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Conveyor Belts Explained

Posted: 20 January 2016

HOW ARE CONVEYOR BELTS MADE?

Ordinarily conveyor belts are made from a pre-punched, mild steel folded framework and supports with a powder coat paint finish for general use such as warehouses or stainless-steel pre-punched folded framework and supports for “clean” factory areas such as pharma, food, drink etc.

Both ends of the belt conveyor frame are fitted with a terminal roller to reduce friction when the belt returns on the underside.

The conveyor belt is then cut to length and assembled into the top frame and runs on either a smooth steel bed or conveyor rollers for heavier weights. The two ends of the belt are then joined together to make it endless

As belts stretch over time, a tensioning device must be fitted to all conveyor belts to avoid the belt slipping. 

To pull the belt along, one of the end rollers can either have an integral drive motor/gearbox or a separate drive which can either be positioned at one end of the conveyor belt or part way along its length if the conveyor belt is to be reversible.  

 

DESIGNING YOUR CONVEYOR BELT

There is a very large number of conveyor belt designs which vary according to the product being handled and if it will travel along the conveyor belt as it must have a mainly flat base to avoid moving around.

If the conveyor belt is required to handle products for human consumption such as pharma, food, drink etc they need to be designed for easy clean down and without dirt traps.

Other factors such as product weight, maximum and minimum dimensions and fragility will determine the conveyor belt size and belt type as it must be capable of handling all possible products.

The maximum weight of the products on the conveyor belt at any one time will ascertain the size of motor/gearbox will be required to pull the belt along as will the speed at which they are to be handled.

If the products on the conveyor belt need to be automatically sorted to decide their destination, such as by barcode, they will need to be gapped using multiple conveyor belts and in the correct alignment for the Barcode reader to be successful.

Not all belt conveyors are horizontal as depending on what process the conveyor belt is designed for it may be necessary for the conveyor belt to be on an angle to convey products up to a higher level either to be overhead or feed an upper mezzanine floor.

 

CALCULATING CONVEYOR BELT LENGTH

Once the length of the conveyor belt frame has been established to move products from “A” to “B” around a factory/warehouse, the length of the belting which carries and transports the products must be calculated.

Once the belting has been laid out on top of the conveyor frame which has a length of “X”, and to make it a complete endless loop, it must be returned on the underside of the frame making the length twice as long (2”X”).

As all types of belting stretch over a period of time, which would allow the belt to slip, particularly once any weight is placed upon it, it is essential to fit a conveyor belt tensioning unit to the frame end drum roller which the belt wraps around. The unit is fitted with long bolts to allow the end roller to be adjusted to increase the effective length of the conveyor belt which takes up any slack.

To get a final design length, the amount of stretch which has to be added to the 2”X” above depends on a number of factors such as conveyor length, width, weight to be carried and number of stop/starts per hour which is a percentage of the overall belt conveyor length.

 

CALCULATING CONVEYOR BELT CAPACITY

The type of item(s) to be moved will determine the design, dimensions and type of conveyor system to be installed.

For example, far more small lightweight padded envelopes or polybags could be conveyed on a belt conveyor system than heavy parcels, fully loaded plastic tote bins or similar.

Design criteria such as type of product and the maximum weight of products on the conveyor belt at peak times are fundamental requirements to help determine the capacity of the conveyor belt.

The maximum dimensions of the product will determine the width of the conveyor belt. The wider the conveyor belt the less weight it can carry over the same distance.

If products are being placed on the conveyor belt whilst it is running continuously it can carry greater volumes than one which has to complete a number of stop/starts per minute i.e., starting to run fully loaded.

 

CALCULATING CONVEYOR BELT HORSEPOWER

The horsepower requirement to drive a conveyor belt depends on a number of factors such as conveyor length, width, weight to be carried etc

If the horsepower selected is too small for the weight on the conveyor belt, it could overload the 3-phase motor on the conveyor belt and cause it to stop running. Conversely if the conveyor belt has a 3-phase motor too large for the requirement it will be a waste of energy usage.

The number of conveyor belt stop/starts per hour will affect the horsepower calculations as the slower the speed, the higher the torque which means the motor/gearbox has to work harder so the design calculation will show more power is required.

If the motor/gearbox on the conveyor belt is designed to run at a variable speed to suit a manufacturing process or to run at high speeds, the horsepower calculation will need to reflect this.

 

Belt conveyors  can also be driven by 24-volt driven rollers which have an integral motor encased within the roller, but horsepower is calculated in the same way.

 

CONVEYOR BELT FABRICATION

The Conveyor belt fabrication process is important to the capabilities, durability, and performance of the entire system.

Different conveyor belt manufacturers use numerous processes to fabricate conveyor belts that suit particular applications. Thermoplastic manufacturers use injection moulding or extrusion to create modular conveyor belt components and then assemble them to make a complete conveyor belt with its own pre-manufactured drive system.

The most common materials used on conveyor belts include fabric such as nylon, polyester, rubber, steel (mild and stainless), and thermoplastics with the material and its strength largely determining the applications for the conveyor system.

General conveyor belt handling applications such as in eCommerce, manufacturing facilities, and distribution centres may use a polyester or other fabric belt for flexibility and ease-of-use whereas Industries such as food, drink and pharma handling operations must use food-grade material conveyor belts such as thermoplastics and stainless steel.

Many thermoplastic, rubber, and fabric conveyor belts have both an inner core layer for strength and cover the top and bottom surfaces in a fabric, plastic, or rubber surface to suit the products being handled.

Food packing and processing businesses commonly use inclined food quality conveyor belts with integral cleats, flights or trough shaping to easily transfer bulk fruit and vegetables into high level weighers/packing/bagging machines.

The pharma industry often relies on thermoplastic and stainless-steel conveyor belt systems to comply with sterility requirements in lab and production settings.

Conveyor belts for Chemical manufacturers and processing plants must choose a material that can withstand corrosives, high temperatures, and other hazardous conditions resulting in the use of thermoplastics, rubber materials or steel-based conveyor belts with special coatings.

Some steel conveyor belts feature small perforations for a vacuum hold on lightweight and delicate items. Woven, hinged, and custom belts can process small electronics components, foods, and production line parts of all kinds.

Stainless steel and aluminium conveyor belts can also be designed with a variety of special coatings such as Teflon or neoprene depending upon whether more or less friction is required.

 

CONVEYOR BELT INSTALLATION

There are several factors to consider well before a conveyor belt system is installed in any building such as an eCommerce fulfilment centre, warehouse, distribution centre, manufacturing facility or assembly plant.

In the event that the new conveyor belt system is to be installed in a fully operational facility, it is imperative to ensure the least disruption to the on-going business along with agreeing procedures for meeting current Health and Safety guidelines so a full site survey by Project Engineers must be carried out well in advance to check provisions for delivery, access, ingress, power supply position and confirm pre-agreed timescales with the customer.

When the conveyor belt system is be installed in a brand-new building, additional considerations    have to be given to the presence of other contractors, lack of lighting/power supply, amenities, additional H.S.E. considerations etc

On larger conveyor belt installations, delivery and installation of the equipment will have to be phased to avoid causing issues for both the customer and making it harder for the installation engineers to find/access the appropriate parts in the correct order.

Normally the equipment is delivered already partially assembled in set lengths on pallets and once these conveyor belt mechanical parts have started to be installed, the controls engineers begin fitting all the electrical items such as cabling, electrical devices, control panel etc

Once all mechanical and electrical work is complete, the pre-written software can be loaded into the panel-based PLC/PC (system controller) to integrate all the information and conveyor belt control processes which create a total working system to integrate and work with a wider warehouse/production automation solution.


After all the motors on the conveyor belts have power to run them, the commissioning phase starts which allows the engineers to ensure they perform the correct function they were designed for and that the products are handled without issues and to the customers satisfaction. At the same time customer personnel training is carried out on how to operate/fault find/maintain the conveyor belt system.

 

HOW MUCH DOES A CONVEYOR BELT COST?

There are several costs to consider when purchasing a conveyor belt system apart from the initial costs which includes the cost of the conveyor belt hardware, controls and installation.

The initial purchase cost of any conveyor belt system includes the cost of painted or stainless-steel framework, precision end terminal rollers, conveyor belting, drive motor/gearbox and then the labour cost to assemble the conveyor belt, all of which can vary widely due to the numerous permutations of sizes, materials, duty etc.

The conveyor belt cost will also include an amount for the bespoke control panel and software which will be sized to suit the extent of the conveyor belt system and number of drives along with all the electrical panel and components to control the operation of the conveyor belts.

Additional to the initial conveyor belt purchase price, operational costs should be considered such as electrical usage and air consumption via a compressor.

Conveyor belt maintenance budgeting must also be considered such as cost of stocking critical spare parts, breakdown replacement parts, in-house labour costs for its upkeep and the cost of a service contract with the manufacturer. 

WHAT MATERIALS WILL YOUR CONVEYOR BELT BE MADE FROM?

Conveyor belt materials and costs vary widely to reflect the operational requirements, durability, and performance of the entire system.

Materials used on conveyor belts which include fabrics such as nylon, polyester, rubber, steel (mild and stainless), and thermoplastics with the material and its strength largely determining the applications for the conveyor system.

ECommerce, manufacturing facilities, and distribution centres may use a lower cost polyester or other fabric conveyor belts for flexibility and ease-of-use whereas Industries such as food, drink and pharma handling operations must use higher cost food-grade material conveyor belts such as thermoplastics and stainless steel.

Most rubber and fabric conveyor belts have an inner layer for strength and the outer surfaces finished in a fabric, plastic, or rubber exterior to suit the products being handled.

Industries such as food, drink and pharma use food quality conveyor belts often use conveyor belt systems with special coatings to comply with sterility requirements in production settings whereas conveyor belts for chemical manufacturers and processing plants must choose a material that can withstand corrosives, high temperatures, and other hazardous conditions.

 

WHAT SIZE WILL YOUR CONVEYOR BELT BE?

The type of item(s) to be moved will determine the size of the conveyor belt system to be installed.

For example, far more small lightweight padded envelopes or polybags could be conveyed on a belt conveyor system than heavy parcels, fully loaded plastic tote bins or similar.

Design criteria such as type of product and the maximum weight of products on the conveyor belt at peak times are fundamental requirements to help determine the size of the conveyor belt.

The maximum dimensions of the products to be carried will determine the size of the conveyor belt with wider conveyor belts being restricted to carrying less weight it can carry over a distance.

A continuously running conveyor belt can affect its size by carrying greater volumes than one which has to complete a number of stop/starts per minute i.e., starting to run fully loaded.

Also, if the motor/gearbox on the conveyor belt is designed to run at a variable speed to suit a manufacturing process or to run at high speeds, the drive size will need to reflect this.

 

COSTS TO BUILD YOUR CONVEYOR BELT?

There are several costs to consider when building a conveyor belt.

All conveyor belt costs include the hardware cost of the steel framework and steel support legs to suit the required height be it bench height or overhead. These can be manufactured in-house from flat steel sheet or bought in pre-made.

All conveyor belts require precision end terminal rollers, conveyor belting, drive motor/gearbox and periphery equipment such as side guides and/or under guarding for safety if above a certain height.

If the conveyor belt is mild steel, it will need additional cost to be preserved from rusting by being de-greased and passed through a paint plant. This is not necessary for a stainless-steel conveyor belt which is more expensive but will not rust.

The cost of the conveyor belting can vary widely and can range from the cheapest and most common materials such as nylon, polyester and rubber up to stainless steel and thermoplastics depending upon the application for the conveyor system. 

A further significant cost when building a conveyor belt is the labour cost to assemble all of the various conveyor belt components to build it into a workable unit.

Besides the hardware and assembly costs, to make it run, the conveyor belt needs to include the cost of the electrical control panel, software and all the electrical components to control the operation of the conveyor belt.

 

COSTS TO INSTALL YOUR CONVEYOR BELT?

There are numerous costs to consider well before a conveyor belt system is installed in any building such as an eCommerce warehouse, distribution centre, manufacturing facility or assembly plant.

In the event that the new conveyor belt system is to be installed into an existing working facility, it is imperative to ensure the least disruption to the on-going business, so costs have to reflect additional considerations such as numerous site surveys by Project Engineers at various times along the project timeline.

These must include provisions for on-going factory operations to work around, delivery dates/times, access, ingress, power supply position and confirm pre-agreed timescales with the customer all to avoid additional costs to the conveyor system.

Also, some “Standby “time must be allowed for in the install cost due to having to wait for a production process to be completed by the customer before starting to install sections of the new conveyor belt system.

When the conveyor belt system is be installed in a brand-new building, additional cost considerations have to be considered due to the presence of other contractors working in the same area, lack of lighting/power supply, amenities, additional HSE considerations etc all of which can increase the install time/cost.

On larger conveyor belt installations, the costs of delivery and installation of the equipment will be more expensive as the equipment has to be phased to avoid causing issues for both the customer and making it harder for the installation engineers to find/access the appropriate parts in the correct order.

To keep costs to a minimum, the equipment is delivered partially assembled in set lengths on pallets.

To avoid the electrical installation engineers being held up and adding to the install cost, the installation plan must ensure they do not hit site too soon to ensure enough conveyor belt hardware has been installed for them to fix to.

The conveyor belt commissioning costs have to be considered. All the motors on the conveyor belts have to be powered up and run which allows the engineers to ensure the conveyor belts perform the correct function they were designed for and that the products are handled without issues and to the customers satisfaction to avoid additional rectification time on site which adds to the cost.

In the event that the customer requires formal personnel training on how to operate/fault find/maintain the conveyor belt system; additional cost should be allowed as this could be required on several shifts around the clock.