Blow Molding Preform Conditioning Core and Cavity Mold
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Solution Overview
Problem
Conventional blow molding devices face challenges in quickly and evenly adjusting the temperature of preforms with thick walls, leading to uneven wall thickness and potential whitening or clouding due to slow cooling, which affects the quality of the molded containers.
Innovation Solution
A blow molding device with a temperature adjustment part that includes a conditioning core mold and a conditioning cavity mold, which compress and deform the preform to ensure even temperature adjustment and shape modification, allowing for rapid cooling and preventing air trapping by gradually increasing the gap between the molds, thus ensuring uniform temperature distribution and preventing defects like whitening and clouding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional temperature adjustment part is used to cool the preform, then the front and back walls of the wall portion can be adjusted in temperature in a short time, but it is difficult to adjust the temperature at the center of the thick wall in a short time
Solution Approach 1:
The temperature adjustment part is divided into multiple independent temperature adjustment units, each capable of independently adjusting the temperature of different regions of the preform. This segmentation allows simultaneous temperature adjustment of both the front/back walls and the center of thick walls, resolving the contradiction between adjustment speed and temperature uniformity.
Solution Approach 2:
Different temperature adjustment units are configured with different cooling capabilities tailored to the specific thermal characteristics of each preform region. The units adjust temperatures locally according to the wall thickness and thermal conductivity of each area, enabling uniform temperature distribution across the entire preform including thick wall centers.
2Productivity
If the injection-molded cooling time is shortened, then productivity is improved, but it is not possible to sufficiently remove the temperature deviation and equalize the temperature of the preform
Solution Approach 1:
The temperature adjustment part performs preliminary temperature equalization of the preform before blow molding. By pre-adjusting the temperature distribution in the temperature adjustment units, the system compensates for the shortened injection molding cooling time, ensuring the preform reaches uniform temperature suitable for blow molding without extending the overall cycle time.
3Object-generated harmful factors
If a slit is formed in the conditioning core mold to allow air escape, then air trapping is prevented, but the trace of the slit is left on the inner surface of the preform deteriorating quality
Solution Approach 1:
The air discharge function is extracted from the conditioning core mold and transferred to a separate air discharge pump. The pump actively removes air from the space between the preform and mold during the conditioning process, preventing air trapping without requiring any slits or openings in the mold that would leave traces on the preform surface.
Solution Approach 2:
The air discharge pump acts as an intermediary device between the preform-mold space and the external environment. It mediates the air removal process by creating a pressure differential that extracts air molecules without physical contact between the mold and the air discharge path, thus preventing surface defects.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient temperature equalization and shape modification of preforms, resulting in high-quality containers with uniform wall thickness and improved physical properties, while also preventing air trapping and maintaining the appearance of the molded containers.
Implementation Method 1
a temperature adjustment part (20, 520) adjusting a temperature of the preform (1) molded by the injection molding part (10)
Implementation Method 2
compress and deform the main body portion (2) of the preform (1) into a desired shape with the main body portion (2) sandwiched between the conditioning core mold (21, 321, 421, 521) and the conditioning cavity mold (22, 322, 422, 522)
Data Source
AI summary
An object of the present invention is to provide a blow molding device, a blow molding method, a mold unit, and a jig capable of shortening a molding cycle time. There is provided a blow molding device (100), in which the blow molding device (100) includes an injection molding part (10) injection-molding a preform (1) having a neck portion (3) on an open side and a main body portion (2) on a closed side, a temperature adjustment part (20, 520) adjusting a temperature of the preform (1) molded by the injection molding part (10), and a blow molding part (30) blow-molding the preform (1) whose temperature has been adjusted by the temperature adjustment part (20, 520), and the temperature adjustment part (20, 520) include a conditioning core mold (21, 321, 421, 521) that is in contact with substantially an entire inner surface of the main body portion (2) and a conditioning cavity mold (22, 322, 422, 522) that is in contact with substantially an entire outer surface of the main body portion (2), and compress and deform the main body portion (2) of the preform (1) into a desired shape with the main body portion (2) sandwiched between the conditioning core mold (21, 321, 421, 521) and the conditioning cavity mold (22, 322, 422, 522).