This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX20, 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 SI50BX20
The AirTAC Airtac SI50 Standard Cylinder SI50BX20 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 SAI50BX20, 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 → SAI50BX20
- 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 SI50BX20
The AirTAC SI50BX20 is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 20 mm stroke. It delivers 982 N of push force at 0.5 MPa through a G1/4 port. The direct replacement is the SAI50BX20, which shares the exact same ISO 15552 mounting interface, output force, and porting to fit existing fixtures seamlessly.
This SAI upgrade introduces a two Y-shaped one-way piston seal for lower start-up pressure and longer life. The -B rod code specifies a SUS304 stainless piston rod for corrosion resistance. Without a -S magnet code, this SKU cannot accept a sensor.
Airtac SI50 Standard Cylinder SI50BX20 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX20 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX20 |
| 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 SAI50BX20 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 SAI50BX20 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 SI50BX20
| 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 SI50BX20 Is Used
Short-Stroke Clamping
Ideal for holding parts in machining fixtures where a compact 20 mm stroke and 982 N force secure the workpiece firmly.
Package Diverting
Provides rapid actuation at 30-800 mm/s to push cartons off a conveyor belt, utilizing the SUS304 rod in mildly humid environments.
Ejector Mechanism
Delivers a fast, 50 kg capable ejection punch for molded parts, taking advantage of the low start-up pressure of the SAI replacement.
Replacing the Airtac SI50 Standard Cylinder SI50BX20 with the SAI50BX20
To replace the SI50BX20, order the SAI50BX20. Confirm the ISO 15552 mounting interface, 50 mm bore, 20 mm stroke, G1/4 port (PT/G/NPT thread options), and your specific mounting accessory. Because this SKU lacks a magnet, it cannot take a CS1-B or DS1-B switch; if sensing is needed, select an SAI model with an S suffix. If you need to hold a load during air loss, note that the cushion only decelerates; you must use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. For sizing alternatives, a 40 mm bore provides 628 N push at 0.5 MPa, while a 63 mm bore yields 1559 N. At 20 mm stroke, side-load risk is minimal, but always guide the load to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX20
- ✓ 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 SI50BX20 FAQ
Yes, the SI50BX20 is discontinued. The direct replacement is the SAI50BX20. It is dimensionally interchangeable per ISO 15552, maintaining the same 50 mm bore, 20 mm stroke, 982 N force, G1/4 port, and mounting interface.
This double-acting cylinder features a G1/4 air port and a 20 mm piston rod. The thrust ratings are: 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Request a Quote for the SAI50BX20
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX20 replacement — usually within 7-8 hours.