- Issue Time
How acceptable is the residual metal impurities in the plastic？
Based on our many years of experience, it can be summarized as follows:
Generally, large-scale or expensive plastic manufacturers generally use plastic metal separators, but most of them only control metal impurities to a certain level. For example, it is generally required that iron not exceed 0.5-1 mm and stainless steel not exceed 1- 2 mm, about 1 mm for other metals.
At present, there is no uniform standard for metal impurities, because the users of raw materials are diverse, and the metal impurities are different. Based on experience:
1) Generally, the injection molding of electronic products, such as printers, copiers, computers, notebooks, etc., requires detection and separation of all metal impurities above 1 mm. Because the diameter of the nozzle and runner of its injection molding equipment are both 1-2 mm, and the thickness of the injection molded shell is generally more than 1 mm, metal impurities less than 1 mm will basically have no adverse effects.
2) The production of connectors, low-voltage electronic connectors and other small plastic parts, generally only need to detect metal impurities of about 1 mm, depending on the row spacing of the connectors.
3) High-voltage resistant electronic connectors, high-end cosmetic plastic products, pill bottles, etc., theoretically require no metal. Generally, all metals above 0.3-0.5 mm are required. Of course, there are also all metals above 0.1 mm.
4) The injection of large plastic parts is based on the principle of not damaging the injection equipment. Generally, only metal impurities of 2-5 mm or more are required.
5) For plastic sheet calendering, all metal impurities of 1-2 mm are generally required, and the principle of not damaging the calendering drum is required.
According to the above situation, as long as the raw material supplier controls the metal impurities below 0.5-1 mm, it will basically not be discovered by the user or returned. To
Whether it is plastic pellet production and modification factories or injection molding factories, most factories use plastic metal separators, so we are more aware of its requirements for metal impurities.