This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX40S, 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 SI50BX40S
The AirTAC SI50 Standard Cylinder SI50BX40S 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 SAI50BX40S, 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 → SAI50BX40S
- 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 SI50BX40S
The AirTAC SI50BX40S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50 mm bore, 40 mm stroke, and a SUS304 stainless piston rod for corrosion resistance. It delivers 982 N push force at 0.5 MPa through its G1/4 port. AirTAC replaced this legacy unit with the SAI50BX40S, a direct replacement matching the exact ISO 15552 mounting interface, bore, stroke, output force, and port size.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The original SI-S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. If you need load holding on air loss, explore the SAIL or BSAI lock variants, as standard cushions only decelerate.
Airtac SI50 Standard Cylinder SI50BX40S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX40S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX40S |
| 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 SAI50BX40S 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 SAI50BX40S 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 SI50BX40S
| 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 SI50BX40S Is Used
Diverting Gate Actuation
Drives lightweight routing flaps on packaging lines where the 40 mm stroke and 982 N thrust provide fast, precise lane changes.
Corrosive Washdown Clamping
The SUS304 rod option makes this 50 mm bore cylinder ideal for holding parts in food or chemical washdown environments.
Short-Stroke Ejection
Pushes completed cartons off a roller bed using a compact 40 mm travel, safely moving loads under the 589 N working limit.
Replacing the Airtac SI50 Standard Cylinder SI50BX40S with the SAI50BX40S
To replace the discontinued SI50BX40S, order the SAI50BX40S. Verify your ISO 15552 mounting fixtures, the G1/4 air port, and the M16x1.5 rod thread. Because this unit has the -B SUS304 rod and -S magnet, confirm those options on the SAI order; note the SI uses legacy CS1-B/DS1-B switches. If you need to size up or down, a 63 mm bore yields 1559 N push at 0.5 MPa, while a 40 mm bore yields 628 N. For applications requiring the cylinder to hold a load without live air, a plain SAI will drift; instead, specify the SAIL air-released lock, the BSAI clamp-lock, or use an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX40S
- ✓ 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 SI50BX40S FAQ
Yes, the SI50BX40S is discontinued. The direct replacement is the AirTAC SAI50BX40S. It shares the identical ISO 15552 mounting interface, 50 mm bore, 40 mm stroke, G1/4 port, and output force, fitting directly into your existing fixtures.
This double-acting cylinder features a G1/4 air port. It generates 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and 1767 N push at 0.9 MPa. The theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX40S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX40S replacement — usually within 7-8 hours.