Every vacuum gripper lives or dies at the interface where it meets the product. On our grippers that interface comes in two forms: foam sealing or suction cups. Both maintain consistent vacuum performance in continuous operation, but they solve different problems, and choosing wrong costs you either grip reliability or cycle speed.
Quick answer: Choose foam sealing in 10 or 20 mm thickness when air can leak through or around the product surface, such as raw corrugate, print, or tape seams. Choose suction cups in 40, 60, or 80 mm diameters for smooth sealed surfaces where speed and clean release matter. Both interfaces are interchangeable on the same Anubis gripper body.
When Foam Sealing Wins
Foam seals in 10 mm and 20 mm thicknesses conform to surfaces that suction cups struggle with: raw corrugate, wood, embossed print, tape seams, and porous or slightly uneven materials. The foam compresses over imperfections and maintains full contact across the sealing area, which keeps vacuum stable on products that leak air through their own surface. If your worst product is a printed shipper case with a warped top flap, foam is your answer.
Thickness matters more than most buyers expect. The 10 mm option suits surfaces with light texture and minor waviness while keeping the seal firm for accurate placement. The 20 mm option absorbs deeper irregularities such as strapping, heavy embossing, or cases that bow under their own contents, trading a little placement stiffness for a lot of tolerance. This is a standard configuration question on carton handling and packaging lines, and it costs nothing to get right at the design stage.
When Suction Cups Win
Suction cups in 40 mm, 60 mm, and 80 mm diameters give you precise, repeatable contact points and release cleanly at speed. They excel on smooth, sealed surfaces: glass, sheet metal, coated cartons, rigid plastics, and shrink wrapped trays. Cup diameter follows product weight and available contact area, and mixed diameters on one tool are routine when the product calls for it.
Cups also make inlet-level flow control possible. On our Area Surface Gripper (ASG), each cup inlet accepts an interchangeable flow restrictor fitting, either a non-return check valve or a calibrated orifice from 1.0 mm to 1.5 mm, so one uncovered cup does not collapse the vacuum for the rest of the array. That single feature eliminates a whole class of dropped-product problems, which we cover in our troubleshooting guide.
The Practical Decision Rule
Ask two questions. Does air leak through or around the product surface? If yes, foam. Do you need maximum cycle speed on a smooth surface with clean release? If yes, cups. When a line runs both kinds of product, the honest answer is often both: our sealing options are interchangeable on the same gripper body, so a changeover swaps the interface, not the tool.
How the Gripper Format Changes the Answer
On a full surface gripper, the interface covers the whole gripping area, so the foam or cup decision applies to the entire tool. On a multi-point tool like the Spider Gripper (SPI), each of the four to eight arms carries its own cup, placed in a balanced geometry that distributes load evenly across every suction point. Multi-point tools are cup territory by nature, and the flexibility lives in cup position and pitch rather than interface choice. Our guide on choosing a vacuum gripper for palletizing covers when each format wins.
What About Mixed or Unknown Products
Contract packagers and lines with frequent SKU changes should default to the more forgiving option, then tune. Foam handles the widest range of surfaces with the least sensitivity to product variation. Add two-zone vacuum control and you can adapt the active gripping area to each format without touching hardware. For products that defy both standard answers, fully custom geometry is our home ground: our retractable arm vacuum gripper case study shows how far a printed tool can bend around a difficult product.
Test with Your Worst Product, Not Your Best
Suppliers demo on the easiest case in the box. Send your most warped, most porous, most awkward product instead, and state your real line speed. A gripper interface proven against the worst case will never surprise you in production. You can compare every configuration in our online catalogue, and the wider selection logic lives on our end-of-arm tooling page.
Lifespan and Maintenance of Each Interface
Both interfaces are consumables, and planning their replacement beats reacting to their failure. Foam wears through abrasion against rough corrugate and shows its age as compression set: the foam stops springing back, contact pressure drops, and marginal products start leaking. Cups wear at the lip, where a nick or a fold that looks cosmetic is a leak path at speed. Neither failure announces itself; both show up first as intermittent drops on the worst product in the mix, which is why our troubleshooting sequence checks the interface before anything else. Keep spares on the shelf, put both on a scheduled swap tied to cycle count rather than calendar time, and the interface disappears as a failure category.
Reading Your Product Mix Like an Analyst
Pull your SKU list and sort it by surface, not by size. Sealed film, coated board, glass, and rigid plastic go in the cup column. Raw kraft, heavy print, embossing, tape seams, and anything that arrives slightly warped go in the foam column. If one column holds ninety percent of volume, spec for that column and handle the exceptions with zoning and flow control. If the split is genuinely mixed, buy the interchangeable body and both interfaces; the changeover is minutes and the alternative is a second tool. This ten minute exercise settles most interface debates before they start.
Frequently Asked Questions
Which is better for a vacuum gripper, foam or suction cups?
Neither is universally better. Foam sealing wins on porous, printed, or uneven surfaces because it conforms over imperfections. Suction cups win on smooth sealed surfaces where precise contact and fast clean release matter.
Can I switch between foam and suction cups on the same gripper?
Yes. On the Anubis Area Surface Gripper the sealing options are interchangeable on the same body, so a changeover swaps the interface rather than the whole tool.
What suction cup size should I use for heavy boxes?
Larger and more cups spread the load: 60 mm and 80 mm diameters suit heavier cases, while 40 mm cups give precision on small or light products. Cup count, size, and pitch are configured to the product during design.
Does foam sealing work on shrink wrapped products?
Yes, foam is often the better choice on shrink wrap because it rides over film wrinkles that would leak under individual cup lips, maintaining full contact across the sealing area.
Get the Right Tool for Your Line
Every Anubis Robotic Tooling product is engineered around your product, your robot, and your cycle time. Tell us about your application and our engineering team will come back with the right tooling and a clear quote. Request a Quote, browse the full range in our online catalogue, or contact our Eindhoven team directly.
