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 tool case gets treated worse than almost anything else in a workshop. It is dropped off a tailgate, stacked under heavier cases, left on a damp floor and opened and closed a dozen times a day, and it is still expected to keep the tools inside exactly where they were put. The case on this page is a two-piece PP molding: a deep tub, a lid with a full-perimeter rim, a hinge along the back, two draw latches at the front and a carry handle molded into the lid.
It is built for hand tools, measuring instruments and hardware kits. The tooling is what decides how useful it is — the outer size, the height of the tub, whether the case carries a lift-out tray or a foam insert, and where the internal dividers land. This page covers the material, the rib structure that stands in for a metal frame, the closure, how the two halves are molded, how each case is checked, and how it is packed for export.
PP is the default material for a case at this duty level, for practical reasons rather than fashionable ones. It keeps a useful part of its impact strength at low temperature, it resists oils, coolants and most workshop chemicals, it does not absorb water, and it is light — a large case that is heavy when empty is a case that stays on the shelf. It also takes its texture and its color straight from the tool, so a scratched matte panel shows far less than a gloss ABS shell would.
The costs are real, and worth stating before a tool is cut. PP is less stiff than ABS or PC, which is why both halves of this case are ribbed: remove the ribs and the same wall thickness feels like a bucket. It also shrinks more than an engineering plastic, and it shrinks unevenly, so a large flat panel wants to bow and a lid wants to twist. Those are tool and process problems rather than material faults, and they are solved with rib layout, cooling, packing pressure and a checking fixture — not by adding wall thickness.
Look at the outside of the case and you see horizontal ribs running across the front; look inside the open lid and you see a grid. Both carry load. The outer ribs stiffen the tub against the squeeze of a stack; the lid grid stops the lid from oil-canning when something heavy is set on top of it, and it keeps the lid flat enough that the rim still meets the tub after a few hundred openings.
Rib geometry is where a toolmaker earns the money. A rib that is too thick sinks the visible face opposite it, and on a black textured panel that sink reads as a flat, slightly glossy patch under a raking light. A rib without enough draft drags and scuffs on ejection. A rib that stops short of the wall creates a stress riser exactly where the case takes its hardest hit. The pattern in this tool is held to roughly half the wall thickness at the root, fully drafted, filleted at the base, and gated so the flow front reaches the far corners of the panel at the same time.
The base carries four molded feet. They lift the case off a wet floor, they let one case sit squarely on the lid of another instead of sliding across it, and they take the wear that would otherwise land on the bottom panel.
The hinge runs the full length of the back. That is not a luxury on a case this size: a short hinge lets the lid rack when it is opened with one hand, and a lid that racks ends up riding on one corner of the rim and standing proud on the other. This tool uses molded knuckles with a pin; where a customer prefers a single molded piece, PP’s fatigue resistance is good enough to carry a living hinge, at the cost of a shorter service life and a stricter gate position.
Two draw latches pull the lid down at the front. Two, rather than one in the middle, because a single latch bows a long lid and leaves both corners open. The rim is a tongue-and-groove: the tongue on the lid drops into the groove in the tub and takes the sideways load, so the latches only have to hold the lid down, not locate it. If the case has to keep water and dust out, a gasket sits in the groove and the closure becomes a sealing problem — groove depth, gasket compression, latch preload — which is a different design conversation, and one worth having before the tool is cut rather than after.
A case that does not close squarely is the first defect a buyer notices, and it is almost always a flatness problem rather than a latch problem. The rim has to be flat within a tolerance the tool can actually hold, the two halves have to be molded from the same cavity set, and the assembly has to be checked closed — a lid measured on its own tells you very little about how it will sit on a tub.
Both halves come from the same tool family, with the cavity finished to the texture the customer chooses — a fine matte in the photos, which hides handling marks and keeps the panel from looking greasy after a day in a van. The gate sits on a face that is not seen when the case is closed, and the ejector marks are confined to the inside of the tub, where the tray or the tools cover them.
On a part this size, cooling dominates the cycle, and cooling is also what controls warpage. The body runs on one of the plant’s 36 machines in the 40–700 ton range, with mold temperature held steady across the shift: a mold that drifts hot in the afternoon produces lids that are slightly more bowed than the ones made in the morning, and those lids will not mix in a carton without a complaint. Hinge pins and latches are fitted after molding, and the assembled case is opened and closed once before it reaches inspection.
The first-article report on a project like this covers the outer envelope, wall thickness at the rib roots, latch engagement, hinge pin retention, color against the approved master, and flatness of the rim on a surface plate. In production, the checks are chosen for the failures that actually reach a customer: a latch that does not catch, a lid that stands proud on one corner, a hinge pin that walks out of its knuckle, a case that is a millimeter too tall for the carton the buyer specified.
Every case is opened and closed by hand before packing, and dimensional checks run on a sampling basis through the shift. Where a customer needs a drop or compression test to a named standard, the load and the drop height are written into the drawing, because a case that survives an empty drop can still fail with a 15 kg tool kit inside it.
Finished cases are bagged individually, packed in export cartons on a fixed count per carton, then stacked and stretch-wrapped on pallets for container loading. Bagging is the step that keeps a textured black panel from being scuffed by the case above it in the carton, and it is also what keeps dust out of the tub during a month at sea.
Two details are worth settling early. The first is the carton: a case designed to the millimeter can still be uneconomic to pack if the carton size forces an awkward count or a carton that is too heavy to handle. The second is the hardware: PP does not rust, but a metal hinge pin and metal latch springs can, and a desiccant bag or a light oil film costs almost nothing against a claim on a container of spotted cases.
Kunshan Maifeng Precision Industry Co., Ltd. builds molds for cases like this in house, molds PP on 36 machines from 40 to 700 tons, assembles the hinge and latches, and packs to the customer’s carton specification. Send a drawing, or a sample case with the interior layout you need, and we will come back with a tooling proposal, a material comment and a packing plan.
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 40 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