TL;DR
Heavy jars are usually gated at the base, and the trimming of the gate vestige is where standing quality is won or lost. The cream jar family records 25 catalog models in PP+PMMA or PP+PETG double-lid constructions, with capacities at 15 ml, 30 ml, 50 ml, and 100 ml. Gate vestige residual height, center-recess depth, and base flatness tolerances are not published by the program; configured and confirmed per project.
[ Heavy Jar Body: Wall & Double-Lid Neck ]
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[ Center-Base Gate: Symmetrical Melt Entry ]
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[ Hot-Runner De-Gating & Vestige Trimming ]
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[ Base Geometric Balance ]
├──► Center Recess (Sub-surface gate pocket)
└──► Standing Ring (Annular load-bearing contact)
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[ Base Flatness & Wobble-Free Verification (Per Project) ]
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[ Cream Jar Family: 25 Catalog Models (15 / 30 / 50 / 100 ml) ]
Why: The Base Is the Surface Everyone Touches
A heavy jar is a centerpiece pack: it is lifted by its double lid and set down on its base more often than any other surface. A jar that rocks, a ring that scuffs unevenly, or a scar at the center of the bottom reads as a quality problem long before the formula is evaluated.
Gate placement is therefore a design decision, not an afterthought. In injection molding, the gate is where molten polymer enters the cavity. For a jar body whose visible surfaces are the outer wall, the threaded neck, and the lid assembly, the base is the natural home for the gate — the one surface that can sit beneath a recess, a standing ring, or a label. But hidden is not the same as absent: every gate leaves a vestige, and how that vestige is trimmed decides whether the jar stands level, whether it spins without wobble, and whether the underside stays clean through filling and decoration.
For the heavy cream jar formats, the base carries real weight, so flatness is not a cosmetic matter. Thick sections cool differently from thin ones, and a heavy base tends to sink, mark, and distort unless geometry, cooling, and trimming are treated as one system.
The discipline that keeps procurement, brand, and quality teams honest is separating what the catalog records from what each project decides.
How: From Gate to Finished Base
1. Why the gate sits on the base
For a round jar body, the practical gate position is the center of the base. A center gate feeds the cavity symmetrically, keeps flow length balanced around the wall, and keeps the gate mark off every surface the consumer sees. The trade-off: the gate site sits inside the standing footprint, so the vestige and the standing geometry compete for the same real estate — and the heavier the filled weight, the more it matters, because full jar weight rests directly on the ring around the gate.
2. De-gating routes and the trim step
Once the part is molded, the vestige has to go. The routes divide by tooling intent: some gate types are designed with a defined break point so the vestige shears cleanly at ejection — automatic, in the stroke of the mold — while others leave a fuller stub that must be trimmed in a separate finishing step after molding. Hot-runner systems deliver melt through a heated manifold and nozzle straight into the cavity, which is why de-gating practice of this kind is common on high-cavity tooling with large shot volumes — the situation in which heavy jar bases are molded.
Here the program boundary is exact: hot-runner de-gating is not a recorded process; injection molding and mold tooling development are the recorded capabilities. The practical reading: the manufacturing record covers the molding operation and the tool development before it, while de-gating technique, trim geometry, and finish are project decisions proven during tool development and sampling.
3. The center recess and the standing ring
The established way to make a gated base presentable is a center recess: a shallow pocket formed into the base by the mold, around the gate area. The trimmed vestige sits inside the pocket, below the surrounding surface, so it never touches the table. The load-bearing element becomes the standing ring — the annular band between the recess edge and the outer diameter.
Two demands meet here. The recess must be deep enough for the trimmed vestige to stay below the standing plane, yet shallow enough that the base does not read as an unstable ring and wall sections stay even for balanced cooling. The Ø of the recess, the Ø of the standing ring, and the ring width are dimensions settled inside mold tooling development; they are not published by the program; configured and confirmed per project.
4. From flat tool to stable stand
Flatness is a property of the assembled base, not of the pocket alone. The standing ring has to run true to the jar axis, stay free of witness marks from ejection, and resist the sink and warpage that heavy sections invite. A base that is level at rest can rock when the ring is interrupted anywhere along its circumference, or drift later as polymer relaxation moves the geometry over the pack’s life.
Verification is therefore a project protocol rather than a catalog number: the ring contact line is checked, standing is confirmed with filled weight, and the result is fixed in the mold trial, with an acceptance band expressed as a ± deviation around the datum plane. The failure-mode map on the twelve-test lab matrix and the quality page show where such checks sit in the chain. On the closure side, the seal-compression mechanics in the airtight cushion compacts and gel eyeliner pot insights apply to the double-lid sealing; base flatness remains a geometry matter of the body tool.
5. What is recorded, what is decided
One sentence carries the whole boundary of this topic: hot-runner de-gating is not a recorded process; injection molding and mold tooling development are the recorded capabilities. Everything about the vestige itself — residual height, center-recess depth, flatness tolerance — is engineering work performed inside each project, and the program publishes no trim standard. When a request for quotation asks for a “smooth base,” the answer should state who measures what, with which method, and which band is acceptable.
What: Recorded Program Data and the Verification Hooks
The list below is the only place in this article where numbers are asserted as program facts:
- Cream jar family: 25 catalog models;
- Constructions: PP+PMMA and PP+PETG double-lid builds (inner and outer lid) are recorded;
- Capacities: 15 ml, 30 ml, 50 ml, and 100 ml are among the recorded capacities;
- Manufacturing capabilities: Injection molding and mold tooling development are recorded;
- Boundary: Hot-runner de-gating is not a recorded process; injection molding and mold tooling development are the recorded capabilities;
- Project layer: Gate vestige residual height, center-recess depth, and base flatness tolerances are not published by the program; configured and confirmed per project.
Gotchas
- Hot-runner de-gating is not a recorded process. Reference it as a project technique built on the two recorded capabilities — injection molding and mold tooling development — and nothing more.
- Do not publish a residual height for the gate vestige. The program records none; heights come from the project’s own tool, material, and cavity.
- A deeper recess does not make a flatter jar. Flatness lives in the standing ring and the tool geometry; the pocket only hides the gate.
- Trim depth and recess depth are coupled. Trim too shallow and the vestige stands above the contact plane; trim too deep and the base floor thins. Both directions are confirmed in the first tool trial.
- Heavy bases sink and mark. Whether a heavy jar base stays true or distorts is set by the cooling design inside the tool, developed per project.
- “Smooth base” is not a specification. State the measurement method, the surface checked, and the acceptance band in the project protocol; the program publishes no default.