Nowdays PLC or microprocessors are used for Blowing system which are time based.
The process delay time is set by operator based on his experience. The
time is also the function of pneumatic cylinders friction and
maintenance done by operator. Therefore it is observed that older
machine have more bottle quality problem and can not be set by operator.
The usage of various grade preform and its dimension has vary the
stretch delay time. Stretching of preform is also the function of its
temperature therefore the lower temperature of preform required more
time delay and vise versa. The operator is not capable to understand
this engineering and he continue by trial and error resulting
inconsistent quality of bottles and the rejection.
To dispense with this problem, Technopet
has devised, the stretch position, based instate of time base system
for activation of valve for pre and main blow. Operator simply feed the
position points of the stretch rod in the mold at which the blow valve
is to activate. Since the blow valve position with respect to bottle
height is fixed the bottle quality variation occurred due to change in
functional parameter are eliminated. No need of operator intervention in
continuous blowing process.