PVC Wall panel problems and soluations

2020年 10月 01日(木曜日) 19:49

wall panel china is a kind of PVC products that has been rising rapidly in recent years. The products quickly win customers' favor by virtue of environmental protection, beautiful appearance, moistureproof and convenient installation.In the process of PVC wallboard extrusion, common abnormal conditions mainly include: wallboard is not straight, wallboard convex and concave uneven, surface is not smooth, high density, wavy grain, toughness is not good, how should we solve these problems?
Panel is not straight
First of all, check whether the mold and die are in alignment. Under normal circumstances, the wall plate may be bent upward because the mold and die are not in alignment and are on the high side.The wall panel bends downward because the mold mouth is too low.
Under the condition that the mold opening and the mold opening have been aligned, check again whether the water cooling tank, traction and saw table are aligned with the mold setting.
After all these reasons have been ruled out, there are two possible causes:
(1) PVC wallboard products cooling degree is not enough, followed by the temperature after the water cooling tank is still relatively high, in the case of external forces and distortion, the specific adjustment method to increase the mold and water cooling tank cooling water or to reduce the cooling water temperature, no longer directly reduce the speed of production;
(2) The discharging speed of both sides is not consistent, adjustment method: adjust the temperature of both sides of the mold to the same and observe for half an hour, if there is no change to see which side of the discharging speed is slow, raise the temperature of which side, or which side of the discharging speed is fast, reduce the temperature of which side by several degrees.
PVC wallboard is locally uneven
The local convex and concave undulations of the general wallboard are mainly found in the vacuum forming section of the mold.If the vacuum degree is not enough, or the cooling water of the mold is not enough, the adjustment method is to increase the local cooling water, through water seal to improve the vacuum degree, to speed up the cooling speed of wallboard products.If the area is uneven at its maximum boiling point, remove the mold and clean its true 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 main engine of the extruder does not work normally, the 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 wallboard water situation occurred.Or the content of the lubricant in the formula is on the high side, especially the amount of external lubrication is excessive.Or the use of inferior stabilizer, internal and external lubrication more, less stable components.
The density is too high and the foam is not good
First of all, to see whether the lubrication is balanced, lubrication too much, resulting in melt strength decline, bubble holes become larger, the density will increase.Once again, the amount of foaming agent can be appropriately reduced or the amount of regulator can be increased to see if there is an effect, according to the feedback to adjust the situation.
Surface ripple
The main reasons are uneven discharge, resulting in uneven discharge of the reasons are: plastic overmelt too soft;Uneven flow of materials;Traction and extrusion mismatch;Melt strength is too large and rebound, etc
We can solve this problem from the following aspects:
I. Technology:
1) Reduce the production speed, such as screw speed, feeding speed, etc., and appropriately increase the traction speed;Sometimes the wavy lines are lost by adjusting them in production.
2) Reduce the extrusion temperature, especially the temperature in the plasticizing section of zone 3 and 4.Itself now the production of clapboard a lot of enterprises are using small tube material, plastic steel material or foam board material for production, these materials belong to the secondary processing materials, plasticizing is very fast, the appropriate reduction of plasticizing for the production and product stability has a certain benefit.
Ii. Equipment
1. Increase the screw clearance, reduce the shearing and slow down the plasticization;
2. Clean the die head and polish it, especially the two ends of the die, to make the molten material flow smoothly.
3. Check if there is a problem with the mold, such as forgetting to install the positioning pin, or whether there is a problem with the screw, such as different cores, etc., which will cause material flow deviation. Generally, wavy lines will only appear on the side with a lot of materials, and it is difficult to eliminate them by adjusting the formula.
Iii. Formula:
1, appropriately increase the amount of external lubrication, reduce the amount of internal lubrication, but not too much adjustment
2. On the premise of not affecting the foaming, the foaming modifier can be appropriately reduced or the foam modifier with small melt strength can be selected. In this case, it is only limited to the case of excessive melt strength, so as to prevent the material at the mold outlet from springback due to excessive melt strength and forming wave pattern.
Toughness is bad
The first is to use too much plastic steel material, small tube material and other secondary materials.Second, consider whether the external lubrication dosage is too much, especially the use of cheap stabilizer, in order not to paste, the dosage will increase, will lead to the overall formula of the external lubrication dosage is too much.Consider again whether PVC material plasticization is in place, poor plasticizing or over plasticizing will make the product brittle.Finally, if the toughness is not enough, the toughening modifier CPE-135A can be appropriately added.

In the PVC wallboard production process to pay attention to the state of equipment, surrounding sanitation and discipline.Equipment state should pay attention to (1) the host current and head pressure is appropriate (2) the temperature of the temperature control table and each ammeter can work normally (3) the temperature of the main motor and reducer is too high (4) the vacuum pump is normal (5) the mold thermocouple can be inserted to the bottom (6) the water and electricity is normal.

登録者:nickwpcdecking

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