Vacuum technology is essential for safely handling food products without damage or waste.
Justin Katz • Manager, Vacuum Automation Components Group • Schmalz Inc. • Raleigh, N.C.
The world wastes about 1.4 billion tons of food every year, according to the United Nations Food and Agriculture Organization. The United States alone annually discards nearly 40 million tons of food, more than any other country. That’s estimated to be 30 to 40% of the entire U.S. food supply, says the USDA.
The food processing industry accounts for a sizeable share of the loss, because products are damaged or contaminated during production, transfer, handling and packaging. Even though more than half of this food would still have been edible, instead, it mostly ends up in landfills and contributes to food insecurity, global warming, and lost profits for manufacturers and distributors.
Schmalz Inc., a supplier of vacuum and handling products and systems and related technologies, is at the forefront of addressing these issues. Its goal is to create innovative solutions that make food-production and packaging processes more efficient, but also more sustainable.
Vacuum technology has become an indispensable part of today’s food industry, and Schmalz engineers and designers have developed a number of products that help meet customers’ demands for top-notch quality and faster throughput, and facilitate high-speed automation. These include grippers that are FDA-compliant and specifically designed to prevent damage and contamination when sorting, separating or transferring products.
One example is the OFG finger gripper, which the company introduced about a year ago. It consists of four silicone fingers that open with vacuum and close with pressure. The orientation of the fingers is variably aligned so that centric or parallel gripping is possible both inwards and outwards. And opening angle, gripping force and finger positions can be flexibly adjusted. The compact base body, made of aluminum or PET-P (hygienic-design version), has a flange for ready connection to common robots.
The unit is also available as a combination gripper with a central bellows suction cup for increased gripping force and stabilization during transfer. In this case, a second pneumatic connection supplies the suction cup and controls suction and blow off.
The gentle and low-marking gripper is suited for a wide range of tasks thanks to a rounded design based on the human hand. Finger grippers can be used for direct contact with food, such as when transferring products into trays or for quality control. The slim and narrow finger design allows small products to be placed close together, for example for packing a sushi lunch box. And it efficiently grasps and transfers organic products with varying shapes and characteristics, such as chicken legs, apples and donuts. Given the universal design, it is also used in logistics for picking and packaging small, irregular parts; and in automated systems that process a variety of different products.
OFG’s flexible fingers with hardness 70 Shore A are about 96 mm (3.8 in.) long, conform to FDA and BfR (German Federal Institute for Risk Assessment) guidelines and are available in high visibility blue. Operating pressure is from -0.8 to 1.0 bar (-11.6 to 14.5 psi), operating temperature range is from -30° to 80° C (-22° to 176° F) and the units are rated protection class IP 68. Lift capacity is up to 1 kg.
Flow grippers for food products
When applications involve delicate food products with minimal surface pressure, users should consider Schmalz Food Grippers, SFG. An SFG flow gripper, equipped with the appropriate suction cup, handles dry baked goods such as cookies, wafers and waffles without damage. That’s despite their highly textured surfaces and, often, a high degree of leakage.
The modular unit generates high suction power and only a low vacuum — to ensure the whole cookie ends up in the packaging. Its soft and flexible lip seals when gripping and effectively dampens and cushions when depositing delicate food products on surfaces.
The gripper features integrated compressed-air vacuum generation and an exhaust duct that controls the direction of outflow air. An optional adapter allows for mounting to horizontal surfaces and standard robot flanges, and the compact and lightweight design (108 gm) and high suction capacity permits highly dynamic processes.
Gripping elements are made of FDA-compliant silicone materials for direct contact with dry food products. Maintenance personnel can easily remove the suction cups without tools, for high system availability. And the hygienic design ensures easy cleaning.
Operating pressure is from 1 to 5 bar (14.5 to 72.5 psi) with suction rates from 270 lpm to 650 lpm (9.5 to 22.9 cfm). For these units, suction and lift capacity vary with volume flow, operating pressure, and the working area of the vacuum cup. For example, static holding force with a 40 mm diameter cup and 1 bar operating pressure (measured on an airtight workpiece) is 3 N (0.67 lbf); with an operating pressure of 5 bar and a 60 mm suction cup, holding force is 34 N (7.6 lbf). Operating temperature range is from 5° to 75° C (41° to 167° F).
Chocolate suction cups
The bell-shaped SPG suction cup picks up confectionery products gently and precisely — regardless of whether they are round, square or oval. It’s designed for high-speed handling and packing of chocolates in combination with delta picker robots.
The SPG, made of FDA-compliant silicone, handles round chocolates with maximum diameter of 35 mm (1.4 in.) and oval/square chocolates with maximum diagonal measurement of 30 mm (1.2 in.).
The suction cup has an extremely thin, soft sealing lip and tapered cup geometry. This enables efficient picking regardless of shape, and it also optimally grips candies with decorative toppings like almond slivers, hazelnut brittle or coffee beans. At the same time, its large opening allows a high flow rate which compensates for any leakage that these structured surfaces or irregular shapes may cause.
Suction area (diameter) is 33 mm, and the suction force and operating vacuum are dependent on the geometry and surface characteristics of the chocolate. Recommended maximum operating vacuum is -150 mbar so as not to damage the workpiece.
A one-piece, insertable connector element with male or female threads lets technicians quickly change out the suction cup. The male version has an integrated O-ring seal.
Another specialty from Schmalz is the round bellows suction pad FG-X family of products. A steep, conical sealing lip reliably grips eggs of different sizes. It’s used for the handling of eggs in packing and sorting machines, and is also suitable for use in breeding stations.
The cone-shaped bellows ensures maximum stroke immediately after contact with the food and then compresses completely within each other. This increases the lateral stability when transporting eggs from a conveyor belt into the carton.
The cups are available in diameters from 30 to 35 mm and bellows with 1.5 to 3.5 folds. Materials include natural rubber and FDA-approved silicone in a hardness range from Shore A 30 to 50.
Even though the egg gripper is considered a unique item in the Schmalz range, it is actually frequently requested and used. This speaks for our technology concepts, which ensure safe and damage-free transport of even sensitive goods.
Schmalz pursues three goals when developing its suction cups for foodstuffs. They must not damage the goods when they are picked up, moved or placed down. The handling processes must be highly dynamic and efficient, and the grippers must meet the current hygiene regulations in terms of design and material. These are specified by the FDA and the EU. Materials that have direct contact with food must not release any ingredients into it, or only in concentrations that are harmless to humans. Schmalz complies with the stricter FDA specifications and relies exclusively on silicone, which does not contaminate food thanks to its temperature and chemical resistance.
Depending on the application, additives expand the function. The SI-MD (metal detectable) version, for example, features detectable silicone: A small amount of metal oxide causes metal detectors to alert if the suction cup or part of a suction cup gets into the tray or food. Its blue coloration is also striking, making it more visible to cameras and humans. This is one way to prevent food contamination.
The SI-HD (heavy duty) material is a particularly wear-resistant silicone. The white food-compliant SI-HD suction cups handle highly abrasive goods and have up to twice the service life of normal silicone suction cups.
In addition to the material, design also plays an important role. Grippers are built to handle sensitive workpieces in many different industries, from the electrical industry to solar cell production. Unlike printed circuit boards or wafers, however, food can leave residues on the suction cups. It must therefore be possible to remove these as quickly and easily as possible.
Hygienic design includes all design measures that make components and systems suitable for cleaning. For instance, consider the OFG finger gripper. The base body of the unit is made of thermoplastic PET-P (polyethylene terephthalate) and horizontal surfaces, fingers and sealing rings are made of silicone and the screws are made of stainless steel. Additionally, the gripper is compatible with existing Clean-In-Place (CIP) or Clean-Out-of-Place (COP) processes.
The pneumatic connection is also hygienically designed. All connection points such as screw connections, where metal meets metal, are sealed smoothly with sealing elements on the outside. This prevents microorganisms from settling when handling foods such as raw meats and cheese. Thus, hygienic design is another key to preventing food losses in production. If grippers are easy to clean, manufacturers minimize the risk of contaminating the products with bacteria or particles. Hygienic design also offers other economic and ecological advantages: faster and easier cleaning requires less water and cleaning agents and equates to shorter downtimes.
With both our special grippers and universal gripping systems, Schmalz supports its customers in resource-saving management, can aid in the reduction of avoidable food waste, and contributes to economical and, at the same time, sustainable production.
Filed Under: End Effectors & Grippers, Pneumatic Tips, Vacuum