How do suction cups work?(3)

The depth of the suction cup cavity therefore plays a vital role in its ability to contact the curved surface, forming a tight barrier to prevent atmospheric pressure from seeping out. Suction cups designed for flat surfaces do not usually take this contour into account, so the depth of the suction cup is often an indicator of the surface it is designed for. Deep suction cups (i.e. 1-3/4" recessed) like the Wood's Powr-Grip N6450 10" Hand Cup are usually designed for curved surfaces.

Porous - Something porous will let something through! In the glass, stone and building materials industries, the porosity of the material plays an important role in determining the type of suction cupbest suited to the job. A material is porous if it allows water, air or other liquids to pass through. Examples of porous materials include things like concrete, wood, or various types of stone, while non-porous materials are usually things like glass, metal, plastic, or varnished wood.

Surface temperature - Different materials and their applications will affect the surface temperature and therefore your decision in choosing the right type of suction cup. For example, the pottery forming process, or removing glass from a tempering furnace, tends to produce high heat surface areas and therefore requires the use of a higher heat resistant compound on the suction cups.

Surface treatments or coatings - Certain materials, either during the manufacturing process or in post-production measures, are often coated or given different surface treatments. Petroleum-based oils are often found on sheet metal and sheet metal, while low-e (low-e) glass coatings are often found in insulating glass window units. Considering the finish or coating of your material is important in determining the appropriate type of compound to use. For example, oil resistant rubber is usually best suited to sheet metal and metal, while coated compatible rubber is designed to handle low-e glass and other coated materials without leaving marks.

Weight and size - The lifting capacity of a suction cup depends on several variables, including the compound of the material used on the suction cup, the surface area of the suction cup, and atmospheric pressure, to name a few. Determining the size and weight of the material, the limitations of the operating dimensions, and the logistical constraints of the project will help determine the type, size and number of suction cups required. Any design should include a safety factor of greater than 2.