## 1 Introduction  
Mass customisation is an economic rebalancing strategy dictated by the current competitiveness of the market. It involves manufacturing different product models while reducing costs in terms of tools and equipment. Manufacturers, in line with this strategy, are faced with the challenge of minimising changes to the production processes, quality, machine facilities, number of employees, or time of delivery by simultaneously improving production flexibility and workforce flexibility [1; 2]. The capability for mass customisation has been identified as an evaluation factor of the producer's ability to compete in a rapidly changing environment. This type of production requires manufacturers to adapt to the preferences of customers and build close relationships with them in order to gain knowledge of their preferences and requirements [3]. This strategy also takes into account that there is a link between satisfaction and loyalty in the context of the consumer's co-design experience [4]. The contemporary consumer market determines the use of mass customisation by manufacturers. Mass customisation is an economic rebalancing strategy that consists of the mass production of customised products at standard costs. It involves manufacturingdifferent product models while reducing costs in terms of tools and equipment [1]. Manufacturers conforming to this strategy are faced with the challenge of minimising changes to production processes, to quality, to machine facilities, to the number of employees, and to delivery times, along with the simultaneous improvement of both production and workface flexibilities [1,2]. From the point of view of the Industry 4.0 concept, a dedicated architecture for the cyber-physical system is required to transform the acquired data into useful information [5]. Moreover, the following Industry 4.0 technologies are relevant to the implementation of the mass-customisation strategy: data and communications, analytics and artificial intelligence, human/machine interactions, and automated machinery [6]. As part of data and connectivity, technologies such as the Internet of Things and Cloud technologies, as an example of Industry 4.0 technologies, are used. They are responsible in the supply chain for centralising storage data, processing it, communication, and the transfer of information. These technologies support the customisation of products by centralising management. They facilitate the availability and feasibility of checking customers' orders and provide, in real time, access to data from all links in the supply chain. They are also used in the production process, where they allow machines to communicate with each other in order to deliver personalised products as quickly as possible [7]. On the other hand, artificial intelligence, in product customisation, can be used to forecast and plan the demand for products by collecting data directly from products sold [8]. The third group of technologies--human/machine interactions in mass customisation, among other things--facilitates the selection process in storage. Therefore, they provide an opportunity to move the production process into distribution, thus facilitating the faster delivery of products to market and increasing the possibility of customising the products supplied [6]. As part of I4.0 technologies, automated machinery, such as 3D printers, is used in mass customisation. Using these 3D printers in production allows products to be produced that are precisely tailored to the customer's preferences. The only limitations in such cases are the types of raw materials from which items can be printed [8]. According to the mass-customisation production strategy, mixed-production-line models are used, which allow different models of the basic product's variant to be produced without high costs. In addition to the diversity of products, such production lines allow a quick response to changing customer expectations and requirements [4,9]. This is, however, associated with certain limitations.