As part of the thesis, we studied the impact of the moisture content of polyamide granules
on the final dimensions of the EFD 10 housing and cover products. It is known that for a
stable injection process prior to the latter, polyamide in the form of granules must be pre-
dried. It must be dried to the prescribed level of humidity specified by the manufacturer of
the granulate. The manufacturer usually gives an upper limit for moisture content.
However, we want to find out what effects on the injection moulding process are hidden in
the prescribed dry area and consequently what are the effects on the final dimensions of the
injection moulds. In order to determine the effects, we prepared samples with different
levels of humidity. To determine the humidity, individual samples were measured on a
humidity meter. Then we injected the granulate samples into the specified products and
monitored the course of the spraying parameters. Finally, the injected samples were
measured on a coordinate measuring machine. From the research, we found that the
moisture of the granulate has an effect mainly on its viscosity and consequently on
injection pressures. However, the humidity of the granules has a slightly smaller or
negligible impact on the final weight of the product and its dimensions.
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