Multi-material 3D Electronic Print LED Light (TfCD)

3D printing is used more and more these days for e.g. prototyping and customised products. FDM printing is the most accessible and commonly used technique. With the printer from Voxel8, components can be placed in the part during printing and conducting traces and circuits can be printed to make a working electronic product.

We wanted to validate the way this works and demonstrate it with a prototype of a simple light configuration. Therefore a button cell battery is needed (we used a CR2032) and a LED light.

Step 1: Figure Out How Your Product Should Work

First, you have to come up with a product that you want to build. In our case a two-part LED light with a battery part and a LED-part that can be connected in order to let the light lit.

When designing the product, you have to consider where you want the electric components and where the traces will run that connects the components.
Draw the configuration of your product part(s), traces and components and make sure the connection will work and won’t shortcut the circuit.
When you have the layout of the product determined, open your CAD software and continue with step 2.

Step 2: 3D Modeling the Product in CAD

If you have the layout clear for yourself you can build your idea in CAD software. We used SolidWorks, but other software would work as well.

We started with creating the basic shape of the light’s parts; the battery-part and the LED-part.
Next model the components that need to be inserted in the part. You can either model the shape or outlines of the components you want to insert (in this case the CR2032 battery and 5mm LED) or import it from websites like Grabcad or Thingiverse. This is necessary if you want to insert a component during printing. The printer will pause the print at the moment it reaches the topmost part of the component you want to add.
We have the basic shape of the products and the components. Now you have to insert the conductive traces that will connect the energy source to the light. For the modelling of the traces it important that you keep yourself on the minimum values to have a working connection.
- The size of a trace has to be minimum 0.5mm wide and 0.19mm high (the height of a single printed layer).
- Between the traces there needs to be a distance of at least 1.5mm to ensure that there will not be any short circuiting.
- It is possible to make a vertical trace or a trace in on a slope, however, If you want an angled trace it needs to be between 15° and 30° and there should be sufficient overlap to assure a working trace (keep in mind the layer by layer build of FDM printing).
Keep in mind that the printer will not be able to print if there are any interferences with parts or components. So at the place where you want for example a trace, there should be no material of parts or components passing through the trace.
When finished modelling the assembly of the product is exported as STL file.

Step 3: Import the STL File in Dashboard

Now the STL files can be uploaded into Voxel8’s Dashboard.
- Because the parts, traces and components are combined in one product, the STL files must be imported in Dashboard altogether rather than separately to ensure correct placement relative to each other as appointed in the assembly.
In the "print setup" menu, you can position your product on the print bed.
Also the three options, plastic (for the housing parts), silver (for the circuit) and component (for the battery and LED) can be assigned here to the different parts of the product.
In the "preview code" menu, you can check the steps the printer will do, e.g. When the components have to be inputted in the print. When you have import the file you can give the parts and components different materials (PLA(for housing) or silver(traces)).

Step 4: Send the G-code to the Printer

The next step is to send your file to the printer and start the print. This is done by selecting “Download G-Code”
Now you can import the G-code into the printing program and start the print.
Don’t worry about when you need to insert the components because the printer will pause automatically enabling you to insert the components (in this case the battery and LED).
Finally start the print by pressing the button on the printer’s touchscreen.

Step 5: Insert External Parts During Printing

When the printer reaches the top layer of a component, it pauses in order to let you place the component.
Insert the component and make sure it is fixed properly. Add some super glue or scrap material to secure the component.
Next resume the printer by pressing resume on the printer’s touchscreen and wait until it is finished.

Step 6: Test the Product, Iterate and Enjoy.

We found out that printing horizontal traces is easier than vertical ones. It seems that the vertical traces did not connect well to the battery. However, when pressing the part with the battery, the traces did connect to the battery. So to ensure a properly working device, the product should be modelled in such a way that you can be sure that a connection will be working anytime (the traces should stick out a bit relative to the plastic parts).