BONDING PULLEY LAGGING TO PULLEYS
Trends, and Where ABEAR Industrial Sees the Future of Pulley Lagging Bonding Technology
This article is intended to be a very brief overview of Pulley Lagging Bonding Technology, Pulley Lagging Technology and where ABEAR Industrial has positioned itself based on trends and ongoing developments.
1. Overview of the Pulley Lagging Manufacturing Methods and Bonding Methods
1.1 Traditional Steam Cured Pulley Lagging
This method involves wrapping uncured rubber sheeting around a Pulley, then curing and simultaneously bonding the rubber to the Pulley in a Steam Autoclave. If a pattern is required in the rubber, such as a diamond profile, it is then cut by hand using a Tread Cutter.
1.1.1 Advantages:
- The process is simple and very well-established as this was the first way in which Pulley Lagging was manufactured.
- The bond to the steel surface is relatively strong and with confidence a manufacturer is able to guarantee the bond.
1.1.2 Disadvantages:
- The pressures achieved by an Autoclave are low, so the rubber is porous and the mechanical properties are compromised.
- The tread patterns are very simple and offer only minimal advantages in terms of maintaining grip.
- Limited to rubber-only type Pulley Lagging.
- Inefficient in terms of energy as the entire Pulley is placed in the Autoclave.
- This is a very slow process, expect a 4 to 5 day turnaround once the Pulley is at the Pulley Lagging manufacturer even if there is no backlog.
- This is an extremely costly method of maintaining or replacing Pulley Lagging. This is because the pulley must be removed from the structure and transported to the nearest Pulley Lagging plant – given that mines are typically in remote areas, the cost of transport, crane hire, labour hire, recommissioning and most of all downtime is astronomical.
- Pulley Laggers that promote this method usually recommend that the mine carries spare pulleys. Again, this is expensive and unfortunately breakdowns are unpredictable – so often there is either no spare available, or the spare has been standing so long that the Pulley Lagging on the spare pulley has degraded and will need replacing first (or the lagging will only last a few shifts so there will be two rounds of downtime in short succession, each with cranes, transport costs etc.).
1.2 Pre-cured Steam Bonded Pulley Lagging
This method differs from Traditional Steam Cured Pulley Lagging in that sheets of Pulley Lagging are first manufactured by compression moulding before applying them to the pulley and placing the pulley in a steam autoclave. The sheets of Pulley Lagging have an uncured sheet of rubber placed underneath them, this uncured sheet is what bonds to the pulley face and the compression moulded Pulley Lagging.
1.2.1 Advantages:
- The bonding process is the same as Traditional Steam Cured Pulley Lagging.
- Slightly more complex designs are possible than what Traditional Steam Cured Pulley Lagging can offer.
- Simple Designs of Rubber Backed Ceramic Pulley Lagging can be applied using this method.
1.2.2 Disadvantages:
- The surface of the Pulley Lagging that interfaces with the conveyor belt is double cured – first through compression moulding and then through the autoclave. This degrades the rubber.
- Although slightly more complex designs are possible, these are still severely limited. This can be noted in the regular large horizontal grooves and very small or narrow diamond pattern grooves (if there are any). These designs can introduce vibration into the conveyor belt system.
- Inefficient in terms of energy as the entire Pulley is placed in the Autoclave.
- This is a very slow process, expect a 4 to 5 day turnaround once the Pulley is at the Pulley Lagging manufacturer even if there is no backlog.
- This is an extremely costly method of maintaining or replacing Pulley Lagging. This is because the pulley must be removed from the structure and transported to the nearest Pulley Lagging plant – given that mines are typically in remote areas, the cost of transport, crane hire, labour hire, recommissioning and most of all downtime is astronomical.
- Pulley Laggers that promote this method usually recommend that the mine carries spare pulleys. Again, this is expensive and unfortunately breakdowns are unpredictable – so often there is either no spare available, or the spare has been standing so long that the Pulley Lagging on the spare pulley has degraded and will need replacing first (or the lagging will only last a few shifts so there will be two rounds of downtime in short succession, each with cranes, transport costs etc.).
1.3 Cold-Bonded Compression Moulded Pulley Lagging
This method involves compression moulding sheets of Pulley Lagging and then applying the Pulley Lagging to the pulley using a chloroprene-based adhesive. Cold-Bonding Technology is seeing the most development work as it offers so many advantages.
1.3.1 Advantages:
- Pulley Lagging can be replaced in-situ in the conveyor belt structure. This results in minimal downtime and associated costs.
- Pulley Lagging can achieve the best possible mechanical properties due to manufacturing method. This Pulley Lagging will typically last the longer in service than either of the Steam Autoclave methods.
- Provided the Pulley Lagging is manufactured with a Semi-Cured Chloroprene-Bonding Layer, the steel to rubber bond achieved is equivalent or higher than steam cured/bonded pulley lagging.
- Complex tread patterns can be manufactured, allowing for Pulley Lagging products to be manufactured that meet different requirements.
- Complex, versatile designs of Rubber Backed Ceramic Pulley Lagging can be manufactured and applied using this method.
- Applicators of Pulley Lagging require only basic power tools and equipment.
1.3.2 Disadvantages:
- Care must be taken when applying the Pulley Lagging as the in-situ environment can be challenging with regards to keeping the bonding surfaces clean.
2. Market and Development Trends
Cold-Bonded Compression Moulded Pulley Lagging offers many advantages over both of the Steam Autoclave processes. These advantages are not only in the overall design, performance and usability of the products, but in particular the cost of maintenance and the reduction in downtime. As such there are trends to further improve the speed of application and bond strengths of Cold-Bonded Pulley Lagging.
Cold Bonding Rubber Technology is under continued development. Well-known adhesive and chemical companies are always in the process of developing and releasing products that are aimed at this market.
3. Where ABEAR Industrial sees the Future Heading
There is no doubt that Cold-Bonded Pulley Lagging is the future of Pulley Lagging. In addition to exploring new bonding products entering the market, ABEAR Industrial has been assisting in the development of a new Cold-Bonding Adhesive, to be named ABEAR GRIP.
ABEAR GRIP is aimed at reducing downtimes further as well as increasing the strength of the bond. After application of the Pulley Lagging (with our CN Bonding Layer) using this adhesive, a conveyor belt system can be started up after just 30 minutes of waiting – this is much, much faster than any other product or method currently on the market.
Below is the results of a 90’ Peel Test, of ABEAR GRIP and our pulley lagging. A bond strength of 38N/mm was achieved; this is far in excess of any other adhesive or method on the market.
90' Peel Test of a 25mm Wide Strip
We have one final stage of testing left, after which we are to begin marketing the adhesive.
Steam Cured or Steam Bonded Pulley Lagging is not the future of Pulley Lagging. Those methods were steps towards where Pulley Lagging Technology is now – ABEAR Industrial views investing in Steam Cured/Bonded Pulley Lagging as a technological and strategic step backwards.
Currently ABEAR Industrial offers the service of installing Pulley Lagging to Pulley OEMs. We have lagged several thousand pulleys in our factory using our current cold-bonding technology. Some of the most well-known global OEM brands use us.
Beyond our services to OEMs, our primary business is selling sheets or rolls of Pulley Lagging to conveyor maintenance service companies. We are the largest manufacturer of Rubber Backed Ceramic Pulley Lagging in Africa, and we believe we lead the global market in terms of the design and bond strengths of these particular product lines.