This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX350, 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 SI40BX350
The AirTAC Airtac SI40 Standard Cylinder SI40BX350 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 350mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX350, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke350 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX350
- 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 SI40BX350
The AirTAC SI40BX350 is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 350 mm stroke. It delivers 628 N push and 528 N pull at 0.5 MPa through a G1/4 port. AirTAC replaced this EOL unit with the SAI40BX350, a direct sharing the exact ISO 15552 mounting interface, bore, stroke, force, and port.
The SAI40BX350 upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. This SKU has a SUS304 stainless rod (B option) but lacks a magnet, so it cannot take a sensor. For high heat, Viton H seals raise the range to 150 C.
Airtac SI40 Standard Cylinder SI40BX350 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX350 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX350 |
| Bore size | Ø40 mm |
| Stroke | 350 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 SAI40BX350 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 SAI40BX350 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 SI40BX350
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×350 | 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 SI40BX350 Is Used
Diverting Gates
Actuates routing flaps on packaging lines, using the 628 N push force at 0.5 MPa to redirect cartons reliably.
Light Pressing
Provides consistent downward pressure for assembling small components, utilizing the 32 kg safe vertical lift capacity.
Pallet Stops
Extends 350 mm to halt pallet movement on roller conveyors, requiring external guides to handle side-load impacts.
Replacing the Airtac SI40 Standard Cylinder SI40BX350 with the SAI40BX350
To replace the SI40BX350, order the SAI40BX350. Confirm the ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 port, and the M12x1.25 rod thread. Because this SKU lacks a magnet (-S), it cannot accept CS1-B/DS1-B switches; order a sensing-ready version if needed. Sizing both ways: the 40 mm bore gives 628 N push at 0.5 MPa, while the neighbouring 50 mm bore offers 982 N. The 350 mm stroke requires external guides to prevent rod bending under side loads. A plain cylinder drifts on air loss—the cushion only decelerates. For load holding, use an external pilot check valve, or specify the SAIL or BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX350
- ✓ 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 SI40BX350 FAQ
Yes, the SI40BX350 is discontinued. The direct replacement is the SAI40BX350. It shares the identical ISO 15552 mounting interface, 40 mm bore, 350 mm stroke, force, and G1/4 port, fitting existing fixtures perfectly.
The G1/4 port bore delivers 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 max of 128 kgf at 1.0 MPa. The speed range is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX350
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX350 replacement — usually within 7-8 hours.