Key Word: Taili Plastic Machinery; Taili Plastic Machinery-Capacity Improving Expert; Efficient; Stable; Weld Mark
Due to the low profit, most of the injection molding product manufacturers choose to use primary or secondary recycled material, whose fluidity is poor. Thus, weld marks, whether obvious or not, will appear on the surface of over 90% of the plastic products.
Recently, Mr. Shi of Guangdong recently received an export order. There was a problem that could not be solved even after a long period of mold test: the weld mark on the surface of the product greatly affected the hand feel. Moreover, there is always a flash on the surface of the weld mark, which is easy to hurt user’s hand. If he asks workers to deal with the flash, the labor cost will be too high. So no good solution has been found.

The main cause of weld marks is the poor fluidity of plastic raw materials, which results in many streams of fluid mixing in the area of uneven flow velocity. It is generally recommended to use the following ideas to solve the problem.
1. Raise the temperature
The temperature here refers to that of the barrel and mold. Increasing the barrel temperature can increase the fluidity of the raw material, so that the material can maintain a relatively uniform flow rate through different wall thickness and further avoid the occurrence of weld marks. If conditions permit, reduce the amount of cooling water in the mold and increase the surface temperature of the mold, so that the material cooling can be relatively uniform.
2. Improved mold
Observe to see if the runner distribution is reasonable. Due to manufacture’s lack of experience, uneven filling speed and even the interruption of the runner will easily occur to the mold. Observing the location of the weld mark and adjusting the mold exhaust properly will help to avoid the weld marks caused by insufficient exhaust.
3. Check the material
If the lubricant is added too much in the raw material or there is release agent in the mold, the weld marks will easily occur. We should carefully check the three small parts of the screw to see if there is cold material affecting the product quality.
After controlling the mold temperature and appropriately increasing the barrel temperature, Mr. Shi solves the problem of the weld marks.
Taili Plastic Machinery always keeps in mind that what a good injection molding machine factory should do is to help improving the capacity and boosting the profits, rather than offer the similar products the customers need. This is also what Taili Plastic Machinery keeps doing.
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