What leak rate should I enter per cup?

Use the vendor figure for the cup at your working vacuum, or measure supply flow with the cups sealed and held against the part. For porous stock, test the actual material because leak rates vary widely.

Why is the required flow higher than the leak total?

The evacuation factor covers the flow needed to pull each cup down within the cycle. The porosity factor covers material that leaks more than the base leak rate.

Can I use one pump for many cups and tools?

Add the leak flows of every cup on line at once, then apply the factors. Tools that only run one at a time do not add together, but shared lines and valves still add losses.

Does the pump size cover vacuum level as well as flow?

No. This tool sizes flow. The pump or ejector must also reach the vacuum level in inches of mercury that the cup holding force needs, and the two curves interact.

Robotics & Automation calculator

Vacuum Pump Capacity Calculator

Size the vacuum source for an end effector from the leak each cup passes and the number of cups. Add flow to pull the cups down within cycle time, then an allowance for porous parts.

What this calculator does

Vacuum pump or ejector flow needed to hold cups through leaks, fast evacuation, and porous parts.

Formula used

Required pump flow (CFM) = per cup leak rate (SCFM) × cup count × evacuation factor × porosity safety factor
Base leak flow (CFM) = per cup leak rate × cup count
Evacuation allowance (CFM) = base leak flow × (evacuation factor − 1)
Porosity allowance (CFM) = base leak flow × evacuation factor × (porosity factor − 1)

Inputs explained

Per Cup Leak Rate: Flow one cup passes at the working vacuum level.
Cup Count: Cups on the tool that leak while vacuum is held.
Evacuation Factor: Flow multiplier for pulling the cups down within cycle time.
Porosity Safety Factor: Extra multiplier for porous parts, cartons or packaging.

How to use the result

Best suited to sizing an ejector for a carton picker, checking pump headroom before adding cups, quoting a porous foam handling tool.
Pump and ejector datasheets rate flow at a vacuum level; check the curve, not the headline rating. A long line or manifold adds pressure drop that the source must overcome. Porous or wet parts can leak more than the porosity allowance covers.

Current U.S. benchmarks

Global copper trades at $13,543 per tonne (IMF via FRED, Jul 2026), up 38.6% in a year, and U.S. industrial electricity averages 9.77 cents per kWh. Both feed electrified-hardware unit economics.

Common questions

What leak rate should I enter per cup? Use the vendor figure for the cup at your working vacuum, or measure supply flow with the cups sealed and held against the part. For porous stock, test the actual material because leak rates vary widely.
Why is the required flow higher than the leak total? The evacuation factor covers the flow needed to pull each cup down within the cycle. The porosity factor covers material that leaks more than the base leak rate.
Can I use one pump for many cups and tools? Add the leak flows of every cup on line at once, then apply the factors. Tools that only run one at a time do not add together, but shared lines and valves still add losses.
Does the pump size cover vacuum level as well as flow? No. This tool sizes flow. The pump or ejector must also reach the vacuum level in inches of mercury that the cup holding force needs, and the two curves interact.

Last reviewed 2026-10-01.