The Eight Core Approach: Quality is never an accident Written by Nohman Mahmud, Manager QA, Dangote Cement Nigeria

Cement plants demand a strict quality regime throughout production in order to maintain control of quality. This is of increasing importance today: New kilns are increasingly in the 10,000 – 12,000t/day range, meaning that loss of quality over even a short period can result in a large amount of unsaleable product. At the same time, cement plants are using an increased range of raw and supplementary cementitious materials, as well as increasingly complex fuel blends, making consistency more of a challenge than in the past.

Consistent high-quality cement leads to customer satisfaction, business growth, enhanced value for shareholders and efficiency savings. In an effort to enhance quality control in the sector, this article will focus on key areas of quality control in general terms. If given due priority and consideration, this will ensure high-quality products.

The Eight Core Approach

The Eight Core Approach (ECA) has been developed by the author and is based on many years of experience in quality assurance in the cement sector (See Figure 1). It is a generic approach that, if implemented correctly and with clear targets, will yield the best quality cement at an optimised production cost. It is presented below in as an accessible way as possible, to engage employees in every role within the cement plant. An educated workforce, including top management, is key to implementing many of the suggestions presented below. The eight elements of the ECA are:

1. Key Performance Indicators (KPIs);
2. Smart Targets;
3. Quality plan;
4. Process approach;
5. Resource provision;
6. Data analysis and statistical tools;
7. Root cause analysis (RCA) and corrective and preventive action (CAPA);
8. Top management commitment and support.

In the centre of the core is the target ‘QUALITY,’ which is protected by the concentric layers of each ECA element. Each layer is important and we should look at each in turn.

1. Key Performance Indicators (KPIs)

KPIs are at the centre of the ECA. The primary inputs that lead to the development of a given cement plant’s KPIs will be derived from national or international product standards in combination with specific customer requirements in the local market. In the cement industry several KPIs are very familiar, for example compressive strength, water demand, setting times, expansion characteristics and fineness. They may also include lesser known or more specific requirements like slump characteristics, total alkali content, heat of hydration, colour, proportion of C3A, and many others.

However, sometimes meeting these ‘official’ KPIs is not enough, particularly for larger clients and in more developed markets. Hence, customers’ requirements should be clearly understood, communicated and agreed upon. This is vital for large projects in order to avoid any issues during the fulfillment stage.

On a particular occasion in the author’s experience, an important customer was particularly worked up about the ‘fact’ that darker cement was ‘higher quality.’ It took a massive effort to dispel this myth. Another time, the distributor at a major cement plant had not been informed that a particular client needed a cement with a specific slump characteristic. This large hydroelectric dam developer was seriously inconvenienced due to a relatively minor communication breakdown at the cement plant.

This points clearly to the fact that KPIs should be based on the requirements of all affected parties: Customers, operations team, quality control, dispatchers and top managment. Define them!

2. Smart Targets

Once KPIs have been identified, the second step is to establish Smart Targets. These may cover objectives like maintaining SO₃ content at 2.5 – 2.6% or keeping the lime saturation factor at 95 – 96%. The inputs for Smart Targets will, like the main KPIs, come from (inter)national product standards and customer needs. They will vary on a plant-by-plant basis. Without Smart Targets, there will be no clear way to achieve the desired objectives of the KPIs.

The main limitations and bottlenecks that might impede the establishment of Smart Targets include: Technological limitations; Cost considerations; Raw material limitations; The play-off between high quality and high volumes, plus a host of other concerns.

In order to achieve the desired Smart Targets, a detailed study of the plant’s entire production process is required to identify its current bottlenecks and inherent limitations. Only once these are clear can the quality control department and plant operators overcome them. Normally, Smart Targets are fixed once they have been developed. However, it is always advisable to review these in line with changing customer expectations and performance
from elsewhere in the group, as well as that of relevant competitors.

3. Quality plans

A quality plan is a roadmap on how the plant can achieve the Smart Targets and KPIs discussed above. It encompasses the entire production process, not just the final product. Quality plans usually include detailed analyses of processes and sub-processes of the cement process, for example quarrying, crushing, raw meal preparation, pyroprocessing, finish grinding and dispatch. Each (sub-)process needs to be identified, with controls and sub-controls implemented in order to achieve the necessary quality of the material entering and leaving each step, ultimately leading to the end product. This requires clear communication of all requirements to all process departments within the entire line. Otherwise, success is not likely.

Smart Targets must be included in the quality plan at every step of the production process. For example, strength targets relevant to the grade of cement being made will affect all parts of the plant, not just finish grinding. The key message is that, as the targets for the end product change, the targets change for all other parts of the process too.

The allocation of responsibilities, authority structures and resources during the different phases of the production cycle with respect to quality control and assurance need to be clearly defined in the quality plan. This should answer questions as specific as: Who will do the sampling, analysis and reporting at each step? Which authority levels can alter the process to meet a SMART Target? What is the chain of command within a specific department in the event of an emergency?

A quality plan also requires specific documented standards, procedures and instructions, if these do not already exist. Wherever possible these should be based on relevant (inter)national sampling and analysis standards. Whenever an in-house method is used, attempts should be made to validate it relative to established norms to ensure that it is fit for purpose.

Of course, the standards defined by the quality plan can only be met if suitable testing, inspection, examination and audit programs are available at each stage. This includes classical sampling and analysis methods, along with modern analytical instruments like XRF/XRD machines. All quality control equipment should be regularly calibrated in order to ensure the accuracy, repeatability and reproducibility of the sampling / analysis procedures.

Finally, documentation and reporting mechanisms must be clearly stated in the quality plan. Whether they are in a book on a shelf or on a globally-accessible network, document control procedures must be clear. This will ensure that those who need to access records can do so. There is no point correctly monitoring quality across the cement making process if records are not made or they are inaccessible when needed.

4. Process Approach

When a cement plant is simplified into individual processes and sub-processes, it makes it far easier to manage, control and improve the production process. The use of this Process Approach enables timely correction in the event of untoward process fluctuations and reinforces the objectives of the Quality Plan. At each process stage, responsibilities and authorities need to be established and communicated and agreed upon by all concerned.

The easiest route to understand the Process Approach is by the construction of detailed ‘flow charts’ of the whole of the process. This helps all levels of plant staff understand the process, even without in-depth knowledge of every stage.

5. Resource Provision

High-quality products can only be produced when the necessary resources can be obtained. Aside from natural raw materials, the most obvious include adequate sampling and testing equipment and a well-educated and motivated workforce. Maintaining resource provision is a continuous process in both domains. Training and staff development should be continuous and new technological advances should be investigated enthusiastically.

Another useful resource are industry publications that keep plant staff informed of the latest trends in the cement sector. These days the best content can even be obtained for free. Staff should make use of such resources.

6. Data analysis and statistical tools

Many plants still attempt to rely on experience and intuition as the guiding force towards quality. However this approach will only get you so far due to its inherent shortcomings. High-quality, 21st Century cement cannot be made until data analysis and statistical tools are used to analyse issues arising, reach conclusions and recommend effective solutions. Common statistical tools that can be used include: Cause and effect / ‘fish-bone’ diagrams; Check sheets; Control charts; Histograms; Pareto charts, and; Scatter diagrams. In addition do not underestimate simple statistical formulae like the mean, minimum, maximum, ranges, standard deviations, pie charts and bar charts.

7. Root Cause Analysis (RCA) and Corrective and Preventive Action (CAPA)

In order to remove quality defects and non-conformance issues, a proper root cause analysis (RCA) and corrective and preventative action (CAPA) mechanism is required. A root cause is the core issue / reason that sets in motion the cause-and-effect chain that ultimately leads to a specific quality issue.

If the only focus of a remedial action is to remove the quality issue without considering the root cause (and potentially further causes behind that), a recurrence is bound to happen. RCA seeks to remove root causes. There is a variety of approaches that can be used, which were mentioned in section six.

It is also possible that new root causes can ‘pop up’ over time. Therefore corrective and preventative action (CAPA) is also needed. Corrective action, where a problem is only addressed once it happens, is only part of the solution. Preventative action, fault forecasting and a continual quest for improvement is needed. Otherwise, faults will continue to occur.

8. Commitment from top management

As the American management consultant Dr William Edwards Deming stated, “Quality begins with the intent, which is fixed by management.” This is as true today as ever: Any effort to improve cement quality will fail unless it is supported by the top management of the organisation.

Quality always comes with an up-front cost. Unfortunately, the easiest route to reduce production costs in the short term is a compromise on quality. However, such actions may ultimately lead to a loss of customer base to competitors, lower revenues and losses to the company. When the cost of production and high volumes are the top management’s main priority, quality failures are inevitable, whatever the quality control department does.

Management support has to come in the form of delegation of authority and provision of proper resources, along with involvement of the quality control department. This is critical to ensure that the right decisions are made with respect to product quality and hence, product acceptance.

Conclusion

By correctly developing and applying each segment of the Eight Core Approach, it is the author’s belief that any cement plant will be able to produce the best quality cement it can, in a consistent manner with the minimum possible waste. This leads to strong profits, as well as employee and customer satisfaction.

All eight elements are inter-related. Any failure to address even a single element will jeapordise the ECA. A chain is only as strong as its weakest link. It is worth reiterating that it’s not just the production process and ECA that have to be ‘water-tight’: Every single member of the workforce must also be committed to quality through application of the ECA, rather than the traditional ‘hit and hope’ method. After all, “Quality is never an accident; it is always the result of intelligent effort.” (John Ruskin).