This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX250S, 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 SI50AX250S
The AirTAC Airtac SI50 Standard Cylinder SI50AX250S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX250S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX250S
- 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 SI50AX250S
The AirTAC SI50AX250S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 250mm stroke, and an SUS420J2 stainless steel rod. Delivering 982 N push force at 0.5 MPa, it is replaced by the SAI50AX250S. This direct successor shares the exact G1/4 port, M16x1.5 thread, and ISO 15552 mounting interface.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure. The -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL lock and BSAI clamp variants.
Airtac SI50 Standard Cylinder SI50AX250S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX250S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX250S |
| Bore size | Ø50 mm |
| Stroke | 250 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 SAI50AX250S 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 SAI50AX250S 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 SI50AX250S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×250 | 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 SI50AX250S Is Used
Diverting Gates
Actuates routing flaps on packaging lines, utilizing the 982 N push force and 250mm stroke to redirect cartons reliably.
Vertical Pressing
Applies downward clamping pressure for light assembly tasks, safely handling loads near the 50 kg vertical lift threshold.
Pallet Stops
Extends 250mm to halt pallets at staging zones, with the SUS420J2 stainless rod resisting humidity in damp logistics environments.
Replacing the Airtac SI50 Standard Cylinder SI50AX250S with the SAI50AX250S
To replace the SI50AX250S, order the SAI50AX250S. Confirm the ISO 15552 mounting interface, 50mm bore, 250mm stroke, G1/4 port, and your specific mounting accessory. The SAI uses an upgraded piston seal but keeps the exact dimensions and 982 N @0.5 MPa force. For sizing, the neighboring 40mm bore yields 628 N push, while the 63mm bore provides 1559 N. At 250mm stroke, ensure adequate guide support to prevent rod bending and side-load wear. This cylinder includes an -S magnet for CS1-B/DS1-B switches; a no-S SKU cannot take a sensor. The air cushion only decelerates; it does not hold load on air loss. For held loads, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX250S
- ✓ 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 SI50AX250S FAQ
Yes, the AirTAC SI50AX250S is discontinued. The direct replacement is the SAI50AX250S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 250mm stroke, G1/4 port, and mounting interface, but features an upgraded piston seal.
This double-acting cylinder has a 50mm bore, G1/4 port, M16x1.5 rod thread, and operates at 30-800 mm/s. Force ratings are: 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 SAI50AX250S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX250S replacement — usually within 7-8 hours.