Pepper ball shell can be divided into plastic material and metal material. The main plastic material is PLA material, which has the advantage of good sealing, but it dissolves slowly in fracturing and is limited by its size. Generally, the size cannot exceed 15 mm. The larger the size, the more difficult it is to produce.The shrinkage rate of PLA material is too high, and it is easy to shrink when injection molding the pepper ball shell, and small holes are formed on the surface of the ball, resulting in poor quality of the pepper ball, with the highest defect rate above 90%. Therefore, the main reason for the high price of PLA pepper ball shell is the high defect rate, and there is no better method to solve the problem of shrinkage of PLA pepper ball shell at present.Pepper ball shell can be divided into plastic material and metal material. The main plastic material is PLA material, which has the advantage of good sealing, but it dissolves slowly in fracturing and is limited by its size. Generally, the size cannot exceed 15 mm. The larger the size, the more difficult it is to produce.The shrinkage rate of PLA material is too high, and it is easy to shrink when injection molding the pepper ball shell, and small holes are formed on the surface of the ball, resulting in poor quality of the pepper ball, with the highest defect rate above 90%. Therefore, the main reason for the high price of PLA pepper ball shell is the high defect rate, and there is no better method to solve the problem of shrinkage of PLA pepper ball shell at present.