This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X40, 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 SI50X40
The AirTAC Airtac SI50 Standard Cylinder SI50X40 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 40mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X40, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke40 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X40
- 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 SI50X40
The AirTAC SI50X40 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 40mm stroke, delivering a push force of 982 N at 0.5 MPa. It features an extruded aluminum barrel, a 20mm piston rod, M16x1.5 rod thread, and a G1/4 air port. As an end-of-line unit, it is replaced directly by the SAI50X40.
The SAI50X40 direct maintains identical ISO 15552 mounting interface dimensions, output force, and port size. The upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. For sensing, note this specific SI SKU lacks a magnet and cannot take a switch.
Airtac SI50 Standard Cylinder SI50X40 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X40 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X40 |
| Bore size | Ø50 mm |
| Stroke | 40 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 SAI50X40 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 SAI50X40 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 SI50X40
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×40 | 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 SI50X40 Is Used
Short-Stroke Clamping
Ideal for holding workpieces in CNC machining fixtures where a 40mm travel and 982 N force at 0.5 MPa securely lock parts without deflection.
Package Diverting
Provides rapid actuation for sorting arms on packaging lines, utilizing the 30-800 mm/s speed range to push items off the main belt efficiently.
Replacing the Airtac SI50 Standard Cylinder SI50X40 with the SAI50X40
To replace the SI50X40, order the SAI50X40, confirming the ISO 15552 interface, 50mm bore, 40mm stroke, G1/4 port (PT/G/NPT), and mounting accessory. Because this SKU lacks a magnet (-S), it cannot accept CS1-B/DS1-B sensors; if position detection is needed, specify a magnet on the new SAI. Sizing both ways: the neighboring 63mm bore yields 1559 N push at 0.5 MPa, while the 40mm bore gives 628 N. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external pilot check valve, or select the SAIL or BSAI lock variants. The SAIF variant adds a built-in valve if needed.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X40
- ✓ 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 SI50X40 FAQ
Yes, the SI50X40 is discontinued. The direct replacement is the AirTAC SAI50X40. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 40mm stroke, 982 N force, G1/4 port, and mounting interface. You simply order the SAI50X40 for your existing fixtures.
The G1/4 port size is fixed by the 50mm bore. Force ratings are: push 982 N and pull 825 N at 0.5 MPa; push 1374 N at 0.7 MPa; push 1767 N at 0.9 MPa; with a theoretical maximum of 200 kgf at 1.0 MPa. Operating pressure is 0.15-1.0 MPa and speed is 30-800 mm/s.
Request a Quote for the SAI50X40
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X40 replacement — usually within 7-8 hours.