As the core tooling for sheet metal forming in
Display Micro Screws, the design of the ejection system directly determines the demolding quality and forming accuracy of the workpiece. Balanced ejection force is a core design indicator for the ejection system. Uneven ejection force distribution can lead to minor issues like sidewall scratches and flange twisting during demolding, or more serious problems like residual mold cavity and ejector pin deformation and breakage. This is especially critical for deep-drawn and complex irregularly shaped drawn parts.
I. Rational Arrangement of Ejection Components
The arrangement of ejection components should prioritize the uniformity of workpiece stress, following the principle of "corresponding center of gravity and strengthening weak areas." For axisymmetric cylindrical drawn parts, ejection points should be distributed symmetrically on the bottom flange or bottom circumference to avoid concentrated ejection on one side. For irregularly shaped parts (drawn parts with reinforcing ribs or local protrusions), ejection points should be preferentially arranged in areas of higher workpiece rigidity (such as the base of reinforcing ribs or non-drawn forming connection parts), avoiding stress-concentrated sidewalls or easily deformable arc transition areas. The ejector pin diameter must match the ejection force requirements of the corresponding location: large-diameter, high-rigidity ejector pins are used in high-stress edge areas, while thinner ejector pins are used in low-load areas. This ensures sufficient local output force while avoiding interference between the ejector pin and the mold cavity. The ejector pin spacing must be adapted to the workpiece contour, typically controlled between 100 and 150 mm. Excessive spacing can lead to insufficient force in the middle of the workpiece, while insufficient spacing increases the difficulty of mold cavity machining.
II. Precise Design of Force Source Distribution The force source distribution of the drawing die ejection system is a key aspect of balancing the ejection force. Common force sources include elastic elements (springs, polyurethane), hydraulic systems, etc. When using elastic force sources, it is necessary to ensure that the pre-compression of each ejector pin matches the spring stiffness: springs on the same ejector plate should be selected from the same batch with a stiffness deviation ≤5%. For the output differences at different ejection points, spring stiffness can be configured differently—ejector pins in weakly stressed areas of the workpiece should use springs with slightly higher stiffness to balance local resistance.
When using hydraulic ejection, each ejection branch must be equipped with an independent throttle valve or pressure regulator. By adjusting the hydraulic pressure in each branch, the movement speed and output force of each ejector rod must be consistent, preventing excessive ejection speed in one area from causing workpiece tilting. Furthermore, the rigid design of the ejector plate is indispensable. Display
Micro Screws require reinforcing ribs on the back of the ejector plate to prevent uneven ejection force caused indirectly by the plate's own bending deformation.
III. Auxiliary Structure and Parameter Optimization Balanced ejection force requires auxiliary structures to ensure a smooth ejection process: Regarding the guiding structure, the ejector rods should be equipped with guide sleeves and the ejector plate for guidance, preventing uneven loading due to tilting. A buffer mechanism (such as a polyurethane buffer pad or hydraulic buffer device) should be installed at the end of the ejection stroke to reduce the impact force upon arrival and prevent workpiece rebound deformation.
In terms of parameter optimization, the ejection process can be simulated in advance using molding simulation software to adjust the ejection point position and ejection force distribution, predict the workpiece stress distribution and deformation trend, and reduce the amount of adjustment required during trial molding. During the trial molding stage, the deformation and scratch marks of the workpiece after demolding can be measured to fine-tune the parameters of local ejection components until balanced ejection force is achieved across all positions.
In summary, balanced ejection force design needs to cover the entire process of layout, force source, structure and parameters. Through targeted configuration and force control strategies, it can ensure demolding efficiency while avoiding defects in workpiece forming quality, which is an important part of improving the overall performance of Display Micro Screws.
