equipment status should be noted as follows:
(1) Whether the host current and nose pressure are appropriate;
(2) Whether the temperature on the temperature controller and each ammeter can work normally;
(3) Whether the temperature of the main motor and reduction box is too high;
(4) Whether the vacuum pump is normal;
(5) Whether the thermocouple of the mold can be inserted to the end (6) whether the water and electricity are normal.