This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X108S, 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 SI40X108S
The AirTAC Airtac SI40 Standard Cylinder SI40X108S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 108mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X108S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke108 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X108S
- 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 SI40X108S
The AirTAC SI40X108S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 108mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI40X108S, matching the interface, force, and mounting exactly.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family also adds SAIL, SAIF, and BSAI lock variants. Your -S suffix means a magnet for CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40X108S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X108S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X108S |
| Bore size | Ø40 mm |
| Stroke | 108 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 SAI40X108S 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 SAI40X108S 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 SI40X108S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×108 | 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 SI40X108S Is Used
Clamp Actuation
Provides 628N of push force at 0.5MPa for securing mid-weight workpieces during machining operations.
Package Diversion
Drives 108mm stroke diverting arms to route lightweight cartons between conveyor belts at high speed.
Gate Control
Operates access gates or material stops in storage zones, benefiting from the compact 40mm profile barrel.
Replacing the Airtac SI40 Standard Cylinder SI40X108S with the SAI40X108S
To replace the SI40X108S, order the SAI40X108S. Confirm the ISO 15552 mounting interface, 40mm bore, 108mm stroke, G1/4 port (PT/G/NPT), and mounting accessory. The -S magnet fits legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. Sizing both ways: a 32mm bore yields 402N push at 0.5MPa, and a 50mm bore yields 982N. A plain cylinder drifts on air loss as the cushion only decelerates; for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. Because stroke is over 300mm, mind side-load and rod-bending forces, using a guide to prevent binding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X108S
- ✓ 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 SI40X108S FAQ
Yes, the SI40X108S is discontinued. The direct replacement is the SAI40X108S. It is dimensionally interchangeable per ISO 15552, keeping the same 40mm bore, 108mm stroke, G1/4 port, and mounting fixtures.
The G1/4 port feeds a 16mm rod. Force output is 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 SAI40X108S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X108S replacement — usually within 7-8 hours.