Nullam dignissim, ante scelerisque the is euismod fermentum odio sem semper the is erat, a feugiat leo urna eget eros. Duis Aenean a imperdiet risus.
A sip lid lives or dies by its sliding closure, and a sliding closure in a transparent lid shows everything: every flash on the track, every witness line where the two materials meet, every speck the melt picked up. The lid shown here is moulded in two shots, a clear outer ring and a tinted centre carrying the slide, so the working parts are visible through the material that surrounds them.
Three photographs show the closed top with the slide across its track, the underside with the closure’s sealing face, and the lid at an angle. The tint is in the compound, not coated, so it reads through the wall and never wears off.
The obvious alternative is a clear lid with a separately moulded slide snapped in. That route works until it is washed: a snap-in slider rattles, collects debris under its edge, and eventually lifts. Moulding the slide’s track and the ring as one structure in two shots puts the boundary where the design wants it, mechanically interlocked, with no joint line across the sealing face and nothing for the dishwasher to find.
The two materials have to agree with each other. Shrinkage rates differ, and where the tinted centre meets the clear ring, a mismatch pulls the interface open or bows the lid. The shot sequence and the interface geometry, undercuts that lock the two together, are designed so the joint is stronger than either material alone at that line.
The closure slides across the drinking aperture, stopping in moulded detents at each end of travel. The feel of that action is the customer’s daily impression of the lid: definite, not gritty. Track walls are small and their tolerances tight, so the parting line around them is planned rather than wherever the tool happens to split, and any flash shows up instantly in the slide’s action.
Detent force is tuned against the weight of the closure and the temptation to over-engineer. Too light and the slide drifts open in a bag; too heavy and one-handed operation, the whole point of a sip lid, fails. The balance is set in the steel and verified by cycling.
Transparency raises the process stakes. Moisture in the resin shows as streaks; regrind contamination shows as specks; a wrong melt temperature shows as haze. All three are invisible in a solid-colour lid and obvious in this one, so drying, melt handling and regrind policy are process controls, not preferences. The same discipline applies to the tool: polished cavities, and a maintenance schedule that keeps the polish, because a mirror finish that degrades over a run reads as cloudiness on every part after it.
Slide action, cycled by hand across a sample from each lot for grit and detent feel. Seal integrity with the lid closed, tipped and squeezed. Interface integrity between the two shots, checked for voids and lifting after thermal cycling. Optical quality against the approved master: haze, streaks and specks are reject criteria, not observations.
Kunshan Maifeng Precision Industry Co., Ltd. reviews two-shot closure designs before quoting, builds the injection molds in house, and molds single-color and dual-color parts on 36 machines from 90 to 700 tons. Send us the tumbler drawing and the slide layout, and we will come back with a feasibility comment and a tooling proposal.
Kunshan Maifeng Precision Industry Co., Ltd. (MIF) has an investment of RMB 35 million and an independent factory of more than 5,000 m². The company operates 36 single- and dual-color injection molding machines from 90 to 700 tons, together with more than 50 sets of mold manufacturing and processing equipment. Our service, management and production team includes over 100 people.
Our parent company was established in 2008. We provide product design, mold design and manufacturing, injection molding and product assembly services for custom plastic parts, supporting both domestic and international customers.
1. Product Design
Product structure design and optimization based on customer drawings and samples.
2. Mold Design
Mold design developed around product geometry, material and production requirements.
3. Mold Manufacturing
Machining, polishing, fitting and assembly for custom injection molds.
4. Injection Molding
Single- and dual-color injection molding for project and order requirements.
5. Product Assembly
Supporting assembly services for molded plastic components.
Chinese 
English