This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X104S, 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 SI40X104S
The AirTAC Airtac SI40 Standard Cylinder SI40X104S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 104mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X104S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke104 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X104S
- 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 SI40X104S
The AirTAC SI40X104S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 104 mm stroke. It delivers 628 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X104S, a direct upgrade sharing the exact same ISO 15552 mounting interface, bore, stroke, output force, and accessories.
The SAI upgrade features a refined piston seal using two Y-shaped one-way elements for low start-up pressure and extended life. The -S suffix denotes a piston magnet for legacy CS1-B/DS1-B sensors; the SAI successor uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X104S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X104S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X104S |
| Bore size | Ø40 mm |
| Stroke | 104 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 SAI40X104S 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 SAI40X104S 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 SI40X104S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×104 | 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 SI40X104S Is Used
Component Clamping
Secures medium-duty workpieces during machining, utilizing the 628 N push force at 0.5 MPa to hold parts firmly against fixturing stops.
Package Diverting
Actuates routing gates on assembly lines, where the 104 mm stroke provides rapid and precise redirection of goods between processing stations.
Vertical Lift Stops
Functions as a pneumatic stop in low-friction vertical material handling tasks, safely managing loads up to the 32 kg vertical lift threshold.
Replacing the Airtac SI40 Standard Cylinder SI40X104S with the SAI40X104S
To replace the SI40X104S, order the SAI40X104S and confirm your ISO 15552 mounting accessories (LB, FA, CA, TC), G1/4 port thread (PT/G/NPT), and the M12x1.25 rod-end thread. Because this is a non-standard 104 mm stroke, verify the exact stroke length on the replacement order. If you need slightly more force, the neighbouring 50 mm bore yields 982 N push at 0.5 MPa; if less is acceptable, the 32 mm bore provides 402 N. Remember that a standard cylinder does not hold load on air loss—the cushions only decelerate near the ends. For static holding, consider an external pilot check valve or explore the SAIL (air-released lock) and BSAI (clamp-lock) variants. The SAIF variant (bores 32-100) integrates a built-in 4M valve if you need localized control.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X104S
- ✓ 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 SI40X104S FAQ
Yes, the AirTAC SI40X104S is discontinued. The direct replacement is the SAI40X104S. It is dimensionally interchangeable per ISO 15552, retaining the same 40 mm bore, 104 mm stroke, G1/4 port, and mounting interface, so it drops directly into existing fixtures.
The 40 mm bore operates at 30-800 mm/s with a G1/4 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.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X104S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X104S replacement — usually within 7-8 hours.