Electric actuator selection is driven by six numbers first — peak force, linear speed, stroke, duty cycle, ambient temperature, and control protocol — before any brand or price discussion, per the FAULHABER L-series datasheet on DirectIndustry [S1].
Electric actuators displace pneumatics where clean rooms, repeatable positioning, and BUS-integrated control matter; hydraulic cylinders are still preferred above roughly 10 kN continuous force where the duty cycle is harsh and dirty. For a broader comparison of motion families see the linear actuator reference, and the electric ball valve page for valve-mounted rotary duty.
Force, Speed, Stroke: the Three Numbers that Gate Every Build
The FAULHABER Linear Actuator L series delivers 425 N to 3,700 N of output force across 22 mm and 32 mm rod diameters, with linear speed from 0.14 mm/s up to 167 mm/s [S1]. Stroke is set by the ball-screw or lead-screw length and the chosen nut/flange configuration; both screw technologies are offered in the same housing to let the buyer trade efficiency (ball screw) for lower cost and finer pitch (lead screw). For motion-control theory behind the force-speed trade, the linear actuator encyclopedia entry covers the screw efficiency curves. A common pitfall: spec force from peak acceleration only and forget the hold-force after stop — a 3,700 N peak unit that holds 425 N statically will drift on a vertical axis if the screw is a lead (slip) type rather than a ball (preloaded) type.
Operating Envelope: -30 °C to +120 °C and IP Rating
The L series is rated for ambient operation from -30 °C (-22 °F) up to +120 °C (+248 °F), built in stainless steel to an ISO-standardised envelope, and the L-series datasheet lists a "robust" protection class for industrial and robotic duty [S1]. Outside that window — cryogenic lines below -30 °C, or paint-shop ovens above +120 °C — a pneumatic or hydraulic alternative is normally specified. For cold-room conveyor duty at -20 °C with food-grade cleaning, the pneumatic actuator reference is the more typical competitor; for outdoor valve duty, the electric ball valve entry shows the rotary counterpart. Three spec points the buyer should pin in writing: minimum ambient, maximum ambient with motor derating, and IP/IK rating after cable gland choice.
Duty Cycle, Lifetime, and the Motor Pairing Decision
FAULHABER's published service-life formula is: axial load × linear speed (output power), motor operating temperature, operation mode, duty cycle, ambient conditions, and mechanical integration all combine to set bearing and screw wear life [S1]. Practically that means a 50 % duty cycle (S3) at 120 °C ambient is the worst case the L-series datasheet accepts; a continuous S1 duty at 80 °C is the realistic upper bound for full L10 life. Pairing the actuator to a motor is not optional — a brushless DC servo, a stepper, or a brushed DC unit will each shift the force-speed envelope along the reduction-ratio range. For high-cycle valve actuation above ~10 cycles/min, a stepper-driven ball-screw with encoder feedback is the most common build; for indexing tables the servo build is preferred. The decision map looks like:
<b>Brushed DC + lead screw</b> — low cost, 0.14-30 mm/s typical, light duty, positioning accuracy ±0.1 mm.
<b>Stepper + ball screw</b> — open or closed-loop, 5-80 mm/s, hold position without brake, repeatability ±0.01 mm.
<b>Brushless servo + ball screw</b> — high speed up to 167 mm/s on the L series [S1], full closed-loop, 24/7 S1 duty, higher cost.
<b>Pneumatic or hydraulic</b> — chosen above ~10 kN, in dirty/explosive atmospheres, or where fail-safe spring return is mandatory. For the latter, the pneumatic actuator and hydraulic actuator encyclopedia entries set out the alternative force bands and standards regimes (e.g. ISO 4414 for pneumatics, ISO 4413 for hydraulics).
Protocol, Feedback, and Hazardous-Area Logic
Standalone electric actuators take discrete I/O or 0-10 V analogue; fieldbus variants use PROFINET, EtherCAT, or IO-Link, and servo variants use CANopen or EtherCAT over CoE — a fact the buyer must confirm on the order code, not the marketing brochure. In Zone 1/Zone 2 hazardous areas the choice narrows to ATEX/IECEx-certified brushless servo units with certified cable glands; the FAULHABER L-series is described as a robust industrial/robotic actuator, not as ATEX/IECEx-certified on the published datasheet [S1], so a chemical or refinery buyer should request the certificate file before purchase. A useful neighbour reference for the same project type is Hazardous-Area Skid Hydraulic Valve Selection: Spec Criteria 2026, which covers the certification axis for valve-mounted rotary duty; the Electric Ball Valve Selection: Five Spec Axes That Decide the Buy piece maps the same five-axis logic on the rotary side. Three protocol/area checkpoints for the RFQ: bus type and cycle time, encoder resolution (incremental vs absolute, single-turn vs multi-turn), and ATEX/IECEx zone + temperature class.
Selection-Software Reality: Vendor Tools vs General Calculators
Free vendor sizing tools such as SMC's "Electric Actuator Selection" (V2.0, 20.8 MB, Windows, 2017 build per the publisher page [S2]; mirrored as a 23.6 MB Chinese-language build, 2020 [S3]) accept input force, speed, stroke, and mounting orientation, and return a model code from the vendor's catalogue. Limitation: the tool only sizes inside that one vendor's product tree, so it can reject a perfectly good solution from a competitor; it also assumes a standard mounting envelope. Independent sizing starts from the same six numbers, adds a 1.5-2× safety margin on force (shock load, seal friction), 1.25× on speed (supply tolerance), and derates continuous force by 0.7-0.8 % per °C above 40 °C ambient. The selection shortlist logic therefore reads: (1) define force, speed, stroke, duty; (2) set ambient and IP target; (3) fix the bus/feedback; (4) confirm hazardous-area certificate scope; (5) pick motor family by duty cycle; (6) only then compare two or three vendor model codes on price and lead time. A trackable signal to watch: a published ATEX/IECEx variant of compact ball-screw linear actuators in the 1-5 kN class would close the gap between clean-room electric builds and Zone 1 chemical-plant valve actuation.