Food for Thought…

H

istory has shown there is one recession-proof industry that continues to show growth year after year. It exists in the U.S., Canada and Mexico, in nearly every state and province. It is reliant upon engineering and high-performing plastics, thus feeding our industry with both new developmental opportunities and a large base of legacy applications. This is the food and beverage industry.

Over the last 50 years, global meat production has increased 500% and poultry by 1,200%. In parallel, a steady rise in aquaculture to support traditional agriculture yields have delivered similar increases in output. Major brands and their manufacturing facilities have grown steadily as retailers and restaurant chains have increasingly pushed for higher quality and lower cost products, creating a pull-through market launching even more opportunities for performance plastics.

Opportunities for performance plastics within the food and beverage industry generally fit into one of three application areas:
Conveying
Processing
Filling and packaging

Conveying

Conveyors occupy more floor space in food and beverage processing facilities than any other part of the operation. Highly automated conveyance systems connect the various stages of production, enabling a perfect match between the cadence of production and packaging. The rate of production and packaging is highly product-dependent, ranging from 2,000 units per minute for high volume filling of liquids, to less than 20 units per hour for highly specialized products.

plastic materials alongside a conveyor built

Photo courtesy of Morrison Container Handling

Ultra-high molecular weight polyethylene (UHMW) is most common in conveying applications. Wear strips, conveyor guide rails, chain guides, timing screws, star wheels and sliding surfaces made from various grades of UHMW, assist the flow of materials and packages through what can be miles of conveyors in a single large-scale facility. Given that plant layouts change over time, parts wear out over time and multiple packages may move along the same conveying systems, a typical facility has a constant need for new and replacement parts.

Larger facilities processing a wide range of products often color code conveying components, which helps to minimize errors for operators and maintenance staff when changing over lines for different packages. These parts are often referred to as “change parts.” They commonly include star wheels, guides and timing screws that position-packages for labeling, filling or closure.

TIVAR HPV Chain Guides

HPV roller and steel roller with HPV bushing

These change parts may be machined from UHMW, acetal, PET, or even nylon. Acetal offers the best balance of stiffness and machinability while UHMW offers the lowest friction and most abrasion resistance at the lowest cost. As line speeds increase, the precision tolerance capability of acetal or PET is a distinct performance advantage.

Due to recent increases in conveyor line speed, engineers are switching to enhanced, self-lubricating grades of UHMW. These next generation materials offer higher pressure (P) x velocity (V) capabilities than unfilled and oil filled UHMW; allowing these conveyors to run quieter and to experience longer MTBR (mean time before replacement). These self-lubricating materials outperform standard grades under the higher pressure conditions that occur at conveyor corners, spiral conveyors, rollers, and bushings and bearings within metallic rollers.

TIVAR 1000 Milk Dosing

Processing

A filling machine used to put liquids or powders into a container also has mechanical systems that create movement using gears, cams, wheels, rollers and bearings mostly made from performance plastics like acetal, PET, nylon or UHMW. Higher temperature processes often bring in higher performance materials such as PEEK, PEI or specialty fluoropolymers like modified PTFEs.

The poultry industry uses as much performance plastics as any industry. Very large cams, fixtures for deboning chickens and many other mechanical parts help processors deliver nearly 25 million chickens per day from approximately 200 U.S. processing plants. That means a single facility may process nearly 100,000 birds per day or 70 birds per minute; more than one bird per second. This type of output demands highly automated processes that include rigid fixtures and many moving parts. Lightweight performance plastics that are inert, non-corroding, easily fabricated and can be readily sanitized make these high- speed processing rates possible.

Very large cams, fixtures for deboning chickens and many other mechanical parts help processors deliver nearly 25 million chickens per day from approximately 200 U.S. processing plants

WATTAgNet

Poultry Cutter Guide

Any food product requiring batch mixing and blending poses another material challenge. It’s easy to mix enough pancake batter for your family’s breakfast using a spatula and a stainless-steel bowl, or ice cream in a one-gallon ice cream maker, however the scale up of such processes introduces new material challenges. Today’s largest commercial mixers have capacities up to 10,000 pounds per batch.

Stainless steel is strong, stiff and durable, but the continuous rubbing against a stainless steel mixing vessel generates wear debris that can end up in the product.

Products that are processed at low temperatures require materials that are impact resistant and durable at freezing temperatures, while cooked or heated products during processing, like ketchup or tomato sauce, require materials that are resistant to citric acid attaching, as well as hydrolysis. Materials such as PTFE, nylon, UHMW and even PEEK, are found as scrapers and mixing blades inside vessels like those shown below.

Photo courtesy of JBT FoodTech

Photo courtesy of Wahl Associates

Filling and packaging

Have you ever wondered how all those bottles and cans get filled? Today’s high speed filling lines can clean, fill and seal up to 2,500 cans or 2,100 bottles per minute. The equipment that delivers such production is highly complex and costs more than $1 million each. A typical facility using such equipment employs more than 500 people and runs 24 hours a day, seven days per week.

Naturally, smaller machines with less output are also used in far greater numbers. They too require performance plastics for mechanical drives, filling nozzles, guarding and wear surfaces. Operating conditions influence the choice of materials; hot filling requires hot water-resistant plastics that can accommodate wide swings in temperature with minimal thermal expansion/contraction, while dry filling requires more abrasion resistant materials.

Kettle agigators

Consolidation with this industry, and the desire to balance production, is creating a situation in which a line originally intended for one product gets converted into filling another product. This re-deployment often comes with new material challenges that require resolution by the facility’s maintenance and engineering teams.

Safety

When was the last time you found a contaminant in a purchased food or beverage product? I bet it has been a while, if ever. Due to the ever-increasing amount of food and drink we consume, it makes sense that we would also see an escalation in the safety of the containers that hold our products. A study of foreign objects found in packaged food products points to plastic contamination as being the second most common type of contaminant. For example, more filler can readily make the material more detectable, but it may also make parts too brittle or too abrasive, causing them to fail prematurely in use.

Where do these material contaminants come from? Often from wear debris, broken parts and even related equipment that is used above an exposed product stream. Metals have a distinct advantage; they can readily be detected using inline X-ray and/or metal detectors. Performance plastics can too, but not as reliably. These two technologies can work together, or they can be deployed independently based on risk. Most food processors employ metal detectors that scan finished products. However, today’s high speed fillers can package thousands of packages before a problem is detected. What if the package container is a metal like a steel or aluminum can? The detection of a plastic or metal part is now highly compromised.

Metal and X-ray detectable performance plastics provide the answer. These materials have been compounded with additives that enable normally “transparent” materials to be detected by the system processors already in place. Originally, the thought was to offer materials that were either metal detectable or materials that were X-ray detectable. Today, there are materials that are simplifying the material selection process. UHMW, acetal and PEEK are now available in three-way detectable grades, offering visual detection via their unique blue color, metal detection and X-ray detection using metallic oxides. The challenge remains to balance the detection limits of these materials while maintaining the durability and properties of performance plastics. For example, more filler can readily make the material more detectable, but it may also make parts too brittle or too abrasive causing them to fail prematurely in use.

VMX mixing paddles in a sausage processing unit

There are multiple touch points for the savvy plastics professional to engage this market segment. Larger volumes of parts and shapes are typically found at the OEMs, the companies designing and manufacturing the equipment. The more exciting opportunities exist at the processor, where one who engages with the maintenance department, production engineering staff or quality departments, has the opportunity to help solve issues in real time. Machine guarding and mechanical consumables are purchased regularly by each facility, providing opportunity to upgrade existing parts to better suited materials. A job well done almost always results in a nice purchase order, as well as a few product samples to bring home or back to the office. Certainly, ‘food for thought!’

Chris Begick is a sales engineer for Mitsubishi Chemical Group. For more information, contact Mitsubishi Chemical Group at 2120 Fairmont Avenue, Reading, PA 19612 USA; phone (610) 320-6730, https://www.mcam.com“