Spare parts system analysis with supply risks and a recycling option

For a supplying company it is important to have enough parts on stock to satisfy their customers. While finding the optimal stock level the company has to take into account a lot of different factors, especially when the company is depending on another supplier company that has to deal with supplying risks as random lead times and supply disruptions. We will look at the effects of not considering the risks in the optimal policy by using a markov-modulated queuing system created by Hekimoglu et al. (2018). We also will try to reduce the total costs by adding an option where the orders can be fulfilled by recycled parts. For the company the most important thing is knowing the situation they need to deal with, no matter how hard the situation is you have to know so you can adapt to the situation and get the best results possible.