This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX25S, 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 SI40BX25S
The AirTAC Airtac SI40 Standard Cylinder SI40BX25S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 25mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX25S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke25 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX25S
- 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 SI40BX25S
The AirTAC SI40BX25S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 25mm stroke. It delivers 628N push force at 0.5MPa through a G1/4 port. The direct replacement is the SAI40BX25S, matching the bore, stroke, force, port, and ISO 15552 mounting interface exactly.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. This specific SI40BX25S includes a SUS304 stainless steel rod and a piston magnet for CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40BX25S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX25S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX25S |
| Bore size | Ø40 mm |
| Stroke | 25 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 SAI40BX25S 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 SAI40BX25S 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 SI40BX25S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×25 | 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 SI40BX25S Is Used
Compact Clamping
Ideal for holding small to medium machined parts during milling or drilling, utilizing the 628N force within tight fixture spaces.
Short-Stroke Diverter
Perfectly suited for 25mm actuation gates on conveyor lines to sort lightweight packages or direct product flow.
Stainless Rod Ejection
The SUS304 rod option excels in mildly corrosive ejection tasks, pushing parts out of automated storage retrieval systems.
Replacing the Airtac SI40 Standard Cylinder SI40BX25S with the SAI40BX25S
To replace the SI40BX25S, order the SAI40BX25S. Confirm the ISO 15552 mounting interface, 40mm bore, 25mm stroke, G1/4 port, and your mounting accessory. This unit has the -S magnet and -B SUS304 rod; the SAI uses current AirTAC switches. For sizing, a 32mm bore yields 402N push at 0.5MPa, while a 50mm bore yields 982N. Note that 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 variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX25S
- ✓ 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 SI40BX25S FAQ
Yes, the SI40BX25S is discontinued. The direct replacement is the SAI40BX25S. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 25mm stroke, force, G1/4 port, and mounting fixtures.
This double-acting cylinder features a G1/4 air port. It provides 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical max force of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX25S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX25S replacement — usually within 7-8 hours.