This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X300, 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 SI40X300
The AirTAC Airtac SI40 Standard Cylinder SI40X300 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 300mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X300, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke300 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X300
- 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 SI40X300
The AirTAC SI40X300 is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 300 mm stroke, delivering 628 N push force at 0.5 MPa. AirTAC replaced this legacy unit with the SAI40X300, a direct upgrade retaining the exact G1/4 port, M12x1.25 rod thread, and ISO 15552 mounting interface for existing fixtures. This non-magnet SKU cannot accept a sensor.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. If high heat is a factor, a Viton H seal option extends the temperature range to 150 C.
Airtac SI40 Standard Cylinder SI40X300 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X300 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X300 |
| Bore size | Ø40 mm |
| Stroke | 300 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 SAI40X300 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 SAI40X300 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 SI40X300
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×300 | 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 SI40X300 Is Used
Package Diverting
Routes medium-weight cartons on packaging lines, utilizing the 628 N push force to actuate routing gates reliably over a 300 mm travel distance.
Pallet Positioning
Indexes empty pallets into a loading station, using the 300 mm stroke to push components into precise alignment before the next production step.
Replacing the Airtac SI40 Standard Cylinder SI40X300 with the SAI40X300
To replace the SI40X300, order the SAI40X300 and verify your ISO 15552 mounting accessory (LB, FA, TC, etc.), G1/4 port thread (PT, G, or NPT), and 300 mm stroke. Because this SKU lacks the -S magnet, it cannot support legacy CS1-B/DS1-B sensors; order a magnet-equipped SAI if position detection is needed. Sizing both ways: the 40 mm bore yields 628 N push at 0.5 MPa (1130 N at 0.9 MPa); dropping to a 32 mm bore gives 402 N, while a 50 mm bore provides 982 N. For this 300 mm stroke, use an external guide to prevent rod bending and side-load damage. Remember that a plain cylinder drifts on air loss; for load holding, use an external pilot check valve or explore the SAIL or BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X300
- ✓ 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 SI40X300 FAQ
Yes, the SI40X300 is discontinued. The direct replacement is the AirTAC SAI40X300. It features the same ISO 15552 mounting interface, 40 mm bore, 300 mm stroke, output force, and G1/4 port, fitting directly into existing machinery.
The 40 mm bore features a G1/4 air port and provides 628 N push / 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. It operates at speeds of 30-800 mm/s.
Request a Quote for the SAI40X300
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X300 replacement — usually within 7-8 hours.