Poor packaging and solutions
Poor overlay defect refers to the use of secondary overmolding
The defect of infirm packaging refers to the plastic parts that are overmolded by secondary overmolding, and the soft glue of the secondary coating of the plastic parts is easy to peel off.
The process of secondary overmolding is to first use the first plastic to form the inner part, then rotate the moving mold, and then use the second plastic to form the outer part, so that the outer part is superimposed on the inner part, such as common mobile phone cases and other electronic products.
For the power tool industry, its plastic parts are often divided into two sets of molds, the first set of molds is used to form the inner layer of parts, the second set of molds is used to coat the plastic, and the second layer of plastic is generally TPE soft glue.
Common defects in this process are poor laping, poor appearance, underinjection, etc.
In the secondary overmolding process, the common solutions for poor overlaying are as follows:
(1) Laminate immediately after the injection molding, preferably two-color injection molding.
(2) When overlaying injection molding, the inner material should be clean (do not be artificially cleaned), free of oil stains and dust.
(3) After finding that the packaging is not firm, the outer soft glue should be removed immediately, and no secondary gluing should be carried out.
(4) When injection molding, a high injection speed and a high melt temperature should be used, which is conducive to improving the bonding firmness
(5) After gluing, it should be placed for a period of time before testing the quality of the plastic parts to judge whether the packaging effect is up to standard.
(6) The surface of the coated part should avoid using release agent.
(7) When there is a problem in plastic raw materials, it is necessary to consider from the two aspects of the inner and outer materials, not only the material factors of the outer soft rubber, but also the coated material has an impact on the laminating effect, especially the additives in the hard glue.
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