Schmalz Vacuum Expertise – Handling Cardboard Boxes with Vacuum Suction Pads

The packaging industry is the second-largest market for robot systems after the automotive industry. Automation makes use of a wide range of vacuum suction pads, electric and pneumatic vacuum generators as well as vacuum components for system monitoring and parts control, such as vacuum switches.

Due to their properties as a workpiece, cardboard boxes place particular demands on the vacuum suction pads that are used:

• The surface is extremely abrasive
• The workpieces are often not completely rigid
• The cardboard boxes are often extremely porous
• The surfaces of filled and sealed cardboard boxes are often covered with adhesive tape
• Cardboard boxes having a resealable flap may exhibit height differences due to two layers of cardboard that overlap

The cartoning process places further demands on vacuum suction pads:

• Because cardboard quality can vary greatly, the vacuum suction pad that is used must cover a range of workpieces as broad as possible
• Extremely high lateral forces, especially in rotation erectors, cause the suction pads to wear out quickly

The combination of all of these challenges results in the profile and characteristics of the new series of ELASTODUR packaging suction pads from Schmalz:

• Soft sealing lip that adapts to the surface structure of the cardboard box
• Made from tough ELASTODUR to cope with the cartoning process, which can wear out the suction pads
• High displacement force in order to absorb lateral forces; this is accomplished using internal friction elements on flat suction pads and through the positive connection of the  bellows and sealing lip on bellows suction pads
• Reinforced basic body so that the suction pad can be stretched (see practical tip below), reinforcing plates prevent the bellows from collapsing
• Large nominal diameters guarantee high suction power on a wide range of workpieces

Practical tips:

Avoid swinging cardboard boxes
Due to their weight, cardboard boxes tend to swing, particularly in palletising processes. Therefore, in practice, mechanical supports are often used, against which the cardboard box is pulled. The result when clamping cardboard boxes is that the bellows suction pads do move to the end-stop. Instead, they stretch a little (see application photo right). Standard suction pads tend to collapse in this case because the bellows are not designed to be used in this manner. Schmalz packaging suction pads prevent this due to their reinforced basic body and integrated support ribs.

Position suction pads on the cardboard box correctly

Filled cardboard boxes bulge very quickly. This causes the cardboard box to tend to separate from the suction pad (peel-off effect). This can be avoided by positioning the suction pads as close as possible to the outer edges of the cardboard box and not in the centre. The increased stability of the cardboard box at the edges enables more powerful forces to be transferred, allowing higher accelerations and process speeds.

Schmalz is the leading supplier of Vacuum Automation Components as well as Robotic and Gantry style Vacuum Gripping Systems. Schmalz supplies modularly constructed area and layer vacuum grippers for flexible handling of varying material properties, configurations and shapes - such as non-rigid cardboard boxes, plastic film and porous materials. Schmalz grippers can handle varying dimensions and undefined positions. The product range of Vacuum Components includes suction cups in (11) standard materials and cup lines for special industry needs, e.g. Automotive cups or cups for the Packaging industry. The product range also includes vacuum generators, mounting elements and system monitoring devices. Schmalz, founded in 1910 in Germany, is family owned and operated in third generation. Schmalz is one of the few positive-energy companies worldwide and has been rewarded for its sustainability several times. Schmalz is DIN ISO 9001 and DIN ISO 14001 certified for more than 10 years.

Schmalz Inc., founded in 1999, is the US-subsidiary of Schmalz. Located in Raleigh, NC, Schmalz Inc. has its own outside sales force and Authorized Schmalz Distributors in all states. Schmalz Inc. is committed to provide an outstanding and timely service nationwide.

Schmalz Inc.
5200 Atlantic Avenue
Raleigh, NC 27616
(919) 713-0880
www.schmalz.com