How to Repair a Conveyor Belt
Stopping a production line for conveyor belt repairs is never welcome but is often essential. Minor damage like cuts, tears and frayed edges can worsen if ignored. Planned repairs are far better than a sudden shut down because of belt failure.
If a damaged area exceeds 25% of the belt’s width, the best option is to fit a saddle. A section of the belt is removed, and a new section spliced in using metal fasteners or vulcanisation.
A rubber conveyor belt is formed of several layers or plies. Splicing involves connecting two ends by layering the plies to form an interlocking join. The length of the new section must be at least the same as the width of the belt and centred on the damaged area.
The three main methods for splicing conveyor belts are mechanical fixing and vulcanising using hot or cold bonding. Each method has its pros and cons. Deciding which to use could have a significant impact on production downtime and profitability.
• Hot Bonding
The process of hot vulcanising involves using a heated press to splice in a new section of rubber. A hot vulcanised joint will be stronger and longer lasting than those formed by other methods.
Belts that have had vulcanised repairs are easier to keep clean as there are no gaps or holes for bacteria to establish in. This is a key issue for businesses where hygiene is an important factor.
On the down side, vulcanisation can only be done if conditions are clean, dry and fairly warm. It must be carried out by experienced operatives and involves more downtime than other methods.
• Cold Bonding
Cold bond resins are used to resurface worn areas and repair minor damage. A vulcanised patch is attached using resin which cures via a chemical reaction. There are no specialist tools required and they can be done quickly and cheaply. Cold bonding is more prone to failure and most often used where hot bonding is not possible.
• Mechanical fasteners
Types of mechanical fastener include staples, wire hooks, solid plates and hinges. Which is best depends on the size and thickness of the conveyor belt, what the conveyor is used for and the nature of the damage.
They are easy and quick to install which helps to minimise downtime. They are ideal for a quick fix in an emergency but can also be a good long-term solution depending on the circumstances.
They can be subject to damage from corrosion or impact and can, in turn, cause damage to machinery or the goods being transported. The risk can be reduced by applying cold bonding resin to seal and protect the metallic fasteners.
There is no single ideal solution when it comes to repairing conveyor belts. Some of the issues that require consideration are:
- The amount of downtime required and associated costs
- What the conveyor belt is used for
- The local conditions
- Longevity of the repair
Taking action before wear becomes too bad will save time and money in the long run.