This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX550, 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 SI40AX550
The AirTAC Airtac SI40 Standard Cylinder SI40AX550 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 550mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40AX550, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke550 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40AX550
- 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 SI40AX550
The AirTAC SI40AX550 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 550mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI40AX550, which shares identical ISO 15552 mounting dimensions, stroke, and force.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. This SKU uses a SUS420J2 stainless rod (option A) but lacks a magnet, so it cannot take a CS1-B/DS1-B sensor.
Airtac SI40 Standard Cylinder SI40AX550 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX550 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX550 |
| Bore size | Ø40 mm |
| Stroke | 550 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 SAI40AX550 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 SAI40AX550 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 SI40AX550
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×550 | 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 SI40AX550 Is Used
Long-Stroke Diversion
Pushes packages across a 550mm conveyor lane using the 628N push force at 0.5MPa, guided externally to prevent rod bending.
Stainless Rod Washdown
Actuates testing or washdown stations where the SUS420J2 stainless piston rod resists moisture better than standard carbon steel.
Replacing the Airtac SI40 Standard Cylinder SI40AX550 with the SAI40AX550
To replace the SI40AX550, order the SAI40AX550. Verify the ISO 15552 interface, 40mm bore, 550mm stroke, G1/4 port, and SUS420J2 rod. This non-magnet SKU cannot accept a sensor; order an -S variant if position detection is needed. For sizing, a 32mm bore yields 402N [email protected], while a 50mm bore yields 982N. A plain cylinder drifts on air loss; for load holding use an external pilot check valve or the SAIL/BSAI lock variant. Because the 550mm stroke is long, use external guides to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX550
- ✓ 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 SI40AX550 FAQ
Yes, the SI40AX550 is discontinued. The direct replacement is the SAI40AX550. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 550mm stroke, G1/4 port, and mounting interface.
The 40mm bore uses a G1/4 port. It generates 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical max of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40AX550
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX550 replacement — usually within 7-8 hours.