Design Consideration for Manufacturability of Injection Mold.

Wall Thickness:

• Uniformity is key: Aim for consistent wall thickness throughout the part. Uneven walls can lead to warping, sink marks, and weak areas.
• Material matters: Different materials have recommended wall thickness ranges. Thicker walls provide strength but cool slower, while thin walls cool faster but can be fragile. Find the balance for your material and part function.

Draft Angles:

• Easy ejection: Draft angles are slight tapers on the sides of the mold cavity. They allow the finished part to be easily ejected from the mold without sticking or causing damage.
• Draft angle depends on factors: The ideal draft angle depends on part depth, material type, and wall thickness. Typically, deeper parts and thicker walls require a larger draft angle (around 1-3 degrees).

Features and Geometry:

• Sharp corners are a no-no: Sharp corners can trap air, create weak points, and hinder material flow. Opt for rounded corners and smooth transitions for better manufacturability and part strength.
• Ribs and Bosses: Use ribs to add strength and stiffness to thin areas. Design them with proper thickness and rounded edges to avoid stress concentration points. Bosses (raised features) should also have proper draft for easy ejection.

Parting Lines:

• Where the mold splits: The parting line is where the two halves of the mold come together. Ideally, position it along a discreet area to minimize its visibility on the finished part.
• Gates and Vents: The gate is the entry point for molten plastic into the mold, while vents allow trapped air to escape. Consider their placement to optimize material flow and prevent air pockets in the final product.

Additional Considerations:

• Undercuts and Holes: Features like internal threads or undercuts require special techniques like side-action cores or collapsible mechanisms in the mold, increasing complexity and cost. If possible, redesign to avoid them.
• Wall Thickness:
• Uniformity is key: Aim for consistent wall thickness throughout the part. Uneven walls can lead to warping, sink marks, and weak areas.
• Material matters: Different materials have recommended wall thickness ranges. Thicker walls provide strength but cool slower, while thin walls cool faster but can be fragile. Find the balance for your material and part function.
• Draft Angles:
• Easy ejection: Draft angles are slight tapers on the sides of the mold cavity. They allow the finished part to be easily ejected from the mold without sticking or causing damage.
• Draft angle depends on factors: The ideal draft angle depends on part depth, material type, and wall thickness. Typically, deeper parts and thicker walls require a larger draft angle (around 1-3 degrees).
• Features and Geometry:
• Sharp corners are a no-no: Sharp corners can trap air, create weak points, and hinder material flow. Opt for rounded corners and smooth transitions for better manufacturability and part strength.
• Ribs and Bosses: Use ribs to add strength and stiffness to thin areas. Design them with proper thickness and rounded edges to avoid stress concentration points. Bosses (raised features) should also have proper draft for easy ejection.
• Parting Lines:
• Where the mold splits: The parting line is where the two halves of the mold come together. Ideally, position it along a discreet area to minimize its visibility on the finished part.
• Gates and Vents: The gate is the entry point for molten plastic into the mold, while vents allow trapped air to escape. Consider their placement to optimize material flow and prevent air pockets in the final product.
• Additional Considerations:
• Undercuts and Holes: Features like internal threads or undercuts require special techniques like side-action cores or collapsible mechanisms in the mold, increasing complexity and cost. If possible, redesign to avoid them.
• Mold Finish: The desired surface finish of the final part can influence mold design. For a high-gloss finish, a polished mold surface might be needed, adding to cost.
• Material Shrinkage: Plastics shrink slightly as they cool. Consider this shrinkage factor during design to ensure the molded parts meet the final dimensional requirements.
• By keeping these design considerations in mind, you can create parts that are optimized for injection molding. This leads to a smoother production process, reduced costs, and higher quality final products.