Checker plate (diamond plate, tread plate) has raised ribs across the whole surface. Hot-rolled plate stored for a while also becomes rusty, rough and uneven. A standard NBR rubber cup has a fairly stiff, thin lip. On this kind of surface the lip only rests on top of the ribs while the gaps between them stay open. Air keeps leaking in through those gaps, so the vacuum never builds up enough, or it builds up and then slowly drops while the plate is in the air.
On flat, clean plate an NBR cup is durable and inexpensive. On checker plate or rough surfaces it is a risk: the plate can slip, tilt or fall during travel. That is why FullSharp recommends foam vacuum cups for this group of materials.
A foam cup has a thick, elastic closed-cell foam layer instead of a rubber lip. When the pad is lowered and vacuum starts, the foam is compressed, follows the shape of the ribs and closes most of the gaps. The vacuum zone inside is then sealed well enough to hold the plate.
On ribbed surfaces the foam can still leak slightly. The system therefore needs a vacuum source with enough flow to compensate, plus a vacuum gauge and alarm so the operator knows when vacuum falls below the safe level.
| Criterion | NBR rubber cup | Foam cup |
|---|---|---|
| Suitable surface | Flat, smooth sheet: sheet metal, stainless, plain plate, glass | Checker plate, ribbed plate, rusty or uneven surfaces |
| Seal on ribbed surface | Poor, the lip only rests on the ribs | Good, the foam follows the ribs |
| Vacuum flow needed | Low | Higher, to compensate for slight leakage |
| Durability | Long life, rarely replaced | Wears faster, especially in hot, humid conditions |
| Running cost | Low | Budget for periodic replacement cups |
A plain steel plate of 3000 x 1500 x 3 mm has an area of 4.5 m² and weighs about 106 kg. A checker plate of the same size is slightly heavier because of the ribs, and usually still stays under 200 kg. For this load the suitable setup is:
If the plate is thicker and exceeds 200 kg, move to an electric or battery-powered pad; see our metal sheet lifting solutions.
Foam is sensitive to heat and humidity. In a hot, humid tropical climate such as Vietnam, especially under metal factory roofs in summer, the foam ages, hardens and loses elasticity faster than it does in cold countries. Sharp plate edges, burrs and rust also wear and tear the foam more quickly.
When buying the equipment, customers should therefore order a spare set of foam cups and keep it in a dry, cool storeroom away from sunlight. When the cups in use wear out, they can be replaced immediately without stopping production to wait for parts. Replace the cups when:
Yes, with foam vacuum cups. Standard NBR rubber cups only rest on the ribs, leak air and cannot hold the plate safely.
A plain plate weighs about 106 kg; a checker plate of the same size is slightly heavier because of the ribs and usually still under 200 kg.
It depends on the lifting frequency, how sharp the plate edges are and the workshop temperature. In hot, humid conditions foam wears faster than in cold climates, so watch its elasticity and the vacuum gauge to replace it in time.
Yes, order them together with the equipment and store them in a dry, cool place away from sunlight, so worn cups can be replaced immediately without stopping production.
Yes. Thin, light plates under 200 kg suit a pneumatic pad, provided it uses foam cups and a stable compressed-air supply.
Send FullSharp the plate size, thickness, weight, a photo of the surface pattern and where the plate needs to go (cutter, press brake, rack), and our engineers will propose a setup and test a sample.