The FESTO DFM-20-80-P-A-GF is a compact guided pneumatic drive (guided cylinder) designed for applications that need repeatable linear motion with better load handling and anti-rotation performance than a standard rod cylinder alone. In practical automation terms, this model is often chosen when a payload must move straight with minimal yaw and twist, while still keeping the footprint tight for machine builders.
This specific configuration combines an 80 mm stroke with a 20 mm piston diameter, and uses a plain-bearing (sliding) guide to stabilize the motion. It is a double-acting pneumatic actuator and supports typical industrial compressed-air systems. The design is especially common in pick-and-place, clamping/positioning, light pressing, and transfer units where the motion must remain aligned over the entire stroke.
A useful way to think about the DFM series is: it’s a cylinder plus guidance in one body, intended to reduce external linear rails, brackets, and alignment headaches. You still need to engineer the load properly, but the product is built to take guiding duties more seriously than a basic cylinder with a long rod.
Key Technical Data (DFM-20-80-P-A-GF)
| Item | Specification |
|---|---|
| Product | Guided drive / guided cylinder |
| Model | DFM-20-80-P-A-GF |
| Part number | 170845 |
| Stroke | 80 mm |
| Piston diameter | 20 mm |
| Mode of operation | Double-acting |
| Guide type | Plain-bearing guide |
| Cushioning | Elastic cushioning rings/plates at both ends |
| Operating pressure | 2 to 10 bar (0.2 to 1.0 MPa) |
| Max. speed | 0.8 m/s |
| Ambient temperature | -20 to +80 °C |
| Pneumatic connection | M5 |
| Product Net weight | 1425 g |
| Product Gross weight | 1800 g |
Why this guided drive exists (and when it’s the right choice)
1) Guidance and anti-rotation in one body
When a load is offset or when a tooling plate wants to twist during acceleration and deceleration, a plain cylinder usually needs external guide rails. The DFM design integrates guidance so you can mount tooling to the yoke and keep motion straight. This can reduce overall mechanical complexity and shorten commissioning time because there are fewer alignment variables to fight.
2) Compact footprint for machine modules
With many automation cells, the design constraint is not force but space. A guided drive like the DFM typically allows a tighter module than “cylinder + separate linear guide,” especially for short-to-medium strokes like 80 mm. It also tends to simplify maintenance because the drive and guidance are in one standardized unit.
3) Stable motion for sensors and repeatability
If your system uses proximity sensors for end-position detection (common in pneumatic systems), stable, non-wobbling motion improves detection reliability. The DFM-20-80-P-A-GF is designed for position detection via proximity switch.
Application Examples (real-world use patterns)
| Application | Why DFM-20-80-P-A-GF fits |
|---|---|
| Pick-and-place Z-axis or small shuttle | Guidance reduces tool plate rotation and lateral drift |
| Part positioning for inspection or assembly | Repeatable straight motion helps accuracy and sensor repeatability |
| Clamping and light pressing | Double-acting control plus cushioning improves controlled end motion |
| Transfer stops, diverters, and gates | Compact guided design simplifies mounting and reduces external rails |
| Packaging equipment modules | Fast cycling supported by 0.8 m/s max speed |
Performance notes for engineers (the stuff that prevents regret)
Force expectations
The datasheet provides theoretical force values at 6 bar (0.6 MPa). These are “math forces” before you account for friction, air line losses, valve sizing, and dynamic effects. Still, they’re useful for early sizing:
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Theoretical force at 6 bar: advance stroke 188 N, return stroke 141 N
If your application needs consistent force at speed, consider:
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valve flow and response time,
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tubing length and diameter,
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load inertia and acceleration profile,
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friction from the guide (plain bearings can add friction compared with rolling guides, but they can be robust in many industrial environments).
Load and moment capacity
Guided drives are often selected because the payload has an offset center of gravity. FESTO’s datasheet includes maximum forces and moments (Fx/Fy/Fz and Mx/My/Mz) and also notes permissible torque load as a function of stroke.
In design terms: do not treat the guide as infinite stiffness. A guided drive is forgiving, not magical. Keep the payload close to the yoke, respect moment limits, and reduce shock loads.
End cushioning
The elastic end cushioning helps reduce impact stress at stroke ends. It’s not the same as adjustable pneumatic cushioning, but it’s often enough for compact automation tasks—especially where you value simplicity and predictable maintenance.
Installation and integration tips
| Topic | Practical guidance |
|---|---|
| Mounting position | Optional (can be mounted in different orientations) |
| Air quality | Use compressed air compliant with ISO 8573-1 class noted in the datasheet; keep filtration consistent |
| Lubrication | Lubricated operation is possible, but if you start lubricating, you typically must keep doing it (avoid switching regimes mid-life) |
| Sensors | Plan switch type and mounting early; stable alignment improves sensing reliability |
| Fast cycling | If running near max speed (0.8 m/s), focus on valve sizing, exhaust flow, and mechanical stops |
Ordering and identification
| Field | Value |
|---|---|
| Model | DFM-20-80-P-A-GF |
| Part number | 170845 |
| Pneumatic port | M5 |
| Weight for logistics | 1425 g (1.425 kg) |
Summary
The FESTO DFM-20-80-P-A-GF is a compact guided pneumatic actuator built for reliable linear motion under real machine loads. With 80 mm stroke, 20 mm bore, double-acting operation, and plain-bearing guidance, it targets automation modules that need stable travel without building a full external rail system.
