Colloquia

Summary

With the fourth industrial revolution, manufacturing sectors are transitioning their existing production units into smart factories by integrating intelligent production systems.  Processes like 3D printing have a great potential for being used on a large scale to increase automation and reduce manufacturing lead times (for complex parts). It offers a wide range of design flexibility and is cost-effective compared to traditional methods such as milling and turning. 

The automotive and aerospace sectors use composites extensively. A wide range of materials, including fiber-reinforced composites, are suitable for 3D printing. However, in printed composite parts, warpage and weak interlaminar bonding reduce the printed parts' mechanical properties. Due to this, the use of 3D printing in these sectors is inhibited.

This thesis focuses on developing a 3D printer setup for room temperature printing of long fiber-reinforced composites based on RLDM (Reactive Liquid Deposition Modelling) to overcome some of the associated limitations (warpage and weak interlaminar bonding) with the existing processes for composites. The research is divided into two parts. 

The first part focuses on determining the liquid thermoplastic resin's processability through UV-assisted photopolymerization. Herein, polymer parts are made by experimenting with different parameters associated with the UV light source. AFM, microscopy, and three-point bending tests are done to assess the quality of these polymers. Based on the overall results from these tests, optimal processing parameters for UV-assisted photopolymerization are obtained.

In the second part, these optimal parameters are used to develop a 3D printer setup. Necessary modifications are done to an existing printer to make it compatible with the RLDM method. The parts with and without reinforcements are then printed using this printer. The parts are then validated using density measurements and void content estimation. And an understanding of the part's quality and the influence of the printing parameter on the part's quality is obtained.