Unravelling Polymers

The Definitive Blog on Polymers by Poly Fluoro Ltd.

Solar Tracker Bearings - A Key Component in Renewable Energy

While the Covid 19 pandemic has caused deep pains across many industries, the world has been careful not to ignore the ever-present threat of global warming. Indeed, with the advent of the coronavirus, many nations have looked towards the renewable energy sector as a magic bullet. Not only do investments in renewable energy allow for a boost in economic activity, but the move away from fossil fuel-based power sources ensures that we continue to aim for the reduction in emissions that remain so vital to our planet’s future.

Some nations, such as Spain, have set aggressive targets for themselves, stating that by 2050 they will be 100% based on renewable energy. Others, such as the UK, have already started setting domestic records for the number of days in which coal-based power has not been required. India has also pledged to move towards solar energy, with many of the projects running well ahead of schedule. Recently, the Adani Group has been awarded the largest such contract on record, underlining the seriousness with which the government is approaching renewable energy.

At Poly Fluoro, we have delved deep into the renewables sector through our involvement in solar tracker bearings. We engaged in the first of such projects in mid-2018, when the industry was still ramping up and when new technologies were only just being understood. The learnings we have uncovered have allowed us to further invest and develop our own polymer technologies, with the aim that we are positioned to take on any project and offer the technical support and guidance needed by our clients.

Before we go into these learnings, let us first understand the purpose of the solar tracker bearing.

For all solar projects, the efficiency of the system is maximised when the installed panels are able to maximise their harvest of the sun’s radiation. Since the sun moves across the sky, the angle of the panels needs to alter as the day progresses. To facilitate this, a tracker is installed, which rotates the panels at the required rate. Since the tracker itself consumes power, it is vital to ensure that the energy expended in rotating the panels does not exceed the extra power generated by this system. It is for this reason that a smooth functioning bearing is essential. The solar tracker bearing clamps around the square tube on which the panels are fixed. The tracker rotates the square tube and the bearing’s job is to allow for this rotation with minimal friction.

Some of our key learnings are as follows:

  1. Size

    For the most part, a solar tracker bearing needs to match the size of standard square tubes. Since most projects would prefer to use off-the-shelf square tube dimensions, the bearings need to be designed accordingly.

    In India, the sizes of 75mm, 100mm, 120mm, and 150mm would be most common. Here too, the preference is for 100mm tubes, as this maximises the number of panels that can be installed on a single length of tube, but minimises on the weight of the tube itself.

    Our designs have focussed on creating a uniform bearing for the 100 square tube. In doing so, we have studied the dimensions of existing bearings to understand how much load and friction the part would be submitted to.

  2. Composition

    Our experience has shown that while erstwhile bearings demand the use of UHMWPE for solar tracker bearings, this polymer becomes problematic as volumes increase. The main reason is that UHMWPE is not injection mouldable. This means that parts need to be machined. Machining is time consuming, expensive, and it also results in a very heavy final component.

    Other candidates include POM (Polyacetal), HDPE, and Nylons. Each of these has advantages, although our preference has been towards POM, as it offers both strength and an ease of moulding. While HDPE is lightweight, it is not nearly as strong as POM. Nylon is the least preferred because it tends to swell when there is moisture. While Nylon bearings may have done well in projects where the climate is dry, the use of Nylon in more humid conditions would not be advisable.

    Other than the polymer, the key lies in what additives one incorporates. There are three primary factors to consider. The first is strength – which is managed by the choice of polymer. A typical solar tracker bearing of 100 square would need to accommodate at least 1000-1500 Kgs of vertical load. The second criterion is friction. The use of friction reducing additives is required in making solar tracker bearings, as it greatly enhances efficiency. Experience has shown us that there is a balance needed here. Too little friction can also be a bad thing, as it may cause the panels to rotate due to wind loads. Finally, the bearing needs to be UV resistant. Poly Fluoro has explored the impact of different fillers on UV resistance. While many manufacturers simply add carbon black and claim that the part is resistant to UV, this can be misleading. Our own research shows that the addition of black pigment can only withstand UV up to a point. In most cases, the bearing will begin to deteriorate within 2-3 years. The more expensive option is to use HALS (Hindered amine light stabilizers), which work by ensuring that the UV radiation is managed within the first 0.1mm of the part’s surface. HALS would allow the solar tracker bearing to have a life of 25-30 years, which is what is required when considering a solar project.

  3. Design

    While smaller projects may opt for machining, it is our belief that an injection moulded part is most suitable for solar tracker bearings.

    Using a special honeycomb or lattice structure, the bearings can be made lightweight, but strong enough to take heavy loads. Furthermore, with a cycle time of only under two minutes, the manufacture of a solar tracker bearing can be done in a fraction of the time it would take to machine the bearing from a rod or sheet.

    The combined impact of the weight reduction and lower cycle time results in a cost saving of over 50% in some cases. For large projects, where tens of thousands of bearings are needed, the machining route is both financially wasteful and unlikely to meet any stringent project timelines.

We hope the above information has been useful in better understanding the structure of the solar tracker bearing. As projects grow in size, we expect to come across more learnings. In the meantime, Poly Fluoro is proud to be one of the pioneers in this space. Our library of solar tracker bearings allows us to take on projects of different sizes and volumes, while offering both a quality product and a genuine academic understanding of the engineering behind it.

Covid 19 - A Boon for the Polymer Industry?

There has scarcely been a time as uncertain as this in the life of any working professional. Whether you are a salaried employee or a businessman, there is no doubt that the current pandemic has caused more than its fair share of sleepless nights. As companies scramble to get back on their feet, they are confronted with a perfect storm of dwindling order books, broken supply chains, and a cash flow crisis like never before. As a result, even companies with relatively strong order pipelines are finding it hard to source raw materials and maintain credit terms with suppliers who may – either due to caution or desperation – need their payments up front.

Manufacturing is no exception to all this, although the impact across the sector has been uneven. While those catering to non-essential products have been hit hard, manufacturers in essential areas have continued to have enough business to at least keep the lights on. That this alone needs to be viewed as a victory in these times tells us the extent of the difficulty. Nonetheless, the rise in certain essential industries along with the indication of where economic activity may be headed once the pandemic subsides should offer manufacturers a road map in terms of where to focus their efforts.

The polymer industry, which has traditionally been naturally diversified across many end-applications, may be well poised to step in and reap the benefits from a world trying rapidly to re-invent itself. Here we look at just a few industries which are evolving and using more polymers as they do.

  1. Automotive

    Although it is sad to say, there is little hope that the automotive sector as we know it will ever regain its earlier shine. Even before the pandemic, auto was in the doldrums, as consumers opted away from car ownership, or held off purchases of traditional fuel-based vehicles for the promise shown by electric vehicles.

    It is difficult to see – given the levels of unemployment, work-from-home directives, and extreme job uncertainty – why anyone would be thinking of buying a motor vehicle at this time or any time in the next four to six months at least. What this might spell for the industry is presently catastrophic.

    However, it is not all glum. The farm sector has seen some activity, as this is one area that has been forced to stay open throughout the lockdown. Farm equipment and vehicle manufacture has kept pace even during the slowdown and will most likely survive. Further, there is – for now at least – little threat of an electric vehicle onslaught on farming.

    Consequently, companies that are able to pivot and remain relevant in the electric vehicle space would survive in the long term. Again, even sales of EV are likely to be highly subdued for the next few quarters, but there is little doubt that companies steeped in combustion engine manufacturing need to start stepping out and engaging in R&D for EVs.

    For polymers, the opportunity remains to offer light-weight, durable solutions to improve efficiencies and performance. Wherein traditional automotive parts would focus on wear resistance and performance under high load and temperatures, the new engineering focusses on insulation, self-lubrication, and high strength-to-weight ratios. As it happens, polymers check all these boxes.

    Key products: Polymer seals, PTFE insulation films, PTFE-Bronze bands for shock absorber struts, Machined parts in PEEK and POM (Polyacetal), injection moulded polymer parts.
     

  2. Medical

    For obvious reasons, the medical industry has been one of the few to have survived the pandemic. Although there has been a massive toll – both financially and emotionally – on hospitals and medical workers, the pharmaceutical industry and medical device manufacturers have struggled to keep with demand.

    Polymers find multiple applications in the medical field. As the demand for certain devices – such as ventilators – has spiked, OEMs are looking for cheaper, better ways to keep pace with demand, while retaining the effectiveness of their products. Being chemically inert and often pre-FDA approved, polymers lend themselves faster to R&D.

    Similarly, in applications such as clean rooms and laboratories, polymer sealing materials are preferred as their behaviour to chemicals is already known.

    Finally, the demand for membranes has continued to spike, as manufacturers struggle to find novel ways to make masks and other personal protective equipment (PPE). ePTFE membranes have pore sizes slightly smaller than the droplets which carry the virus. In addition to this, they are hydrophobic, meaning that droplets do not adhere to their surfaces. This makes ePTFE an ideal venting material for masks.

    Key products: Polymer valves, customized polymer components - both machined and moulded, ePTFE (expanded PTFE) sealing tapes, ePTFE (expanded PTFE) membranes, PTFE tubes.
     

  3. Water

    As an essential service, water has operated through the pandemic and is an industry poised to keep benefiting from as cities expand and existing water sources become scarce. The future of freshwater may depend heavily on desalination plants, which would need waterways and pipelines to connect them to the water supply of cities.

    Again, due to their inert nature, polymers are well placed to benefit from the surge of activity expected in this sector. Polymer parts, seals, sealing tapes, and tubes are ideal for applications involving both freshwater and saltwater. The corrosive nature of saltwater and the effluents arising from desalination and water treatment mean that metal can never perform as effectively as polymers.

    Key products: PTFE Tubes, PTFE pipe lining, PTFE pipe support bearings, Polymer seals, Polymer valves, ePTFE Gasket Tapes
     

  4. Renewable Energy

    Even before the pandemic, the urgency for shifting to renewables was at an all time high. Countries that have agreed to the Paris Climate Agreement all accept that without a near-total shift into renewable energy, the global climate crisis cannot be averted. With this in mind, companies in the renewable energy industry have been pushing manufacturers to come up with novel, cost-effective, and workable solutions to be used across the spectrum of applications in renewables.

    It is for this reason that we have seen a huge amount of development for self-lubricating polymer parts in wind turbines, moulded polymer parts for solar applications, and high performance sealing materials in hydro-electric applications.

    Everyone agrees that renewables are here to stay. With polymers having a huge part to play in this sector, we may see a rapid offtake in the years to come.

    Key products: Solar Tracker Bearings, PTFE sliding bearings, Machined polymer insulator blocks, PTFE Seals, ePTFE (expanded PTFE) gasket tapes. 

 

Is Covid 19 the last nail in China's manufacturing coffin?

For anyone in manufacturing, the China threat has been genuinely concerning for decades now. It almost makes no sense to manufacture something that the Chinese already supply. Yet, Indian companies have hobbled on, using a mixture of proximity and good customer service as a way to hold on to clients.

It is precisely for this reason that most successful manufacturing outfits have survived or even thrived by staying one step ahead on the value chain, or by investing efforts and capital in technological differentiation. 

In our own example, Poly Fluoro withdrew from the manufacturing of what we call ‘stock shapes’, back in 2007. Stock shapes are typically items like polymer rods and sheets, which come in certain standard dimensions. It was our understanding that the commoditisation of this space would drive margins so low, that the slightest shift in the market could lead to unmanageable losses. Furthermore, we perceived a genuine dilution in the quality metrics. This made it impossible to compete with Chinese material, which would often be substandard, but marketed in such a way that the end-users would be unaware of the same.

One offshoot of this was seen in the PTFE (Teflon) industry, where the proliferation of reprocessed, or recycled, material had started eating into the market for genuine material. Since there was anywhere between a 15% to 40% price difference between reprocessed and genuine PTFE, competition became impossible, unless the end user was discerning enough to demand the right quality, and knowledgeable enough to test for the same.

Rather than compete on volumes with Indian companies as well as traders who imported in bulk from China, Poly Fluoro invested in technologies such as PTFE extrusion, CNC machining, injection moulding, PEEK moulding, and expanded PTFE (ePTFE) manufacture. In some cases, we spent months or even years developing new processing techniques in-house. While these technologies are also available in China, our aim was to develop the same for high-precision products aimed at clients for whom quality was the key concern. In doing so, the China threat was minimised.

Other Indian companies, who have continued to take the China challenge head-on, have suffered.

Off late, however, multiple factors have started to chip away at the Chinese advantage. These have allowed Indian companies (and indeed companies everywhere), to realise that the China threat was never about fundamentals. In other words, we were not disadvantaged by higher productivity, or more streamlined operations in China. Rather, the competition was largely man-made.

  1. Lower labour costs

    Along with India, China has always promoted the idea that their labour is cheaper. While this is certainly true when we compare them with the West, the fact remains that for many years, Chinese labour laws were extremely exploitative. In contrast, Indian firms have had to conform to things like ESI and PF, where both health insurance and provident fund contributions were mandatory for any firm hoping to compete globally.

    The recent introduction of social security in China has pushed up the labour costs there, to the extent that the difference between India and China is now negligible. Indeed, we have recently received requests from Chinese companies for machined parts. When we inquired, sceptically, why they would want to come to us, we were told that machining costs have increased significantly in China.

    China’s push to appear more like a global super power and less like a low cost country has also impacted this. Fewer youths are interested to work in manufacturing, causing labour rates to spike. India still has a large labour workforce who, if supported ably by minimum wage laws, still see manufacturing as a profession worth getting into.

  2. Environmental concerns

    In 2016, the PTFE industry was rocked by capacity constraints caused by the shutting down of three large raw material manufacturers in China. The revelation here was that these plants had been flouting environmental laws and dumping effluents in nearby rivers. The moment the companies were held accountable, the price of Chinese materials began to rise. Again, India’s only PTFE raw material manufacturer – Gujarat Fluorochemicals – had installed a state-of-the-art plant that conformed to all the environmental requirements from day one.

    Again, it is no wonder that Indian firms were struggling to compete, considering the cost benefits afforded by ignoring regulation. Once the rules were followed, the cost advantage immediately eroded.

  3.  Government subsidies and currency

    Customers often ask us why we in India are unable to compete with Chinese companies. To this, our reply is simple: “We are not competing with Chinese companies, we are competing with the Chinese government”.

    Given the extent of subsidies and drawbacks thrown on Chinese exporters, it is hardly fair to expect an MSME in India to have there wherewithal to engage competitively. Despite this, we are often told that our prices are only 10-15% higher than the prices from China. In other words, with subsidies in the range of 30-35%, Indian firms are still able to harness our productivity and ingenuity to remain somewhat competitive.

    In addition to subsidies, the Chinese currency has been consistently pegged below its true value, lending another blow to Indian manufacturers when we quote clients in US$ or Euros.

  4. Social issues

    Finally, there is little doubt at this time that working with China raises some serious doubts with regards to what we are encouraging. Although this is not a cost concern, companies in the West need to start acknowledging that in encouraging China, we are giving indirect approval for a host of human rights violations that have now become too obvious to ignore.

    With the advent of the Covid 19 crisis, the world needs to take an even sterner view regarding China trade, since it appears that there is very little accountability internally for the manner in which they operate. Even now, as the cases spike around the world, China remains stoic in claiming that they have nearly eradicated the virus within their own borders.

    Regardless, we have heard of many cases where companies in Europe and the USA have gone right back to buying from China, because the economics are favourable.

    While there are definitely calls for companies to pull manufacturing operations out of China and move them to countries like India, it remains to be seen whether these are genuine or simply lip service during a time where anti-China sentiments are everywhere.

The aim of the article is not to put down China, or to claim that they do not deserve to compete in global trade. However, with so many factors benefiting Chinese manufacturers, the world needs to even the playing field by insisting that Chinese companies play by the same rules as the rest of us. As Indian manufacturers, we’re happy to complete on a level footing. What we cannot be expected to do is survive against competition that is so unfairly stacked against us using man-made economic measures.

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