This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X300STC, 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 SI40X300STC
The AirTAC Airtac SI40 Standard Cylinder SI40X300STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 300mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X300STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke300 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X300STC
- 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 SI40X300STC
The AirTAC SI40X300STC is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 300mm stroke. It delivers 628N push force at 0.5MPa through a G1/4 port. The direct replacement is the SAI40X300STC, retaining the exact same TC trunnion mounting interface, output force, and dimensions.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. Because the -S suffix denotes a magnet, the legacy SI used CS1-B/DS1-B switches, whereas the SAI takes current AirTAC sensors. Note that a plain cylinder drifts without air; the SAIL or BSAI lock variants are needed to hold loads.
Airtac SI40 Standard Cylinder SI40X300STC Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X300STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X300STC |
| Bore size | Ø40 mm |
| Stroke | 300 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 SAI40X300STC 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 SAI40X300STC 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 SI40X300STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×300 | 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 SI40X300STC Is Used
Package Diversion
Actuates routing gates on packaging lines where 628N push force at 0.5MPa easily shifts cartons, utilizing the 300mm stroke to clear the conveyor belt path.
Vertical Material Lift
Raises lightweight tote bins up to 32kg in pick modules; the TC trunnion mount accommodates the pivot arc required during the 300mm vertical lift cycle.
Clamp Actuation
Drives secondary clamping fixtures on machining cells, providing 528N pull force at 0.5MPa to hold workpieces securely during light milling operations.
Replacing the Airtac SI40 Standard Cylinder SI40X300STC with the SAI40X300STC
To replace the SI40X300STC, order the SAI40X300STC. Confirm the ISO 15552 TC trunnion interface, 40mm bore, 300mm stroke, G1/4 port (PT/G/NPT thread options), and the -S magnet for current AirTAC switches. If sizing up or down, a 32mm bore yields 402N push at 0.5MPa, while a 50mm bore yields 982N. For the 300mm stroke, use external guides to prevent rod bending and side-load wear. The air cushion only decelerates at stroke end; it does not hold position. For load holding on air loss, use an external pilot check valve, rod lock, or the SAIL/BSAI lock variants. The SAIF variant integrates a 4M valve if needed.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X300STC
- ✓ 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 SI40X300STC FAQ
Yes, the AirTAC SI40X300STC is discontinued. The direct replacement is the SAI40X300STC. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 300mm stroke, G1/4 port, TC trunnion mount, and output force, so it drops directly into existing fixtures.
The 40mm bore uses a G1/4 air port and a 16mm rod with an M12x1.25 thread. Force ratings are 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. Operating speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X300STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X300STC replacement — usually within 7-8 hours.