How to Choose an Electric Gripper: A 6-Step Selection Guide

Choosing the right electric gripper comes down to six variables: payload, stroke, gripping force, precision, speed and available space. Get one wrong and you either crush the part or drop it. This guide walks through each one with the actual formulas engineers use, plus a comparison of our four gripper models to shortlist from.

Electric grippers have largely replaced pneumatic ones in modern automation because they need no compressor, no air lines and no filter — and they offer force control that air simply cannot deliver. But "electric" is not a single product category. A gripper built for 0.1 s pick-and-place is a completely different machine from one built to lift 5 kg with adjustable stroke.

Step 1: Calculate Required Gripping Force

This is where most selection errors happen. Gripping force is not the same as part weight — it depends on friction, how many fingers contact the part, and your safety margin.

The Formula

F = (m × g × SF) / (μ × n)

• F — required gripping force per finger (N)
• m — workpiece mass (kg)
• g — 9.81 m/s²
• SF — safety factor (see below)
• μ — friction coefficient between fingertip and part
• n — number of contacting fingers (usually 2)

Safety Factor

Condition	Safety Factor
Static handling, low acceleration	2
Normal pick-and-place	3
High acceleration or robot arm motion	4–5
Vertical lift (gravity works against grip)	Add 20–30%

Friction Coefficients

Fingertip / Part	μ
Steel on steel (oily)	0.1–0.15
Steel on steel (dry)	0.2–0.3
Aluminium on steel	0.3–0.4
Rubber fingertip on most surfaces	0.5–0.8
Custom machined fingertip matched to part	0.8+

Worked example: A 0.3 kg aluminium housing, rubber fingertips (μ = 0.6), two fingers, normal pick-and-place (SF = 3).

F = (0.3 × 9.81 × 3) / (0.6 × 2) = 7.4 N per finger

A gripper rated 8–20 N covers this comfortably. This is why our KVG-20S Ultra, with its adjustable 8–20 N range, is often the safe default — you can dial the force up if your friction estimate was optimistic.

Step 2: Match Stroke to Part Size

Total stroke is how far the two jaws travel from fully closed to fully open. The rule is simple but often ignored:

Required stroke ≥ part width + clearance (typically 2–5 mm each side)

Adding unnecessary stroke costs you cycle time — the jaws travel further than needed on every pick. If you handle parts of varying sizes, an adjustable-stroke gripper lets you set the opening per part instead of always running full travel.

Our KVG-20 is the only model in our range with adjustable stroke (up to 20 mm), which makes it the natural choice for mixed-size production lines.

Step 3: Decide If You Need Force Control

Not every application needs adjustable force. Here is how to tell:

Your situation	What you need
Single part type, rigid, repeatable	Fixed force is fine
Fragile or deformable parts (eggs, glass, soft packaging)	Adjustable force required
Multiple part types on one line	Adjustable force required
Part dimensions vary batch to batch	Force feedback or tactile sensing

Both our KVG-20S Ultra (4-level, 8–20 N) and KVG-20 (30–80 N) offer adjustable force. The KVG-20S Ultra suits light precision work; the KVG-20 covers heavier parts needing up to 80 N.

Step 4: Check Cycle Time

Stroke speed directly determines throughput. Compare the one-way stroke time against your target cycle:

• 0.1 s — high-speed small-part pick-and-place. Our KVG-8S is the fastest in our range.
• 0.15 s — fast precision work, e.g. the KVG-20S Ultra.
• 0.2 s — general purpose, e.g. the KVG-12.
• 0.45 s — heavier duty where force matters more than speed, e.g. the KVG-20.

Remember to budget time for robot motion, vision and I/O handshake — gripper stroke is usually a small fraction of total cycle, but on high-speed lines it adds up.

Step 5: Verify Space and Mounting

This is the constraint that kills otherwise-perfect selections. Check three things:

1. Cross-section — will the body fit between fixtures?
2. Weight — does it eat too much of your robot's payload?
3. Mounting pattern — do the bolt holes match your tool flange?

For tight workcells, a narrow body matters more than raw force. The KVG-12 has a 32 mm narrow profile, and the KVG-8S is the smallest overall at 30 × 24 × 93.9 mm and just 0.25 kg — ideal for lightweight collaborative arms where every gram counts.

Step 6: Confirm Integration

All our grippers use digital I/O control — simple, robust and compatible with most collaborative robots, industrial controllers and PLC systems. If your application needs bus communication or force feedback, check the specification before ordering.

For applications where a two-jaw gripper cannot work — irregular shapes, human-like manipulation, in-hand reorientation — consider a multi-DOF dexterous hand instead. Our KVD-Hand6 offers 6 degrees of freedom with 5 kg lifting capacity.

Quick Comparison: Which Gripper Fits Your Job?

Model	Stroke	Force	Speed	Size (mm)	Best for
KVG-8S	8 mm	8–20 N	0.1 s	30×24×93.9	Speed, smallest body
KVG-12	12 mm	30 N	0.2 s	48×32×105.6	Narrow access
KVG-20S Ultra	20 mm	8–20 N	0.15 s	43×24×93.9	Long stroke, precision
KVG-20	20 mm adj.	30–80 N	0.45 s	44×30×124.7	High force, adjustable stroke

Five Mistakes We See Repeatedly

1. Sizing force on part weight alone — ignoring friction and safety factor. Always run the formula.
2. Over-specifying stroke — wasted travel time on every cycle.
3. Ignoring gripper weight — a heavy gripper on a small cobot can consume 20–30% of usable payload.
4. Assuming all electric grippers have force control — many entry-level models are fixed-force only.
5. Forgetting fingertips — stock fingers rarely match your part. Machined custom fingertips raise μ dramatically and often let you use a smaller, cheaper gripper.

Frequently Asked Questions

Electric or pneumatic — which should I choose?

Choose electric if you need force control, clean operation (no oil mist), or you lack compressed air. Pneumatic still wins on raw cost per unit for simple open/close tasks in existing air-equipped plants. See our detailed comparison in the Resources section.

What safety factor should I use?

3 for normal pick-and-place. Go to 4–5 if the robot accelerates hard, and add 20–30% for vertical lifts.

Can one gripper handle multiple part sizes?

Yes, if it has adjustable stroke and adjustable force. Our KVG-20 is designed exactly for this.

How do I avoid crushing fragile parts?

Use a gripper with adjustable force and set it just above the calculated minimum. Adding a tactile sensor gives closed-loop control — our KVD-Hand6 supports optional 5-channel tactile feedback for 3–10 N dynamic force control.

What if my part shape is irregular?

Two parallel jaws need roughly parallel surfaces. For truly irregular objects, a dexterous hand or custom-machined fingertips are the practical answers.

Get Help With Your Selection

Send us your part weight, dimensions, material, cycle time and mounting space — our engineers will run the numbers and recommend a model within 24 hours. Contact us for a free selection check.