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Extrusion head with an integrated screw and UV-diodes attachments

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Aalto.png This page was part of an Aalto University course 3D Printing of Open Source Hardware for Science

Please leave comments using the discussion tab. The course runs in the Fall semester 2017. It is not open edit.


Extrusion head


Project[edit]

Extrusion of UV-sensitive materials justs starts to be commerically available. A suitable extrusion head for experiments related to such materials (e.g. biomaterials & photoinitiator) can be seen in this concept study.


Concept

This extrusion head can be used for extrusion-based printing processes only. It has a nozzle diameter of 0.5 mm (changes can be conducted with open scad) and an integrated screw, which is attached to a motor and allows accurate extrusion. Additionally, this extruder head can be equipped with up to 4 UV-diodes to allow curing of UV-sensitive printing material. The whole component is designed as one part (non-assembly), suitable additive manufacturing processes are Stereolithography and probably metal- and plastic-based Powder Bed Fusion as well. The crucial factors for printablity are the accuracy level and the removal/existance of support structure. Functionality proved using Stereolithography, problems when using Fused Filament Fabrication because of inner support structures.


Bill of Materials

1) This is a non-assembly! only one part for the actual extruder head: The part can be found at the NIH Printing repository here

2) motor (outer shaft diameter of 5 mm)

3) tube (inner diameter of 4 mm)


Estimated Cost

Part cost of the original design: 25.50 € without shipment and needles. [1]

3D-printed substitute of this part with increased funcionality: 12.75 € using SLS, 21.15 € using SLA, without shipment [2], FFF would result in costs of less than 5 €, but funcionality cannot be guaranteed at this point.

Can be probably also printed as a metal-part (using metal-based Powder Bed Fusion, approx. 50 €). In general, funcionality compared to original design significantly improved: screw cannot pop-out, part more robust, UV-diodes can be added.


Directions

1) Print the part using SLA here(layer thickness 0.050 mm, clear resin, orientation as shown in the picture below), remove supports and post-process it in an alcohol bath and 1-2 h post-cure the component

2) Attach the part to a small motor (outer shaft diameter of 5 mm) and a tube (inner diameter of 4 mm)

3) buy diodes [3]and attach them to the extruder, connect them with each other apply energy

4) on the side of the part you will find a hole for fixations


Designer Niklas Kretzschmar, Aalto University

Parts[edit]

extruder head  
visualization of the inner screw  


Final Prints[edit]

Stereolithography, inside the printer  
Stereolithography, after post-processing  
Fused Filament Fabrication, inside the printer  
Fused Filament Fabrication, after post-processing