How to solve the problem of PVC wood plastic foam wallboard?
In the process of pvc wallboard extrusion, common abnormal conditions mainly include: wall panels are not straight, wall panels are uneven, the surface is not smooth, high density, poor toughness, etc., how should we solve these problems?
Wallboard is not straight
First of all, it is necessary to check whether the fixed mold and the mouth mold are aligned. In general, bending the wall board upward may be due to the fact that the fixed mold mouth and the mouth mold are not aligned and the position is high; and the wall board is bent downward because the shaping mold mouth appears. Low condition.
Under the condition that the shaping die and the die have been aligned, check whether the water cooling slot, traction, and saw are aligned with the final model.
After these reasons are eliminated, there are two possible reasons for not being straight:
1 pvc wallboard products cooling degree is not enough, followed by the water cooling tank is still relatively high temperature, in the case of external forces and distortion, the specific adjustment method to increase the amount of cooling water in the fixed mold and water cooling tank or to reduce cooling Water temperature, if not, directly reduces the speed of production;
2 The speed of discharging on both sides is inconsistent. Adjustment method: After adjusting the temperature on both sides of the mold to the same level, observe for half an hour. If there is no change to see which side is discharging slowly, increase the temperature by a few degrees or which side Whichever material is faster, then which temperature is lowered by a few degrees?
PVC wall board uneven
The unevenness of local wall panels is mainly found in the vacuum setting section of the sizing die. If the vacuum is not enough, or the cooling water of the sizing die is not enough, the adjustment method is to increase the amount of cooling water in the part and increase the vacuum degree through the water seal to speed up the cooling rate of the wallboard products. If the local water is still unacceptably large, remove the sizing mold and clean the vacuum air path.
The overall surface of the wallboard is not smooth
The reason is that the overall temperature of the mold is too high or the vacuum pump of the extruder host is not working properly. Adjustment: Reduce the temperature of the mold by a few degrees or clean the extruder vacuum pump.
Look to see if there is any damage to the wallboard. Or the content of lubricant in the formula is high, especially the amount of external lubrication is too much. Or the use of a relatively inferior stabilizer, the amount of internal and external lubrication is too much, the stability of the component is less.
The density is too high and the foam is not good
First of all, to see whether the balance of lubrication, lubrication is too much, resulting in decreased melt strength, larger cells, the density will increase. Again, the amount of foaming agent may be appropriately reduced or the amount of modifier may be increased to see if it is effective, and the adjustment may be made according to the feedback.
The first is the use of excessive plastic materials, small tube materials and other secondary materials. Secondly, consider whether the amount of external lubrication is too high, especially the use of inexpensive stabilizers. In order not to paste, the amount will increase, which will lead to an excessive amount of external lubrication for the overall formulation. Considering whether the plasticization of PVC material is in place or not, poor plasticization or over-plasticization will make the product brittle. Finally, these problems can be ruled out if toughness is not enough, and toughening modifier CPE-135A can be appropriately added.
In the production of pvc wallboards, attention must be paid to the state of the equipment, surrounding hygiene and discipline. The state of the equipment should be noted: (1) Is the host current and the head pressure suitable? (2) Is the temperature on the temperature control table and each ammeter able to operate normally? (3) Is the temperature of the main motor and gearbox too high (4) ) Whether the vacuum pump is normal (5) Whether the thermocouple of the die can be inserted in the end (6) Whether the water and electricity are normal.
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