Yerba Mate Cup Embossed Decorative Ring

A full-circumference relief makes this an embossed zinc die casting rather than a plain ring: the pattern has no start or finish, and the cast surface has to stay crisp enough to plate in antique silver.

The Challenge

• Relief running the full circumference needs a ring-shaped slider mould. Slider fit has to be tight, or the pattern flashes and comes out misaligned where the two halves meet.
• Zinc shrinks as it cools, so a thin-walled ring tends to go oval. Roundness and the assembly clearance depend on reworking the gating and cooling layout, not on straightening afterwards.
• Fine grooves are hard to fill. Without enough fill velocity the casting short-shots or cold-shuts in the relief and the embossing loses its depth.
• Porosity under the plate shows up as defects, and the antique finish only works when recess and relief catch light differently. Both the casting and the plating have to be right.

Process Approach

• The relief runs continuously around the whole circumference, which needs a ring-shaped slider mould. Slider shut-off clearance is controlled tightly so the ring comes out without flash or a misaligned pattern.
• Gating, overflow and cooling were redesigned to control shrinkage, so the ring keeps its roundness inside the assembly tolerance instead of going oval after cooling.
• Die casting parameters were tuned to raise fill velocity. The fine relief grooves fill completely, which cuts short-shot and cold-shut rejects and keeps the embossing three-dimensional.
• Casting quality is held tight to reduce pinholes and porosity before plating, because a pore under the plate shows up as a defect. Plating is run with our finishing partner to keep the antique silver process stable and give the relief its light-and-shadow contrast.
• First-article inspection continues through production, so dimensions stay stable and parts remain interchangeable across export batches.

About Xiuhui

Dongguan Xiuhui Precision Technology Co., Ltd. is based in Houjie, Dongguan, and specialises in precision structural and cosmetic parts in zinc and aluminum alloys. Thin walls, tight tolerances and plated surfaces are the work we take on, and most of our projects start as a casting problem someone else could not solve. Customer size does not decide whether we engage; the engineering does. Customers and industry peers are both welcome to contact us about zinc and aluminum die casting.

Parts cast and finished on the same lines include the Optical Module Housing and the Atomizer Metal Housing.