Case Study  ·  Automotive Exterior

PC/PBT Tow Hook Cover Multi-Slider Mold with DFM Risk Resolution

Tier-1 supplier to a European luxury automaker · Family mold (1+1) · 250,000-shot production run

7 days

Drawing to DFM sign-off

4 + 3

Sliders + lifters

250K

Forecast mold life (shots)

BACKGROUND

A Tier-1 supplier to a European luxury automaker required injection molds for a front and rear tow hook cover set. The parts are visible exterior trim on a premium passenger vehicle, demanding high dimensional accuracy, consistent surface finish, and reliable long-run tooling. The supplier needed a mold house that could deliver a thorough DFM review,not just tool fabrication.

PART SPECIFICATIONS

Rear tow hook cover:3D geometry (rear view)

Front tow hook cover: 3D geometry (front view)

Material

PC/PBT blend, medium grey

Shrinkage Rate

0.8% (X/Y/Z isotropic)

Rear Part Size

180 x 58 x 51 mm

Front Part Size

150 x 67 x 47 mm

Wall Thickness

3.0 mm nominal

Cavity Steel

1.2343 · HRC 52-54

Gate Type

Sub-gate via hot runner

Machine Tonnage

100T (tie bar 420 mm)

CHALLENGES

DFM PROCESS& PROACTIVE RISK RESOLUTION

A full Design for Manufacturability review was conducted covering parting line definition, slider and lifter layout, core/cavity insert design for rib venting, ejector pin placement, draft angle analysis, and wall thickness uniformity.

Parting Line Definition

Rear cover — parting line along outermost edge

Front cover — parting line along outermost edge

Slider And Lifter Layout (4 Sliders)

Rear cover — slider 1 & 2 configuration

Rear cover — slider 1 & 2 configuration

Key Risk Caught During DFM

A structural bridge in the part geometry was only 3 mm wide — too narrow to position standard ejector pins without risking stress concentration and premature mold fatigue. Rather than proceeding, we flagged the issue, proposed a geometry modification, and obtained customer sign-off before cutting steel. This single intervention meaningfully extended projected tool life.

Mold Build

The finished mold used 1.2343 tool steel throughout (cavity HRC 52-54, core HRC 45-52, sliders and lifters HRC 48-50) with a 600# cosmetic polish. A turnable sprue bushing was designed to allow the mold to run either part independently or as a family tool depending on production scheduling.

Cavity side: 4-slider configuration visible

Core side : ejection system and hot runner inlet

Full mold assembly side view

Full mold assembly isometric view

OUTCOMES

Have a complex exterior or structural part?

We review DFM thoroughly and we flag issues before they become costly.

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