Accepted: 17 May 2016 In flexible manufacturing systems the most important element in determining the proper course of technological processes, transport and storage is the control and planning subsystem. The key planning task is to determine the optimal sequence of production orders. This paper proposes a new method of determining the optimal sequence of production orders in view of the sum of the costs related to the delayed execution of orders. It takes into account the different unit costs of delays of individual orders and the amount of allowable delays of orders involving no delay costs. The optimum sequence of orders, in the single-machine problem, in view of the sum of the costs of delays may be significantly different from the optimal order, taking into account the sum of delay times.

Accepted: 8 July 2014The article addresses the problem of determining the sequence of entering orders for production in a flexible manufacturing system implementing technological operations of cutting sheet metal. Adopting a specific ranking of production orders gives rise to the vector of delays and waste in the form of incompletely used sheets. A new method was postulated for determining the optimal sequence of orders in terms of two criteria: the total cost of delays and the amount of production waste. The examples illustrate the advantages of the proposed method compared with the popular heuristic principles.

The paper presents the problem of determining the prioritisation of production orders. The proposed criterion function allows a comprehensive evaluation of various ways of prioritising taking into account both the income derived from the execution of production orders and the penalty for any delays which may occur. The criterion function was implemented in an algorithm based on the operation of a colony of bees. The experiments which have been carried out make it possible to evaluate the solutions obtained through the provided algorithm and compare them with the solutions obtained through the typical heuristic rules. The results show that the prioritisation obtained through the algorithm is characterized by the highest qualities of the criterion function and is definitely superior to that obtained through the simple heuristic rules.

One of the main tasks in the planning of production processes is to satisfy the needs of the customers in terms of quantity, quality and time. The issue of the timely execution of production orders is becoming increasingly important. Based on the conducted studies it can be concluded that the size of the delay depends on the adopted scheduling of orders. This paper focuses on the problem of implementing a scheduling of production orders that will allow to avoid delays, and in the event such a scheduling is not possible, for minimizing the sum of delays of all the orders. A new algorithm has been proposed that allows to determine of the optimal sequence of production orders with the minimum sum of delays. The considerations have been limited to the issue of a two-machine system in which the orders are carried out in a flow.

In the era of Industry 4.0, the digitization of production processes is one of the important elements contributing to the reduction of uncertainty related to the implementation of new production methods. The worldwide epidemic situation and its constraints have resulted in supply chain continuity problems. These problems make enterprises look for the possibility of producing products that they need at the moment and which they cannot obtain from the market. In special cases, this may also apply to spare parts necessary to maintain the continuity of production. The main reason for research on comparing production processes is meeting the challenges related to the pandemic situation and problems in maintaining timeliness, fl exibility, and continuity of the supply chain. The fi rst stage of the research was to visualize the course of the process and determine the lead times for both production methods. For further analysis, a digital process model was used to compare the hybrid and the classical method to check the viability of the interchangeability of methods for the production process of the fl ange part. The interchangeability of production methods was dictated by problems related to the supply of components for the execution of orders. The article simulates the model for unit and small-lot production in batches of 10 and 100 pieces, considering such aspects as: order completion time, energy consumption of the process, production costs, taking into account the classic and hybrid methods. The conducted research was aimed at determining the profi tability of the production of fl ange-type products by means of classical processing and hybrid and checking the interchangeability of production methods in accordance with quality requirements as well as reducing uncertainty with the implementation of new production systems in changing market conditions. The simulations show that the use of hybrid production is recommended for unit production. In the case of small-lot production, already with 10 items, production in the traditional process is 21% cheaper, and for the production of 100 items, the cost of traditional production is reduced by 33% compared to hybrid production.