This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X20LB, 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 SI40 Standard Cylinder SI40X20LB
The AirTAC Airtac SI40 Standard Cylinder SI40X20LB is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 20mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X20LB, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke20 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X20LB
- 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 SI40 Standard Cylinder SI40X20LB
The AirTAC SI40X20LB is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 20mm stroke. Delivering 628N push force at 0.5MPa via a G1/4 port, it is replaced by the SAI40X20LB. This direct successor matches the exact ISO 15552 mounting interface, bore, stroke, force and port.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. Note this no-S SKU cannot take a sensor, unlike CS1-B/DS1-B legacy switches. For high heat, Viton H seals raise temps to 150C.
Airtac SI40 Standard Cylinder SI40X20LB Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X20LB |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X20LB |
| Bore size | Ø40 mm |
| Stroke | 20 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40X20LB carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40X20LB produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40X20LB
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | 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 SI40 Standard Cylinder SI40X20LB Is Used
Short-Stroke Ejection
Ideal for popping small machined parts out of fixtures using a compact 20mm stroke and 628N of push force at 0.5 MPa.
Clamp Actuation
Provides reliable clamping pressure for light assembly tooling where a 40mm bore delivers the required holding without excessive bulk.
Diversion Gate
Snappy 20mm stroke action to push lightweight product guides or diversion flaps on packaging lines at speeds up to 800 mm/s.
Replacing the Airtac SI40 Standard Cylinder SI40X20LB with the SAI40X20LB
To replace the SI40X20LB, order the SAI40X20LB keeping the LB foot mounting and G1/4 port. Verify your thread option (PT/G/NPT) and rod material (carbon, SUS420J2 A, or SUS304 B). This non-magnet SKU cannot fit a sensor. Sizing both ways: if 628N at 0.5MPa is insufficient, step up to the 50mm bore (982N); if oversized, drop to 32mm (402N). The air cushion only decelerates; it does not hold load on air loss. For held loads, use an external pilot check valve or explore SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X20LB
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40X20LB FAQ
Yes, the AirTAC SI40X20LB is discontinued. The direct replacement is the SAI40X20LB. It shares the identical ISO 15552 mounting interface, 40mm bore, 20mm stroke, 628N force, G1/4 port and LB foot mount, fitting directly into existing fixtures.
This 40mm bore double-acting cylinder uses a G1/4 air port. It generates 628N push and 528N pull at 0.5 MPa, 879N push at 0.7 MPa, 1130N push at 0.9 MPa, and a theoretical maximum of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X20LB
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X20LB replacement — usually within 7-8 hours.