## 5 Conclusions  
This paper reports an experimental study on a novel manufacturing process for adding complex features to 3D-printed components. Automation and cold embossing have been used to imprint lens features onto the surface of ABS polymer parts. This scientific finding underscores the delicate balance required in cold embossing processes, where precise control over parameters like \(\mathrm{E_{t}}\) and cycle time is essential for successful replication. The following conclusions can be made based on the reported research:  
* The first hypothesis (H1) established that the developed VS conditions are correctly set for the cold embossing process. Gloss analysis is performed on the parts to test H1. The pooled average of all 169 measurements show that the VS has a significant influence on gloss on the test parts. The GU result evidences that surface softening has occurred, which is a pre-condition for cold embossing.
* Conventional HE of polymers is a time-consuming process. In this research the second hypothesis (H2) establishes that a high-speed automation process with correctly controlled factors for cold embossing can imprint Fresnel lens design features onto 3D-printed ABS parts. It was demonstrated that 48 embosses can be performed in just over one minute.
* Replication quality is dependent on embossing time (\(\mathrm{E_{t}}\)) and embossing velocity (\(\mathrm{E_{v}}\)). A low \(\mathrm{E_{t}}\) of 0.01 s resulted in no observed replication of the lens features. In contrast, an increase in \(\mathrm{E_{t}}\) to 0.1 s yielded optimal results, with all tests across 48 segments of the test piece successfully embossed.
* This study reveals that polymer flow is hindered by insufficient cycle times, but excessive durations lead to surface-hardening of the polymer, obstructing effective replication.  
The insights from this research pave the way for advancements in integrating complex features, such as Diffractive Optical Elements, into 3D-printed parts. Automation enhances the potential for both precision and productivity, enabling the production of 3D-printed products with functionalities that exceed standard printing capabilities. However, for broad adoption of this novel method across various 3D-printed products and ABS-based applications, future research must address several challenges associated with traditional HE of polymers. These challenges include feature characterisation, replication fidelity of nanoscale structures, adhesion and demoulding forces between the stamper and component, air evacuation, incomplete cavity filling, and precise alignment between the component and stamper.  
**Author Contributions:** Conceptualization, C.A.G.; methodology, C.A.G.; validation, A.R.; formal analysis, C.A.G.; investigation, A.J.M.; data curation, A.J.M.; writing--original draft preparation, A.J.T.; writing--review and editing, A.J.T. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Data Availability Statement:** The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflict of interest.