Proportional Solenoid Valve for Molding Unit Insert Control
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Solution Overview
Problem
Current container manufacturing techniques face challenges in precisely controlling the position and rate of travel of a movable insert during the boxing process, particularly due to variable resistant forces and compressibility of gases, leading to inconsistencies in container formation quality.
Innovation Solution
A molding unit equipped with a solenoid valve and processing unit that controls the fluid flow to the insert, allowing for precise control of its position and travel by varying the electric control signal applied to the solenoid valve, linked by the function S=K1.E+K2, where E is the electric signal, S is the passage section, K1 is a coefficient, and K2 is a constant, enabling precise control of the insert's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a movable insert is used to form recessed reserved spaces on the container, then the container can be formed with additional functional features (handles, curves, stretched bottoms), but the insert cannot completely apply the material against the mold relief in areas facing the neck due to insufficient blow-molding pressure
Solution Approach 1:
The insert is retracted before blow-molding to allow material to flow freely into the mold cavity, then deployed after material injection to apply the material against the insert relief for forming reserved spaces. This preliminary retraction ensures complete material application while the subsequent deployment creates the desired container features.
Solution Approach 2:
The molding process is segmented into distinct phases: first allowing material to fill the cavity without insert interference, then introducing the insert to shape specific reserved spaces. This temporal segmentation resolves the conflict between material flow requirements and precision forming requirements.
2Adaptability or versatility
If the movable insert is deployed during forming to push back the container wall, then recessed reserved spaces can be formed, but the insert movement is difficult to control precisely due to variable resistant forces and gas compressibility
Solution Approach 1:
The mechanical control system is replaced with a pneumatic system using a double-action cylinder. This substitution provides more precise control over the insert's movement by using pressurized gas to independently control both deployment and retraction, overcoming the limitations of variable resistant forces and gas compressibility that plague purely mechanical systems.
Solution Approach 2:
The control system varies the pressure parameters of the gas acting on the piston to precisely control the insert's position and speed during movement. By adjusting pressure levels in the two chambers of the double-action cylinder, the system can achieve accurate positioning despite the compressibility of gas and variable resistant forces.
3Speed
If a double-action cylinder with flow restrictor is used to control insert movement, then the insert speed can be modulated, but the compressibility of gas causes delayed action that prevents precise position monitoring
Solution Approach 1:
A sensor is integrated into the system to detect the insert's position or speed during movement. This sensor provides feedback to the control system, enabling real-time monitoring and adjustment of the insert's position. The feedback mechanism compensates for the delays caused by gas compressibility, allowing precise position control throughout the insert's travel.
4Productivity
If the insert travels quickly to complete boxing operation, then productivity is improved, but the variable resistant force and gas compressibility cause inconsistent container formation quality
Solution Approach 1:
The insert movement is divided into periodic phases with different speed profiles: a rapid initial movement to overcome inertia and variable resistant forces, followed by a controlled deceleration phase to ensure precise material application. This periodic variation in speed maintains high productivity while ensuring consistent formation quality at critical moments.
Solution Approach 2:
The pressure parameters of the control gas are dynamically changed during the insert's travel. High pressure is applied initially to achieve rapid movement for productivity, then pressure is reduced or modulated to control the insert's final positioning and ensure high-quality material application, resolving the conflict between speed and precision.
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
This solution enhances the quality of container formation by accurately monitoring and controlling the insert's position and travel, addressing the issues of variable resistant forces and gas compressibility, resulting in improved container shape and structural integrity.
Implementation Method 1
a solenoid valve (37) mounted on the primary fluid circuit (32), with this solenoid valve (37) comprising a fluid outlet (38) connected to the primary chamber (30) and defining a variable passage section (S) based on an electric control signal (E) applied to the solenoid valve (37)
Implementation Method 2
a primary chamber (30) that is connected, via a primary fluid circuit (32), to a primary fluid source (33) under a primary pressure (P1)
Implementation Method 3
a secondary chamber (31) that is connected, via a secondary fluid circuit (34), to a secondary fluid source (35) under a comparatively lower secondary pressure (P2)
Data Source
AI summary
A molding unit for the manufacturing of a container from a blank made of plastic material includes: a mold equipped with a wall and a movable insert; and at least one boxing system including a cylinder that is integral with the insert. The boxing system includes: at least one solenoid valve mounted on a primary fluid circuit, with this solenoid valve including a fluid outlet connected to a primary chamber and that defines a variable passage section based on an electric control signal applied to the solenoid valve; and a processing unit connected to the solenoid valve and programmed to vary the electric control signal applied to the latter.