This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X1550S, 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 SI40X1550S
The AirTAC Airtac SI40 Standard Cylinder SI40X1550S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 1550mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X1550S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke1550 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X1550S
- 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 SI40X1550S
The AirTAC SI40X1550S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 1550mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. Because 1550mm exceeds the 1200mm standard maximum, this is a non-standard made-to-order unit requiring external guide support to prevent rod bending over such a long distance.
You should order the direct replacement SAI40X1550S. It shares the exact ISO 15552 mounting interface, M12x1.25 thread, and 128kgf max output. The SAI upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure. Note that plain cylinders drift without air; use the SAIL lock or BSAI clamp-lock variants for load holding.
Airtac SI40 Standard Cylinder SI40X1550S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X1550S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X1550S |
| Bore size | Ø40 mm |
| Stroke | 1550 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 SAI40X1550S 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 SAI40X1550S 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 SI40X1550S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×1550 | 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 SI40X1550S Is Used
Long-Stroke Material Push
Uses the full 1550mm travel to transfer products across wide conveyor belts, relying on external guides to prevent rod bending during the 628N push.
High-Bay Diversion
Actuates diverter arms in storage systems where the 32kg vertical lift capacity and extended reach are required to sort inventory.
Elevated Platform Lowering
Controls the descent of light fixtures using adjustable air cushions, though an external rod lock is needed if pneumatic pressure is lost.
Replacing the Airtac SI40 Standard Cylinder SI40X1550S with the SAI40X1550S
To replace this SI40X1550S, order the SAI40X1550S. Confirm the ISO 15552 mounting interface, G1/4 port, M12x1.25 rod thread, and the -S magnet for CS1-B/DS1-B sensors. Since 1550mm exceeds the 1200mm standard stroke, it is non-standard and demands external guides to prevent rod bending. If you need less force, a 32mm bore gives 402N at 0.5MPa; if you need more, a 50mm bore gives 982N. A plain cylinder does not hold load without live air—the cushion only decelerates—so consider the SAIL lock, BSAI clamp-lock, or an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X1550S
- ✓ 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 SI40X1550S FAQ
Yes, the SI40X1550S is discontinued. The direct replacement is the SAI40X1550S. It shares the same ISO 15552 mounting interface, 40mm bore, 1550mm stroke, G1/4 port, and output force, dropping directly into existing fixtures.
The G1/4 port bore delivers a push force of 628N and a pull force of 528N at 0.5MPa. At 0.7MPa push is 879N, and at 0.9MPa it is 1130N. The theoretical maximum force is 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X1550S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X1550S replacement — usually within 7-8 hours.