Method and apparatus for providing an internal surface temperature profile of a thermoplastic preform during a stretch blow moulding process

A method of assessing the internal surface temperature profile of a plurality of preforms in a stretch blow moulding production process, the method comprising:

• (a) heating a plurality of in-line cold preforms in the production process to provide a plurality of in-line heated preforms;
• (b) diverting at least one of the in-line heated preforms to provide at least one off-line heated preform;
• (c) providing the remaining in-line heated preforms to one or more stretch blow moulds for forming the heated preforms into blow moulded products;
• (d) locating one or more temperature sensors inside the or each off-line heated preform of step (b) to provide an inside surface temperature profile of said preform(s);
• and
• assessing the inside surface temperature profile of at least some of the remaining in-line heated preforms of step (c).

A stretch blow moulding production process comprising at least the steps of:

• (a) heating a plurality of in-line cold preforms in the production process to provide a plurality of in-line heated preforms;
• (b) diverting at least one of the in-line heated preforms to provide at least one off-line heated preform;
• (c) providing the remaining in-line heated preforms to one or more stretch blow moulds for forming the heated preforms into blow moulded products;
• and
• (d) locating one or more temperature sensors inside the or each offline heated preform of step (b) to provide an inside surface temperature profile of said preform(s), preferably to provide a quality control of the production process.

Apparatus for a stretch blow moulding production process at least comprising:

• a heating station to heat a plurality of in-line cold preforms to provide a plurality of in-line heated preforms;
• diverting means to divert at least one of the in-line heated preforms to provide at least one off-line heated preform;
• one or more stretch blow moulds for receiving the remaining in-line preforms and forming the heated preforms into blow moulded products;
• and
• one or more temperature sensors able to be located inside the or each offline heated preform to provide an inside surface temperature profile of said preform(s).