Today, our customer ask our help to guide them how to solve the problem of uneven color in the co-extrusion layer of WPC profile?
Before they do good production with our WPC profile machine and molds, the product quality is good and production is stably.
recently they have changed a new mold which is bought from an unprofessional mold maker with cheap price,
but then the production is not stably and the co-extrusion surface color got problem, the wooden grain color only go to the top surface, the bottom surface and sides without wooden grain color, and this is not acceptable.
So our engineer has given them below suggestions to check and solve the problem of uneven color in the co-extrusion layer of WPC profile:
1, Please check the wooden grain color masterbatch percentage is enough?
0.3%-0.5% wooden grain color masterbatch is suggested.
2, if the percentage of color masterbatch is enough, then you need to adjust the temperature of co-extrusion by increasing the temperature little by little, because if the temperature is not enough, then the masterbatch cannot be good melted and mixed, so the color may only show by one place. so you can increase the temperature little and check the result.
3, if above method still not work, then you need to check your co-extrusion mold pressure design. if the co-extrusion mold design is not good( bottom co-extrusion flow pressure is designed lower than the WPC core layer flow pressure, then the co-extrusion masterbatchl cannot good extruded to the bottom or corners, it is suggested that the co-extrusion die flow should be designed 0.5-1.0MPA higher than WPC core layer flow), then you need to ask your mold supplier to help you to modify the mold.
4, you can check the co-extrusion layer thickness of the top surface and bottom surface, is it uniform or not? if the bottom co-extrusion layer thickness is less than top surface, then the problem may because the gap between bottom of co-extrusion die and core layer die is too big.
Finally, the customer find the problem is the mold flow design, and then they modified the mold with much headach work, luckily finally they solved the problem.
If you are also meeting any problem for WPC production, you may contact Yongte team to give you some suggestions!
