Wall thickness is one of the most important design factors in Electronic Injection Molding. It affects strength, cooling time, appearance, and part performance. A skilled Mold Maker knows how to manage wall thickness to ensure high-quality results.
In this article, we’ll explore the key rules and guidelines for designing wall thickness in plastic housings. You’ll learn how thickness affects molding and why it’s so important to get it right.
Why Wall Thickness Matters
Wall thickness directly impacts how molten plastic flows inside the mold. If walls are too thin, the plastic may not fill properly. If they’re too thick, it can lead to warping, sink marks, and long cooling times.
In Electronic Injection Molding, consistent wall thickness is vital. It helps maintain part strength and ensures components fit properly. A good Mold Maker uses design tools to control thickness from the start.
Recommended Wall Thickness for Common Plastics
Different plastics behave differently in molds. Here are typical wall thickness ranges used in Electronic Injection Molding:
- ABS: 1.2 to 3.5 mm
- Polycarbonate (PC): 1.0 to 3.0 mm
- Nylon (PA): 0.75 to 3.0 mm
- Polypropylene (PP): 0.8 to 3.8 mm
- Polystyrene (PS): 0.9 to 3.0 mm
Choosing the right thickness depends on part size, function, and material. A skilled Mold Maker considers all of these before finalizing the mold design.
Rule #1: Keep Wall Thickness Uniform
Uniform thickness allows the plastic to flow evenly. If the wall suddenly changes thickness, the plastic may slow down or speed up. That causes stress, weak spots, or defects.
In Electronic Injection Molding, electronics often need flat, tight-fitting housings. Any variation in thickness can cause warping. That can ruin how parts snap or screw together.
Mold Makers use 3D modeling software to spot and fix uneven areas. They also work with engineers to create smooth transitions where needed.
Rule #2: Avoid Thick Walls
Thick plastic walls take longer to cool. This slows production. Worse, they can create sink marks and internal stress.
If your design needs strength, try using ribs or gussets instead of thick walls. A Mold Maker will often add these support features in critical spots.
For most electronic housings, 2 to 2.5 mm is a good target. If a thicker section is needed, the Mold Maker will taper or core the area to control shrinkage.
Rule #3: Use Smooth Transitions
When a wall must change thickness, the change should be gradual. A sharp jump in wall size causes turbulence. That leads to flow lines or weld lines.
A smooth taper or radius helps the molten plastic flow naturally. In Electronic Injection Molding, this improves strength and looks. A good Mold Maker adds generous radii to inner and outer corners for this reason.
Rule #4: Design for Flow
Wall thickness affects how plastic flows inside the mold. Long, thin sections are hard to fill. Thicker areas near the gate help the flow start strong.
The Mold Maker chooses gate locations based on part geometry. If wall thickness is too thin near the gate, it may freeze early. That creates short shots or defects.
Using flow analysis software, the Mold Maker tests how plastic moves. This helps them balance flow paths and ensure complete filling.
Rule #5: Think About Cooling
Thicker walls cool slower than thin ones. This can cause internal stress. In Electronic Injection Molding, parts must cool evenly to avoid warping.
A Mold Maker places cooling channels close to thick sections. They also may use conformal cooling, a 3D-printed solution that follows complex shapes.
Balanced cooling shortens cycle time and improves part quality. It also extends mold life by reducing thermal shock.
Rule #6: Minimize Shrinkage
All plastics shrink as they cool. Uneven wall thickness causes uneven shrinkage. This can bend or distort the housing.
Electronic housings need tight fits. Warped parts won’t close or snap well. A good Mold Maker predicts shrinkage based on the plastic used and wall thickness. They adjust the mold size to compensate.
Rule #7: Use Ribs for Strength
Instead of thick walls, ribs can add strength. They support larger surfaces without making them solid.
Ribs should be about 60% of the wall’s thickness. They must be spaced apart and include draft angles for easy ejection.
In Electronic Injection Molding, ribs are used inside housings to support screw bosses or mounting posts. The Mold Maker helps decide where to place them.
Rule #8: Consider Assembly Fit
Wall thickness affects how parts fit together. Snap joints, clips, and screw bosses all rely on consistent walls. A housing that’s too thick may not snap. One that’s too thin may crack.
The Mold Maker uses tolerance data to check fit. They may test early samples to confirm strength and assembly quality.
Rule #9: Don’t Forget the Draft Angle
Even if wall thickness is correct, parts still need to be ejected. A small draft angle—1° to 2°—helps this. Without it, the housing may stick.
Draft angles affect wall design. Too much angle reduces usable space. Too little makes release hard. A balance is needed. The Mold Maker builds this into the design from the start.
Wall thickness plays a huge role in product success. In Electronic Injection Molding, it affects flow, strength, cooling, and final fit. Uniform thickness, proper transitions, and smart design features all help.
A skilled Mold Maker brings experience to each project. They know the rules. They test, adjust, and perfect the mold for long-term use.
Getting wall thickness right avoids delays and costly defects. It ensures strong, professional plastic housings. It supports high-speed, high-volume production.
If you’re designing a new electronic housing, work with a trusted Mold Maker from the start. Their input can improve your product before the mold is even built.