There is a specific and expensive failure that happens on scissor lift tables: the prototype lifts the load perfectly during testing, then stalls the first time an operator tries to raise it from the fully lowered position with the pallet pushed to one end.

The actuator was not undersized for the load. It was sized for the wrong geometry.

Quick answer A scissor lift table's actuator does not see the payload weight. It sees the payload divided by a geometry factor that collapses as the platform approaches its lowest position. Size at the fully lowered position with an off-centre load — every other position is easier.

Why Scissor Lifts Break the Normal Sizing Rule

For a directly coupled vertical lift, actuator force equals load. Simple.

A scissor mechanism inserts a linkage between the actuator and the platform, and that linkage has a variable transmission ratio. The actuator typically pushes at a shallow angle against a scissor arm; the closer the scissors are to flat, the worse the leverage.

Three consequences follow, and all three are counterintuitive:

1. Peak force occurs at the bottom of travel, not at the top and not under maximum speed.
2. The force curve is highly non-linear. The requirement can rise steeply over the last part of the descent, so a design that works at 30% raised may stall at 5% raised.
3. The actuator's own force capability is not constant either. Speed and force trade against each other — our FY015 spec table publishes 5 mm/s at 7,000 N versus 160 mm/s at 750 N.

How Do You Calculate Actuator Force for a Scissor Lift Table?

Step 1 — Define the total moving load

$m_{\text{total}}=m_{\text{payload}}+m_{\text{platform}}+m_{\text{upper linkage}}+m_{\text{fixtures}}$

The platform deck and the upper scissor arms are routinely forgotten. On a heavy industrial table the structure alone can be a substantial fraction of the rated payload.

Step 2 — Find the worst-case angle

Let  $\theta$  be the angle between the scissor arms and the horizontal. Determine  ${\theta }_{\min }$  — the angle at the fully lowered position. This is your design point.

Step 3 — Apply the mechanical advantage relationship

For a scissor lift with the actuator mounted between the arms, the required force takes the general form:

$F_{\text{actuator}}=\frac{W\cdot L_{\text{load}}}{k\cdot L_{\text{act}}\cdot \sin \theta }$

where  $W$  is the total moving weight,  $L_{\text{load}}$  and  $L_{\text{act}}$ are the effective lever arms of the load and the actuator about the scissor pivot, and  $k$  accounts for the number of scissor stages and the actuator mounting arrangement.

The critical behaviour is the  $\sin \theta$ term in the denominator. As  $\theta$  decreases toward the flat position,  $\sin \theta$  approaches zero and the required force rises without bound. In practice, mechanical stops and the actuator's mounting geometry prevent the true singularity, but the steep rise is real and is exactly what catches undersized designs.

⚠️ Do not take a generic multiplier from a blog and apply it to your table. The exact factor is entirely determined by your pivot positions and actuator attachment points. Derive it from your own CAD geometry, or send us your linkage drawing and we will work it through with you.

Step 4 — Add eccentric loading and margin

Two adjustments before selecting:

• Eccentric load. A pallet placed at one end of the platform loads one side of the linkage more than the other. If a single central actuator drives the mechanism, the resulting racking increases friction throughout the joints.
• Design margin. Choose so the worst-case demand sits meaningfully below the actuator's rated capacity — this preserves screw life and keeps current, and therefore heat, down.

Our industrial series published capacities give you the ladder to select from:

​Values as published on the linked product pages. Stroke is built to order.

Where to Mount the Actuator: Four Configurations Compared

The trade-off is consistent: configurations that reduce force demand require more stroke or more height. Which means the sizing exercise is really a three-way negotiation between force, stroke and collapsed height.

Because collapsed height and stroke are so tightly coupled here, ask for the retracted length of a candidate model at quotation stage, not after the frame is welded.

Hold Load vs Dynamic Load: Two Different Numbers

Two distinct requirements, often conflated:

• Dynamic load — the force required to move the platform. This is what the sizing calculation above produces.
• Hold load — the force the mechanism must sustain while the platform is stationary and loaded, which is where a table spends most of its life.

Ask your supplier explicitly whether the drive is mechanically self-locking at your load, or whether it holds by remaining energised. This matters twice over:

1. Safety — a non-self-locking drive that loses power could allow descent, so an independent mechanical safety device may be needed in your machine design.
2. Duty cycle — if the actuator holds under power, that hold time counts as on-time. Every model in our industrial series publishes 10% duty as 2 min on / 18 min off, so a table that holds electrically for minutes at a time will consume its allowance quickly. See duty cycle for 24/7 warehouse actuators.

Our published product pages do not state self-locking behaviour, so confirm it with us for your specific model and load rather than assuming it either way.

One Actuator or Two? Sizing a Wide Platform

If you go with two, they must stay in step — a few millimetres of drift across a wide platform generates significant binding forces in the linkage. The implementation options are covered in our existing guide, how to sync two linear actuators, so we will not repeat them here; for lift tables the decision criterion is simply whether platform width and load eccentricity make a single drive point untenable.

Sizing note: do not size each of a pair at exactly half the total demand. Under a fully eccentric load the split can be considerably worse than even, and the more heavily loaded unit sets the requirement.

Stroke, Speed and the Duty Cycle Trap

Stroke is set by the required vertical rise and the linkage ratio — for many arm-to-arm configurations the actuator stroke is substantially shorter than the platform rise, which is one of the benefits of the geometry. Work it out from your CAD, then order the exact figure; stroke is made to order across our industrial series.

Speed is where lift tables bite. Consider a 600 mm rise where the actuator must run slowly to deliver high force: at 5 mm/s an equivalent actuator travel of 300 mm takes 60 seconds. Up and down is 120 seconds — and that is a full minute of the two-minute continuous on-time allowance consumed by a single cycle.

The practical consequences:

• Lift tables are usually duty-limited on continuous on-time, not on cycles per hour.
• Faster models reduce this pressure, but speed costs force — check the force/speed pairing published for the model, as with the FY015's 5 mm/s @ 7,000 N versus 160 mm/s @ 750 N.
• If your process needs frequent full-height cycles, raise it at enquiry stage. It changes the model choice.

Environment. Indoor assembly and packing: IP65. Dusty bulk handling or a dock-adjacent position: IP66. Wash-down: IP67. See the warehouse IP rating guide. Published operating temperature on the FY028, FY020 and FY015 spec tables is −20°C to 65°C.

Specification Checklist for a Lift Table Actuator

Rated payload:                    ____ kg
Platform + upper linkage mass:    ____ kg
Platform dimensions:              ____ mm × ____ mm
Vertical rise required:           ____ mm
Collapsed (lowered) height limit: ____ mm
Scissor angle at lowest position: ____ °
Actuator mounting configuration:  arm-to-arm / base-to-arm / horizontal / direct
Load placement:                   always centred / can be fully eccentric
Full cycles per hour:             ____
Holding requirement:              seconds/minutes held under load: ____
Environment:                      indoor / dusty / wash-down / cold chain

The three lines most often missing from enquiries are collapsed height, scissor angle and holding time — and all three change the answer.

Frequently Asked Questions

Why does a scissor lift need more force at the bottom? 

The scissor angle is smallest there, so the effective lever arm is shortest and the required actuator force peaks. Size at the fully lowered position.

How much force does a lift table actuator need? 

A multiple of the load, determined by your specific pivot and mounting geometry. Derive it from your CAD or send us the linkage drawing.

One actuator or two? 

One for narrow tables with centred loads; two for wide platforms or eccentric loading — synchronised, and each sized above a simple 50/50 split.

Can the table hold position without power? 

Only if the drive is mechanically self-locking at your load. Confirm this per model; if it holds electrically, that time counts against duty cycle.

What stroke will I need? 

Usually less than the platform rise, because the linkage multiplies travel. Calculate from your geometry and order the exact figure.

Which model suits a 1,000 kg table? 

That depends entirely on the geometry multiplication factor, not on the 1,000 kg alone — a table needing 3× multiplication at its lowest point demands roughly 30 kN at the rod, above our published single-unit maximum of 16,000 N, and would point toward a two-actuator layout or a revised linkage. Send us the drawing and we will confirm.

Get Your Lift Table Sized by Our Engineers

Send payload, platform size, rise, collapsed height limit and your scissor geometry (a sketch or CAD screenshot is enough) and we will return the required rod force at the worst-case position, a model recommendation and the achievable stroke.

Request a lift table sizing review → · Industrial actuator series → · Back to the material handling guide →