Conveyor manufacturers rarely design their products with pharmaceutical and medical packaging in mind. It’s easier to go big and overdesign (more robust frames and bigger ball bearings, for example) than it is to go small. Since smaller parts tend to be less durable, reducing the size of a conveyor adds additional engineering challenges.
Then there are the products themselves: Medical and pharmaceutical products are small, lightweight, and fragile. That makes them difficult to handle, orient, and move. Clean room requirements also have to be considered, as do any space constraints.
Conveyors are a critical part of pharmaceutical manufacturing, and there are conveyor manufacturers that understand this. Accumulation, high speed bottle filling and blister packaging, labeling, and tracking—all require conveyors that work quickly, precisely, safely, and cleanly. You don’t have to settle for a conveyor that doesn’t.
Size and Speed
It is possible to find high-performing conveyors that are well-suited to lightweight products, precision applications, and the flexible layouts often found in pharmaceutical manufacturing.
If your product is less than an inch wide, you don’t need a belt that is 10 times that. A quality manufacturer should be able of offer conveyors in small widths that can still run at high speeds.
If your line includes accumulation, make sure the manufacturer you’re considering can provide a biflow conveyor scaled for smaller products. Most product accumulation conveyors are scaled for standard food and beverage size containers, meaning that smaller pill bottles or packs will tend to tip and jam more.
In pharmaceutical manufacturing, transfers from one conveyor to the next is key. Products smaller than an inch (which is most, if not all, pharma products) need a roller diameter that is less than an inch, otherwise the product will fall between the conveyors.
Typical conveyors usually have a roller diameter of 32 mm or larger. But it is possible to find conveyors with end rollers as small as 16 mm, and even smaller nose bars, that can transfer products of less than an inch in diameter.
Without smaller rollers, one way around this problem is a waterfall transfer, where the roller of one conveyor is placed over the roller of another and parts fall from one to the other. But waterfall transfers do not maintain orientation, and product can still be damaged in the fall.
Another option is side transfer, where the product is transferred off the side of one conveyor to another parallel conveyor. However, this is only possible if the bearing housings on the conveyors are inside, instead of outside, the frame, so that the belts can be positioned flush with one another.
Having a flat, true belt is important for applications such as filling and labeling. But this is especially hard to achieve with lightweight products for several reasons. Lightweight pharmaceuticals can’t force the conveyor belt flat. Plus, the belting used on small end rollers needs to be very thin, and thin belts tend to curl when placed under tension.
Typical conveyors need larger bearings and rollers to run under the high tension required to drive the belt. Some smaller conveyors employ pinch drive designs that forces the conveyor belt against the drive roller, allows it to run with almost no tension.
Lighter products also are difficult to keep in place on a belt, making precise spacing and orientation a challenge. Vacuum belting can help hold down light items like blister packs, and can be customized depending on the size and shape of your product.
Sanitation and Safety
Asking a few questions about your conveyor system requirements also can help you maintain safety and sanitation standards. Are the conveyors or belting you’re considering able to withstand wipe-downs and comply with other clean room requirements? Look for stainless steel or anodized aluminum frames, enclosed drives, and urethane belts.
What are your inspection and tracking needs? Are you required to have lockable reject bins as part of your rejection system? Does your sanitary conveyor need to be compatible with metal detectors or x-ray units? Do you need photo eyes or servo drive kits to assist in inspection, and accurate positioning for date coding and labeling?
Much more than moving product from point A to point B, conveyors can be a crucial part of your production process. More advanced setups can even integrate your conveyors with system controls and networks for real time performance and tracking information.
Size, speed, sanitation—with so many variables, there is a lot to consider. A reputable conveyor manufacturer will have already considered them. Going with an outside vendor, instead of trying to adapt more standard conveyors or building in-house, will save you a lot of frustration and stop you from having to reinvent the wheel (or roller, in this case). Any extra up-front cost will be made up by less down time, easier maintenance and standard replacement parts, not to mention the peace of mind of being backed by a manufacturer’s warranty and service experts.
About the Author
Mike Hosch is the Vice President of Industrial Business for Dorner Manufacturing Corp., based in Hartland, WI. Dorner designs, manufactures, and distributes high-quality conveyors and related equipment.