Die-Casting Piston Refill Control for Low-Porosity Filling
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Solution Overview
Problem
Die-casting machines face challenges in achieving short casting cycle times, low air porosity, minimizing wear on casting components, and preventing molten droplet formation in the sprue cone area.
Innovation Solution
A die-casting machine and method that involves closing the shut-off valve during the initial part of the refilling phase, allowing molten material to be drawn back into the melt outlet channel, and controlling the shut-off valve to adjust the extent of recirculation, reducing the stroke of the casting piston, and optimizing the mold-filling phase to minimize air porosity and droplet formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the casting piston stroke is reduced to minimize wear, then wear on casting components is minimized, but the mold filling speed may be insufficient
Solution Approach 1:
The melt outlet channel is pre-filled with molten material before the casting cycle begins. This preliminary action ensures that when the piston moves forward, the material is already in position and can be injected immediately, eliminating the need for a long piston stroke to fill the channel during each cycle.
Solution Approach 2:
The system uses a periodic refilling mechanism where the melt outlet channel is replenished with molten material at regular intervals between casting cycles. This periodic action maintains a continuous supply of material ready for injection, allowing shorter piston strokes while maintaining filling speed.
2Productivity
If the casting cycle time is reduced to improve productivity, then productivity is improved, but air porosity and molten droplet formation may increase
Solution Approach 1:
The melt outlet channel is pre-filled with molten material before the casting cycle begins. This preliminary preparation eliminates delays during the casting cycle, allowing the process to proceed faster without compromising material supply, thereby reducing cycle time without increasing air porosity.
Solution Approach 2:
The system maintains a continuous supply of molten material in the outlet channel through periodic refilling. This continuity ensures that the casting process can proceed without interruption or air entrapment, allowing faster cycle times while maintaining low air porosity and preventing droplet formation.
3Manufacturing precision
If the piston stroke is extended to ensure complete mold filling, then mold filling is complete, but wear on casting components increases
Solution Approach 1:
The melt outlet channel is pre-filled with molten material before each casting cycle. This preliminary action ensures that the channel is already full when the piston begins its stroke, so a shorter piston movement is sufficient to complete mold filling without requiring extended stroke length that would increase wear.
Solution Approach 2:
The material supply function is segmented into two parts: periodic refilling of the outlet channel between cycles, and piston-driven injection during the cycle. This segmentation allows the piston to perform only the injection function with a shorter stroke, while the refilling function handles channel replenishment, reducing overall wear.
4Speed
If additional piston stroke is allocated for faster mold filling, then mold filling speed is improved, but cycle time may increase due to longer piston movement
Solution Approach 1:
The melt outlet channel is pre-filled before the casting cycle begins. This preliminary preparation eliminates the need for the piston to travel a longer distance to fill the channel during the cycle, allowing faster mold filling speed without extending the overall cycle time.
Solution Approach 2:
The periodic refilling mechanism maintains continuous material availability in the outlet channel. This continuity allows the piston to focus solely on the injection action at high speed without interruption for channel filling, achieving fast mold filling while maintaining short cycle times.
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 approach reduces cycle time, minimizes wear on casting components, and significantly improves casting quality by reducing air porosity and preventing molten droplet formation, while allowing additional piston stroke for faster mold filling.
Implementation Method 1
molten material in the casting chamber is forced under pressure through the molten outlet channel into a mold cavity
Implementation Method 2
the casting piston is moved back to the casting start position, thereby supplying molten material back to the casting chamber via the melt inlet channel
Data Source
Figure 1~2
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Figure 9~12
AI summary
1. Die-casting machine and operating method. 2.1. The invention relates to a die-casting machine with a mold (1), a casting chamber (2), a casting piston (3) arranged axially movable in the casting chamber, a melt inlet channel (4) leading into the casting chamber, a shut-off valve (5) in the melt inlet channel, a melt outlet channel (6) leading from the casting chamber to the mold, and a control unit (7) for controlling the casting piston, as well as to a method for operating such a die-casting machine. 2.2. In the die-casting machine according to the invention, the control unit (7) and the shut-off valve (5) are configured, according to one aspect of the invention, to move the shut-off valve (5) into a closed position and to control the casting piston (3) in the casting chamber (2) to advance it from a casting start position to a filling end position during a mold filling phase, in order to carry out a respective casting process.to force molten material (14) through the melt outlet channel (6) into the mold (1), and in a subsequent refilling phase, first to open the shut-off valve and control the casting piston to move back to the casting start position in order to supply molten material to the casting chamber via the melt inlet channel, and to control the shut-off valve back to its closed position before the casting piston reaches its casting start position through its return movement, and to control the casting piston to draw back molten material into the melt outlet channel through the further return movement of the casting piston. 2.3. Use e.g. in hot-chamber die-casting machine technology.