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.
This white cylinder is the outer housing of a handheld electric nasal irrigator. It is the part the user actually holds: the tank sits in the collar at the top, the pump, battery and board live inside it, and the window on the side lets the user see what is going on without taking the device apart. Every visible surface of the machine that is not the tank is this one molding.
It is injection molded in ABS as a thin-walled shell, with the port collar, the side window and the grip recess formed in the tool rather than cut afterwards. This page covers the material choice, the three features that decide whether the tool works, what the white finish costs in process control, and what happens between the machine and the carton.
ABS is chosen here for three reasons that matter on a handheld device: it is stiff enough that a thin wall does not feel hollow, it takes a molded texture and holds a sharp edge, and it is dimensionally stable enough that the collar and the window stay where the assembly drawing puts them. It also bonds and prints easily, which matters if the customer adds a label or a pad-printed logo later. Compared with PP, it is the more expensive pellet and it has to be dried before molding — but it does not have PP’s soft, waxy surface, and on a device that is handled daily that difference is the first thing a buyer notices.
White is the hard part. A white shell shows every flow line, every weld line, every sink mark and every speck of contamination that a black or grey part would swallow. It also punishes a mold that runs hot in the afternoon: the same tool that produces a clean part at 8 a.m. can produce a faintly yellowish one at 4 p.m. if the barrel temperature and the residence time are not held. That is why the color is controlled against an approved master under a fixed light source, and why the grade is specified with a stabilizer rather than bought as a generic natural.
One point worth settling before the tool is cut: if the housing will be cleaned with alcohol or any other solvent on a routine basis, or if it counts as a patient-contact surface in the customer’s risk file, the grade and the documentation change. ABS can be supplied with biocompatibility and regulatory paperwork for that case, but it has to be chosen at the start, not swapped in after validation.
Three features decide whether this tool is straightforward or difficult.
The port collar at the top is a recessed ring with an oval opening through it. In the mold it is a tall core standing in the middle of the cavity, and it is the last place to cool. If that core runs cold, the collar comes out oval instead of round, and the tank either will not seat or seats with a gap on one side. The core is baffled and cooled separately, and the collar diameter is checked on the first shots rather than assumed from the model.
The side window is the feature that shapes the tool. A rectangular opening in a cylindrical wall cannot be molded with a simple two-plate tool; it needs a side action, and the slider has to shut off against steel on all four edges if the window is to have clean corners and no flash. The parting line of that slider leaves a witness mark, and where it lands is a design decision as much as a tooling one — on this part it is held inside the recessed frame so the mark reads as part of the feature rather than as a defect. The window also interrupts the flow front, so a weld line forms at its far edge; the gate position is chosen to keep that weld line in the shadow of the frame.
The grip recess on the opposite side is a shallow cored pocket with a generous draft. It looks cosmetic and is structural: it stiffens the wall exactly where a hand squeezes, which is what allows the rest of the shell to stay thin.
The shell closes on a line that runs around the body and up over the shoulder. On a two-plate tool that line is unavoidable; the job is to put it where the hand does not rest and where it reads as a molded feature. The tool is finished to a fine matte texture rather than a polish, for two reasons: a matte surface scatters light, so the small scratches a device collects in a bag do not show, and it hides the sink marks that form opposite the internal bosses. A gloss white shell of the same geometry would show both.
Sink is the other white-surface problem. Where a boss or a rib meets the wall, the thick section cools last and pulls the visible face in. The usual fix — thinning the rib and shortening the boss — is applied at the design stage, and the tool is then run with enough packing pressure and hold time that the face stays flat. On a white part this is checked visually under raking light, not just with a caliper.
The housing runs on a single cavity tool in ABS, dried to the grade’s specification and molded with a hot runner so there is no sprue to trim on a visible surface. Cycle time is set by the collar core; the rest of the part is thin and cools quickly.
The video below follows the part after the mold opens: the housing drops onto the conveyor, and the next station is a small press where an insert is seated into the shell by hand under a guided tool. That second operation is deliberately kept out of the mold. The insert varies — a seal, a plug or a foot depending on the customer’s bill of materials — and a mold that tried to overmold it would have to be rebuilt every time the BOM changed.
A white cosmetic shell is judged by eye before it is judged by a gauge, so the inspection starts there: color against the master, flow marks, sink on the shoulder, flash at the window frame and at the parting line, and the witness mark left by the slider. Anything that would read as a defect in a customer’s hand at arm’s length is a reject, whether or not it is inside the drawing tolerance.
The dimensional checks follow the assembly, not the drawing in isolation: collar diameter and roundness, window opening position relative to the collar, height from the base rim to the collar face, wall thickness at the collar root, and the seating depth of the insert after the press step. The collar and the base rim are the two faces the rest of the device is built from, so they carry the tightest tolerances; if they are right, the [waterway base](https://www.mold-mif.com/waterway-integrated-base-for-medical-nasal-irrigator/) and the upper assembly go together without shimming.
Parts are bagged individually and packed in cartons on a fixed count. On a white textured shell the bag is not decoration — it is what keeps the part from being scuffed by the one above it before it reaches the assembly line.
Kunshan Maifeng Precision Industry Co., Ltd. builds the mold in house, molds ABS on 36 machines from 40 to 700 tons, and runs the secondary press and packing operations in the same plant. Send the housing model with the internal layout and the color standard, and we will come back with a tooling proposal that names the side action, the gate position and the texture before any steel is cut.
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.
English 
Chinese