This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX400, 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 SI40BX400
The AirTAC Airtac SI40 Standard Cylinder SI40BX400 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 400mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX400, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke400 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX400
- 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 SI40BX400
The AirTAC SI40BX400 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 400mm stroke. Featuring a SUS304 stainless piston rod for corrosion resistance, it delivers 628 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI40BX400 direct replacement, retaining the exact ISO 15552 mounting interface, bore, stroke, force and port size.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. Note this SKU lacks a magnet and cannot take a sensor; the legacy SI -S type used CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40BX400 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX400 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX400 |
| Bore size | Ø40 mm |
| Stroke | 400 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 SAI40BX400 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 SAI40BX400 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 SI40BX400
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×400 | 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 SI40BX400 Is Used
Stainless Rod Diverters
Actuates routing gates on washdown-resistant conveyor lines where the SUS304 rod prevents corrosion.
Vertical Package Lifts
Raises 32 kg cartons through a 400mm vertical stroke using the 628 N push force at 0.5 MPa.
Pneumatic Indexing Stops
Functions as a physical stop pin for pallet positioning, requiring external guides due to the long stroke.
Replacing the Airtac SI40 Standard Cylinder SI40BX400 with the SAI40BX400
To replace the SI40BX400, order the SAI40BX400. Verify the ISO 15552 mounting interface, 40mm bore, 400mm stroke, G1/4 port (PT/G/NPT thread options) and your mounting accessory. Because this 400mm stroke is long, use an external guide to prevent rod bending and side-load wear. Sizing both ways: a neighbouring 32mm bore gives 402 N push at 0.5 MPa, while a 50mm bore yields 982 N. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. This no-magnet SKU cannot accept a sensor.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX400
- ✓ 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 SI40BX400 FAQ
Yes, the SI40BX400 is discontinued. The direct replacement is the SAI40BX400. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 400mm stroke, 628 N force, G1/4 port and mounting interface.
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. It operates at 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX400
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX400 replacement — usually within 7-8 hours.