Molded orifice
- One part, no insert to load
- Lowest cost per nozzle
- Wears open where the liquid carries grit
Molded part guide: nozzles
Injection Molded Nozzles
A nozzle turns pressure into a pattern. Whether that pattern is a fine cone, a flat fan, or a straight jet is decided by a handful of features smaller than a grain of rice, and by whether they are exactly where the drawing says. A tiny shift in the opening sends the whole spray off to one side.
Small features
The pattern is decided by the smallest features
Spray nozzles, fan nozzles, misting nozzles, garden nozzles, and dispensing tips.
The opening is formed by a small pin meeting a matching seat when the tool closes. Where those two meet decides the opening size and whether it is centered. If the pin sits slightly off, the opening is no longer concentric with the passage behind it, and the spray leaves at an angle instead of straight ahead. A nozzle that sprays off to one side is almost always this.
Keeping the pin centered is a tooling problem. The pin is thin, it sticks out into the flow, and melt rushing past pushes it sideways. Supporting the pin at both ends, feeding the nozzle so the melt arrives evenly around it, and checking the first parts for concentricity rather than just opening size are the ways this is controlled.
The pattern itself comes from what happens just before the opening. Slots or angled passages set the liquid spinning so it leaves as a hollow cone. A flat chamber across the opening spreads it into a fan. A straight passage gives a jet. Those features are small, so any flash across them changes the pattern, which is why the parting line is kept away from them.
Then there is wear. Water carries grit, cleaning chemicals attack, and every particle that passes through the opening takes a little material with it. As the opening wears it gets bigger and the pattern spreads, so the nozzle uses more liquid and covers less well. Where that matters, the opening is a hard metal insert molded into a plastic body.
Features
Nozzle features and what each one controls
Every feature sits within a few millimeters of the tip.
| Feature | Purpose | Design note |
|---|---|---|
| Orifice | Sets flow and pattern size | Must stay centered with the passage behind it |
| Swirl features | Make a hollow cone | Slots or angled passages just behind the opening |
| Fan chamber | Makes a flat fan | Shallow chamber across the opening |
| Body passage | Feeds the tip | Smooth, with no sharp turn just before the opening |
| Thread or bayonet | Fits the wand or the line | Sealed by a gasket or by a tapered thread |
Concentricity
An opening that is not centered sprays sideways
The pin that forms the opening is thin, and melt pushes it around.
- Melt rushing past a thin unsupported pin pushes it away from center
- An opening off center is no longer aligned with the passage behind it
- The spray then leaves at an angle instead of straight ahead
- Supporting the pin at both ends and feeding evenly keeps it centered
Orifice
Molded orifice or metal insert orifice
How long the pattern has to stay the same decides this.
Metal insert orifice
- Holds its size and pattern far longer
- Suits abrasive liquids and long duty cycles
- Adds an insert and a loading step at the press
Drawing
What to send with a nozzle
The pattern and the liquid set everything else.
Nozzle CAD, or the pattern and flow you need
Working pressure at the nozzle
Liquid type, and anything abrasive in it
How the nozzle attaches, thread or bayonet
Expected service life before the pattern shifts
Expected annual volume
Keep reading
Related guides
Other fluid parts, small openings, and the flash that spoils them.
Irrigation fittings
Barbs, threads, and sunlight.
Irrigation fittingsValve bodies
Cored passages and seal seats.
Valve bodiesFunnels
Cones, stems, and air channels.
FunnelsPipette tips
Thin tips and clean openings.
Pipette tipsFlash
Thin films across small features.
FlashInsert molding
Metal orifices in plastic bodies.
Insert moldingTight tolerances
When small features need control.
Tight tolerancesIndustrial and transportation
How we support industrial programs.
Industrial and transportationMolded parts hub
Every part-type guide, grouped by family.
Molded parts hubFAQ
Questions about molded nozzles
Why does our nozzle spray off to one side?
The opening is not concentric with the passage behind it, usually because the pin that forms it moved. Supporting the pin at both ends and feeding evenly around it brings the spray straight. Spraying onto a marked card at a fixed distance makes a sideways pattern obvious in seconds.
Why does the pattern change between nozzles?
Small differences in the opening and in the swirl features are enough. Checking concentricity as well as opening size on the first parts shows which one is moving. Keeping the parting line away from the swirl features means flash never lands where it would change the pattern.
Why does flow rise over months of use?
Grit in the liquid slowly wears the opening open. A metal insert orifice holds its size far longer where the liquid is abrasive. Where flow has to stay steady for a long duty cycle, an insert orifice is usually the difference between one season and several.
Which resin suits a nozzle?
Acetal and filled nylon are common for their stiffness and wear. Where strong cleaning chemicals are used, a more resistant grade is worth checking against that specific chemical. A grade that shrugs off the chemical but wears quickly is no better than the reverse, so both are checked together.
Next step
Quote a nozzle with its pattern
Upload the nozzle, or describe the pattern and pressure. DFM feedback covers orifice concentricity, swirl features, flash risk, and insert options.