Vaidya Reveals How BKT Designs Radial OTR Tires
“Only innovation will take us to the next level," said Dilip Vaidya, president and director of technology, at BKT's celebration of its Earthmax radial OTR tire line in Crete, Greece, on June 6, 2018.
Speaking to attendees from around the globe, Vaidya shared the challenges BKT faces in the development of OTR radial tires. Here is his speech, divided by topics.
"I am always focused on innovation and new technologies that will lead the company to the next level. There are several fields we are allotting our investments in R&D: product design and development, machinery, quality, technology and innovative raw materials.
"Keeping in 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."
Product design and development
"Having had the opportunity to study several markets over the last decade, we have learned 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, (and) 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 27.00R49 size in three 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. This knowledge will be applied for designing optimized tread patterns for 51-inch and 57-inch sizes, which are expected to be released in the second quarter of 2019 and the second quarter of 2020, respectively, thanks to significant investments into new tire building machinery that is suitable for the sophisticated and complex processes of building Giants.
"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 FEA -- 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 synchronized 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.
"Another significant investment was allotted to the purchase of a state-of the-art steel cord cutter. Especially in the case of heavy loads acting on the tire, a particularly critical stage in the manufacturing process is cutting the steel cords. 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. The technical improvement lies mainly in the high-precision shear cut and the possibility of cutting tire casings up to 63 inches 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.
"Quality has always been a core issue for BKT as proven by the many certifications obtained. In order to ensure the same or even more accurate quality standards to Giant tires, and in order to also meet the specific requirements set by original equipment manufacturers, many additional tools, systems and processes have been introduced such as a visual Kanban project management tool to increase traceability of all materials and compounds, a chartless CPU recorder for tire curing, a customized jumbo inspection hoist for OTR Giant tires, additional preventive and predictive quality checks, advanced statistical evaluation to improve critical parameters as to OEM specifications, in addition to rigorous shop-floor training on quality and safety, to name but a few."
"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.
"Even if some of these trends are still in its early days, we are researching into solutions to cope with sensor-assisted autonomous transportation, enhanced tire and equipment integration systems, data flow and analytics optimization for increased productivity, and so forth -- all this in compliance with the mega-trends in terms of sustainability, diverse mobility, electrification, and safety. 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 built, and save time from design schedules.
Innovative raw materials
"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, indeed entered into a joint research agreement with Kultevat Inc., a leading U.S. biotechnology company that is specialized in the cultivation and processing of TKS dandelion as a renewable and sustainable alternative for natural rubber, which as you all know has become a critical raw material. 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 2018, whereas Stage 2 of the project provides the supply of one metric ton of stabilized TKS rubber by October 2019. In addition to lab optimization and manufacturing process trials on all of our tire ranges, we will also focus on compounding methods for the specific OTR segment."
"Another major project we are working on is the development of high-performance compounds by means of nanomaterials or nanocomposites, materials in which at least one dimension is sized below 100 nanometer. 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 black, 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 customize 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 (India) 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 customized carbon black of non-ASTM grades that are not available on the market."
On-site OTR tire service -- Tools and Support
There is a topic that is of central concern for BKT, the importance of providing on-site OTR tire service.
"Mining is one of the most complex and most challenging businesses on Earth: Maximized productivity, cost effectiveness and efficiency are number one requirements.
"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), a great step in the direction of smart tires. The system 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 important tool 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 synchronized 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.
"BKT has always been committed to progress by means of significant investments into research, by subsequent investments into the implementation of our findings, by providing our end users with a high-quality product, by entering and conquering the OTR radial tire segment first, and by reaching the next level through the manufacturing of OTR Giant tires."
BKT is short for Balkrishna Industries Ltd., an Indian company with four tire manufacturing plants. For more information on BKT and its products, check out these links: