This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X420, with the same bore, stroke, output force, port and mounting, so it fits the same application. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac SI40 Standard Cylinder SI40X420
The AirTAC Airtac SI40 Standard Cylinder SI40X420 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 420mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X420, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke420 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X420
- 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 SI40 Standard Cylinder SI40X420
The AirTAC SI40X420 is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 420 mm stroke. Delivering 628 N push force at 0.5 MPa, it is replaced by the SAI40X420 direct. This successor matches the G1/4 port, M12x1.25 rod thread, and 27 mm cushions.
The SAI upgrade features two Y-shaped one-way piston seals for low start-up pressure and long life. Note this SKU lacks a magnet, so it cannot take CS1-B/DS1-B sensors. For load holding, the cushion only decelerates; use SAIL or BSAI lock variants.
Airtac SI40 Standard Cylinder SI40X420 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X420 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X420 |
| Bore size | Ø40 mm |
| Stroke | 420 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 800 mm/s |
| Cushion | Adjustable, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40X420 carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40X420 produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40X420
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×420 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac SI40 Standard Cylinder SI40X420 Is Used
Material Diversion
Actuates routing gates on package lines using its 628 N push force and 420 mm travel to redirect bins between chutes.
Vertical Lift Stops
Raises and lowers lightweight pallet stops up to 32 kg, relying on the 27 mm adjustable cushions to brake at stroke end.
Clamp Actuation
Drives long-throw clamping arms on machining fixtures where the 40 mm bore provides steady holding pressure.
Replacing the Airtac SI40 Standard Cylinder SI40X420 with the SAI40X420
To replace the SI40X420, order the SAI40X420. Verify the ISO 15552 mounting interface (LB, FA, TC, etc.), the 420 mm stroke, and the G1/4 port. Because this non-magnet SKU cannot accept a sensor, order a magnet-equipped SAI40X420S if position feedback is needed. At 0.5 MPa the 40 mm bore yields 628 N push; sizing down to 32 mm gives 402 N, while sizing up to 50 mm yields 982 N. The 420 mm stroke requires external guides to prevent rod bending under side loads. Finally, the air cushion only decelerates; use a pilot check valve or the SAIL/BSAI lock variants to hold loads securely.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X420
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40X420 FAQ
Yes, the SI40X420 is discontinued. The direct replacement is the SAI40X420. It shares the identical ISO 15552 mounting interface, 40 mm bore, 420 mm stroke, force, and G1/4 port, fitting existing fixtures perfectly while offering an upgraded piston seal.
The 40 mm bore features a G1/4 port. It delivers 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, and 1130 N push at 0.9 MPa. The theoretical maximum force is 128 kgf at 1.0 MPa.
Request a Quote for the SAI40X420
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X420 replacement — usually within 7-8 hours.