This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X650STC, 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 SI40X650STC
The AirTAC Airtac SI40 Standard Cylinder SI40X650STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 650mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X650STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke650 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X650STC
- 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 SI40X650STC
The AirTAC SI40X650STC is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 650 mm stroke, delivering 628 N push force at 0.5 MPa through a G1/4 port. Because this SI series is end-of-life, AirTAC specifies the SAI40X650STC as the direct replacement. It retains the same ISO 15552 mounting interface, M12x1.25 rod thread, and 27 mm cushions, dropping directly into existing TC trunnion fixtures.
The SAI upgrade introduces a two Y-shaped one-way piston seal for lower start-up pressure and longer life. For load holding, note that a standard cylinder drifts without live air; the cushions only decelerate. Use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. With the -S magnet, this legacy SKU uses CS1-B/DS1-B sensors (the SAI uses current switches).
Airtac SI40 Standard Cylinder SI40X650STC Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X650STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X650STC |
| Bore size | Ø40 mm |
| Stroke | 650 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 SAI40X650STC 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 SAI40X650STC 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 SI40X650STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×650 | 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 SI40X650STC Is Used
Long-Stroke Diversion
Drives sorting paddles across wide conveyor belts, using the 650 mm stroke to push products cleanly into downstream packaging lanes.
Pneumatic Slide Transfer
Actuates traverse carriages between assembly stations, relying on the TC trunnion mount to accommodate angular alignment shifts.
Replacing the Airtac SI40 Standard Cylinder SI40X650STC with the SAI40X650STC
To replace the SI40X650STC, order the SAI40X650STC. Verify the ISO 15552 TC trunnion interface, 40 mm bore, 650 mm stroke, G1/4 port (PT/G/NPT thread options), and the -S magnet for sensing. The SAI family also adds SAIF (integrated 4M valve) and SAIL/BSAI lock variants if your fixture needs braking. For sizing, a 40 mm bore yields 628 N push at 0.5 MPa; dropping to a 32 mm bore gives 402 N, while a 50 mm bore provides 982 N. Because 650 mm exceeds 300 mm, add external guides to prevent rod bending and side-load damage. Remember, a plain cylinder does not hold load on air loss—install a pilot check valve for suspended loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X650STC
- ✓ 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 SI40X650STC FAQ
Yes, the SI40X650STC is discontinued. The direct replacement is the SAI40X650STC. It is dimensionally interchangeable per ISO 15552, keeping the same 40 mm bore, 650 mm stroke, 628 N force, G1/4 port, and TC mounting interface.
This 40 mm bore cylinder features a G1/4 air port. It 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 maximum force of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X650STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X650STC replacement — usually within 7-8 hours.