The electronic factories have problems from the inefficiency of producing and delivering products as PER customer's order. This is because customer orders ended up being more than forecast in some periods of time and the factory did not have enough raw materials to produce customer demands. In duration of time, Customers have suddenly increased the volume of products. The factory does not have enough materials and additional raw materials, ordered will have a lead time of more than the date specified by the customer to deliver the product. If the manufacturer is unable to produce the product according to the Lead Time and Cost agreement with the customer, this will then affect customer confidence and satisfaction. This would cause customers to move their demand to another manufacturer then effect the opportunity cost. From the past about two years data (2021-2023) , It found that orders ended up being more than customer demands by about 51%. This study aims to reduce the problem of material shortage and opportunity cost by selecting the most impact model and do regression by Minitab program. The curve fitting regression was used to forecast the demand that was close to linear line of difference customer orders. The accuracy of the forecast can be decreased to 31% It will use the curve fitting regression for forecast and prepare the material in the future and to avoid opportunity cost.