Preliminary Design on Screw Press Model of Palm Oil Extraction Machine The concept of the screw press is to compress the fruit bunch between the main screw and travelling cones to extract the palm oil. Visual inspection, model development and simulation of screw press by using Solidworks 2016 and calculation of design properties were performed to support the investigation. The project aims to analyse different design of screw press which improves in reducing maintenance cost and increasing lifespan. The currently existing of screw press can endure between 500 to 900 hours and requires frequent maintenance. Different configurations have been tried in determination of best design properties in screw press. The results specify that screw press with tapered inner shaft has more total lifespan (hours) compared existing screw press. The selection of the screw press with tapered inner shaft can reduce maintenance cost and increase lifespan of the screw press. The palm farmers of Bangladesh are suffering for want of an extraction machine. Therefore, a research was undertaken to design and develop a manually operated palm oil extraction machine at the department of Farm Power and Machinery, Bangladesh Agricultural University. It is a press type machine. A screw leads a piston manually in a perforated cylinder to press the mesocarp (pulp of palm fruit) to extract oil. The volume of the cylinder of the machine was found 0.03 m3 and maximum 20 kg fruits can be accommodated at a time. The amount of crude palm oil press at full capacity of the machine was found 8 kg/hr., which is higher than any manually operated extracting machine available in the market. The crude oil extraction efficiency of the machine without palm kernel was also found satisfactory. Application force on screw can be increased by increasing the length of the handle and number of persons according to filling condition of the cylinder. The machine was developed with locally available materials for having low purchase price and smooth repair and maintenance. So that, it will be easily affordable to the palm farmers of Bangladesh. The developed machine will solve the burning need of palm farmers in Bangladesh. One of important sources of biomass-based fuel is Jatropha curcas L. Great attention is paid to the biofuel produced from the oil refinery extracted from the Jatropha curcas L. seeds. A mechanised extraction is the most efficient and feasible method for oil extraction for small-scale farmers but there is a need to extract oil in more efficient manner which would increase the labour productivity, decrease production costs, and increase benefits of small-scale farmers. On the other hand innovators should be aware that further machines development is possible only when applying the systematic approach and design methodology in all stages of engineering design. Systematic approach in this case means that designers and development engineers rigorously apply scientific knowledge, integrate different constraints and user priorities, carefully plan product and activities, and systematically solve technical problems. This paper therefore deals with the complex approach to design specification determining that can bring new innovative concepts to design of mechanical machines for oil extraction. The presented case study as the main part of the paper is focused on new concept of screw of machine mechanically extracting oil from Jatropha curcas L. seeds. The use of bioenergy as energy derived from biofuels in the world permanently increases [1, 2]. Biomass-based fuels as renewable organic source of bioenergy have advantages (e.g., no harmful carbon dioxide emissions, reduction of dependency on fossil fuels, and versatility) and some disadvantages (e.g., requiring more land, relative ineffectiveness when compared to gasoline, and problematic supply chain) as well [3–6]. One of important sources of biomass-based fuel is Jatropha curcas L. [7–10]. Jatropha curcas L. is crop with inconsiderable potential due to its high oil content, rapid growth, easy propagation, drought tolerant nature, ability to grow and reclaim various types of land, need for less irrigation and less agricultural inputs, pest resistance, short gestation periods, and suitable traits for easy harvesting enumerated [11]. Biooil extracted from Jatropha curcas L. seeds has positive chemical properties (e.g., better oxidative stability compared to soybean oil, lower viscosity than castor oil, and lower pour point than palm oil) [12]. Jatropha significant advantage is that it is one of the cheapest sources for biodiesel production (compared to palm oil, soybean, or rapeseed) [13]. On the other hand former and recent findings [14–17] also show that researchers, economists, biochemists, farmers, machine designers, and biofuel producers should not just automatically follow the initial Jatropha hype but critically reflect on, for example, current economic situation, state biofuel policy, institutional factors, labour costs, water irrigation, local differences, and last but not least farmer's needs. The evaluations [15], for example, opened many questions connecting with Jatropha processing profitability. One of the recommendations in [15] mentioned mechanised extraction as the most efficient and feasible method for oil extraction for small-scale farmers. Consequently one of the strategies of how to produce biofuel from Jatropha curcas L. in more efficient manner is to increase the effectiveness of oil processing machine, which would increase the benefits of small-scale farmers. This objective can be achieved through the further innovations of mechanical expellers or presses for small-scale farmers. Due to the great attention paid to this issue [18–26] innovators should be aware that further Jatropha-presses development is possible only when applying the systematic approach and design methodology in all stages of engineering design as an essential part of Jatropha-press life-cycle. Systematic approach in this case means that designers and development engineers rigorously apply scientific knowledge, integrate different constraints and user priorities, carefully plan product and activities, and systematically solve technical problems. Basic phases of the engineering design process have been in the past developed into more detailed procedures focused on the systematic development [27–33], on creative solution of technical problems [34–37], or on the preliminary and detailed embodiment design [38–40]. The correct definition of the right problem in the form of design specifications is widely regarded as a decisive step towards the effective implementation of all engineering design procedures [41–43]. Two information transformations are required to determine design specification. During the first information transformation the user's needs are translated to functional requirements. The second information transformation takes place when converting the functional requirements to machine characteristics (design specifications) that have been selected to ensure fulfilment of specified functional requirements. By performing these transformations design assignment is then defined as an information input to concept generation phase and subsequent detailed designing. During this process various methods such as marketing research [44, 45], voice of customer (VOC) [46, 47], usability testing (thinking aloud protocol) [48, 49], Kansei engineering [50, 51], or quality function deployment (QFD) [52–54] are systematically utilized. Innovation science using function-object analysis [55, 56] or main parameter value [57] is also important to mention. For the conceptual design phase of innovation process is suitable to use modern creative techniques supporting idea generation and overcoming technical and physical contradictions based on TRIZ [58–61]. The process of concept generation is finished by choosing between concept alternatives by simple evaluation charts [28] or advanced techniques or analytic hierarchy process [4]. Since the above methods are becoming standards when upgrading technical products in 21st century it is clear that further development and innovation of machine for mechanical extraction of oil from Jatropha curcas L. require similar advanced techniques and methods. In today's world of technology, which leads to accelerated development, for example, in technologies or material science, to include to the mentioned transformations only information from users (farmers) or information about other similar products is insufficient. That is because users do not have and cannot have sufficient knowledge of the possibilities of current technologies or have not access to information about trends in the relevant fields of technology. Users (farmers) can only guess at what is possible in present and near future design. For that reason it is necessary to enrich traditional approach to determination of the design specification. First technological, ecological, economic, and social trends should be included in a set of functional requirements (needs)—Figure 1. Second relevant engineering characteristics with affinity to technological, social, or economic trends should be involved into process of design specification determining as well (Figure 1). Third designers should additionally include information obtained by modelling that can objectively on the basis of physical and chemical laws extend set of suitable engineering characteristics describing future machine (Figure 1). Basic functions of the oil dewaxing machine consist in separating the solid component (structures) and liquid component (oil). Linear or nonlinear pressing (vertical, horizontal, or angled) by a sliding piston or rotary screw is frequently used for small-scale production. As the technological set-up for Jatropha processing is not yet fully developed and progress may be made in terms of mechanisation [15] we present mentioned complex approach in the following case study focused on conceptual design of screw extractor press extracting biooil from Jatropha curcas L. seeds for small-scale production. First, the research team analysed sources [7–9, 13–17, 19] and information obtained during interview realized in Sumatra and Java (Indonesia)—Figure 2. Low production cost [14], high productivity [16], and higher oil yield [19] were considered as essential extracting machines user's needs (Table 1).