The AirTAC Airtac SCD Standard Cylinder SCD40X20 is a genuine double-acting DOUBLE-ROD air cylinder: the Ø16mm piston rod extends from BOTH end caps, giving equal effective area — and therefore equal force — in push and pull. Ø40mm bore, 20mm stroke, PT1/4 ports and adjustable end cushioning.
The SCD40X20 is a compact double-rod pneumatic cylinder that outputs an identical 528 N of force in both extend and retract strokes at 0.7 MPa, thanks to its 16 mm through-rod subtracting the same area from each piston side. With a short 20 mm stroke and a body length A(SCD) of 191 mm, it is built for tight spaces where a rear rod connection is needed for a sensor flag or secondary tooling.
This genuine AirTAC unit operates on filtered air from 0.15 to 1.0 MPa and uses PT1/4 ports. Its adjustable air cushion decelerates the piston over the final 21 mm of travel, protecting end-cap components during high-cycle, short-stroke indexing tasks.
| Model | Airtac SCD Standard Cylinder SCD40X20 |
|---|---|
| Series | SCD double-rod tie-rod cylinder |
| Bore size | Ø40 mm |
| Rod diameter | Ø16 mm (both ends) |
| Stroke | 20 mm |
| Rod configuration | Double rod — rod through both caps |
| Acting type | Double acting |
| Port size | PT1/4 |
| 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, 21 mm |
| Max stroke | Up to 1200 mm |
Specifications follow the official AirTAC SCD (double-rod) datasheet. Because the rod runs through both caps, the effective area is (bore² − rod²) in both directions. Confirm against the product label before installation. Thread options: PT (standard) / G.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 528 N | 528 N |
| 0.7 MPa | 739 N | 739 N |
| Max (@1.0 MPa) | 108 kgf | |
Push and pull are EQUAL on a double-rod cylinder — both chambers lose the rod area, so effective area = (bore² − rod²) each way. Actual usable force is lower than theoretical due to friction and back-pressure; size with a safety margin.
| SCD | Double-rod tie-rod cylinder series (rod out both ends). |
|---|---|
| 40 | Bore size in mm. |
| ×20 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Related types: SC (single rod), SCJ (adjustable stroke), SCT (multi-position). SCD mounting: Basic, FA, LB, TC, TCM1. Seals: TPU standard / H = Viton / N = NBR. Thread: blank = PT, G = G thread.
The equal 528 N force in both directions makes this cylinder ideal for two-sided clamping fixtures where a workpiece must be held with consistent pressure from either side.
The protruding rear rod provides a perfect mounting point for a sensor flag or cam, enabling end-of-stroke detection on the cap-end side without adding length to the main tooling.
With a rod guided through both end caps, the SCD40X20 resists rotation better than a single-rod cylinder, useful for maintaining the orientation of small alignment pins in assembly jigs.
Select the SCD40X20 when you require a 20 mm stroke with equal push-pull output and a rear rod extension. If your force requirement is lower, the 32 mm bore SCD32 series provides 345 N at 0.5 MPa; for more thrust, the SCD50 delivers 825 N at the same pressure. A double-rod design offers better bearing support than a single-rod SC cylinder, but for applications with significant side loads, a guided cylinder is the correct choice.
As a direct replacement, match the 40 mm bore, 20 mm stroke, PT port thread, and basic mounting. For position sensing, specify the -S magnet option to use clamp-on sensors on the tie-rod barrel.
Double-rod checklist
Because it is a double-rod cylinder, the push and pull forces are identical. At 0.5 MPa it produces 528 N, at 0.7 MPa it produces 739 N, and at the maximum operating pressure of 0.9 MPa it produces 950 N in both directions.
Choose the SCD when you need equal speed and force in both directions, or when you require a rear rod extension to mount a sensor, stopper, or secondary tool. The through-rod also provides better guidance and anti-rotation than a single-rod cylinder, though it is not a replacement for a fully guided unit under heavy side loads.
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