A 3-motor system ― lift, backrest and leg section ― covers the great majority of professional facial and spa beds. Add a fourth motor when the equipment must deliver an independent tilt or Trendelenburg movement, or when the backrest must be split into thoracic and head sections for medical-aesthetic procedures. The fourth axis adds roughly 25‒30% to the drive system bill of materials and a meaningful jump in control complexity, so it should be justified by a treatment the bed cannot otherwise perform ― not added as a marketing bullet.

This guide breaks down what each axis does, what force and stroke it actually needs, and where the cost and engineering risk sit.

What each motor actually does

An "electric beauty bed" is a set of independent axes. Counting motors is really counting the movements your end customer can sell a treatment around.

Axis 1 ― Height / lift (always present)

The lift axis raises and lowers the whole platform. It is the highest-load axis on the bed because it carries the client, the entire frame, and every other actuator mounted on it.

• Load: 4,000‒6,000 N for a professional spa bed; 6,000‒8,000 N for an aesthetic or medical chair
• Stroke: typically 250‒500 mm depending on the low height you need to reach
• Why it matters most: height range determines both therapist ergonomics and, in North America, whether your equipment can meet accessibility transfer height requirements

This axis is usually a lifting column or a heavy actuator in a scissor or parallelogram frame. The FY018 lifting column at 6,000 N, or a high-load actuator such as FY031 or FY032, fit here.

Axis 2 ― Backrest (always present)

Moves the client between lying flat and an upright or semi-upright seated position. Essential for facials, lash work, injectables and consultation.

• Load: typically 2,000‒4,000 N, driven by torso weight and lever arm
• Stroke: commonly 100‒200 mm, with the angle set by the linkage geometry rather than raw stroke
• Critical requirement: smooth start and stop. Jerky backrest motion is the single most common source of end-client complaints, because the client feels it directly

The FY011F at 3,000 N or the brushless FY011CR at 3,500 N are typical for this position, the latter where noise and vibration are a selling point.

Axis 3 ― Leg / footrest (the third motor)

Raises and lowers the leg section independently, enabling a lounge position, circulation-supporting elevation, and pedicure or lower-body treatment positions.

• Load: typically 1,500‒3,000 N ― lower than backrest, since legs are lighter and the lever arm is usually shorter
• Stroke: commonly 100‒200 mm

This is the axis that turns a two-motor table into a genuinely versatile treatment bed, and it is why 3-motor is the volume configuration in professional equipment.

Axis 4 ― Tilt / Trendelenburg, or split backrest (the fourth motor)

Two different jobs get assigned to a fourth motor, and they are not interchangeable.

Option A ― Trendelenburg tilt. Tilts the entire platform so the head sits below the level of the feet. This is a clinical positioning requirement, used in aesthetic medicine for procedures where blood flow to the head matters, and as a response option if a client becomes faint during a treatment. It requires the tilt actuator to move the whole loaded platform, so it is a high-load axis ― comparable to the lift axis, not to the leg axis.

Option B ― Split backrest / independent headrest. Separates head and thoracic support so the practitioner can fine-tune neck position independently. This is common on hair transplant, injectable and dental-adjacent chairs where the head must be held at a precise angle for long periods. It is a low-load, short-stroke axis ― the FY022 mini actuator at 2,000 N with a compact footprint and low-noise design suits this position.

Note the implication: "4-motor" tells a buyer almost nothing on its own. A 4-motor bed with Trendelenburg and a 4-motor bed with an independent headrest are entirely different machines at entirely different price points.

Side-by-side comparison

When the fourth motor genuinely pays for itself

Add the fourth axis when at least one of these is true:

• The end customer performs procedures requiring Trendelenburg. Aesthetic medicine clinics do. General beauty salons do not.
• You are selling into medical or clinical channels where positioning flexibility is compared line-by-line against LINAK- and TiMOTION-equipped competitors.
• Head position must be independently adjustable and held precisely for extended periods ― hair transplant, injectables, some dental-adjacent applications.
• You need a premium tier in a product family where the 3-motor bed is your volume model and the 4-motor is your margin model.

Stay with three motors when:

• The equipment targets general beauty, lash, facial and massage use
• Price sensitivity is high and the market is comparison-shopping on specification sheets
• Your control architecture and after-sales support are not yet set up for the added complexity ― every extra axis is another warranty conversation

The engineering issues that decide whether it works

Synchronisation

Multi-axis beds need axes that move predictably relative to each other, and in some configurations two actuators must move as a matched pair. That requires closed-loop control: Hall sensors or potentiometers for position feedback, a PWM or PLC controller managing them, and ― the part that is often overlooked ― identical mechanical mounting and evenly distributed load across the paired actuators. Mismatched geometry defeats even a good controller.

Duty cycle across four axes

Standard DC actuators in this class, including the JDR range, are rated at a 10% duty cycle (2 minutes on, 18 minutes off). More axes means more total actuation events per treatment. A four-axis bed in a high-throughput clinic can push individual actuators past their thermal budget even though each single movement is short. Model the realistic cycle count per axis per day before you finalise the specification.

Stroke versus retracted length

The constraint that most often forces a redesign is not stroke ― it is retracted length. Every actuator needs somewhere to live when fully retracted, and on a bed that must descend to a low transfer height, the space under the platform is exactly what you are trying to eliminate. Resolve this at concept stage. All JDR actuators are offered with customisable stroke, which means the retracted length can be engineered to your frame instead of your frame being designed around a catalogue part.

Emergency lowering

Any bed that can raise a client needs a defined way to bring them down safely if power fails. Specify this alongside the motor count, not after it. It affects controller selection and, on higher-specification systems, whether battery backup is required.

Recommended JDR configuration

Specifications below are as published on the JDR product pages.

3-motor professional facial / spa bed

4-motor medical-aesthetic chair

Choose the IP rating for the actual environment ― IP43 is suitable for enclosed dry furniture, while IP65-class sealing belongs anywhere the unit faces disinfectant application or water exposure. Browse the full Medical Actuator Series.

Frequently asked questions

What is the difference between a 3-motor and 4-motor beauty bed?

A 3-motor bed drives height, backrest and leg section independently. A 4-motor bed adds either full-platform tilt (Trendelenburg) or a split backrest with independent head adjustment. The fourth axis adds roughly 25‒30% to drive system cost and requires a higher-specification controller.

Do I need Trendelenburg on a facial bed?

Generally no. Trendelenburg is a clinical positioning requirement for aesthetic medicine and procedures where head-below-heart positioning matters. A general beauty or facial bed rarely justifies it.

How much load should each motor handle?

Lift 4,000‒6,000 N for spa beds and 6,000‒8,000 N for medical-aesthetic chairs; backrest 2,000‒4,000 N; leg 1,500‒3,000 N. Always calculate from your actual mounting geometry and worst-case load angle rather than from body weight alone.

Can two actuators be synchronised on one axis?

Yes, with closed-loop control ― Hall sensors or potentiometers, a PWM or PLC controller, and identical mounting with balanced load across both units.

Can I upgrade a 3-motor design to 4-motor later?

Only if the frame and controller were planned for it. Retrofitting a fourth axis usually means a new control box and often frame modification, so decide the maximum axis count at concept stage even if you launch the 3-motor version first.

Specify your configuration

Send your axis loads, stroke requirements and mounting geometry and the JDR engineering team will propose a matched actuator and control set ― then request test samples to validate it on your own rig before committing to tooling.

Contact the engineering team 

Related reading:

• Linear Actuators for Beauty, Spa & Aesthetic Equipment: The 2026 OEM Sourcing Guide
• ADA & MDE Compliance: Specifying 17-Inch Low-Height Actuators for Treatment Tables
• Replacing Hydraulic Lifts with Electric Actuators in Spa & Beauty Tables

Sources

• JDR product specifications: https://www.jederoo.com/products
• JDR technical FAQ on actuator synchronisation and selection: https://www.jederoo.com/after-sales/faq