Why an OES is so essential and yet, so underrated
So how does an OES influence an organization? Is it solely a tool needed to meet audit requirements? Just an instrument that produces a Test Certificate that would meet specific customer asks? Or just something that sounds nice and important when making a sales pitch to a castings buyer? Is grade checking not the only thing it does? Why not just use a simple handheld XRF instead? Several, if not most companies mistakenly think of an OES as simply an expensive QC tool that adds to their cost and is only used to meet the demands of specific buyers or certification agencies.
In truth, an OES does far more than just this. When used well, a good OES can save companies millions a year – adding this directly to profits! Indeed, a good OES positively impacts every single profit-driver, including revenues, material costs, productivity and profitability resulting in higher gross and net margins!
To understand just how an OES does all this though, it is important to first understand what “Quality” is – and perhaps for some, to change how Quality is perceived in the organization!
Quality – Investment and not a cost:
Historically, many organizations through the early- and mid-1900s made the mistake of viewing the Quality Department as no more than a cost center – since there is no visible revenue stream it contributed. Since the latter part of the 1900s however, with the advent of better analysis and benchmarking, it has been conclusively proven that quality management provides two clear benefits:
- Businesses that invest in quality earn more revenues, more profit margins (EBITDA) and add more value (Enterprise Value) consistently for decades
- They last longer; companies that invest in quality are 5-8X more likely to survive economic cycles.
Not only do such companies enjoy better reputations, but they also accrue far higher revenues and – almost counter-intuitively – lower costs per unit; this holds true across all manner of industries and geographies, seeing no exceptions! In the Automotive sector, for example, this is almost essential, since failures can be not just expensive and messy affairs, but also catastrophic, with casualties, fatalities, lawsuits and of course, immense reputational damage – and the resultant loss in customer confidence, market image and market share as well. Thus, it is no surprise that without exception, market participants insist on the highest quality – and the only ones that survive and profit long-term are the ones with the most stringent standards.
Even in a commodity market (like in castings, foundries etc.) where quality and price are not always perceived as being strongly correlated, profits of firms with high quality are higher – since they have a lower cost structure overall. This is also evident by a simple empirical view of the largest and best firms. Without exception, they have higher profits – and also have the highest expenditure on quality. The questions that leadership teams must ask therefore are not about whether to invest in quality, but what tools to invest in and how to drive profits using these.
Quality Needs in Metals
When a firm produces any defective material, even if they don’t realize it, they make a loss. The material must either be re-melted and re-cast or must be scrapped with a new production run taking place. Energy cost, labour cost and operating costs as well as all overheads for this particular lot are therefore doubled. This isn’t a visible loss but is tangible if one were to really drill into the cost structure. Hence, as firms grow, they must start focusing on eliminating or at least, significantly reducing the probability of a defective unit being produced at all. This really is a paradigm shift in approach.
This encompasses better processes being instituted of course, but also places a premium on in-process testing. If one catches a potential defect at the point it’s being produced, it could be addressed there and then, ensuring it doesn’t consume more capital as it continues through the process – and ultimately ensuring that the final product is always good enough to pass the Final Quality Check (FQC). This ensures that First Time Right (FTR) is high.
Now, from a quality standpoint, the key issues a metal producer or caster must address are:
- Ensuring that the metal / alloy composition is as per the targeted ranges
- Ensuring that there is no presence of elements (like Hydrogen) which can lead to unacceptable quality issues such as porosity in the end-product
Not just must these be tested, they should be tested at different stages to ensure that any errors are caught and rectified as early as possible. The key testing points are:
At raw material stage
This involves the checking of all material that is taken into the melt; checking this gives an accurate idea of inputs – which can then aid in computing the ideal mix to reach the desired output.
In-process prior to casting
This involves checking the metal / alloy while it’s still in molten form (prior to casting) to ensure that the melt is as per the desired composition. This ensures that the final product is not rejected based on composition issues!
This is the test of the final product, the results of which go into the “test certificate” (TC) that customers will assess. If the first two tests have been done well, this one should become merely a “validation” rather than the most critical or only testing point!
Each of these stages clearly needs testing – and with their rapid speed, high accuracy and precision and extremely low associated time, cost and labour overheads, Optical Emission Spectrometers (OES) are the ubiquitous and most optimal solution.
Testing with Spectrometers (OES) – The Core Function
An OES, as its core function, measures the elemental composition of the material in weight percentages. Within 10 – 25 seconds (depending on model of OES and the metal being tested), the OES provides extremely accurate, precise and very granular results. This is invaluable as the user can now assess his future course of action. If buying Raw Material, he can set / assess the price. The same results would then go into computation of the melt inputs too. During in-process testing, these results will tell a Smelter whether the melt can be cast or whether some changes are needed to save the melt. And of course, there is the Final QC, during which these results help make the TC proving the product to be “QC Pass”.
Spectrometers – Measuring gaseous elements in the melt
While OES solve the vast number of issues faced by casting units and foundries, one key requirement typical of the Ferrous and Aluminium industries is the measurement of gaseous elements in the melt. Nitrogen (N) is typically the first gaseous element that comes to mind for users with ferrous applications. Let’s look further however, given that OES now offer excellent solutions for N measurement. Indeed, Metal Power now offers N measurement on every single OES model – including the entry-level!
What about Oxygen? For Steel and Copper, the presence of Oxygen (O) is something that’s always been a focus area. While some grades of Copper (ETP Copper in particular) require Oxygen to be added as an alloying element, all grades of Pure Copper and of course, all grades of Steel, need Oxygen to be minimized. The other key gaseous element of importance in high-end production is Hydrogen (H). In Steels, the presence of Hydrogen leads to Hydrogen embrittlement and rejections based on this. Both can be measured – and exceedingly well, on an OES.
Example: Measuring Oxygen in Ferrous metals
In Ferrous metals, Oxygen is typically contained to under 20 ppm (parts per million) i.e. 0.0020% (some applications may require control to as low as 10 ppm as well). Likewise, in Pure Copper, the Oxygen content is maintained at below 10 ppm (for OF Copper) or below 5 ppm (for OFE Copper). This level of measurement has hitherto not been feasible on anything other than gas analysers (combustion method). While these instruments offer excellent performance and results, they do add a substantial amount of cost – particularly given that they only measure 2-3 gaseous elements, making their usage additional to that of an OES – which measures all manner of elements. This scenario has changed dramatically however, in the last 3 years or so. Today, OES like the Metavision-10008X offer Oxygen analysis all the way down to 1 ppm (0.0001%)! This allows firms to simplify their infrastructure and reduce capital as well as operating costs – and of course, testing time – since a single test gives them all the information needed.
Other Benefits of OES
As mentioned previously though, there are also additional benefits that an OES offers – ones that are frequently lost sight of! Today, OES have become a must-have – and this is because they have advanced so much that they offer a host of capabilities and features that save time and improve a firm’s ability to increase profits.
Savings on expensive alloying elements
For every alloy, the key elements have a target range. The elemental composition must be within this range for the product to be acceptable. The firm therefore has the choice of whether to work at the absolute margin of these limits or to build safety buffers. The idea of safety buffers is appealing, but this comes at a cost! Staying above the min. level of expensive alloying elements like Ni (Nickel), Cu (Copper), Ti (Titanium) etc. would mean significantly higher raw material costs! None of this higher cost though will result in improved revenue realization though.
Hence, the best practice for profit-optimization is to be close to the minimum level specified – ensuring a safety margin, but also minimizing the material cost as much as possible. This requires knowing the actual concentration of these elements in the melt before casting! This is where a spectrometer comes in. Process controls do not give full control – leading to users keeping a wide margin for error. An OES though solves this issue. Using sampling moulds, a sample can be taken from the melt and tested within seconds, giving highly accurate analysis while the metal is still in the melt.
If analysis results show that the melt is of the correct mix, then it may be poured. If not, then adjustments can be made rapidly and without going through any rejection / re-melting process. This ability to make proactive change is only possible if you have a spectrometer of the required quality working in the Laboratory. The higher the resolution of the Laboratory’s spectrometer, the better is the capability of the instrument to support work closer to the margins, regardless of the limits and ranges involved.
In our interactions with customers, large steel plants save about INR 60-100 crores (USD 8-13 Mn) per year using a Spectrometer. But limits are not restricted to them! Even small Cast Iron foundries save 50-200 Lakhs per year (USD 65K-200K) simply by optimizing Nickel and Copper levels! That is how valuable a spectrometer is!
Of course, there are added upsides in pricing! A buyer could set prices for scrap based on the composition of the incoming scrap. Stainless steel scrap, for instance, can vary widely on value based on the assessed Nickel content. Accurate testing could save / gain a buyer a lot of money, aside from simply helping him compute the input mix to achieve targeted outputs. There is similar impact on the selling price of alloys like brass. In short, an OES can help unlock price benefits in both Purchase and Sales.
Ability to get more orders and customers
Today, most astute buyers first define the quality benchmarks they are seeking and only then do they evaluate the commercial aspects – which are only assessed for those suppliers that meet quality requirements! These requirements too have become increasingly stringent. They not only cover the material characteristics and composition, but also cover supplier processes and their in-house Quality systems including the supporting infrastructure. One of the increasingly common demands we have seen our customers faced with, is that of having an in-house OES. Some common examples of OES requirements include those from Automotive majors and also buyers like Aerospace, Aviation, Railways and the Defence sector.
In this scenario, a spectrometer is no longer just a quality management tool, but indeed has become a qualifying requirement for firms that aim to do business with better quality and more astute buyers.
Improvement in system productivity
Productivity is typically defined as usable or saleable output per unit of input – manpower, equipment or capital money. In the metal industry, gross margin per unit is thin. This means that the focus for those that aim to increase profits must be on improvements in productivity – so that they can produce more saleable output from existing resources, without having to invest more capital. The simplest way to drive dramatic productivity improvements is to reduce internal / stage-wise rework and also reduce rejection and returns levels.
Doing this frees up equipment and labour capacity for fresh lots / batches, thereby ensuring that there is higher production, while absolutely no additional cost is incurred barring the raw material costs. When accounting for the cost of an additional batch that is produced by simply having eliminated one re-melt, the additional cost is just that of the raw materials! Another example of rework / duplication of work could well be the need for multiple instruments for analyzing the same sample! For example, some firms are forced to use a different instrument for assessing gaseous element concentration and yet another for analysis of inclusions (soluble-insoluble analysis) and perhaps a fourth too if they wish to analyse ultra-fine wires or very thin foils! Today, the most advanced OES – like the Metavision-10008X offer the facility to analyse all of these samples on the same instrument! Not only does this save a huge amount in terms of capital expense, it also enables a significant productivity improvement as all analyses are done on the same instrument without any movement and duplication of effort or labour.
Of course, another upside of such elimination of rework and rejections is the market reputation of the firm – which would suffer with each rejection but become stellar if it were known that each lot was absolutely assured to be exactly what was ordered by the buyer and claimed by the supplier. Such reputations themselves contribute even further to profit and revenue upsides, becoming a virtuous cycle.
Spectrometer impact on R&D
Spectrometers are also an essential tool for the R&D teams of firms in metal industries. The focus of R&D firms is typically on newer alloy types that improve quality of the metal or reduce cost while retaining the same quality or of course, on failure analysis on parts that fail when they should not have done so. Further, R&D teams – when equipped with the ability to monitor a wide range of elements even at ultra-low levels are able to research upon and develop the best ways to optimize recovery factors for all manner of grades. This becomes increasingly important as production levels increase.
This plays a critical role in optimizing raw material cost too! All this requires an OES to be used which can – almost literally – measure any element at all and measure it at any level of concentration. Today, leading spectrometers like the Metavision-10008X offer ultra-low detection limits, even in the sub-ppm range (of the order of 0.00001%) for several elements, while also offering the highest levels of accuracy, precision and stability. Whether to study the impact of small changes in elemental concentration, work on micro-alloys, the development of newer alloys and techniques to meet application needs or to conduct failure analyses, these OES are essential tools for R&D personnel.
Advantages to OEMs and their vendors
There is high vendor-dependence in multiple industries – right from sourcing of raw material to sourcing parts, components and various castings, assemblies and sub-assemblies. Both OEMs and their vendors benefit when the vendor base invests in the right spectrometers. These benefits include:
- Greater assurance of part quality to OEMs and assurance of low rejections for vendors
- Reduction of lead times / buffer stock for the OEMs and holding times for vendors
- Cost advantages to all parties as overall costs reduce
Despite this, apart from the suppliers of critical / high-importance parts / materials, most suppliers seem to refrain from having in-house spectrometers and buyers too have not made these mandatory, assuming the cost for an instrument of acceptable quality would be too high for their smaller vendors. This, however, is no longer true.
Today, there are high-quality OES available at extremely low price-points (well below USD 15K) that would meet the quality needs of the vast majority of suppliers. Featuring analysis of all key elements, including Pb, Zn, Ce, As, Cd, and low levels of C, S, P, B and even N etc. the market, led by Metal Power, offers high-quality and yet, very economical solutions for the needs of vendors.
To summarize therefore, there is a lot more than just material testing that an OES can contribute to an organization. The benefits of metal testing – when done well – can positively impact every single operational profit-driver for a firm. The key to unlocking these benefits lies in understanding what is possible – and then investing in the optimal solution.
Is there anything more to know about OES?
Of course! As with any field, this is merely the beginning. For more, do refer to: