Kevin Gingerich
Bosch Rexroth Corp.
Buchanan, Mich.

How does a typical conveying application work in a packaging setting?

Typically, conveyors fall into two main camps: synchronous and nonsynchronous. Synchronous conveyors provide indexed movement of parts or products from station to station along a fixed path and at a fixed rate. They are usually automated and run quick cycles. Cycle rate depends on the slowest process in the system.

Nonsynchronous conveyors provide independent movement of parts or products from station to station on an as-needed basis. In other words, a flexible path routes work pieces independently and delivers them to processing stations. This type of conveyor maximizes automated machinery throughput and manual workers' productive time.

One commonality between both types of conveyors is that they rely on a conveying medium, such as (plastic) belts, (stainless-steel) chains, and rollers, which mounts to a steel or aluminum chassis. A powered drive unit then pulls the chain or belt to deliver motion. While most chassis and drives mount to legs or posts, some are suspended from the ceiling. A moving belt in a mounted frame is the simplest example of a conveyor.

The fixed path, synchronous system does not provide for cycle independence. Throughput depends on the slowest operation on the assemblly line.

What are the primary types of motion in conveying applications?

The goal of motion in conveyors is to put products in the right place at the right time for maximum output. Components that contribute to smooth motion are critical, especially under load. A powered drive, for example, can pull the belt or chain at constant speed, or, in the case of a variable frequency drive, let users change conveyor speed at any time. This is important for in-process buffering systems because conveyor speed can then match variations in machine output to "balance" the entire operation's timing.

Conveyor layouts often make creative use of space for product transport or storage. For example, while many conveyors are deployed at a single level, others elevate items, snake around obstacles, and transport products between factory floors. Motion components involved in such routing utilize pneumatic and electrical actuators, ballscrew drives, linear guides, bushing and shaft assemblies, and sophisticated controllers. In conveyor systems that make tight curves, transport products vertically, or require precise positioning, the belt or chain's flexibility and friction can influence the conveyor's success. Complex packaging systems encompass any and all of these situations.

With many synchronous conveyors in packaging, boxes, bottles, or cans sit directly on the chain. External guides mounted on the conveyor's sides control chain motion. To move up or downhill, for example, conveyor chains are outfitted with (roller) cleats or friction pads to prevent products from sliding.