This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X55H, 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 SI40X55H
The AirTAC Airtac SI40 Standard Cylinder SI40X55H 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 SAI40X55H, 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 → SAI40X55H
- 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 SI40X55H
The AirTAC SI40X55H is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 55 mm stroke. Delivering 628 N push force at 0.5 MPa via a G1/4 port, it is replaced by the SAI40X55H. This direct successor shares identical mounting, force, and port specs, fitting existing fixtures perfectly.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure. This non-magnet SKU cannot take a sensor, but the -H Viton seal allows 0-150 C heat. For load holding, use a pilot check valve or SAIL lock, as cushions only decelerate.
Airtac SI40 Standard Cylinder SI40X55H Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X55H |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X55H |
| 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 SAI40X55H 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 SAI40X55H 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 SI40X55H
| 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 SI40X55H Is Used
Hot End Ejection
Ideal for pushing parts at elevated temperatures using the Viton H seal, providing 628 N of thrust at 0.5 MPa in automated ejection arrays.
Replacing the Airtac SI40 Standard Cylinder SI40X55H with the SAI40X55H
To replace the SI40X55H, order the SAI40X55H. Verify the ISO 15552 interface, 40 mm bore, 55 mm stroke, G1/4 port, and M12x1.25 rod thread. This non-magnet version cannot accept a CS1-B/DS1-B sensor; if sensing is needed, select an SAI model with the -S magnet option. The -H Viton seal is required here for 0-150 C high-temperature environments. If sizing up or down, neighboring bores are 32 mm (402 N push @0.5 MPa) and 50 mm (982 N push @0.5 MPa). Note that a plain cylinder drifts on air loss; cushions only decelerate. For held loads, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The SAIF variant adds a built-in valve for bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X55H
- ✓ 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 SI40X55H FAQ
Yes, the AirTAC SI40X55H is discontinued. The direct replacement is the SAI40X55H. It is dimensionally interchangeable per ISO 15552, matching the 40 mm bore, 55 mm stroke, G1/4 port, and output force for a seamless fixture swap.
The 40 mm bore uses a G1/4 port. Force output is 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical maximum of 128 kgf at 1.0 MPa. It operates at 30-800 mm/s.
Request a Quote for the SAI40X55H
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X55H replacement — usually within 7-8 hours.