## 1 Introduction  
Vegetable oil processing belongs to the essential sectors of the food industry. Vegetable oil is used in the food industry, in food production, and as a raw material in the chemical and medical industries. Since 2011, the Republic of Kazakhstan has been steadily strengthening its position as a producer of oilseeds. The most popular type of vegetable oil in Kazakhstan is sunflower oil; it is consumed by almost 96% of Kazakh families [1]. Sunflower is a major agricultural oilseed crop. In order to ensure food security in the Republic of Kazakhstan, measures are being taken to increase the production of oilseeds. In Kazakhstan, the Northern, Eastern, and part of Western regions are the leaders in sunflower cultivation [2]. The souring area for sunflower seeds increased from 960.5 thousand hectares in 2021 to 1 million hectares in 2022. There are more than 36 high-yielding varieties and hybrids of sunflower, which are characterized by high oil content (46-52%) and low huskiness (23-28%). Production of unrefined sunflower oil in the Republic of Kazakhstan at the end of 2022 increased twofold compared to 2021. At the end of 2021, Kazakhstanoil plants produced 183.6 thousand tonnes of unrefined sunflower oil. In 2022 (from January to November), the processing companies produced 337.6 thousand tonnes of these products [3; 4]. Sunflower oil is a widely consumed and valuable vegetable oil known for its various culinary, industrial, and nutritional applications. Its extraction can be achieved through different methods, such as hard pressing, prepress solvent extraction, expeller pressing (also known as cold pressing), and aqueous extraction [5]. At present, the continuous method of pressing on screw presses is mainly used. It is effective not only because it provides for the mandatory inclusion of screw presses in continuous action lines, but also allows for the complete mechanization of production processes [6; 7]. The screw press, operating within a cylindrical cage, exerts high pressure on the material, resulting in oil extraction. The process begins with feeding the processed sunflower seeds into the hopper of the screw press. Preheating the pressing cage raises the temperature before the actual pressing. As the screw rotates, it pushes the seeds forward against the pressing cage, creating pressure and friction that lead to oil extraction. The oil flows through the gaps in the pressing cage and is collected, while the remaining crushed seeds form the seed cake [8; 9]. Using a screw press ensures a mechanical extraction method without additional chemicals, preserving the oil's quality and nutrient content. The efficiency of oil recovery from sunflower seeds through this method typically ranges from 86% to 92% [10; 11]. During the pressing process, several physical changes occur in the sunflower seeds. The compression exerted on the seeds in the pressing chamber causes them to be crushed and flattened. Squeezing, induced by the pressure and friction from the rotating screw, separates the oil from the solid components of the seeds [12]. The applied pressure can also create cracks in the seeds, facilitating easier oil extraction. The resulting seed cake contains the solid material after oil extraction, rich in protein and dietary fiber, and suitable for use as animal feed [13; 14]. Oilseed screw press manufacturers are mainly focused on the production of large-sized and high-capacity screw presses. For example, the screw presses of Goyum Company (Punjab, India) produce oil presses for high-capacity oil millers (up to 250 tons per day) [15]. Screw presses of MIKIM Machinery (Tianjin, China) are characterized by high capacity (up to 14 tons per day) and high oil yield [16]. In addition to large-sized and highly productive presses, more compact oil presses are produced, specially designed for mini-enterprises and farms. For example, Farmet Company (Ceska Skalice, Czech Republic) is producing screw presses for pressing oilseeds without preliminary preparation of the processed raw material.