This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX20S, 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 SI50AX20S
The AirTAC Airtac SI50 Standard Cylinder SI50AX20S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 20mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX20S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke20 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX20S
- 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 SI50AX20S
The AirTAC SI50AX20S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 20 mm stroke. It delivers a 982 N push force at 0.5 MPa and uses a G1/4 port. The direct replacement is the SAI50AX20S, matching the original bore, stroke, force, port and ISO 15552 mounting interface for existing fixtures. This unit includes a magnet for position sensing and features a SUS420J2 stainless steel rod.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. For applications needing load holding on air loss, the SAI family adds SAIL and BSAI lock variants the SI lacked.
Airtac SI50 Standard Cylinder SI50AX20S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX20S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX20S |
| Bore size | Ø50 mm |
| Stroke | 20 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 SAI50AX20S 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 SAI50AX20S 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 SI50AX20S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×20 | 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 SI50AX20S Is Used
Short-Stroke Clamping
Applies 982 N of clamping force at 0.5 MPa for securing workpieces in machining fixtures.
Ejector Mechanism
Provides rapid 20 mm part ejection from molds, operating reliably at speeds of 30-800 mm/s.
Gate Diversion
Actuates lightweight routing gates on packaging lines with a 50 kg vertical lift margin.
Replacing the Airtac SI50 Standard Cylinder SI50AX20S with the SAI50AX20S
To replace the SI50AX20S, order the SAI50AX20S. Confirm the ISO 15552 mounting interface, the 50 mm bore, the 20 mm stroke, the G1/4 port, and the -S magnet for legacy CS1-B/DS1-B sensors. The -A rod material specifies SUS420J2 stainless steel for corrosion resistance. Sizing both ways: the neighbouring 63 mm bore offers 1559 N push at 0.5 MPa, while the 40 mm bore provides 628 N. A plain cylinder drifts on air loss as the cushion only decelerates; for held loads use an external rod lock or pilot check valve. Because the 20 mm stroke is short, side-load risks are minimal, but ensure precise alignment to avoid rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX20S
- ✓ 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 SI50AX20S FAQ
Yes, the SI50AX20S is discontinued. The direct replacement is the SAI50AX20S, which shares the same ISO 15552 mounting interface, 50 mm bore, 20 mm stroke, force, and G1/4 port.
The 50 mm bore features a G1/4 port. Force output is 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX20S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX20S replacement — usually within 7-8 hours.