How to Select Ultra-Thin Linear Modules for Compact Machines

Designing compact automation equipment is always a balancing act: you need precise linear motion, but you only have a few centimetres of space inside the frame, under a vision camera, or beside a robot gripper. That’s exactly the situation the QF Series from W-Robot (威洛博) was built for – an ultra thin linear module family optimised for short stroke actuators in tight layouts.

1. Where QF Series Fits in the W-Robot Portfolio

Within W-Robot’s linear motion range, QF sits in the ball screw linear module group and is explicitly tagged as “Ultra Thin, Short Stroke”. w-robot.com+1

Key positioning points:

Drive type: precision ball screw drive with ground screw and recirculating ball nut

Stroke range: up to 420 mm across all sizes – this is truly a short stroke actuator family w-robot.com

Repeatability: up to ±0.006 mm, suitable for demanding positioning tasks in 3C electronics, inspection machines and small assembly systems w-robot.com+1

Body width: from 56 mm (QF6N) through 200 mm (QF20), giving several levels of stiffness while staying relatively low in height w-robot.com

Typical application labels on W-Robot materials include:

compact linear module for automation

linear module for 3C electronics and small fixtures

short-stroke axis in XYZ linear module platforms or 2-axis gantry stages w-robot.com+1

If your design brief says “short travel, limited space, but still need accurate positioning,” the QF series is usually the first place to look inside W-Robot’s catalog.

2. Understand the QF Size Ladder

The QF family is not one product but eight sizes of the same architecture. All share the same maximum stroke (420 mm) and repeatability, but differ in body width and allowable load. w-robot.com

All of them are built around a linear guide rail + ball screw drive + aluminium base structure, with front and rear support bearings. This gives a predictable relationship between stroke length, load capacity, and deflection—key factors in linear actuator sizing.

3. When QF Is the Right Choice (and When It Isn’t)

Choose QF Series when…

Stroke is ≤ 420 mm

Height adjustment, clamp positioning, vision focus, tool approach and retract moves.

Space is limited in height or width

Inside compact inspection machines, under conveyors, or beside an electric cylinder where every millimetre of clearance matters.

You need ball-screw-level precision

Applications like linear module for inspection machines, small pick and place heads, or test fixtures where ±0.006 mm repeatability is valuable. w-robot.com+1

Load is moderate to high, but travel is short

For example, lifting a small robot gripper, positioning a heavy camera, or moving a welding or dispensing head over a short path.

Consider other W-Robot families when…

You need a longer stroke (over ~400–500 mm):
look at belt-driven series such as EB or OB timing belt drive modules. w-robot.com

The environment is dusty or oily and contamination is serious:
a fully enclosed linear module such as the VGTH series may offer better protection than an open ultra-thin design. w-robot.com+1

You require extremely high dynamics over short strokes:
W-Robot’s VL/VGL linear motor modules provide direct-drive performance where linear motor vs ball screw becomes an important trade-off. w-robot.com

4. How to Select the Right QF Size for a Compact Machine

Once you know QF is the right family, follow this practical checklist.

4.1 Step 1 – Calculate payload and moments

Add up:

Tooling + end-effector (for example a robot gripper or small electric cylinder)

Workpiece mass

Adapter plates and brackets

Then estimate the centre-of-gravity offset from the carriage centre. Even with short strokes, a tall bracket can generate significant pitch/yaw moments.

Use that to decide:

QF6N / QF8 for light heads and sensors

QF10 / QF12 / QF13 for medium-load linear actuator for pick and place

QF14 / QF17 / QF20 when the axis supports a small gantry beam or heavy tooling

The wider models are not just stronger in straight-line load; they also offer better resistance to Mx/My/Mz moments thanks to a larger linear guide rail spacing.

4.2 Step 2 – Check stroke and effective length

All QF motors support up to 420 mm stroke, but in a compact housing you still care about overall length. w-robot.com

Confirm your working travel (for example 120 mm)

Add space for homing and deceleration (often 10–20 mm per side)

Check the 3D model: total actuator length = stroke section + bearing blocks + support bearing + motor flange

If the axis mounts inside a frame window, verify that motor and coupling do not collide with nearby plates or cable ducts.

4.3 Step 3 – Speed profile and screw lead

W-Robot’s QF actuators are designed as short stroke actuators that can run repetitive cycles in assembly and test rigs. The exact screw lead values depend on the specific model, but the selection logic is consistent:

Smaller lead → higher thrust, finer resolution, lower top speed

Larger lead → higher speed but lower mechanical advantage

For a linear module for 3C electronics or small inspection machine, a medium lead usually balances speed and force; the axis spends much of its time accelerating and decelerating rather than cruising.

When sizing the servo or stepper motor, treat the QF as a standard servo motor linear module:

Use the load and inertia data from the datasheet

Check that peak torque covers acceleration demands with margin

Confirm that your motion controller supports the desired profile (S-curve, jerk limits, etc.)

4.4 Step 4 – Motor, driver and integration

W-Robot notes that actuators in this family can be upgraded by changing the motor, control system and guide rail to meet different performance levels. w-robot.com+1

You can therefore:

Start with a stepper motor linear module for cost-sensitive automation

Move to a servo motor linear module configuration when you need higher speed or better synchronisation

Use integrated motor and driver units to keep electrical panels compact

For multi-axis projects—such as an XYZ linear module platform or 3-axis linear motion system feeding a small robot cell—keeping one QF size and one motor family across axes simplifies spare parts management.

5. Example Configurations with QF Series

To make the selection logic more concrete, here are three realistic layouts based on W-Robot’s own application directions.w-robot.com+1

5.1 Compact vision inspection station

Axis: QF6N or QF8 (56–80 mm body width)

Role: move a camera or sensor head over a product in a short scanning stroke

Drive: stepper or small servo; modest acceleration, high repeatability

Add-ons:

small robot gripper on a separate Z-axis for sample pick-up

clean cable routing for trigger and lighting

5.2 Short-stroke pick & place over a tray

Axis: QF10 or QF12

Role: X-axis in a mini linear actuator for pick and place cell, with a Z-axis electric cylinder on the carriage

Payload: 3–8 kg including tooling

Drive: mid-size servo, coordinated by a multi-axis motion controller

Note: stroke 250–300 mm; QF’s 420 mm capability leaves margin for future tray sizes.

5.3 Vertical short-stroke lifter in a battery line

Axis: QF14 or QF17

Role: vertical lift for fixtures in a linear actuator for battery production line, where space above the conveyor is limited

Payload: 30–60 kg, including fixture and product

Features:

high stiffness from wider body

braking servo motor for safety

possible combination with dustproof linear module solutions (covers, shields) on other axes

6. Why Staying Within the Ecosystem Helps

Choosing QF as your ultra thin linear module also keeps you aligned with the broader W-Robot ecosystem:

For long-stroke X-axes in the same machine, you can pair QF with timing belt drive modules (EB/OB) while re-using similar motors and controllers. w-robot.com

For harsh environments you can mix in dustproof linear modules or fully enclosed linear modules from the VGTH family without changing supplier. w-robot.com+1

For part handling you can bolt W-Robot robot grippers or small electric cylinders directly to QF carriages, building compact multi-axis linear actuators around a common mechanical interface. w-robot.com

This consistency matters when you scale from one prototype to a full production line with many identical stations.

7. Quick Checklist Before You Order

Before you send a QF model number to purchasing, verify these points:

Stroke: commanded travel + homing + safety margin ≤ 420 mm.

Space: body width/height and total length (including motor and coupling) fit your envelope.

Load & moments: within the chosen QF size limits with a sensible safety factor.

Dynamics: motor + screw lead combination can meet your move time and acceleration.

Integration: mounting patterns match your frame; cable routing and sensor placement are planned.