This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X55, 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 SI40X55
The AirTAC Airtac SI40 Standard Cylinder SI40X55 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 55mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X55, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke55 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X55
- 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 SI40X55
The AirTAC SI40X55 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 55mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI40X55, which matches the exact mounting interface, bore, stroke, output force and port size.
This SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and longevity. Note this specific SI40X55 SKU lacks a magnet (-S), so it cannot accept CS1-B/DS1-B sensors.
Airtac SI40 Standard Cylinder SI40X55 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X55 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X55 |
| Bore size | Ø40 mm |
| Stroke | 55 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 SAI40X55 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 SAI40X55 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 SI40X55
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×55 | 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 SI40X55 Is Used
Clamp Actuation
Provides 628N of push force at 0.5MPa, ideal for securing medium workpieces in CNC machining or welding fixtures.
Package Diverting
The 55mm stroke quickly pushes cartons or parts between adjacent conveyor lanes in material handling lines.
Part Ejection
Delivers a fast 30-800mm/s ejection cycle to clear molded or stamped components from a press bed.
Replacing the Airtac SI40 Standard Cylinder SI40X55 with the SAI40X55
To replace the SI40X55, order the SAI40X55. Verify your ISO 15552 mounting accessory (LB, FA, TC, etc.), 55mm stroke, G1/4 port, and thread (PT, G or NPT). Because this SKU lacks a magnet, it cannot support position sensing; order an SAI40X55S if a switch is required. For sizing, the 32mm bore offers 402N push at 0.5MPa, while the 50mm bore provides 982N. If you need to hold a load vertically without drifting on air loss, use an external pilot check valve or the SAIL/BSAI lock variants. The 55mm stroke is short, so side-load risks are minimal.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X55
- ✓ 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 SI40X55 FAQ
Yes, the SI40X55 is discontinued. The direct replacement is the SAI40X55. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 55mm stroke, force, G1/4 port and mounting interface.
This double-acting cylinder uses a G1/4 port. It generates 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a maximum theoretical force of 128kgf at 1.0MPa.
Request a Quote for the SAI40X55
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X55 replacement — usually within 7-8 hours.