What are the major conveyor types?
The major types of industrial conveyor systems are:
- Belt conveyor
- Gravity roller conveyor
- Chain conveyor
- Live Roller conveyor / CDLR
- Motorized roller conveyor / 24V MDR
- Slat conveyors
- Beam trolley systems
- Overhead conveyor
- Power and Free conveyors
- Over Under conveyors
- Inverted conveyors
- Lineshaft conveyors
- Chute conveyor
Conveyor types, categories and uses
Industrial conveyor systems have many different designs and uses. Common conveyor types are belt conveyors, roller conveyors, motorized roller conveyors and overhead conveyors. We categorize them as floor conveyors (mounted on the floor) or overhead conveyors. Use them to move products, create buffers and deliver products in sequence in a production process.
Why do people use conveyors?
Manufacturing engineers include conveyor systems in their production facilities for many reasons:
- Moving products from point A to B (to avoid wasted time walking, or to reduce movements of forklifts, etc)
- To carry products that are too heavy to for team members to lift
- To move a product while operators are working on it (or adding to it). Like a final assembly conveyor at an auto plant
- To deliver products to a robot for processing. Or to receive products from a robot that are ready for the next step
- To store products between processes or at the final process step
- To create a buffer or accumulation bank. This is a flexible storage system. Use it where the quantity of products in storage can be lower or higher as required to balance process flow
- To avoid injury to workers from repetitive movement. Or to prevent damage to products caused by movement
- To sequence or re-sequence products between processes. Conveyor types like power and free conveyors can provide this
Conveyors are one of the most flexible types of industrial equipment. When correctly specified and installed they can dramatically improve productivity, efficiency and safety. Ultimation has solutions as affordable as a $50 roller conveyor, or as sophisticated as a $5M or more fully automated conveyor system. Conveyors are used to transport bulk material too, like gravel or iron ore.
How to choose the right type of conveyor system
- We begin with the basic product information. It’s helpful for us to understand the productive role that your conveyor performs. Is it moving parts, storing them, re-sequencing them or providing a working surface while they move? Based on these factors we can then select from the various conveyor types available. Then see which ones can do the job and provide the best benefits.
- Next comes the constraints. Available space in production environments can be at a real premium. And although conveyors can add a lot of productivity, they can also get in the way of other operations. Carefully check the space they occupy. This gives us the input for our next decision point which is whether the conveyor operates at floor level or overhead.
- Conveyors are categorized as floor conveyors or overhead conveyors as this is an important decision point. Overhead conveyors can take many different forms (see this graphic here on the different types). But they all share the benefit that the conveyor itself is mounted above the part it is moving. Therefore they use production space that is not occupied with other equipment. This can enable the overhead plant space to become productive, like using it for a buffer or storage bank. If more space is available, floor style conveyors may be more suitable. These include belt conveyors, gravity roller conveyors, skatewheel conveyors and slat conveyors.
- Consider how the loading and unloading of the conveyor is to be done. Some processes require precise positioning of the part (like for robot loading or unloading). Conveyors equipped with tooling, pallets or carriers can accommodate this. A simple belt or roller conveyor by itself cannot maintain the part in a precise location.
- The speed required and investment available can drive the choices. Simpler, faster and more affordable conveyor systems are great. Other solutions need more sophisticated automated conveyor lines.
The material below has a short summary of each one of the more common conveyor types that are available.
Sometime our customer call these “Conveyor belts”. This is actually the belting material. A belt conveyor is one of the simplest conveyor types. It moves parts from one end to the other. Speed can be variable with a variable speed drive. Belt conveyors can’t be used as a working surface, they can’t be used to present parts to a robot, and they can’t buffer or sequence parts. But their simplicity makes them one of the most common conveyor types available.
They belong to the floor conveyor group. Belt conveyors typically move the belt across a supporting steel plate so that as the belt moves it is supported from below. This style is called a slider bed style. Alternatively, the belt can be supported on top of closely spaced rollers. This style is called a roller belt style or roller conveyor belt. Learn more about them here. Ready to buy? Here’s the range available for online purchase.
Gravity Roller Conveyor
Also one of the simplest types, they are very affordable. A series of rollers mounted on a side frame provides the rolling surface. When mounted on a decline angle, parts move by themselves. However if using gravity conveyors for parts of different size and weight it can be difficult to control the speed and angle. Parts running into each other may cause damage. But compared with carrying parts from point A to point B, a gravity conveyor is often a great starting point for productivity improvement. Learn more about them here. Ready to buy? Here’s the range available for online purchase.
Floor mounted chain conveyors are great for heavy items and especially for items that have an uneven lower surface. The chains provide two or three contact points on the bottom of the load, and as the chain moves it carries the product forward. They’re used to carry pallets and large industrial containers. If necessary, products can be mounted on a fixture, or “skid” and the fixture can be carried along the chains. This is a common application in auto plants. They are heavy duty, and generally move at slow speeds. Learn more about them here. Ready to buy? Here’s the range available for online purchase.
Live Roller Conveyor / Chain Driven Live Roller Conveyor (CDLR)
If we combine the rollers from a gravity conveyor with the chains of a chain conveyor, we can link the rollers. Add a motor and gearbox and now we have a live roller conveyor or chain driven live roller conveyor. Sometimes people in the industry use the acronym CDLR. They are members of the floor conveyor family, and they are heavy duty conveyors. Use them to transport pallets, seats (on skids or pallets), tires, containers and a multitude of products. If fitted with loose plastic sleeves over the rollers as shown in the photo below, they can accumulate or buffer product. The rollers can keep moving even though the product on top is not moving. Chains are linked together from one roller to the next on the side. Learn more about them here.
Motorized roller conveyors – 24V MDR Conveyors
What if we put the motor inside the conveyor roller? These modern conveyors are at the heart of today’s sophisticated distribution centers. With high speeds of 200 feet per minute or more, your Amazon and mail packages delivered to your home passed along miles of these type of conveyors. They use one or more motor driven roller per zone to create a series of zones along the conveyor.
The motorized roller is connected to the other rollers in the same zone by plastic or reinforced belts. Photo eyes turn the motors on and off, and parts move to the next zone when space is available. This way the parts never touch, avoiding damage. This is named “zero pressure accumulation” and it’s a very valuable benefit. An added bonus? You can convert a gravity conveyor to a motorized roller conveyor. Learn more the motors and how MDR conveyors work here. Ready to buy? We have a range of MDR conveyors, motors and power supplies available for online purchase.
A slat conveyor is basically a two-strand chain conveyor with slats connected to the chain and a guiding system for the slats. This creates a smooth surface to which tooling details or fixtures can be mounted to hold parts in the desired position. Sometimes the fixtures can also allow the part to rotate 90 degrees or 180 degrees as required in several planes. Therefore you can use slat conveyors as a working surface for assembly operations. Positioning of the part is also quite precise, so it’s common for robots to perform the loading or unloading operation at one or more ends of a slat conveyor. Learn more about them here.
Overhead hand push beam trolley systems
Moving on to the overhead family of conveyor types, the simplest systems are hand pushed beam trolley systems. Using either an enclosed track or I-beam section as a track, these conveyor types are extremely versatile, easy to set up and affordable. They can be mounted above the workplace with roof-supported or floor supported steel structures. For more information on the nine different types of overhead conveyors, see this graphic. You can purchase trolleys for these systems for under $50 each and the tracks are also very affordable. Learn more about them here or buy them online here. Beam trolley systems are especially popular for painting and finishing operations, as the mechanism remains above the part and is not covered.
Motorized overhead conveyor systems / Monorails
One of the most common conveyor types is an overhead conveyor with the trolleys connected together with a chain. The chain can either be enclosed (“enclosed track”) or open below an I-beam. These style of conveyors are installed in nearly every high volume production facility. The chain is driven by a motor with a gearbox, and the parts to be moved are suspended from trolleys attached to the chain. Many different attachment types are used, and for complex parts a fixture or carrier is suspended from several trolleys to locate the part in position. The chain can be constantly moving, or alternatively the system can index parts from one assembly station to the next at a predetermined interval. Learn more about them here.
Power and Free Conveyors
Also in the overhead conveyor family is the power and free conveyor. It’s like a regular motorized overhead conveyor, except it has two tracks. In one track, the chain is continuously running. In the other track, the trolleys are moved along by the chain with pusher mechanisms (known as “pusher dogs”) mounted at regular intervals. When two trolleys are pressing against each other, the dogs can slide over the top. Likewise, a stop blade can be used with a pneumatic cylinder to replicate this geometry. This allow trolleys to start or stop movement virtually anywhere in the system. This versatility makes power and free conveyors perhaps the most productive style of overhead conveyor. They can start, stop, buffer and re-sequence parts with switches. Learn more about them here.
Over Under Conveyors
As the name implies, they go over, and they go under. Available in hand push, motorized and power and free versions.
Inverted monorails and inverted power and free
Just like their overhead configurations, except the track is on the ground and the load is above the track. Useful in paint finishing applications to avoid dust or oil dripping onto parts. Widely used in automotive final assembly operations.
Electrical Controls Systems for Conveyors
Just as there is a diverse range of conveyors that can potentially be used for any application, so are the electrical control systems that are used with them. The simplest systems require no electrical control at all. These conveyor types would include gravity roller conveyors and hand push overhead style beam trolley or enclosed track systems. Motorized conveyor systems can utilize simple start-stop switches for simple applications. However it’s more typical to have a control system that is able to utilize input from sensors such as photo eyes, limit switches or proximity sensors. These sensors can tell a processor when to stop, start or perform another function.
Programmable logic controllers (PLCs) are used with larger systems and can control conveyors and also any other process equipment. These systems are often also fitted with a variable frequency drive (VFD) to adjust the speed of AC motors. And finally, the DC electric motors in 24V systems are sold with their own specialized motor controllers which enable inputs from sensors, processing of outputs and network connectivity via ethernet.
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