The SMC CDQMB20-30 is a compact, guide-rod type pneumatic cylinder designed for applications that need reliable linear motion with built-in guidance and anti-rotation accuracy—without the extra footprint of external guide rails. In the CQM/CDQM family, the cylinder body, guide rods, and tooling plate are integrated as one assembly, so you can mount a workpiece directly onto the plate and keep motion stable under lateral loads. This makes the CDQMB20-30 a practical choice for pick-and-place tooling, small presses, clamping and positioning fixtures, and compact automation stations where space and repeatability matter.
What makes CDQMB20-30 different in real machines
A standard compact cylinder can push and pull, but it isn’t happy when the load is off-center or when the tooling wants to twist. The CDQMB20-30 addresses that by adding guide rods and a plate to resist side load and maintain orientation. SMC’s CQM concept is aimed at higher lateral load resistance and better non-rotation behavior than a basic compact cylinder, which is exactly what you need when the cylinder is doing “actuator + guide” duties in one component.
Another useful detail: this model is described as a double-acting cylinder with cushioning, and for this specific configuration the cushioning is a rubber bumper on both ends—simple, robust, and suitable for high-cycle general automation.
Key Specifications (CDQMB20-30)
| Item | Specification |
|---|---|
| Manufacturer / Series | SMC, C(D)QM (CQM) Compact Cylinder, Guide Rod Type |
| Model | CDQMB20-30 |
| Bore / Stroke | 20 mm bore, 30 mm stroke (from model designation) |
| Acting Type | Double-acting |
| Cushioning | Rubber bumper on both ends |
| Non-rotating accuracy (plate) | ±0.1° |
| Allowable rotational torque | 0.21 N·m |
| Proof pressure | 1.5 MPa |
| Max piston speed | 500 mm/s |
| Pneumatic connections | 2 ports |
| Port thread | M5 (input and exhaust) |
| Ambient temperature (with magnet) | -10°C to 60°C (no freezing) |
| Theoretical force @ 0.5 MPa | Advance 157 N, Return 118 N |
| Product Net weight | 0.197 kg |
Design and performance details that matter
1) Stable, guided motion in a compact envelope
The guide-rod structure keeps the tooling plate aligned, reducing the chance of binding when loads are offset. This is useful for end-effectors that contact parts with small misalignment, or where the mechanism must keep a consistent orientation through the full stroke. SMC describes this family as a compact cylinder integrated with a guide rod and plate, enabling direct mounting of work.
2) Speed capability for short-stroke automation
With a listed maximum piston speed of 500 mm/s, the CDQMB20-30 supports typical high-cycle pneumatic automation on short strokes, especially when paired with appropriate flow control and cushioning strategy.
3) Simple cushioning, fewer surprises
The rubber bumper cushioning at both ends is straightforward and durable. In many production lines, the best feature is the one that stays predictable after millions of cycles.
4) Pneumatic interface that fits tight manifolds
The datasheet indicates two pneumatic connections with M5 input and exhaust connections, which suits compact valve manifolds and small-diameter tubing commonly used in dense fixtures.
Typical applications
-
Pick-and-place slides where the tooling plate must not rotate
-
Part clamping / indexing fixtures that see side loads or off-center forces
-
Small press and insertion stations requiring guided linear motion
-
Assembly jigs where compact size and repeatability outweigh heavy-duty linear guides
Because the cylinder integrates guidance and actuation, it often reduces BOM count and simplifies mechanical design—especially in compact stations where a separate guide module would add cost, alignment work, and space.
Installation and selection tips (useful in practice)
-
Mind the side-load reality: Guided cylinders tolerate side loads better than unguided types, but they still have limits. Keep the load as centered as possible on the plate and avoid unnecessary torque—your repeatability will be better over time. The datasheet’s allowable rotational torque value is a good engineering checkpoint during fixture design.
-
Control speed and impact: If you run near the speed limit, tune flow controls so end-of-stroke impact stays controlled. Rubber bumpers help, but your air circuit tuning often matters more than the bumper itself.
-
Temperature and magnet considerations: If you use an auto-switch/magnet configuration, stay within the listed ambient temperature range (-10°C to 60°C, no freezing) to keep sensing stable and seals healthy.
-
Plan tubing and fittings: With M5 ports, confirm fitting availability in your region and standardize tubing OD for maintenance simplicity.
Summary
The SMC CDQMB20-30 is a compact, guided pneumatic cylinder built for repeatable linear motion with strong anti-rotation behavior in space-constrained automation. It combines cylinder + guide function in one unit, offers predictable end cushioning, and supports fast short-stroke operation.
