This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X155SN, 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 SI40X155SN
The AirTAC Airtac SI40 Standard Cylinder SI40X155SN is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 155mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X155SN, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke155 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X155SN
- 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 SI40X155SN
The AirTAC SI40X155SN is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 155 mm stroke. It delivers 628 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X155SN, a direct replacement matching the exact ISO 15552 mounting interface, bore, output force, and cushioning.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. This SI40X155SN includes a magnet for CS1-B/DS1-B switches and an NBR seal (-20 to +70 C), with Viton H available for high heat. Note that 155 mm is a nonstandard stroke length.
Airtac SI40 Standard Cylinder SI40X155SN Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X155SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X155SN |
| Bore size | Ø40 mm |
| Stroke | 155 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 SAI40X155SN 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 SAI40X155SN 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 SI40X155SN
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×155 | 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 SI40X155SN Is Used
Component Clamping
Secures mid-weight machined parts during CNC milling, utilizing the 628 N push force at 0.5 MPa for rigid holding.
Package Diverting
Actuates routing gates on assembly lines, where the 155 mm stroke provides sufficient travel to redirect product flow.
Pallet Stops
Controls pallet movement on gravity conveyors, using the NBR seals to withstand typical industrial shop temperatures.
Replacing the Airtac SI40 Standard Cylinder SI40X155SN with the SAI40X155SN
To replace the SI40X155SN, order the SAI40X155SN direct equivalent, verifying the ISO 15552 mounting interface, G1/4 port, and M12x1.25 rod thread. Because 155 mm exceeds standard increments, confirm this nonstandard stroke length is still required or step up to a 160 mm standard stroke. If downsizing, a 32 mm bore offers 402 N at 0.5 MPa; if upsizing, a 50 mm bore provides 982 N. This unit has a magnet (-S) for CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. For load holding, a plain cylinder drifts without live air—the cushion only decelerates—so use an external pilot check valve or the SAIL/BSAI lock variants. Since the stroke is near 160 mm, ensure guide alignment to prevent rod bending under side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X155SN
- ✓ 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 SI40X155SN FAQ
Yes, the AirTAC SI40X155SN is discontinued. The direct replacement is the SAI40X155SN. It features the same ISO 15552 mounting interface, 40 mm bore, 155 mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly.
The bore is 40 mm with a G1/4 air port. Force output is 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical maximum of 128 kgf at 1.0 MPa. The rod is 16 mm with an M12x1.25 thread.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X155SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X155SN replacement — usually within 7-8 hours.