Patent ID: 7993548
Filing Date: 2011-08-09
Classification: B01L,B29C,B29L

Abstract:
1. A method of manufacturing a sample tube having a predetermined volume and mass, said method being carried out by injection moulding in an injection moulding machine using a molten thermoplastic resin, the method comprising the steps of: forming an oversized mould cavity with an opposing pair of mould members of said injection moulding machine, the mould members being movable relative to each other and between which mould members said sample tube is formed; injecting into said oversized cavities a volume of resin exceeding the prescribed volume of the sample tube to be formed, said injecting comprising a first stage of injection at a first speed followed by a second stage of injection at a second speed, with the second speed being slower than the first speed and the second stage of injection comprising a slower pressurization than the first stage of injection; and during said second stage of injection, applying force to said mould members to reduce the volume of said mould cavity for displacing molten polymer in the cavity and for compressing the polymer to form said sample tube and simultaneously cooling the polymer in compressed condition for preventing deformation of the sample tube.