Mold Clamping Cylinder Speed Control via Deceleration Section
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Solution Overview
Problem
Existing methods for controlling mold clamping devices in hydraulic injection molding machines face challenges in precision control due to viscosity and temperature changes in hydraulic oil, leading to variations in mold closing positions and times, which can result in collisions and decreased productivity.
Innovation Solution
A method that sets a predetermined speed control pattern with a mold closing section, deceleration section, and low-pressure low-speed section, using a variable discharge type hydraulic pump and sub-tank to control the mold clamping cylinder, allowing for precise speed adjustments and software-based deceleration to prevent collisions without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a variable discharge type hydraulic pump is used to control discharge flow rate, then productivity can be increased through faster mold closing speed, but control precision deteriorates due to longer hydraulic circuit length causing larger viscosity and volume changes
Solution Approach 1:
A deceleration section is introduced as an intermediary phase between the high-speed mold closing section and the low-pressure mold clamping section. This deceleration section gradually reduces the mold closing speed before reaching the clamping position, preventing collision while maintaining high productivity. The mediator (deceleration section) resolves the conflict between fast closing speed and precise position control.
Solution Approach 2:
The mold closing process is segmented into three distinct sections: (1) high-speed mold closing section for rapid approach, (2) deceleration section for speed reduction, and (3) low-pressure mold clamping section for precise positioning. This segmentation allows each phase to be optimized independently, achieving both high productivity and high precision.
2Reliability
If brake valve and additional circuit elements are added to prevent mold collision, then reliability improves, but device complexity and cost increase
Solution Approach 1:
The invention extracts the collision prevention function from the traditional brake valve approach and implements it through software-based speed control in the deceleration section. By taking out the need for additional hardware brake valves and circuit elements, the system achieves reliable collision prevention while reducing device complexity and cost.
Solution Approach 2:
The mechanical brake valve system is replaced with a software-based speed control system that manages deceleration through hydraulic flow control. This substitution eliminates the need for additional mechanical braking components and simplifies the hydraulic circuit while maintaining reliable collision prevention.
3Reliability
If sufficient low-pressure mold clamping section is arranged to prevent collision, then reliability improves, but cycle time increases reducing productivity
Solution Approach 1:
The mold closing process is segmented into three distinct sections: (1) high-speed mold closing section for rapid approach, (2) deceleration section for speed reduction, and (3) low-pressure mold clamping section for precise positioning. This segmentation allows each phase to be optimized independently, achieving both high productivity and high precision.
Solution Approach 2:
The system dynamically adjusts the mold closing speed through the deceleration section, transitioning from high speed to low speed in a controlled manner. This dynamic speed adjustment allows the mold to reach the clamping position quickly while ensuring gentle, collision-free contact, thereby reducing cycle time without compromising reliability.
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 method improves control precision, reduces variations in mold closing positions and times, prevents collisions, and allows for shorter cycle times while minimizing the need for low-pressure sections and additional hardware, thus enhancing productivity and reducing costs.
Implementation Method 1
a hydraulic pump capable of controlling a discharge flow rate by varying the number of revolutions of a drive motor
Implementation Method 2
viscosity, volume, and the like of the hydraulic oil changes according to temperature
Implementation Method 3
volume, and the like of the hydraulic oil changes according to temperature
Implementation Method 4
an inertial force is generated in the hydraulic actuator
Data Source
AI summary
A predetermined speed control pattern B is sct. In a mold clamping process, in a mold closing section Zm, mold closing control is performed at a mold closing speed Vm, and based on a current mold closing speed Vd and a current mold closing position Xd, which are both detected, a deceleration starting position Xmc of the deceleration section Zmd, where the current mold closing speed Vd becomes a zero (O) at a virtual stop position Xc, is sequentially forecasted at each predetermined time interval by calculation. Upon reaching the deceleration starting position Xmc the deceleration section Zmd is started, and in the deceleration section Zmd, based on the detected current mold closing position Xd, a speed command value Dm corresponding to the speed control pattern B is obtained sequentially by calculation, and according to the speed command value Dm deceleration control is performed. Upon reaching a mold clamping-transition speed Vc, a predetermined mold clamping processing is performed via a low-pressure low-speed section Zc.