A linear actuator is the complete motion package — motor, gearbox, drivetrain, nut, housing and feedback — that pushes a load along a straight line; a lead screw is one of the drivetrain components inside many of those packages, a rotating threaded shaft that converts rotary input to linear travel via a sliding or rolling nut. Published 2026 product data confirms the split: ZERO-MAX Europe lists Roh'Lix actuators that pair ball screw or lead screw with DC, AC or synchronous servo-motors in stainless or carbon-steel housings, and Tolomatic's IMA linear servo actuator ships in ball-screw or roller-screw variants with strokes to 457 mm and forces to 8,000 lbf (35.8 kN) [S1][S8].
Both terms get used loosely in purchasing documents. Intellidrives notes that "linear actuator" describes any device producing force in a linear manner, covering pneumatic, hydraulic, piezo and electromechanical variants [S3]. That umbrella is the first thing to lock down when writing a spec: an electric linear actuator with a built-in servo is a different procurement line item from a bare lead-screw-and-nut assembly bought by the metre and integrated downstream.
Force, Stroke and Speed: Where the Numbers Actually Sit
Tolomatic's IMA actuator datasheet specifies forces up to 8,000 lbf (35.8 kN) and strokes up to 18 inches (457 mm) in a ball-screw or roller-screw configuration with an IP67 sealing option, and that figure anchors the high end of integrated electric actuators in 2026 [S8]. At the mid-range, MECVEL's EC1 electric actuator delivers up to 5,000 N of force with ball-screw or lead-screw technology, planetary gearing, IP65/IP54 protection, and a footprint aimed at presses, lifting platforms and oil-and-gas service [S2]. MathWorks' controlled linear-actuator example uses a more modest design point: 24 V DC, worm gear 6.25:1, 3 mm lead, 1,000 N rated load at 19 mm/s, 4,000 N static hold, 5 A max current [S7].
Lead screws by themselves are typically spec'd in the hundreds-of-newtons to a few-kN range, with lead values from 1 mm to 40 mm in stock catalogues and standard nut materials including bronze, PTFE-composite and ball-bearing variants. Higher-force builds shift to ball screw geometries (rolling contact, higher efficiency) or roller screws (planetary rollers, very high load and stiffness), which is why a single product line — the IMA — offers ball and roller screw as parallel options at the same 35.8 kN ceiling [S8].
Drive Technologies: Lead Screw, Ball Screw, Belt and Piezo Hybrid
The 2026 igus catalogue groups its linear actuators into belt-driven, screw-driven and electric families under the Drylin brand, with the Drylin SAW-0630 being a screw-driven unit aimed at low-maintenance polymer-nut applications [S5][S9]. Each drive type maps to a different cost/efficiency/load envelope: lead screws are cheapest, self-locking, and run at 30-50% mechanical efficiency; ball screws climb to ~90% efficiency but lose the inherent self-lock; belt drives trade load capacity for the longest strokes and the highest travel speeds; roller screws add load capacity and stiffness at a price premium. MathWorks' hybrid linear actuator reference model stacks a DC motor + lead screw (large stroke, slow response) in series with a piezoelectric stack (±0.1 mm, fast response) to get both long travel and high bandwidth — a useful pattern when nanometre tracking is needed over centimetres of stroke [S6].
For engineers choosing between a linear actuator and a lead screw assembly, the decision collapses to three numbers: peak force, required stroke, and positioning repeatability. Force under ~2 kN and strokes under ~300 mm with sub-1 mm tolerance usually lands on a lead-screw actuator with a polymer or bronze nut. Above 2 kN, or when cycle times push efficiency losses into the heat budget, ball or roller screws enter the conversation. Above 10 kN with industrial cycle rates, the spec almost always becomes an integrated ball- or roller-screw linear actuator — the lead screw is still inside it, but it is no longer the procurement axis.
Selection Criteria: Duty Cycle, Environment, Feedback and IP
Four criteria separate acceptable from wrong spec. (1) Duty cycle and life: lead-screw actuators using polymer nuts from igus target low-duty or cleanroom use; bronze or ball nuts extend life into millions of cycles. (2) Environment: IP65 (dust-tight, jet-rated, e.g. MECVEL EC1) is the typical industrial floor; IP67 (immersion to 1 m, e.g. Tolomatic IMA option) is the washdown and outdoor band; the MathWorks reference is an IP20 lab-grade example, not a field-ready unit [S2][S7][S8]. (3) Feedback: integrated linear encoder feedback on a ball-screw actuator will hold sub-micron repeatability; an open-loop lead-screw actuator with limit switches only is good to a few tenths of a millimetre. (4) Backdriving and holding: lead screws are self-locking (the load cannot back-drive the motor when unpowered); ball-screw actuators usually need a brake on the motor for vertical loads, and that brake cost belongs in the spec.
Power source is the second split. 24 V DC brushless or brushed DC units dominate the sub-2 kN bracket (the MathWorks model runs 24 V DC at 5 A for 1,000 N rated [S7]); 220-480 V AC servos take over above 5 kN, which is the band where the Tolomatic IMA and the higher-force MECVEL EC1 operate [S2][S8]. A useful sanity check: requested linear speed × peak force must fit the motor's continuous-torque thermal envelope. Ignore this and the actuator passes factory acceptance but trips an over-temperature fault on the production line.
Comparison: Lead Screw Actuator vs Ball Screw Actuator vs Integrated Servo Actuator
Four criteria line the three main options up for a specifier. Cost per unit force: lead-screw actuator is lowest; ball-screw actuator is 1.5-3× higher; integrated servo actuator (ball/roller screw + servo + encoder) is 3-6× higher. Mechanical efficiency: lead-screw 30-50%, ball-screw ~90%, roller-screw ~85-90%. Self-locking when unpowered: lead-screw yes, ball-screw generally no (needs motor brake), roller-screw no (needs motor brake). Positioning repeatability: lead-screw ±0.05-0.1 mm typical with open-loop control, ball-screw ±0.005-0.02 mm with encoder, roller-screw and integrated servo ±0.001 mm class with closed-loop control. The cost/precision step from lead to ball to integrated servo is roughly tenfold per tenfold of repeatability, which is the rule of thumb for budget conversations before vendor quotes are pulled. [S1]
Force ceilings follow the same order. igus Drylin SAW screw-driven actuators target the polymer-nut, low-force market [S5]. The MathWorks lead-screw reference model holds 4,000 N static and 1,000 N dynamic at 24 V DC [S7]. MECVEL's EC1 publishes a 5,000 N maximum in a lead-screw or ball-screw configuration [S2]. Tolomatic's IMA pushes 35.8 kN in ball-screw or roller-screw variants [S8]. Anything beyond 35.8 kN tends to leave the linear-actuator product line and go to hydraulic cylinders or rack-and-pinion drives — which is a different sourcing exercise.
Modelling and Integration: How Actuators Are Built in 2026
Simulink's linear-actuator examples from MathWorks show the canonical architecture in 2026: a DC motor drives a worm gear (6.25:1 in the controlled example) which drives a 3 mm lead screw, producing linear motion with a no-load speed of 26 mm/s, 19 mm/s under rated load, and 4,000 N static hold [S7]. The hybrid model replaces the worm gear with a direct-drive DC motor + lead screw plus a piezo stack for fine positioning [S6]. The Lead Screw Joint block in Simscape Multibody converts a revolute joint to four cylindrical joints and back-computes required torque from the translational demand, which is the standard way to size a motor on a screw-driven axis [S10].
For system builders, the integration logic mirrors the procurement logic. A linear guide carries the bending load; the linear actuator supplies the thrust; the linear encoder closes the position loop. Skip the guide on a cantilevered load and the screw will see a bending moment it was never designed for; skip the encoder and the actuator can only do open-loop point-to-point moves. The same three-component stack — guide, actuator, encoder — shows up in igus' gantry and Cartesian-robot product lines and in Tolomatic's integrated actuator catalogues, which is a strong signal that the architecture is mature and stable [S8][S9].
Use Cases and Where Each Option Fails
Lead-screw actuators fit valve throttling, small-format solar trackers, medical beds, format-change adjustment on packaging lines, and lab automation — anywhere the force is below a few kN, the duty cycle is moderate, and self-locking on power loss matters. The Intellidrives applications page lists the same range, emphasising that linear actuators are "present everywhere" from medical imaging gantries to automotive seat adjusters [S3]. Ball-screw actuators fit CNC axes, semiconductor wafer handling, machine-tool tool changers, and high-cycle press automation. Integrated roller-screw servo actuators (Tolomatic IMA class) fit steel-mill screwdown, injection-mould clamping, and large-press slide positioning where 35.8 kN and IP67 are both required [S8].
Failure modes to spec against: lead-screw actuators whip and lose accuracy above ~500 mm unsupported stroke; ball screws lose preload and accuracy after backlash accumulation if maintenance is skipped; worm-gear-driven actuators (the MathWorks reference architecture) have low efficiency and heat up under continuous duty; belt-driven actuators stretch over time and need tension re-set; piezo hybrids need protection circuitry and are not drop-in replacements for a screw-driven axis. The pneumatic-versus-electric decision is a different axis entirely — for torque, air supply and fail-safe sizing on pneumatic actuators, the criteria overlap with screw-driven electric sizing but the supply-side constraints (line pressure, air consumption) dominate.
Standards, Sourcing and What to Watch
No single IEC or ISO standard governs the actuator as a whole; relevant references include ISO 3408 for ball-screw accuracy classes, DIN 69051 for lead-screw geometry, and the IEC 60034 motor-efficiency series for the integrated servo. For hazardous-area service — oil-and-gas, chemical — the actuator assembly carries the ATEX or IECEx marking rather than the lead screw alone, and a 5,000 N IP65 unit like the MECVEL EC1 is a typical starting point for Zone 2 builds [S2]. Sourcing reality in 2026: igus catalogues polymer-nut lead-screw actuators with online configuration and short lead times for the sub-1 kN bracket [S5][S9]; integrated servo actuators in the 5-35 kN bracket carry 4-8 week lead times from vendors like Tolomatic [S8]; the very-high-force and ATEX-certified tiers run 10-16 weeks. The related Tolomatic-class procurement question — how load, stroke, duty cycle and IP ratings move the spec band — is covered separately in the linear actuator selection guide and pairs naturally with the price-band analysis in the pneumatic actuator price guide 2026 for plants mixing electric and pneumatic axes.
Trackable signals for the rest of 2026: igus expanding its Drylin SAW screw-driven family with higher-force polymer-nut units; Tolomatic adding more roller-screw stroke lengths to the IMA line; the MathWorks Simscape library adding multi-axis coordinated-actuator examples that close the loop on lead-screw + piezo hybrids.