Vape cartridge intake hole size explained

What the intake hole is

Inside a 510 cartridge, oil sits in the tank and the heating element sits in a chamber below it or beside it. The intake holes are the openings that connect the two. They are cut into the centre post on a post design, or into the base of the wick chamber on a postless design. Nothing else feeds the element. Their diameter and their count set how fast oil can move across under gravity, capillary action and the pressure drop created by a draw.

Suppliers quote intake as a diameter with a count. "4 x 1.2 mm" means four openings of 1.2 mm each. Some datasheets quote only the diameter and leave the count on the drawing, so ask for both. Two cartridges that both say "1.2 mm" can differ in total open area by a factor of two.

Which diameters are commonly offered

Most 510 platforms sit in a band from roughly 0.8 mm to 2.0 mm, offered in steps of about 0.2 mm. Counts are usually two or four. The table below is an orientation, not a specification. Confirm any starting point against a sample of your own fill at your own filling temperature.

Hole count versus hole diameter

These are not interchangeable. Open area scales with the square of the diameter, so four holes of 1.0 mm come to about 3.14 mm² of total area, which is almost exactly the same as one hole of 2.0 mm. The flow is not the same.

For viscous flow through a channel, resistance depends on far more than cross-sectional area. In the pipe-flow case described by the Hagen-Poiseuille relation, volumetric flow scales with the fourth power of the radius. Cartridge intakes are short orifices rather than long tubes, so real behaviour sits somewhere between area-limited and radius-limited, but the direction holds: several small holes pass thick oil more slowly than one large hole of the same total area.

Count still earns its place. Multiple holes distribute oil around the circumference of the core, which matters for even saturation and for how the cartridge behaves when it is stored on its side. A single large hole feeds one point. The trade-off is that a single large hole is easier to fill through and easier to clear of trapped air.

What changes as the hole gets larger

• Refill rate rises. The core re-saturates faster between draws, which reduces dry hits and the scorched taste that comes with them.
• Thick oil becomes workable. Extracts that will not move through a 1.0 mm aperture at room temperature will move through 1.8 mm.
• Leak margin falls. Warm oil, a pressure drop in an aircraft hold, or a cartridge left in a car will all push oil through a larger opening more readily.
• Flooding risk rises. If oil enters the chamber faster than it is vaporised, it pools, gurgles and finds the airpath.

What changes as the hole gets smaller

• Leak margin rises. A small aperture holds oil against temperature and pressure swings better, which is the main reason thin fills are matched to small intakes.
• Starvation risk rises. If the core cannot re-wet between draws, the element runs dry. That burns the residue on the wick and can damage the element itself.
• Temperature sensitivity rises. A fill that flows acceptably at 25 °C may not flow at 8 °C. Cold-chain and winter shipping change the answer.

How to specify intake size on an order

Give the supplier the fill, not just the number. State the extract type, the diluent if any, the filling temperature, and the tank volume. Ask for the intake diameter and the hole count as separate figures, ask whether the holes are in the post or the base, and ask which core material the platform uses. If you are choosing between architectures first, read postless versus pillar 510 cartridges. If you are matching intake to a specific extract, read matching cartridge intake size to oil viscosity.

Order a small batch and test it before you commit volume. Our MOQ starts at around 500 units, so a trial run is a realistic step rather than a favour. Made-to-order runs are around six weeks. CE, RoHS, REACH and EU Battery Regulation documentation is available on request, and the compliance page sets out what we can supply and what stays your responsibility as the party placing the filled product on the market.

FAQ

What is a common intake hole size for vape cartridges?

Most 510 cartridge platforms are offered somewhere between 0.8 mm and 2.0 mm, and 1.0 mm to 1.2 mm is the usual default for standard distillate. The correct figure depends on the viscosity of your fill and on your filling temperature, not on a universal number.

Do four small intake holes flow the same as one large hole?

Not quite. Four holes of 1.0 mm have almost exactly the same total area as one hole of 2.0 mm, but viscous flow resistance rises steeply as a channel narrows, so the four small holes pass thick oil more slowly. Multiple holes do feed the core more evenly around its circumference.

What happens if the intake hole is too large?

Oil enters the heating chamber faster than it is consumed. That shows up as flooding, gurgling, oil in the airpath and seepage around the mouthpiece, most often when the cartridge is warm or when ambient pressure drops during air freight.

Sources

• Directive 2011/65/EU on the restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS) (recast), the official text on EUR-Lex.
• Regulation (EC) No 1907/2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), the official text on EUR-Lex.
• Regulation (EU) 2023/1542 concerning batteries and waste batteries, the official text on EUR-Lex.

Trade guidance for B2B buyers, not legal advice. We sell empty hardware only; you are responsible for the fill and for finished-product compliance in your market.