This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X550, 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 SI40X550
The AirTAC Airtac SI40 Standard Cylinder SI40X550 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 SAI40X550, 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 → SAI40X550
- 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 SI40X550
The AirTAC SI40X550 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 550mm stroke, delivering 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the current-production SAI40X550, which maintains the exact same interface, force, and mounting dimensions.
The SAI upgrade features an improved piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Note this specific SKU lacks a magnet (-S) and cannot accept position sensors.
Airtac SI40 Standard Cylinder SI40X550 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X550 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X550 |
| 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 SAI40X550 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 SAI40X550 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 SI40X550
| 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 SI40X550 Is Used
Extended Stroke Diversion
Pushes packages across a 550mm transfer gap on a sorting line using 628N of thrust at 0.5MPa.
Long-Reach Ejection
Ejects machined aluminum parts from a press bed over a 550mm distance before the next cycle begins.
Replacing the Airtac SI40 Standard Cylinder SI40X550 with the SAI40X550
To replace the SI40X550, order the SAI40X550. Verify your ISO 15552 mounting accessory (LB, FA, TC, etc.), G1/4 port thread (PT/G/NPT), and M12x1.25 rod-end thread. Because this 550mm stroke exceeds 300mm, use an external guide to prevent rod bending and side-load wear. If sizing up or down, the 32mm bore offers 402N push while the 50mm bore provides 982N at 0.5MPa. This plain cylinder cannot hold a load without live air; for load-holding, use an external pilot check valve or the SAIL/BSAI lock variants. Since this SKU has no magnet, it cannot take CS1-B/DS1-B sensors.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X550
- ✓ 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 SI40X550 FAQ
Yes, the AirTAC SI40X550 is discontinued. The direct replacement is the SAI40X550. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 550mm stroke, G1/4 port, and mounting interface.
The 40mm bore features a G1/4 air port and M12x1.25 rod thread. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a maximum theoretical force of 128kgf at 1.0MPa.
Request a Quote for the SAI40X550
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X550 replacement — usually within 7-8 hours.