New designs and innovative conveyor technologies such as electroadhesion are giving design engineers new options to solve material handling challenges.
By Stacy Johnson | Dorner Mfg. Corp.
Walk through any modern-day assembly and packaging facility and the conveyor systems may well resemble roller coasters at an amusement park – going up steep inclines, down drops, twisting and turning around equipment and machinery as they move product along its track.
Conveyors have evolved to become critical, integral components of material handling systems both large and small. Many of these systems are using elevation and motion control to maximize a facility’s available space, especially where space has become a premium in many manufacturing facilities.
More complex processing requires conveyor systems to work in sync with other conveyors and functions within the larger application. Conveyors need to be robust to withstand 24/7 operation, yet agile and flexible enough to be quickly re-configured to meet the challenging needs of modern manufacturing and assembly practices, such as switching between sizes, shapes, speeds, etc.
These six types of conveyors give designers options for a wide range of applications in material handling.
Perhaps the most well known method for elevating product is the Z-Frame conveyor. As implied by its name, Z-Frame conveyors are designed with either one or two pivot points, resembling the angled points in the letter Z, to move product up or down along the conveyor.
Z-Frame conveyors are ideal for navigating obstacles within the product flow of production. Often, the lack of space prohibits conveyors from going around an obstruction. Z-Frame conveyors can be pivoted at steep angles to move product up and over (or conversely down and under) an obstacle. Various types of friction insert chains or belt cleats keep product in place during incline or decline movement.
There are some applications, such as moving delicate flexible pouches, where cleated conveyors don’t work very well for incline movement. That’s because if a pouch lands incorrectly on a cleat, the bag could rip, spilling product and leading to costly downtime to clean the conveyor. The best solution for these types of applications is a belt-over-belt conveyor. This design involves two flexible polyurethane belts that are positioned on top of each other. As flexible pouches are moved into position, they are gripped between the twin conveyor belts, which create a pocket to securely convey the product up or down.
90° Vertical Conveyors
Some applications are more challenging than others. Moving bulk products in straight-up 90° applications is one of them. The previous solution was a traditional bucket conveyor, but these had inherent design flaws with the durability and replacement of the belt. A better answer are 90° vertical conveyors. These types of conveyors move product in a straight-up, 90° angle to go up and over an obstacle or to re-connect with another system.
A key advantage they have over bucket conveyors is that their streamlined design allows for greater pocket capacity to lift more products. Also, 90° vertical conveyors have self-releasing side walls for better product release, and a damaged section of the belt can be replaced without removing the entire belt.
Flexible Chain Conveyors
Flexible chain conveyors are suitable for navigating obstacles as they can snake around machinery and other impediments by making tight turns and steep circular inclines. These types of conveyors allow for incline or decline movement through corners and straights, and provide capability for vertical incline with minimal space. They are capable of twisting 360° turns to move product vertically within an extremely small footprint, all while maintaining speeds and loads through the angled curve. Flexible chain conveyors are also ideal for accumulating, buffering and cooling product between processes or machines.
Products sometime need to be aggregated or herded together on a conveyor line. Other times, applications require that products be spaced out along the conveyor belt. Pacing conveyors can accomplish both tasks by using more than one belt on the same line. These types of conveyors take unevenly spaced product and create even spaces or alternating batches of product, depending on the application, to meet the application’s spacing needs.
The system is set up to track both the leading edge and trailing edge of the product, so product does not necessarily need to be the same size or shape in order to be gapped appropriately. As randomly spaced products enter the conveyor, a photo eye detects the product spacing. In response, the servomotor control automatically varies the conveyor speed and conveyor junction placement in order to generate evenly spaced product. An operator controls product spacing, speed, and orientation, preparing products for machine-vision inspections, prepping them for packaging, or getting the entire multi-conveyor layout to merge several lines without stopping products from moving or using gates.
Electroadhesion Technology Conveyors
A relatively new design on the market, conveyors with electroadhesion technology hold boxes and packages securely to the belt for movement on steep inclines or declines, and at fast speeds. The technology acts like a magnet, and is activated by a switch to create a strong holding force between the box or package and the belt. Using a conveyor with a plastic bedplate, a high voltage/low amp controller powers two electrically conductive strips along the conveyor to energize the belt. Electrically conductive patterns meshed into the fabric of the belt create the force to hold products in place during movement.
How to select a conveyor
Conveyors play a key role in packaging and material handling applications. They’ve evolved over the years to become more sophisticated and flexible to accommodate many different types of applications.
Conveyors handle many different types of products including metals, food, cosmetics, medical supplies, plastics, and boxes. This is why they come in all shapes and sizes, from belt widths of less than two inches (for moving extremely small parts) to several feet wide for transferring bulky packages. Once viewed as an afterthought, conveyors have become an integral component in many automated facilities and applications.
To select the right conveyor for your application, consider these design factors:
- Product to move: What types of product is the application moving? What is the maximum weight of the product being moved? Conveyors for material handling of bulk product are more rugged than those for moving discrete product. On the other hand, the latter often requires conveyors that can advance product with more precision.
- Layout/ design type: How does surrounding equipment interact with the product riding on the conveyor? This will make a difference in the kind of conveyor selected. Also, does the application require the conveyor system to have inclines, declines or curves? If so, you may need to look for conveyor features that secure or enclose material or product onto the conveyor.
- Motion design issues: Does the conveyor need to operate at a certain speed? Are there starts/stops involved or is it continuous motion?
- Environmental issues: Will moisture be present in the application? Does the application need to be sanitary? You may need to consider rugged or washdown-ready conveyors with open frames.
Dorner Mfg. Corp.
Related: How to determine the cost of making your own conveyor
In a recent post, Dorner published the below infographic on how to decide between building or buying a new conveyor system. Click the image to check out Dorner’s post on the topic.