This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X680S, 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 SI50 Standard Cylinder SI50X680S
The AirTAC SI50 Standard Cylinder SI50X680S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 680mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X680S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke680 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X680S
- 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 SI50 Standard Cylinder SI50X680S
The AirTAC SI50X680S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 680mm stroke, and a built-in piston magnet. It delivers 982N push force at 0.5MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X680S, a 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 lower start-up pressure and longer life. For load holding, note that standard cylinders drift without live air; the SAIL or BSAI lock variants are required for secure braking. This SI50X680S used CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI50 Standard Cylinder SI50X680S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X680S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X680S |
| Bore size | Ø50 mm |
| Stroke | 680 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI50X680S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The SAI50X680S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI50 Standard Cylinder SI50X680S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×680 | 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 SI50 Standard Cylinder SI50X680S Is Used
Long-Stroke Material Handling
Drives 680mm transfers on packaging lines. Use external guides to prevent rod bending during heavy carton pushes.
Vertical Lift Stations
Requires a pilot check valve to prevent drifting down.
Assembly Line Indexing
Moves pallets between stations. The G1/4 port and 982N force ensure reliable shifting of mid-weight fixtures.
Replacing the Airtac SI50 Standard Cylinder SI50X680S with the SAI50X680S
To replace the discontinued SI50X680S, order the SAI50X680S. Confirm the ISO 15552 mounting interface, 50mm bore, 680mm stroke, G1/4 port (PT/G/NPT thread options), and the -S magnet requirement. When sizing, the 50mm bore yields 982N push at 0.5MPa; dropping to a 40mm bore gives 628N, while a 63mm bore offers 1559N. Because this is a 680mm stroke, add external guides to prevent rod bending and side-load damage. The adjustable 30mm air cushions only decelerate the piston near stroke end; they do not hold the load. For dead-load holding without air, use the SAIL air-released lock, the BSAI clamp-lock, or an external pilot check valve. Rod material options include carbon steel, SUS420J2 (A), or SUS304 (B).
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X680S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI50 Standard Cylinder SI50X680S FAQ
Yes, the SI50X680S is discontinued. The direct replacement is the AirTAC SAI50X680S. It features the same ISO 15552 mounting interface, 50mm bore, 680mm stroke, output force, and G1/4 port, fitting directly into existing fixtures.
The 50mm bore uses a G1/4 air port. Force ratings are: 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N push at 0.9MPa, and a theoretical maximum of 200kgf at 1.0MPa. Operating speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X680S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X680S replacement — usually within 7-8 hours.