The Control Principle of Material Flow in Medical Equipment Micro Screws Draw Bead Design
2026,08,20
In
Medical Equipment Micro Screws, draw beads are the core structure for controlling material flow and ensuring part forming quality. Essentially, they are raised components placed in the die flange area.
Artificially increasing material flow resistance coordinates the feed speed in different areas and solves common defects such as wrinkling, cracking, and surface distortion during the drawing process of complex curved parts. It is a key aspect of the drawing process design.
Common draw beads are divided into two main categories: circular beads and rectangular beads. Circular beads, due to their smooth rounded corners, exhibit a gradient change in material flow resistance and are often used for high-strength steels with poor flowability or deep-drawn parts, avoiding localized stress concentration.
Rectangular beads have concentrated resistance and high deformation resistance, suitable for shallow drawing or areas requiring strong resistance control, quickly limiting excessive material inflow into the flange area. The size and arrangement of these two types of beads directly determine the coordination of material flow.
The core parameter of draw beads is crucial for controlling material flow: the bead height should be 1.5 to 3 times the material thickness. If the bead height is insufficient, the material flow resistance is too low, and excessive material flow into the die in the flange area can easily cause wrinkling.
Excessive rib height results in excessive resistance, causing the material to become excessively thin when flowing into the punch radius, leading to cracking of the part. Adjustments need to be made based on the material grade. For example, the rib height can be appropriately reduced for aluminum alloys, while the rib height needs to be increased for high-strength steel to ensure resistance.
