A 3D printer that prints integrated electronics

Abstract

The goal of the project is formulated. The process to tackle the project is visualised. The goal of this project is: Building a cost-effective, compact and simple 3D printer that can print electronics for technical integration of prototypes. This thesis is the basement of this project goal, therefore the focus was on developing the extruder that prints conductive material and how this goes together with filament. In the research phase, first research questions are formed to structure the research. The main research question is: What is needed to make a cost-effective extruder printing integrated electronics? Based on this question and on the goal of the project sub questions are made. These sub questions are answered per chapter. From the research it can be concluded that solder paste will be used as conductive material, for having a good conductivity and low price. For the extruding method, it has been chosen to continue with the Archimedes screw and plunger method. These are low cost, simple and compact solutions. There are several thermoplastic filaments possible that might be able to withstand the heat of curing. The shape of the trace has to be found out as this has influence on curing the solder paste. The way of curing solder paste has to be found. The solder paste is cured in the oven. In conceptualization phase the two main things are explored, how to cure the solder paste and how to extrude solder paste. Three big experiments are done to find the right combination of solder paste with the thermoplastic filament and the reflow settings. Next to this, an extrusion method has been chosen. The solder paste has the composition of: Sn42Bi57,6Ag0,4. The melting temperature is 138 [oC]. The chosen thermoplastic material is PLA X3, this filament can withstand the curing temperature. Curing has been done in the oven, heating the oven to 142 [oC] with the sample in the oven. Then leaving the sample at this temperature for ten minutes, when the sample has cooled down by opening the door the electric circuit is ready to be used. The prototype of the extruder head, that has been developed, has two extruders: the thermoplastic extruder and the solder paste extruder. The bracket is designed as such so the thermoplastic extruder can be lifted manually. The printing process is as follows: 1. Design the 3D CAD model 2. How to slice and adjust the g-code 3. Preparing the printer 4. Printing the solder paste in the 3D print 5. Pick and place components 6. Curing the 3D print Making sure to design the prototype according to a set of design guidelines. The most important guidelines are to design the electric circuit in 2D and to 3D print the circuit in the XY plane. To proof the designed concept and settings are working a demonstrator is developed. It is wanted to create a simple prototype that easily proofs the printers capacities. There is chosen to make a flashlight. After some iterations the final design is simple: containing a battery, an LED, a resistor and a switch. The future of the designed proof of concept is shown. The 3D printer can print prototypes with an integrated electric circuit at a low cost. After the developed proof of concept, the project is evaluated on the basis of the design rules and design drivers. The project goal is satisfied. A cost-effective, compact and simple proof of concept for a 3D printer that can print electronics for technical integration of prototypes is designed. A solid base has been created that can easily be broadened and used to develop a product out of it. The most important recommendation is to further research the possibilities to 3D print the solder paste.