This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X686, 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 SI40X686
The AirTAC Airtac SI40 Standard Cylinder SI40X686 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 686mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X686, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke686 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X686
- 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 SI40X686
The AirTAC SI40X686 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 686mm stroke, delivering 628N push force at 0.5MPa. The direct replacement is the SAI40X686, retaining the same G1/4 port, M12x1.25 thread, and mounting interface. The SAI upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure and longer life.
This non-magnetic SKU cannot accept a position switch. The SAI family adds SAIL, SAIF, and BSAI lock variants the SI lacked. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For the 686mm stroke, use external guides to prevent rod bending.
Airtac SI40 Standard Cylinder SI40X686 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X686 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X686 |
| Bore size | Ø40 mm |
| Stroke | 686 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 SAI40X686 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 SAI40X686 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 SI40X686
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×686 | 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 SI40X686 Is Used
Long-Stroke Diversion
Pushes packages across transfer lines using the 686mm stroke, relying on external guides to prevent rod bending.
Automated Door Operation
Opens and closes equipment safety doors, utilizing the 628N push force and adjustable 27mm air cushions.
Replacing the Airtac SI40 Standard Cylinder SI40X686 with the SAI40X686
To replace the SI40X686, order the SAI40X686, confirming the ISO 15552 interface, 40mm bore, 686mm stroke, G1/4 port, and mounting. Because this SKU lacks the -S magnet, it cannot take a CS1-B/DS1-B sensor. For sizing, the 40mm bore yields 628N push at 0.5MPa; dropping to 32mm gives 402N, while 50mm provides 982N. For the 686mm stroke, add external guides to prevent rod bending under side loads. A plain cylinder does not hold load without air; use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant for secure holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X686
- ✓ 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 SI40X686 FAQ
Yes, the SI40X686 is discontinued. The direct replacement is the SAI40X686. It is dimensionally interchangeable per ISO 15552, keeping the same 40mm bore, 686mm stroke, 628N force, G1/4 port, and mounting fixtures.
The 40mm bore features a G1/4 port. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, and 1130N push at 0.9MPa. The theoretical maximum force is 128kgf at 1.0MPa.
Request a Quote for the SAI40X686
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X686 replacement — usually within 7-8 hours.