Airtac PU Straight Fitting PU6D
The AirTAC Airtac PU Straight Fitting PU6D is a genuine straight union for push-in tube connection, rated 0 - 1.0 MPa (0 - 10 kgf/cm2) with a 1.5 MPa proof pressure.
- TypeStraight union
- SeriesPU
- Working pressure0 - 1.0 MPa (0 - 10 kgf/cm2)
- Proof pressure1.5 MPa
- Temperature-20 to +70 °C
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac PU Straight Fitting PU6D
The PU6D is an AirTAC PU straight union, a tube-to-tube one-touch fitting that joins two lengths of Dia 6 mm soft nylon or polyurethane tubing in a straight run. Push each tube home and the stainless spring gasket and chuck grip it against the POM seal; press the release ring and the tube frees again. Because it carries no thread, the fitting itself adds no port and nothing to seal against the machine.
This D-suffix version is the black-body variant - on the PU union family the D changes the whole body colour, unlike on the PC and POC connectors where black applies to the release button only. Internally it is the standard resin build: POM button and chuck, aluminium-alloy guide, stainless spring gasket and NBR O-ring. It is rated 0-1.0 MPa working pressure, -750 mmHg (10 Torr) vacuum, 1.5 MPa proof pressure and -20 to +70 C.
Airtac PU Straight Fitting PU6D Technical Specifications
| Model | Airtac PU Straight Fitting PU6D |
|---|---|
| Type | Straight union |
| Series | PU |
| Connection | Push-in one-touch |
| Working pressure | 0 - 1.0 MPa (0 - 10 kgf/cm2) |
|---|---|
| Negative pressure | -750 mmHg (10 Torr) |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Applicable tubing | Soft nylon or polyurethane tube |
| Thread standard | PT (Rc tapered) unless the code says otherwise |
POM release button and chuck, aluminium-alloy guide, stainless spring gasket, NBR O-ring; body brass or PBT depending on the part. AirTAC publishes flow as a characteristic curve rather than a single figure, so no L/min value is listed.
Model Code: Airtac PU Straight Fitting PU6D
| PU | Straight union. |
|---|---|
| 4 / 6 / 8 / 10 / 12 | Tube outside diameter in mm (3.2 mm exists on the mini series). |
| M5 / 01 / 02 / 03 / 04 | Thread: M5x0.8, 1/8", 1/4", 3/8", 1/2" (M3 on the mini series). |
| D | Black. Blank = grey. |
Fitting & Sealing Notes
- check Cut the tube square and clean before pushing it home, or the seal will leak.
- check Push until it stops, then pull back to check the chuck has gripped.
- check To release, press the collet ring fully in and pull the tube out.
- check Threaded parts arrive with sealant on the thread; M5 sizes use a sealing gasket.
- check Match the tube OD exactly - a 6 mm fitting will not hold 1/4" tube.
Where the Airtac PU Straight Fitting PU6D Is Used
Extending cylinder drop lines on a pick-and-place gantry
When a Dia 6 mm drop from the manifold falls short of the X-axis cylinder on a pick-and-place gantry, a straight union splices in extra tubing without adding a threaded port anywhere on the moving carriage.
Feeding a vacuum ejector on a conveyor-mounted gripper
Conveyor-mounted suction grippers need their ejector vacuum line repaired fast. The PU6D is rated for -750 mmHg (10 Torr), so it holds a Dia 6 mm ejector feed line even under full vacuum on the packaging line.
MRO splice on a screen printing machine
Screen printing presses run many short Dia 6 mm squeegee and clamp air lines that crack near hot platens. A black PU6D union replaces a damaged section in-line, and the one-touch release makes the fix a two-minute job.
Is the Airtac PU Straight Fitting PU6D the Right Part?
Size both neighbouring unions before ordering: PU4 steps down to Dia 4 mm tube for compact sensor and pilot lines, while PU8 steps up to Dia 8 mm for higher delivery to larger actuators. A 6 mm union sits in the middle of the ladder and is the usual choice for cylinder ports up to about Dia 20 bores fed at short runs. The tube size must match exactly - a Dia 6 chuck will not seal 1/4 inch (6.35 mm) tube, even though the numbers look close.
If you actually need to transition between two different tube sizes in-line, you want the PG different-diameter straight union instead of the PU, which is same-size only. And if the run has to pass through a sheet-metal panel, the PM bulkhead union with its M14x1 locknut (Dia 6) is the right shape rather than this open union.
Quick checklist
- ✓ Tube outside diameter matches exactly
- ✓ Thread size and standard match the port
- ✓ Working pressure within 0 - 1.0 MPa (0 - 10 kgf/cm2)
- ✓ Temperature within -20 to +70 °C
Airtac PU Straight Fitting PU6D FAQ
The PU6D is a straight union one-touch fitting with Dia 6 mm tube on both ends and no thread. It is part of the resin/brass one-touch family: working pressure 0-1.0 MPa (0-10 kgf/cm2), vacuum capability -750 mmHg (10 Torr), proof pressure 1.5 MPa, and operating temperature -20 to +70 C. It suits soft nylon or polyurethane tubing only. The D suffix gives the full body a black finish.
No. The chuck set inside this union is machined for exactly 6 mm outside diameter tube, and 1/4 inch tube measures about 6.35 mm OD - close enough to insert but too loose to seal reliably. Never mix inch and metric tube in one-touch fittings. If you need a genuine size transition, use the PG different-diameter straight union instead, and check the release ring frees cleanly on the exact tube you plan to run.
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