Technical Summary Of Automotive Lamp Molds

Product Material: PP + T20 / PP + T40

Product Features:

• Multiple assembly positions.
• Sealing requirements for the lamp adjustment holes and wiring harness connector holes.

Mold Key Points:

• The mold has many components, inserts, and sliders, which may easily cause flash.
• Cooling channel design should be grouped properly to prevent product deformation.
• EDM machining time is relatively long.

Common Mold Steel:

• P20 / 2738 (28–34 HRC)

Mold Structure (as shown below):

• Fixed Mold
• Moving Mold
• Angle Lifter

Product Material:

• PC / PBT + GF / PBT + PET / PA66 + GF

Product Features:

• Aluminum vacuum metallization directly on the surface.
• Appearance part with very high surface quality requirements.

Mold Key Points:

• Weld line position must be carefully considered during the early design stage.
• Preventive design is required to avoid sticking to the cavity side (fixed mold).
• Early design considerations are needed to prevent product deformation.
• Attention should be paid to the texture depth, as flow marks may easily occur.
• The molding process window is relatively narrow, and bright spots on the surface are difficult to control.

Common Mold Steel:

• Cavity Side (Front Mold) NAK80 (37–43 HRC) / 2343 ES / SMV3W / 8407 (46–49 HRC)
• Core Side (Rear Mold) P20 / 2738 /8407 (46–49 HRC)

Product Material: BMC (Bulk Molding Compound), PEI is also used in some cases.

Product Features:

• Strict light distribution requirements.
• Direct aluminum vacuum metallization on the surface.

Mold Key Points:

• The parting line has no clearance, which may cause flash.
• Mold flow analysis should focus on the last filling area to avoid air traps.
• For heated molds, the heater layout must ensure uniform temperature.
• Heating power needs proper calculation.
• For non-heated molds, an integrated mold structure is preferred.
• High surface accuracy required; profile tolerance ≤ 0.05 mm.
• Ejector pins with sleeves are recommended.

Common Mold Steel:

• Cavity Side (Front Mold)  SKD11 (54–56 HRC) / SMV3W / 8407 S136 / 2343 ESR
• Core Side (Rear Mold)  2344 / H13 / SKD61 / 8402 /2343 (46–49 HRC) / 2738

Material: PC

Product Features:

• Outer surface is Class A surface.
• Outer surface has hard coating.
• Single-color parts usually require internal side actions.
• The design is gradually shifting to two-shot molding.
• Two-shot molding can eliminate internal side actions.

Mold Key Points:

Single-color:

• Most designs require internal sliders.
• Some structures combine internal sliders with lifters or ejectors.
• Control of slider lines and lifter lines is critical.

Two-shot:

• Inverted mold design (ejection from cavity side).
• Key point is secure positioning of the first-shot part.
• Second shot requires multiple gates to ensure strong bonding.
• Two-shot molding has a narrow processing window.

Common Mold Steel:

• Cavity: NAK80 / 2343ESR / SMV3W / 8407
• Core: NAK80 / 2343ESR / SMV3W / 8407

Headlamp Section

• BMC Reflector
• PC HL Lens and Multicolor Lens
• Head Lamp Bezel
• Head and Tail Lamp Housing
• Others
   

Taillight Section

• Multicolor Lens
• Rear Lamp Bezel
• Tail Lamp Housing
   

Fog Lights, High-Mount Stop Lights, and Small Parts

• Adjustment Elements

Material：ABS + PC

Product Features:

• Light distribution requirements.
• Direct aluminum vacuum metallization.
• Sealing required.

Mold Key Points:

• Air traps are likely on the plated surface.
• Cavity-side sliders (front mold) are common.
• Core-side water-stop wall ejection is critical; parts may stick.
• Pay attention to insert parting lines for decorative textures.
• Cooling channel layout on the core side requires careful analysis.
• Some core-side structures have internal sliders.
• Insert parting lines for textures are a machining focus.

Common Mold Steel:

• Cavity (Front Mold): NAK80 (37–43 HRC), 2343 ESR, SMV3W, 8407
• Core (Rear Mold): 2344, H13, SKD61, 8402, 2343 (46–49 HRC), 2738, P20

Material: PMMA

Product Features:

• Mostly dual-color transparent
• Some parts in three-color or four-color
• Light distribution requirements
• Reflective patterns

Mold Considerations:

• Fixing the product for first-shot molding
• Whether secondary molding requires overmolding
• Strength of assembly/joining
• Venting
• Ejection of areas where material is not fully filled
• Two rear molds must be identical
• Allowance on front mold before secondary molding and product sealing

Common Mold Steels: NAK80 (37–43 RC) / 718HH (36–41 RC)

NIMAX (39–43 RC) / 2343ESR / SMV3W / 8407 (46–49 RC)

Material: PC

Product Features:

• Wall thickness usually greater than 4 mm
• Light-transmitting patterns

Mold Considerations:

• Selection of gate location to ensure proper packing and molding
• Design and machining of inlaid light-transmitting patterns

Common Mold Steels:

• 2343ESR
• SMV3W
• 8407 (46–49 RC)