Flaskless Molding Machine Back Pressure Circuits
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Solution Overview
Problem
Existing flaskless molding machines face challenges in applying uniform pressure to mold sand, leading to variations in mold hardness, which affects the quality of the molds and casting products produced.
Innovation Solution
The introduction of back pressure circuits in the oil-hydraulic systems of the flaskless molding machine, which include electromagnetic valves and counterbalance valves, allows for the adjustment of squeeze forces between the upper and lower molds, ensuring uniform pressure is applied to the mold sand through controlled oil flow and resistance mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional oil-hydraulic cylinders are used for squeezing mold sand in upper and lower molds, then the squeeze force can be applied, but the pressure distribution becomes uneven leading to non-uniform mold hardness
Solution Approach 1:
The patent introduces back pressure circuits with counterbalance valves specifically for the upper flask oil-hydraulic cylinder and lower filling frame oil-hydraulic cylinder to locally adjust and equalize the pressure distribution on mold sand, ensuring uniform squeeze force across different regions of the mold
Solution Approach 2:
The patent implements a feedback control mechanism where the back pressure circuits continuously monitor and adjust the oil pressure to maintain equal squeeze forces on the upper and lower molds, automatically compensating for pressure imbalances to achieve uniform mold hardness
2Strength
If the squeeze force is increased to improve mold quality, then the mold hardness increases, but the pressure distribution becomes more uneven
Solution Approach 1:
The patent uses back pressure as a counterbalancing force against the squeeze force. The counterbalance valves in the back pressure circuits generate an opposing pressure that compensates for the uneven pressure distribution, allowing high squeeze forces to be applied while maintaining uniform pressure distribution across the mold sand
3Manufacturing precision
If manual adjustment of squeeze force balance is performed, then the squeeze forces can be equalized, but the control process becomes complex and time-consuming
Solution Approach 1:
The back pressure circuits with counterbalance valves automatically equalize the squeeze forces on upper and lower molds through self-regulating pressure feedback, eliminating the need for complex manual adjustment mechanisms and reducing control system complexity while maintaining precise squeeze force balance
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 enables the formation of high-quality molds and casting products by maintaining consistent pressure across the molding surfaces, improving the uniformity and quality of the products while simplifying the control process and reducing cycle time.
Implementation Method 1
the counterbalance valve adjusts the pressure of oil freed by the electromagnetic valve
Implementation Method 2
back pressure serving as a resistance against movement
Data Source
Figure 1
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AI summary
A flaskless molding machine 1 includes: an upper flask 15 and a lower flask 17 capable of clamping a match plate; a drive unit (37) moving the lower flask in a vertical direction; a lower filling frame 41 capable of communicating with the lower flask; an upper plate 25 capable of entering and being retracted from the upper flask; a lower plate 40 capable of entering and being retracted from the lower filling frame; an upper flask oil-hydraulic cylinder (16) coupled to the upper flask; a first oil-hydraulic circuit (81) of the upper flask oil-hydraulic cylinder; a lower filling frame oil-hydraulic cylinder (42) coupled to the lower filling frame; a second oil-hydraulic circuit (83) of the lower filling frame oil-hydraulic cylinder; and drive units (37, 80) performing a squeeze process by moving the lower plate in an upward direction. The first oil-hydraulic circuit includes a back pressure circuit (82) applying, to the upper flask oil-hydraulic cylinder, a first back pressure serving as a resistance against an upward movement of the upper flask toward the upper plate during the squeeze process. The second oil-hydraulic circuit includes a back pressure circuit (84) applying, to the lower filling frame oil-hydraulic cylinder, a second back pressure serving as a resistance against a downward movement of the lower filling frame toward the lower plate during the squeeze process.