Molding technology

What is insert molding?

insert molding

Insert molding is a process in which resin is injected into a mold that contains a pre-placed insert. The result of insert molding is a compound component in which plastic and inserted part are integrated. (In the case of compression molding, a plastic insert is placed in the mold, and then the mold after placing resin is closed.) 

Any article capable of withstanding the pressure and temperature of the molding process can be used as an insert, including metal, thermoset plastic molds, ceramics, rubber products, leather, film, glass, wood, or fabric, according to the application. We can meet needs of various industries.

Insert molding has a great advantage in that much higher strength and durability can be achieved than when articles are installed in the process after molding.

Characteristics of insert molding

  • Insert molds have a higher strength and durability compared with molds into which an insert is placed after molding.
  • A wide range of products integrating the advantages of the inserted article with the excellent flexibility and durability of thermosets can be developed.
  • Shapes that would otherwise be difficult to make after molding has been completed can be produced (the insert can be fully encapsulated.)
  • Better appearance, resulting in higher added value.

Insert molding by Naniwa Gousei Co., Ltd.

While insert molding has many advantages, deformation of inserts and springback cause significant problems with respect to dimensional accuracy.

However, Naniwa Gousei Co., Ltd. has accumulated substantial experience with many types of insert molding, through which we have cultivated the know-how and technical expertise enabling us to minimize the shortcomings in dimensional accuracy.
It is on this basis that we have established a reputation for high quality among manufacturers of industrial machinery parts, medical equipment, measuring equipment, and the like, whose industries demand strict dimensional accuracy.

Insert molding is very cost effective, in addition to providing good strength and durability. For example, molds combining metal parts having rigidity, local strength and electrical conductivity with thermosets having high formability and insulation properties, promise customers unparalleled cost effectiveness.

Insert molding can be used not only in conjunction with metal parts, but in a wide variety of applications. When you are contemplating product development or cost reduction options, please feel free to contact us.