Post-harvest losses of vegetables in Ghana can raise up to 50% (Saavedra et al., 2014) depending on the crop. Combatting these losses is crucial for ensuring financial security among commercial smallholder farmers. Amongst other reasons, lack of effective packaging practices is a major contributor to this issue. This thesis therefore focusses on the design of a packaging solution for fresh vegetables for Ghanaian commercial smallholder farmers to reduce post-harvest losses. The challenge lies in designing a simple, cheap and accessible solution that is buildable in the local context.

Extensive literature, desk & field research is conducted to get a broad understanding of the fresh vegetable chain in Ghana and its stakeholders. Part of the research phase takes place in Ghana where stakeholder interviews and field observations are conducted. Visits are made to local farms, markets and supermarkets and interviews are conducted with farmers, market women, consumers, horticulture company and agricultural college. From this opportunities, challenges and barriers within the chain are identified to choose a focus for where to introduce a solution.

With all insights from the research, the focus with the most potential for making impact is chosen together with local stakeholders. The focus of the project with the most potential is: Using banana leaves as transport packaging to local market for tomatoes in crates. The first reason for this is that banana leaves are a cheap material widely available in Ghana that has the potential to be used for packaging purposes. Secondly, inadequate transport packaging is one of the biggest reasons for post-harvest loss. Lastly, tomato is the most grown, eaten and lost vegetable in Ghana. Current packaging in crates offers insufficient protection, but introducing a solution to add to these crates could have a great impact on fighting post-harvest loss without the need for farmers to invest in new crates.

Material tests are performed with banana leaves to discover material boundaries and possibilities of the leaves with which ideas can be evaluated on feasibility. Through rapid prototyping of ideas, iterations are brought to life and evaluated at a fast pace to check their potential. This process eventually leads to the design that has the most potential to reduce post-harvest losses in combination with being cheap and simple to produce without needing many additional resources or tools. This is the leafpad.

The leafpad is a transport protection sheet for transporting tomatoes in crates that can be produced by Ghanaian farmers themselves and is placed in between layers of tomatoes when being transported in wooden crates. The leafpads consist of layers of banana leaves placed over each other and glued with the veins perpendicular to each other. This increases the strength of the sheets. During drying of the sheets, the leaves shrink slightly, creating air pockets that give the sheets thickness that functions as padding. The leafpad absorbs shock and vibration during transport as a result of bad road conditions and function as a layer between the fruits so they don’t directly touch each other. For the production some simple tools are used that can be created at home by the farmers themselves with the help of an instructions guide. Materials are widely available in Ghana and production is cheap.

The design is validated through a transport simulation test and validation with stakeholders in Ghana. For future development scaling up the production process and turning it into a business is recommended so that farmers and other target groups can buy the sheets readily made, eliminating the need for taking time to produce the leafpads at home.

“3D Printing of Large Objects with PET Flakes” is the Graduation project of Daniël Eikelenboom of the Faculty of Industrial Design Engineering of the TU Delft for the Rotterdam based company 3D Robotprinting. The project focusses on the development and implementation of an ‘all-inclusive’ PET bottle recycling unit containing a large-scale 3D printer as made by 3D Robotprinting and the development of a preliminary set of guidelines for manufacturing products using the 3D printer. The aim is to enable the 3D printer to use PET flakes gained from bottles as feedstock. Therefore, the 3D printer was adapted and guidelines for manufacturing were developed. An iterative approach is followed, in which the exploration of the ‘novel’ source material and defining the design guidelines for manufacturing are at the heart of the project. After defining the context, the 3D printer was analysed and a literature study was performed, from which was concluded that the current polymer extrusion machine is likely too small to process the initial flake sample. With an initial sample of the material, experiments were performed in order to examine directions for a possible solution and to determine the most important properties, like flake material density, particle size distribution and funnel flow behaviour. By increasing the polymer extrusion screw channel depth at the feeding zone to 8 mm and compression ratio to 4:1 (resulting in a screw diameter of 30,4 mm), the 3D printer should be able to process PET flakes with a diameter up to 4 mm. To ensure the material does not contain particles larger than 4 mm in diameter, it should be shredded, granulated with a 3 mm mesh and sifted using a 4 mm sieve consecutively. Using literature of previous experiments, preliminary design guidelines for creating products with the 3D printer from 3D Robotprinting were set up. From a set of ideas gained from context analysis, a children’s slide was chosen to experiment on. Multiple prototyping rounds were done to perfect the slide’s printing performance and to refine the design guidelines. The project’s final results are: • Advised dimensions on the most important part of the system: the polymer extruder. • A list of preliminary design guidelines for optimizing a product for manufacturing on the 3D printer. • A children’s slide showing the application of the design guidelines.