Dilip Vaidya, president and director of technology of BKT, illustrates the challenges in the development of OTR radial tires, its investments in the field of R&D, and speaks about innovation and new technologies:
BKT executive: “Only innovation will take us to the next level
Keeping mind that the mining sector is one of the toughest sectors on Earth. So are the requirements for equipment - and tires, of course. In these rocky, abrasive and harsh environments, tires are exposed to extreme mechanical stress and fatigue, to extremely heavy loads at the toughest handling and transport conditions. In addition, extraction is moving to always greater depths.
That is why BKT has introduced automated equipment and monitoring tools to enhance performance and productivity on the one hand, and to reduce the miner’s exposure to hazards in this hostile environment by increased safety on the other hand.
Design & development
Having had the opportunity to study several markets over the last decade, we have learnt that according to the specific country and location, particularly taking into account climate and geophysical conditions, every mine management has different expectations to the product, formulating site-specific performance criteria. To meet these requirements, new products are needed with specific product design.
Over the last decade, we have developed a variety of different OTR radial patterns and sizes for specific applications or environmental conditions such as snow, aggregates, mud and earth, rock, recycling, or underground mining. We have started from smaller sizes for loaders, added tires for rigid dumpers and finally reached the giant segment.
After the development of the 27.00 R49 size in 3 different patterns, namely Earthmax SR 45 Plus, SR 46 and SR 48, we had the opportunity to study the effects of tread design features on tire performance taking into consideration heat development, heat dissipation, and wear characteristics.
The major challenge in giant tire development compared to previous production is the high speed with extraordinarily heavy loads over long distances in addition to extreme lateral forces provoking mechanical stress on belt edges.
Coping with these challenges we have reached a stage of advanced engineering, in which the analysis of the entire tire structure and all features is essential.
For this purpose, tire simulation by means of Abaqus finite element analysis is applied to work on all tire components including inner liner, belt, tread and beads, sidewall, carcass and bead fillers plus reinforcements.
After having shifted the OTR all steel radial production from our pilot plant in Chopanki to our state-of-the-art production plant in Bhuj enabling large-scale manufacturing, we have invested into first-class machinery and equipment from premium suppliers all over the world.
For the purpose of improving compound uniformity, seven latest-generation 440 lt-HF Mixers were purchased, providing automated temperature control and enhanced rotation by means of synchronised technology. As a result, the entire compound mixing process is enhanced by optimal specific energy supply leading to ideal silanization.
Another essential purchase from a worldwide leading supplier in this field was a 4-roll calender for steel cord processing, which enables us to calender higher-diameter cords for Giant tires and which provides the possibility to control top and bottom calendering thickness for best adhesion and improved final quality.
If this step is not done with utmost precision and quality, this might result in “flying cords” and increase the risk of separation in the carcass’ turn-up points.
Technical improvement lies mainly in the high-precision shear cut and the possibility of cutting tire casings up to 63” with a cord diameter of up to 5 mm.
The new piece of equipment provides an automatic steel cord splice joint control in addition to an automatic belt-edge strip-cover system to avoid any air entrapment.
The advantages provided by this machine are reflected on the entire all steel radial production - in other words, the technological improvement for giants leads to a further improvement of the existing tire lineup.
To complete and enhance the complex tire manufacturing process, a new tire building machine with three carcass drums was purchased. We could say that for building a giant tire, a giant process is needed.
We have actually implemented a specific green tire building process for giant tires to guarantee utmost material cohesion during the several deposition and turning up stages.
The movement of packages is performed in such a way that perfect alignment is ensured by means of a transfer ring. Among other features, the machine also provides a specific lamination process for tread and cushion preparation resulting in high-precision tread profiles and improved uniformity.
In order to ensure the [most] accurate quality standards to giant tires, and in order to also meet the specific requirements set by OEMs, many additional tools, systems and processes have been introduced.
These include: a visual Kanban project management tool to increase traceability of all materials and compounds; a chartless CPU recorder for tire curing; a customised jumbo inspection hoist for OTR Giant tires, additional preventive and predictive quality checks, advanced statistical evaluation.
On our path to the next level, of course, we cannot ignore current trends in the tire industry that is facing unprecedented changes in technology at a global level. Next-generation tire technology is on the advance in line with forthcoming changes in the vehicle-equipment development resulting in new concepts in the fleet and site management.
Through tire simulation, for instance, we gain a full and in-depth knowledge and control of a series of parameters such as inflated dimensions, the static footprint under different load conditions, load deflection behavior in the contact area, contact pressure distribution, rolling circumference data, the impact of the steel belt width on tire performance.
This kind of tire simulation leads to the creation of a virtual prototype enabling a more rapid product development. We can hence significantly reduce the number of physical prototypes to be build, and save time from design schedules.
One of the megatrends, and a major issue concerning all of us, is sustainability. While improving our products and enhancing technologies, it is our responsibility and also a great opportunity and challenge to make our contribution to a more sustainable future for everyone living on this planet.
BKT is at the forefront for sustainable tire manufacturing. We have entered into a joint research agreement with Kultevat Inc., a US biotechnology company that is specialised in the cultivation and processing of TKS dandelion as a renewable and sustainable alternative for natural rubber.
Following the agreement, after a series of studies and experimentation, we will develop new compounding methods to be integrated in the tire manufacturing process, and TKS Rubber will gradually replace the use of natural rubber.
The agreement involves a first project stage with several sample deliveries for lab research by October, whereas stage 2 of the project provides the supply of one metric ton of stabilised TKS Rubber by October 2019.
In addition to Lab optimisation and manufacturing process trials on all of our tire ranges, we will also focus on compounding methods for the specific OTR segment.
Blending a nanomaterial with other materials you obtain a nanocomposite showing significantly different properties than the main material alone, leading to enhanced performance such as thermal or mechanical stability.
Just to mention some more examples, we have done quite a lot of research and experiments into graphene, a really exciting material. It is considered as the thinnest, the strongest, and the most conductive material in the world in terms of both electricity and heat.
In the tire manufacturing process, graphene provides increased wear and puncture resistance, higher tensile strength as well as improved rolling resistance, and extraordinary durability. We are currently conducting studies and experiments on several other nanomaterials, such as nanoclay and nanocallulose.
Talking about new technologies, I would like to mention as well a different material, carbon nlack, one of the most common reinforcing fillers in rubber compounding, used in various formulations with different rubber types to enhance the mechanical properties of the polymer.
Being available in different grades and particle sizes, Carbon black is able to customise the performance properties of tires. Especially, with the focus on giant tires, large quantities of carbon black and a variety of specialty formulations to satisfy specific performance criteria are required.
To cater for this need, and for major flexibility in dosing, without depending on external suppliers, BKT has recently set up its own carbon black manufacturing plant stretching over approximately 8 hectares within the Bhuj production site.
This plant enables us to better ensure raw material qualities, and a greater variety of high-quality carbon black to be used for specific formulations during the compounding stage.
As a carbon black manufacturer, we are also able to produce customised carbon black of non-ASTM grades that are not available on the market.
On-site OTR tire service
To achieve this, man and equipment operate in day and night shifts all around the clock in heavy-duty service, no matter how harsh environmental conditions are. Every minute of downtime for a single piece of equipment - be it a haul truck or dumper or any other mining vehicle – is considered a loss for the mining management.
The major cost factors in mining operations are investment in machinery and tires, fuel, spare parts, manpower; about 30% of operating costs in large mines are the investment in tires. No mine manager on earth would ever accept a complete set of giant tires for free - not even if we add a full set of replacement tires ¬- without the guarantee that proper OTR tire maintenance and service will be provided.
For the purpose of a proper on-site OTR tire service, BKT suggests the use of some practical service tools.
The first tool is a tire pressure monitoring system (TMPS), which measures the tire chamber pressure and temperature as well as cold adjusted pressure, displaying these data in the operator’s cabin in real time. By means of GPS, exact location information and time is added. If actual tire pressure and temperature parameters exceed the set limits, an alert is triggered.
The second is Spotech, an innovative tool developed by BKT in-house to provide information about a dumper’s exact position as tracked by satellite.
The system incorporates an “accelerometer” in the data logger, which is placed on a level part of the dump truck recording latitudinal, longitudinal and vertical motion and forces involved in addition to speed, cycle times, and other parameters.
A GoPro camera is mounted to capture videos from the operator’s perspective and synchronised with the data for a complete picture of the operation. As output, the fleet manager receives a presentation including the analysis of all recorded data including recommendations.
Here, the OTR tire service provider comes into play, since he or she should be able to assist the mine management with right interpretation and suggestions, but above all to carry out possible corrective actions on tires.