Design Methodology and Dimension Determination for Angle Lifters:

Determine the core-pull distance based on the product shape: S_pull = S_undercut + (2~3)mm.

Calculate the lifter angle α based on the ejection stroke (tan α = S_pull / S_eject). The α value should not be excessive, as a large angle increases bending stress and risk of fracture. Typically, 3° ≤ α ≤ 8°.

Determine the datum point P of the lifter within the mold, preferably using an integer coordinate.

Determine the lifter thickness L1 based on the specific application. This value should not be too small to ensure sufficient lifter strength.

The sealing height H between the lifter and the core insert is generally 5~10mm (depending on core thickness).

Key Considerations During the Design Process:

The lifter must not damage other parts of the product during ejection.

The clearance pocket in the support plate must fully contain the lifter throughout its travel.

Determine the size and orientation of the sliding groove for the lifter block on the ejector plate. Ensure smooth operation by providing sufficient clearance for the lifter's movement on the ejector plate. Specifically, ensure greater clearance on the side corresponding to the lifter block's movement direction and that L2 > S_pull.

Parting Line Design

Basic Parting

Radius (R) Treatment

Interference Issue 1: Insufficient Travel Space

Solutions:

(1) Shift or cut into the product (recommend to customer).

(2) Reduce the lifter thickness (while maintaining strength).

(3) Change the direction of core pulling (to lengthen the travel).

Interference Issue 2: Product has a downward curvature along the pulling direction, preventing lifter retraction.

Solutions:

(1) Reduce material on the product (recommend to customer).

(2) Add an angle b to the bottom of the lifter block to delay lifter ejection. Requirement: b ≥ i°, c ≥ b°.

Draft angle ≥ 2°. Due to the relatively small pulling force of angle lifters, a sufficient draft angle is crucial to prevent ejection difficulties.

Fitting between Angle Lifter and Core Insert

Basic Fitting: Wire-cut the angled hole in the core insert.

Adding Guidance: When the lifter is wide or the guiding on the core insert is too short, the lifter may tilt toward the product during ejection, shortening the effective travel and making demolding difficult. Guidance should be added in forms such as:

a. Adding a T-hook on the side (single-sided).

b. Adding a hook or dovetail slot on the back.

Core Insert: When the core insert is very thick (e.g., >150mm), wire-cutting becomes less accurate (wire deflection increases), takes longer, and drilling start holes is difficult. Consider using an insert.

Key Points for Clearance Pockets in the Core:

a. Priority order for pocket shape: round holes first, then square holes, then irregular shapes.

b. Use the double-section method to check the size and position of clearance pockets, especially near 1st knock-out pins (1KP).

c. Clearance pockets must be drawn on the assembly plan to check for interference with seals, water lines, ejector pins, screws, etc.

d. Prioritize using integer dimensions for pocket location and size.

Connection between Angle Lifter and Ejector Plate

Connection Type 1: Lifter connected to the lifter block via a T-hook. For thin lifters, use a single-sided hook. A wear plate is required on the bottom of the core. Adjustment is difficult; therefore, reserve 1~2mm at the bottom of the lifter block for assembly adjustment.

Connection Type 2: Lifter is connected to the block via a shoulder screw (dowel pin with head). Other aspects are the same as Type 1.

Connection Type 3: Extend the lifter length and shorten the angled section (to increase stiffness). No wear plate is needed on the core.

Connection Type 4: Use a shouldered pin with a retaining clip as the lifter block.