Author: M.Temel AYGUN
Lean production often appears as an approach that comes from the large-scale production of automobiles and from time to time reaches its limits in the project business of machine and system engineering. A high percentage of customer individuality, a low repetition frequency of activities, and extensive work contents impede the standardization of procedures and thereby prevent the basis for a sustainable introduction of lean. Especially the aspect of overcoming these limits through digital opportunities will play a role in the following chapter. For each element of the TPS the underlying mindset will be briefly introduced and where the practical implementation often reaches its limits will be shown. Subsequently, the opportunities for overcoming these limits within the context of digitalization and Industrie 4.0 will be presented.
Stable and Standardized Processes
The stabilization and subsequent standardization of processes is the foundation for continuous improvement processes. The recognition of deviations is only possible through standards with a continuous target/actual comparison. Stability and standardization are furthermore the prerequisite for running further TPS elements, such as flow production or the triggering of PDCA cycles. Therefore, stability and standardization build the foundation of the TPS.
Limits of Stable and Standardized Processes: Customer-specific individual products cause a high processing effort from sales to adjustment development, purchasing, and work preparation all the way to production and service. The creation of standard work instructions for individualized products and their components is time-consuming and error-prone. The processing and cycle times vary both in production and in all other areas. Frequently changing processing tasks mean that it is almost impossible to set times for workplaces and systems. But without standard specifications, deviations and underlying problems can hardly be recognized.
Opportunities through digitalization and Industry 4.0 :
- Opportunity 1: Extend standard work in customer-individualized production: Analogous to the structure of the product program, related work and process standards can be modularized and digitalized. Subsequently, the work documents are adaptively configured for each of the products to be produced and digitally made available to the operator on-site. In this way, quantity and time per unit can also be specified for non-series production. These adaptive work standards, in turn, are the basis for managing deviations as a foundation of continuous improvement processes.
- Opportunity 2: Reducing effort in production preparation, avoiding mistakes during execution: The modularization and digitalization of work instructions means increased initial effort, but subsequently reduces work preparation effort for individual orders. Digital worker assistance systems provide the current information and thereby avoid improper processing caused by outdated paper documents. This way, paper will continue to be increasingly replaced in production by networked, electronic media. At the same time, assistance systems (e.g. pick-by technologies in commissioning) can avoid or recognize wrongful acting. Thereby, quality can be improved, order throughput time be reduced and flexibility be increased.
- Opportunity 3: Increasing the reliability of machines: Many companies measure the efficiency of their machinery and equipment and record the reasons for loss. Regardless, unplanned breakdowns still occur. The targeted equipping of existing systems with networked sensors can help to detect critical conditions (contamination, filling levels, wear and tear) at an early stage and to plan the maintenance or replacement of components in good time (e.g. during the next planned maintenance shift). The next predictive level of maintenance can be reached with machine learning. Through the linking of a machine’s condition data with labeled event data (dimensions, surface areas, tool breakage, etc.), connections can be found and future events predicted.
The visual representation of process conditions and performance as well as standard procedures and work documents provides employees and management with the opportunity to recognize deviations immediately and without additional aids and activities. A good visualization makes standards simple and easy to understand through optical elements without additional tools so that no deviation keeps consealed. The identification of deviations is in turn a trigger for continuous improvement processes.
Limits of Visual Management: Manual recording, continuous updating and subsequent visualization of key figures is time consuming and error-prone. The performance of a process is often only recorded at the end of a shift or a week. This wastes valuable response time for managers and employees.
Opportunities through digitalization and Industry 4.0
- Opportunity 1: Early detection of deviations – Employee perspective: Important information about one’s own process can currently be made available to the employee directly at his or her workstation or anywhere else. In the simplest case, this is the current target/actual performance comparison (e.g. for number of units/productive time and scrap/rework time). This way, the employee can react or escalate in a timely manner. By expanding information to a simple trend analysis all the way to the prediction of deviation (realized through machine learning), the employee can engage proactively before negative effects on the process occur. Already today, for example, the failure of tools can be predicted. Depiction can take place, depending on the user, on-site via monitor, smartphone, or directly on a smart wearable (watch, glasses, etc.). This way, information can be made available directly to the respective employee.
- Opportunity 2: Early detection of deviations – Management perspective: Through the digital and direct provision of actual values, trends, and prognoses, management is provided with the opportunity to intervene more quickly. The daily meetings on the shop floor can be supported by the current values of important workstations, machines and systems, which are sent via radio technology directly to a device. Escalation cascades are pushed beyond the limits of manufacturing execution systems (MES) or enterprise resource planning systems (ERP) and management can provide support early on, reallocate resources, or situationally find solutions.
- Opportunity 3: Solving problems more quickly with digital shop floor management: In daily shop floor meetings, above all, it is about recognizing target/actual deviations and describing these for the subsequent problem solving as comprehensively as possible. Figures, measurement results, and process data provide help and enrich the structured problem definition. Their digital measurement can bring about a temporal relief. The far greater benefit of digitalization lies in the possi bility of detecting relations between deviations (e.g. product defects) and the associated process data (such as temperatures, power consumption, feed forces, etc.). In this way, the point at which the error occurs can be narrowed down more quickly and more reliably. Utilizing documented digital PDCA cyclesenables a networked search for similar events and thereby successful solutions.
The direct transfer of fluctuatingdemand to production leads also to a fluctuating capacity utilization. This results in provision of additional capacity, unused capacity, as well as continuous plan changes, also in supply. The stronger the fluctuation of capacity, the harder it is to adhere given standards and processes, with the corresponding consequences for quality as well as managing deviations. Therefore, through levelling and smoothing, the planning of production is decoupled from the market demand to a certain extent. This takes place, on the one hand, with a view to the overall capacity of production, in which orders are planned only until the attainment of maximum capacity. On the other hand, orders are scheduled with a smoothing pattern (“mix”) so that individual stations are not overloaded while others are simultaneously underloaded.
Limits of Levelled Production: Levelling and smoothing fluctuating demand for customer-individualized products is a challenging task. This is mainly due to the very different character of products and the associated fluctuating load of individual workstations or production areas. In this environment, master data, order data, resource data or project data are barely maintained or not available. Furthermore, available resources are unknown when decisions on the quantities and deadlines are made. Cooperation between sales, customization development and work scheduling is not synchronized, which is why customers are promised orders that cannot be realized within the specified time frame.
Opportunities through digitalization and Industrie 4.0
- Opportunity 1: Making better decisions in sales: For the even planning of orders, it is already necessary in sales to estimate a new project’s capacity requirements in individual areas or at different locations and to synchronize it with the available capacity. The basis for this is on the one hand the division of the available capacity into so-called capacity buckets On the other hand, maintaining bills of material and standard times in the ERP system is needed. While this is a standard function of current ERP systems, the great opportunity lies in making the capacity available for sales via a mobile frontend. Within a time frame (e.g. one week), only a certain amount of orders is confirmed until the associated capacity bucket has been exhausted. This way, customers can be promised more realistic delivery dates and throughput times decrease, as the inventory of already begun orders is avoided by less rescheduling.
- Opportunity 2: Better utilization with simpler planning: For certain product properties, a solution space can be defined that can be mapped by production without major planning and set-up effort. Configurators enable the sales department or even the end customer to find their individual solution based on rules. If the affected production system is prepared for all parameter combinations without major set-up effort, customers can book the next free deadline for their orders themselves. There is no need for the creation of engineering drawings, the writing of offers, as well as activities in work preparation.
- Opportunity 3: Self-organized pull planning: In defined segments of production (e.g. final assembly), free workstations can pull the next suitable order from a reserve of released and prepared orders. This is supported by automated guided vehicle systems (AGV) which transport the preliminary product and the required material to the next free station. The goal is an efficient and even use of available capacities.
See you in next blog with the following topics :
- Takt, Flow, Pull
- Autonomation / Jidoka
- Continuous Improvement Process (CIP)
Kadıköy, İstanbul – TURKEY
M. Temel AYGÜN, Ph. D. in Aerospace Eng.