Individual research contributions to Group project

28/02/2025

In this group assignment, I was actively involved in the research and discussion of three projects: SLA 3D printer, drone, and pedestrian traffic light. I was mainly responsible for helping the group to identify the topics and make sure that the research directions were clear, feasible and in line with the requirements of the project.

During the subsequent investigation, I proposed to combine the LiDAR and sensor technologies previously proposed by Peckshien and apply them to the pedestrian traffic light project. This solution uses LiDAR's high-precision environmental sensing capabilities to detect the location and direction of pedestrian movement, and combines it with sensor technology to collect data on traffic flow and other relevant data to optimize the signal's intelligent control. This improvement not only enhances the adaptability of the signal light, improves traffic efficiency, but also effectively enhances pedestrian safety, providing a more innovative and practical technical solution for the project.

Throughout the process, I actively communicated with my group members and exchanged views with each other to ensure the progress of the group assignment went smoothly. I not only paid attention to my own tasks, but also actively listened to the ideas of my group members and offered constructive comments in the discussion to help the team optimize the solution. Through efficient communication and collaboration, we successfully integrated our respective research results so that the project could proceed smoothly as planned, improving the overall efficiency and quality of the group work.

06/03/2025

I provided the team with the first version of the Introduction and Citations, which not only laid a solid foundation but also provided clear direction for the subsequent work. This allows team members to build upon it, discuss, and refine the content rather than starting from scratch, significantly improving overall efficiency.

28/03/2025

Following the video conference, we recognized that there remain multiple aspects requiring refinement in the project. Given the division of responsibilities among team members, I will enhance our primary and secondary research by collecting more empirical data. As advised by Professor Brad, we will conduct focused field investigations in high-traffic residential and commercial areas. Through systematic on-site photographic documentation, we aim to substantiate how our proposed solutions can effectively improve pedestrian safety.

01/04/2025

last week, I added images relevant to our topic to the technical report and reviewed the entire document to ensure coherence and consistency. I assisted my team members in summarizing their citations, standardized the citation format, and revised each section as required. Additionally, I not only gathered more secondary research based on our previous discussions but also conducted primary research—visiting a busy roadway for on-site investigation and documenting the observations through photographs to support the report’s analysis and conclusions。

zhiguang_Reader Response_Final Draft

The Stereolithography (SLA) technique is considered to be the most prominent and popular 3D printing technology and has been used extensively worldwide (Jacobs, 1992). It was first proposed and developed by Hull (1986) and later commercialised by 3D Systems Inc. SLA is a process where liquid photosensitive resin is poured into a vat and UV light selectively polymerises the resin to create high-precision parts. SLA is capable of fabricating parts of high surface quality at fine resolutions down to the micrometre scale (Wu et al., 2016). As the most common resin 3D printing technology, SLA has gained widespread popularity for its ability to produce highly accurate, isotropic, and waterproof prototypes and end-use parts (3DEXPERIENCE Make, n.d.). Professional SLA 3D printers, such as Formlabs' Form 4, can produce walls as thin as 0.2mm, with embossed and engraved details as fine as 0.1mm and 0.15mm respectively (Formlabs, 2024a). Advances in hardware, software, and materials science have made SLA technology more affordable and accessible, transforming prototyping and production workflows across industries.

 

In the construction sector, SLA 3D printing technology offers significant potential for rapid, accurate, and bespoke manufacturing (e.g., topology-optimised structural connectors and customised building envelopes).

 

The main advantage of using SLA is the speed factor, as one of the main challenges of construction projects is the long construction period, which often exceeds the original schedule (Assaf & Al-Hejji, 2006). A major contributor to these delays is the communication challenge, as frequent design changes by architects are difficult to communicate accurately using traditional 2D drawings. In contrast, architectural models produced using SLA 3D printing technology can more visually represent design changes, reducing misunderstandings and improving communication (Formlabs, 2024a). While traditional mold making involves multiple steps (design → prototyping → mold machining → testing) and typically takes 4–8 weeks, 3D printing allows production directly from the digital model, reducing the lead time to 1–2 weeks (Singh & Singh, 2018). For example, Renzo Piano's company, RPBW, used SLA 3D printers to produce its latest model in less than 24 hours (Formlabs, 2024a), and Formlabs' latest SLA 3D printer, the Form 4, prints in as little as two hours, a significant improvement in efficiency (Formlabs, 2024b).

 

The second reason for advocating the use of SLA 3D printing technology in engineering is its high level of accuracy. The core strengths of SLA are its precision and accuracy, making it ideal for processes where shape, fit, and assembly are critical. For example, the tolerances of SLA parts are typically less than 0.05mm, ensuring smooth edges and reducing irregularities that are common with traditional manufacturing methods (3D Systems, 2023). This level of accuracy not only improves the quality of the final product but also saves time and resources by minimising the need for post-processing.

 

The third way in which the adoption of SLA printing has significantly changed the construction industry is in its ability to enable mass production without compromising individuality. Mass customisation (i.e., building products for individual customer orders rather than for stock) has been a goal of the construction industry for decades, and 3D printing technology can help build bespoke products without adding to costs (Wu et al., 2016).

 

Despite the many advantages of SLA, other 3D printing technologies such as Fused Deposition Modelling (FDM) and Selective Laser Sintering (SLS) are also used in the construction industry. Each printing technology offers unique advantages, and the choice of application usually depends on factors such as cost, print time, accuracy, and available materials. SLS has advantages over FDM and SLA for complex designs, and SLS-printed parts have excellent mechanical properties for structural components (Formlabs, 2024a). In contrast, FDM has a wider range of material compatibility (e.g., HIPS, PP, TPE, nylon, PLA, and ABS) and lower material costs ($80 to $210 per litre) compared to SLA’s light-curing resins (Wu et al., 2016). Also, because most SLA printing materials are based on photosensitive resins, they can still be affected by UV light when exposed to sunlight for long periods of time, compared to the materials used in FDM. UV rays can trigger a photodegradation reaction that can lead to yellowing of the material's colour, brittleness, and even loss of performance, making it less durable than FDM (Xometry, 2023).

 

The performance of SLA 3D printing in real-world applications depends on many factors, including print accuracy, material selection, cost control and print speed. Therefore, the construction industry needs to choose the right 3D printing technology, such as SLA, FDM and SLS, to optimise its application. With technological advances and material innovations, the development of SLA 3D printing technology has opened up many opportunities for the construction industry (e.g., significant reduction in CO2 emissions (UNEP, 2022)), but there are still many challenges to its wider application, including suitability for large-scale construction projects, meeting the need for mass customisation, and controlling the lifecycle costs of construction products. Currently, the application of SLA 3D printing technology in the construction industry is still in the exploratory stage, and many customised applications have yet to be fully validated. However, by gradually overcoming technical bottlenecks, this technology is expected to revolutionise the construction industry, driving it in a smarter and more sustainable direction, and ultimately realising a more efficient and environmentally friendly approach to building production.

(Used ChatGPT to check my grammar)

 

References

1. 3D Systems. (2023). Stereolithography (SLA) 3D printing technology. https://www.3dsystems.com/stereolithography
2. 3DEXPERIENCE Make. (n.d.). SLA stereolithography 3D printing services. https://www.3ds.com/make/service/3d-printing-service/sla-stereolithography
3. Assaf, S. A., & Al-Hejji, S. (2006). Causes of delay in large construction projects. International Journal of Project Management, 24(4), 349–357. https://doi.org/10.1016/j.ijproman.2005.11.010
4. Formlabs. (2024a). 3D printing architectural models. https://formlabs.com/asia/blog/3d-printing-architectural-models/
5. Formlabs. (2024b). The ultimate guide to stereolithography (SLA) 3D printing. https://formlabs.com/asia/blog/ultimate-guide-to-stereolithography-sla-3d-printing/
6. Hull, C. W. (1986). Apparatus for production of three-dimensional objects by stereolithography (U.S. Patent No. 4,575,330). U.S. Patent and Trademark Office. https://patents.google.com/patent/US4575330/en
7. Jacobs, P. F. (1992). Rapid prototyping & manufacturing: Fundamentals of stereolithography. Society of Manufacturing Engineers.
8. Singh, R., & Singh, S. (2018). Time and cost comparison between rapid casting and conventional sand casting. Journal of Manufacturing Processes, 34, 307–315. https://doi.org/10.1016/j.jmapro.2018.04.017
9. United Nations Environment Programme (UNEP). (2022). 2022 global status report for buildings and construction. https://www.unep.org/resources/publication/2022-global-status-report-buildings-and-construction
10. Wu, P., Wang, J., & Wang, X. (2016). A critical review of the use of 3D printing in the construction industry. Automation in Construction, 68, 21–31. https://doi.org/10.1016/j.autcon.2016.04.005
11. Xometry. (2023, December 4). 3D printing: SLA vs. FDM. https://xometry.pro/en-eu/articles/3d-printing-sla-vs-fdm/

Reader Response And Thesis Draft#4

 

Stereolithography (SLA) Printing Technology

 

Stereolithography (SLA) printing technology, invented in 1986 by Chuck Hull, is a 'vat polymerisation' 3D printing process that has revolutionised the field of additive manufacturing (3D Systems, 2023). In this process, liquid photosensitive resin is poured into a vat, and UV light selectively polymerises (i.e., cures or solidifies) the resin to create high-precision parts. As the most common resin 3D printing technology, SLA has gained widespread popularity for its ability to produce highly accurate, isotropic, and waterproof prototypes and end-use parts (3DEXPERIENCE Make, n.d.). According to Formlabs (2024), SLA 3D printing offers the fastest speed, highest resolution, sharpest detail, and smoothest surface finish of any 3D printing technology. Professional SLA 3D printers, like Formlabs' Form 4, can produce walls as thin as 0.2 mm, with embossed and engraved details as intricate as 0.1 mm and 0.15 mm, respectively. Additionally, the versatility of SLA materials—from commodity to engineering-grade resins—enables the creation of parts with different optical, mechanical, and thermal properties. Advances in hardware, software, and materials science have made SLA technology more affordable and accessible, transforming how companies approach prototyping, testing, and production.

 

SLA in the Construction Sector

 

In the construction sector, SLA 3D printing technology offers significant potential for rapid, accurate, and customised manufacturing. Despite its many advantages, SLA has certain limitations compared to Fused Deposition Modelling (FDM) technology, which has a similar historical development.

 

One of the major challenges in construction projects is the lengthy construction phase, which often exceeds the original schedule (Assaf & Al-Hejji, 2006). A significant factor contributing to these delays is communication challenges, as frequent design changes by architects are difficult to communicate accurately using traditional 2D drawings. In contrast, architectural models produced using SLA 3D printing technology can demonstrate design changes more visually, reducing misunderstandings and improving communication (Formlabs, 2024). For example, Renzo Piano's company, RPBW, used SLA 3D printers to produce its latest model in less than 24 hours, saving up to 80% of the time it would have taken using traditional manual modelling (Formlabs, 2024). Furthermore, Formlabs' latest SLA 3D printer, the Form 4, can complete prints in as little as two hours, increasing efficiency and offering remote monitoring capabilities, allowing architects to monitor progress in real-time from anywhere (Formlabs, 2024).

 

High Precision in Engineering Applications

 

The high precision of SLA 3D printing technology is particularly evident in engineering applications. SLA's core strengths lie in its precision and accuracy, making it ideal for processes where shape, fit, and assembly are critical. For example, SLA parts typically have tolerances of less than 0.05 mm, ensuring smooth edges and reducing irregularities commonly associated with traditional manufacturing methods (3D Systems, 2023). This level of precision not only improves the quality of the final product but also minimises the need for post-processing, saving both time and resources.

 

Customisation Across Industries

 

The customisation capabilities of SLA 3D printing technology extend beyond the construction sector, finding applications in various industries. According to MDPI (2024), SLA's high-precision and rapid manufacturing capabilities enable the production of customised parts in disaster scenarios, providing timely and effective relief. Similarly, during the COVID-19 pandemic, SLA technology played a crucial role in helping hospitals quickly obtain high-precision medical devices, alleviating resource shortages (ScienceDirect, 2021). These successes highlight the key advantages of SLA 3D printing: speed, precision, and customisation.

 

Comparison with FDM Technology

 

Despite its many advantages, SLA 3D printing technology cannot fully replace Fused Deposition Modelling (FDM) technology for certain applications. FDM, also known as Fused Filament Fabrication (FFF), is currently the most popular 3D printing method in the consumer market. FDM printers build objects by heating and extruding thermoplastic filaments layer by layer and depositing the molten material onto a print platform (Formlabs, 2024). FDM offers unique advantages over SLA, including cost-effectiveness, ease of use, and the ability to produce large functional parts, making it particularly suitable for users with limited budgets.

 

Future Prospects

 

Looking ahead, SLA 3D printing technology is poised for significant advances and wider adoption. With rapid technological iterations and breakthroughs in materials science, SLA is expected to become more optimised and accessible over the next decade. In the construction industry, SLA holds particular promise for improving efficiency, enabling rapid construction, and overcoming technical challenges associated with traditional methods. By reducing manual labour and optimising construction processes, SLA 3D printing technology has the potential to improve site safety and move the industry towards smarter, more sustainable practices.

 

### References

 

3D Systems. (2023). *Stereolithography (SLA) 3D printing technology*. Retrieved from https://www.3dsystems.com/stereolithography

 

3DEXPERIENCE Make. (n.d.). *SLA stereolithography 3D printing services*. Retrieved from https://www.3ds.com/make/service/3d-printing-service/sla-stereolithography

 

Assaf, S. A., & Al-Hejji, S. (2006). Causes of delay in large construction projects. *International Journal of Project Management, 24*(4), 349–357. https://doi.org/10.1016/j.ijproman.2005.11.010

 

Formlabs. (2024). *The ultimate guide to stereolithography (SLA) 3D printing*. Retrieved from https://formlabs.com/asia/blog/ultimate-guide-to-stereolithography-sla-3d-printing/

 

Formlabs. (2024). *3D printing architectural models*. Retrieved from https://formlabs.com/asia/blog/3d-printing-architectural-models/

 

MDPI. (2024). Applications of 3D printing in disaster relief. *Multidisciplinary Digital Publishing Institute, 7*(6), 143. Retrieved from https://www.mdpi.com/2624-6511/7/6/143

 

ScienceDirect. (2021). The role of 3D printing in COVID-19 response. *Scientific African, 12*, e01234. https://doi.org/10.1016/j.sciaf.2021.e01234

Summary Draft #3

Stereolithography (SLA) is a high-precision additive manufacturing process based on slot photopolymerization, which utilizes ultraviolet (UV) light to selectively cure liquid photosensitive resins to build solid structures layer-by-layer, achieving extremely high molding accuracy (±25 μm) (Formlabs, 2024). The superior surface finish (Ra < 0.5 μm) and higher dimensional accuracy of SLA compared to extrusion additive manufacturing technologies such as fused deposition modeling (FDM) make it a standout in applications with complex geometries and high smoothness requirements. In addition, continued innovations in resin materials have further expanded the range of SLA applications, with some resin formulations offering optical transparency approaching that of PMMA, tensile strengths up to 55 MPa (comparable to ABS), and heat deflection temperatures in excess of 200°C. These improvements in material properties, coupled with a gradual decrease in equipment costs, have allowed the technology to expand from traditional prototyping to end-product production (Formlatting) in a variety of industries. End-product production in multiple industries (Formlabs, 2024)

In the construction sector, SLA3D printing technology shows great promise for its ability to produce fast, accurate, consistent, and customized manufacturing.

For example, SLA-printed construction molds can achieve dimensional tolerances of ±0.1%, compared to about ±2% for conventional processes, dramatically improving the accuracy and efficiency of the construction process (Gibbons & Williams, 2004). However, the application of this technology in the construction industry is still constrained by two main limitations: high material costs: photopolymer resins are 40-60% more expensive than the thermoplastics used in FDM (Finnes, 2015). Limited print size: the standard print size of mainstream SLA equipment is 33.5 × 20 × 30 cm³, which somewhat limits its application in the fabrication of large structural components (West et al., 2001).

Utilizing SLA 3D printing technology into the construction workflow has greatly improved efficiency.Delays in manufacturing and assembling molds in traditional construction account for 60-80% of the total project duration (Park et al., 2005). In contrast, SLA-printed molds can reduce lead times by 30-40% by optimizing thermal regulation and reducing labor (Lim et al., 2016). For example, in the manufacture of complex architectural columns, the SLA workflow reduced production time by 22% over steel molds while maintaining ±0.1% dimensional accuracy (Gibbons & Williams, 2004).

For large-scale construction components, the precision and consistency of SLA printing provide distinct advantages. Lim et al. (2016) demonstrated that by employing curved-layer printing paths optimized for SLA, material waste can be reduced by 15–20% while still preserving the structural integrity of components exceeding 8 m³. Moreover, the high dimensional stability of SLA-printed parts—achieving tolerances within ±0.1%—greatly reduces the need for post-production rework and can cut maintenance costs by approximately 25% compared to traditional construction methods. This level of precision is especially critical for fabricating components with tight tolerances, such as interlocking structural elements or façade panels.

Despite the high accuracy of SLA 3D printing, its use in large-scale construction is limited by the volume of the build. west et al. (2001) found that parts larger than 1 cubic meter had to be printed in smaller sections, which then had to be assembled manually. This division poses two major challenges in comparison: Alignment accuracy - the bonding surfaces must be aligned to less than 0.02 mm, which requires specialized tooling. Mechanical consistency - the joints between segments have 18-23% less flexural strength than if printed as a single piece, which affects the overall structural performance.

FDM is proving to be a cost-effective alternative to SLA in applications where structural durability is higher than ultra-high precision. Field data from Zongheng3D (2025) showed a 200% increase in impact resistance of FDM printed parts (15 kJ/m² vs. 5 kJ/m²) and a 40% reduction in material costs (25€/kg for ABS vs. 65€/kg for industrial resins). In addition, accelerated ageing tests by Finnes (2015) have shown that FDM parts retain 85% of their load-bearing capacity after the equivalent of 10 years of weathering, while SLA parts retain only 62% of their load-bearing capacity. These properties make FDM particularly suitable for non-critical structural components such as temporary scaffolding or conduit housings.

SLA 3D printing technology will achieve "targeted adoption" rather than "full-scale replacement" in the construction sector: Its core strength lies in addressing demands for ultra-precision, highly complex components unattainable through conventional methods, while continuous optimization of material and equipment costs will drive its transition from a "luxury resource" to a cost-effective solution. With escalating industry requirements for customization and sustainability, SLA is projected to cover 15–20% of the global precision architectural component market by 2035, collaborating with FDM to establish a tiered additive manufacturing ecosystem.

Reference

1. 1. Finnes, A. (2015).
      Comparative Analysis of Material Costs and Durability in Additive Manufacturing Technologies.
      

   2. Formlabs (2024).
      Technical Specifications and Application Guidelines for Stereolithography Systems.
      Formlabs White Paper.  https://formlabs.com/

   3. Gibbons, R. & Williams, T. (2004).
      High-Precision Mold Fabrication Using Stereolithography in Architectural Applications.
      Journal of Construction Innovation, 12(3), 45-60.
      

   4. Lim, S., Le, T., & Buswell, R. (2016).
      Curved-Layer Printing Optimization for Large-Scale Construction Components.
      Automation in Construction, 68, 21-31.
      

   5. Park, M., Lee, H. S., Kwon, H., & Wang, X. (2005).
      Time Efficiency Analysis in Traditional Construction Workflows.
      Construction Management and Economics, 23(7), 721-735.
      

   6. West, A. P., Sambu, S., & Rosen, D. W. (2001).

      Scale Limitations and Assembly Challenges in Stereolithography-Based Manufacturing.
      Computer-Aided Design, 33(1), 65-80.
      

   7. Zongheng3D (2025).
      Cost-Benefit Analysis of FDM vs. SLA in Construction Additive Manufacturing.
      Zongheng3D Industry Report. https://zongheng3d.com/

Summary + Thesis + Supports #2

Summary

Stereolithography (SLA), a vat photopolymerization-based additive manufacturing process, employs ultraviolet (UV) light to selectively cure liquid resin into solid layers with exceptional precision (±25 μm) (Formlabs, 2024). Unlike extrusion-based methods such as FDM, SLA achieves superior surface finishes (Ra <0.5 μm) and dimensional accuracy, making it ideal for applications requiring intricate geometries and smooth surfaces. Furthermore, advancements in resin chemistry have expanded SLA's material portfolio, with formulations now offering optical clarity comparable to PMMA, tensile strengths rivaling ABS (up to 55 MPa), and heat deflection temperatures exceeding 200°C. These material innovations, combined with declining equipment costs, have enabled SLA to transition from prototyping to end-use production across various industries.

Thesis

In the construction sector, SLA3D printing technology shows great promise for its ability to produce fast, accurate, consistent, and customized manufacturing.

Support #1: SLA demonstrates significant potential through its ability to produce highly accurate and customized components 

Support #2: The integration of SLA into construction workflows has demonstrated measurable efficiency gains

Support #3: SLA's precision and consistency offer distinct advantages.

updated 11/2/2025