PP pepper ball is translucent. The appearance of PP pepper ball refers not only to the surface smoothness, but also to the bubbles inside. Some demanding customers don't accept the bubbles in the middle of PP plastic ball. The larger the size of PP pepper ball, the more bubbles are formed. The main reason is related to the cooling time during the injection molding of PP pepper ball.Bubbles generated in the middle of PP pepper ball also have something to do with the exhaust of the mold. If the exhaust of the mold is not done properly, the gas in the mold will not be exhausted during injection molding, and bubbles will be formed inside the pepper ball. The improvement method is to exhaust the mold again, so that the exhaust is smooth and the bubbles will be improved.The bubble in the middle of PP pepper ball is related to the firing rate of injection molding machine. If the firing rate is too fast, the gas in the mold can not be discharged in time, and it will be trapped inside the pepper ball to form bubbles. The improvement method is to slow down the firing rate of injection molding machine, and the bubble problem will be improved.