Proj 24 – DSV – Plastic Consumables Recycling

Project Roadmap

Research

At the start of our project, we were invited to DSV Global Transport and Logistics warehouse to observe and learn more on their day-to-day operations.

Site Visit

The following table shows the type of materials that were available as well as their primary Polymer Type that was discovered during our site visit

Waste Object	Primary Polymer Type
Plastic Pallet	Low-foam Polypropylene (PP)
Plastic Shelf	High-Density Polyethylene (HDPE)
Shrink Wrap/Top Sheet	Low-Density Polyethylene (LDPE)
Gloves	Nitrile Butadiene Rubber (NBR)
Hair Nets	Synthetic Polymers
Shoe Covers	Chlorinated Polyethylene (CPE)

Feasibility Study

Upon further research on their properties and considering various factors such as Processing/Recycling Methods, Costs of processing, Sustainability Value, Material Volume and Quality, we ultimately decided on the PP sheets due to its overall Low Contamination, high volume availability, ease of sorting and processing and its impact on greenhouse gas emissions. This was further reinforced by our group sentiment, where we believed that the material PP was the most appropriate material in creating the furniture required to refurbish the room as requested by DSV

Processing

To turn the PP sheets into usable material, it underwent through a physically and time intensive process consisting of Pre-Processing, Plastify-Processing and Finishing.

Pre-Processing

In order for our PP material to fit into the specialised machines in Plastify, we had to cut them into smaller pieces. This was done via circular saws and Bandsaws in the Fablab. Other cutting methods proved to melt and potentially damage the sheets, which was not helpful and dangerous. After obtaining the small plastic chunks, we then had to clean these chunks to remove as much contaminants as possible. Presence of such contaminants might structurally hurt the overall homogeneity and cleanliness of our final end product.

Plastify Processing:

With cleaned chunks on hand, we then brought them over to Plastify for further processing. This involved further shredding and carefully laying out the fragments into their sheet press as evenly as possible. The initial pressing took a day to complete, however to further ensure the sheets were truly flattened, we did two more presses for each sheet produced. The end result of our time at Plastify was two beautiful blue PP sheets, which we delivered back to SUTD.

Finishings:

With the sheets on hand, we then begun cutting and iterating our modular units to make our furniture.

Iterations

Term 7 Iterations

Initially, we explored various forms of upcycled furniture, focusing on standard beam constructions and traditional mechanical joint mechanisms using the pressed PP sheets.

Observations: A critical hurdle was encountered during the fabrication phase. The recycled PP sheets exhibited a strong tendency to warp and bend after the pressing and cooling process. Since traditional furniture designs and our early modular concepts relied on tight tolerances and rigid geometry to remain stable, this warping rendered our initial joining methods inconsistent and weak.

Learning Point: We needed a design that could absorb or negate these material imperfections rather than fight against them.

Term 8 Iterations

Our subsequent iterations involved the ‘C-Piece’. From the use of magnetic assemblies for quick assembly, E-Piece Connectors as a companion connector module and physical Dowel joints, our attempts of a flat-packed module was met with further observations and learning points.

To summarise, these iterations highlighted a clear trade-off: designs that were structurally sound (resisting diagonal flex) relied on tight tolerances that our warped recycled PP couldn’t provide, while designs that ignored tolerance (like the magnetic C-Piece) suffered from joint failure. This led directly to our final design philosophy: a zero-component friction joint.

Final Solution: The "X-Piece" Module

To address the material inconsistencies, we adopted a purist approach for our final design, eliminating the need for screws, nails, dowels, or non-plastic adhesives. The result is a standardized modular unit we call the “X-Piece”.

Design Specifications:

Dimensions: A 40cm by 40cm square. Given that our press creates 1m x 1m sheets of recycled PP, a single sheet yields exactly four X-Pieces, minimizing offcuts and waste during CNC milling.
Joinery: The module features four rectangular slots (gaps) cut into the centre of each of its four sides, creating an “X” silhouette.
The Interlock: Crucially, one of these four rectangular gaps is cut deeper than the others, extending all the way to the centrepoint of the square.

Overcoming Warping:

This specific geometry is how we solved the warping issue. By utilizing deep, interlacing friction joints, two X-Pieces can be slid together along their deep slots to form a freestanding “+” sign structure (a cross-section). This simple, robust joint is highly forgiving of slight warps in the plastic, as the interlocking perpendicular planes brace against each other, forcing stability.

This base “+” configuration immediately functions as a sturdy stool base. By continuing to interlock the modules via the shallower edge slots, users can build outwards to form larger structures, such as a bench or, using eight pieces, a complete table.

Life Cycle Assessment (LCA)

A critical component of this project was validating our assumption that upcycling these pallets is environmentally superior to traditional disposal or buying new furniture. We conducted an LCA comparing the production of Virgin PP, our Upcycling Process, and standard commercial furniture (using IKEA products as a benchmark). The energy and carbon footprints for our proposed upcycling stages were estimated by calculating the energy demand of the machines used in each process. This energy use was then converted into carbon emissions based on Singapore’s grid electricity emission factor of 0.402 kg CO₂/kWh.

Baseline 1: Standard Virgin Material Production (per comparable unit)

Process Stage	Energy Footprint (MJ)	CO2 Footprint (kg)
Primary Material Production	1835.125	61.35
Material Processing	720.27	54.325
Usage	0	0
End-of-Life: (Combustion)	-83.475	83.21
Total	2638.87	198.9

Our Solution: Upcycling PP Pallets Process

Process Stage	Energy Footprint (MJ)	CO2 Footprint (kg)
Pre-Processing (Cut, Wash, Shred)	Pre-processing: 7.13 Shredding (~1 hour): 37.8 Total: 44.93	5.02
Heat Press (~1.5 hours)	172.8	19.296
Machining and Assembly (CNC Machining ~2 hours)	36.0	4.02
Total	253.73	28.336

Baseline 2: Commercial Furniture Comparisons

Product	Materials	Energy Footprint (MJ)	CO2 Footprint (kg)
IKEA Coffee Table	Glass, Steel, Particle board	Production: 586.9 End-of-Life: 197.5 Total: 784.4	Production: 257.1 End-of-Life: 1.23 Total: 258.3
IKEA Side Table	Fibreboard (5.96kg)	Production: 65.56 End-of-Life: -125.16 Total: -59.6	Production: 2.21 End-of-Life: 10.73 Total: 12.94
Low Back Armchair	Birch, Polyurethane, Polyester	Production: 317.0 End-of-Life: -173.8 Total: 143.2	Production: 17.89 End-of-Life: 6.48 Total: 24.37

LCA Insight

These figures suggest a substantial environmental improvement. Our upcycling process yields a dramatic reduction in CO2 emissions (~28.3 kg), which is a Substantial 85.8% reduction compared to manufacturing from conventional virgin PP (~198.9 kg). Furthermore, when replacing high-impact commercial furniture like the IKEA Coffee Table (which produces roughly 258.3 kg of CO2), our upcycled PP furniture provides immense environmental savings.

Pictures

A short collage of the journey we had taken from Term 7 to Term 8. It was a long and arduous journey, but a fun and eventful one.

Further Deliverables

Beyond simply delivering our X-Pieces, to ensure that they are practical and accessible for DSV staff to use, we developed accompanying materials and ecosystem to guide assembly, akin to a Lego manual. These include Our Renders, The Digital Cookbook and The Physical Cookbook.

Our Renders

The Digital Cookbook

The Physical Cookbook

The “Digital Cookbook” was designed to make the Plastoform system understandable, usable, and replicable beyond the physical prototype alone. It enables staff to quickly visualise how furniture can be assembled, what configurations are possible, and how much recycled material a design would require. Instead of relying on technical drawings or abstract instructions, users can easily understand the system through a visual, interactive and familiar environment.

The static website includes:

A Process Journal: A living record of the project’s development
The Build Studio: Assemble virtual furniture before committing to fabrication
A Site Planner: Placing virtual furniture within the actual room layout

Recognising that workers on the warehouse floor might not always have access to a digital device, we created a physical “Cookbook.” Similar to instructions included in modular toy sets, this manual provides step-by-step pictorial guides for assembling common, highly useful furniture items utilizing the X-Pieces in an easy-to-follow manner The current edition includes instructions for:

A standard stool
Two variations of a coffee table
A shelving unit

PHYSICAL COOKBOOK

Complete Process Map

While we have described the design process for our furniture thus far, this is what we envision the complete lifecycle of the PP plastic—from its decommissioning as a pallet to its second end-of-life as furniture based on the feasibility and integration of our solution within DSV’s operations.

Decommissioning: PP shipping pallets reach the end of their operational lifespan at the DSV warehouse.
Pre-Processing (Collection & Shredding): The pallets are collected by an external plastic waste management service. They are mechanically broken down into smaller plastic flakes (maximum 10cm by 10cm).
Washing: The shredded plastic pieces undergo a cleaning process to remove dirt, oils, and other warehouse contaminants that could compromise the integrity of the recycled material.
Manufacturing (Heat Pressing): The clean plastic flakes are transported to a local recycling partner (e.g., Plastify). Using a hydraulic heated press, the flakes are melted and formed into flat, 1m x 1m recycled plastic sheets.
Fabrication (Machining): The pressed sheets are cut into the modular “X-Pieces” using a CNC machine or waterjet. (Alternative Scalability Note: For mass production, a specialist could create a mould to produce these pieces directly via extrusion, bypassing the sheet-pressing phase).
Deployment: The finished X-Pieces are transported back to the DSV warehouse, where staff assemble them into desired furniture (stools, tables, shelving) using the provided Cookbooks.
End-of-Life (Second-Generation Recycling): When the furniture is ultimately broken or no longer needed, it can be disposed of into a dedicated PP waste stream. Because this plastic has now been melted twice, its molecular chains will be degraded, resulting in a lower tensile strength. Therefore, this “2nd life” recycled plastic will be diverted to produce non-load-bearing products.

In partnership with :

Supported by :

Acknowledgements

DSV Global Transport and Logistics

Plastoform would like to firstly thank DSV Global Transport and Logistics for the project and their involvement throughout these 6 months. They have provided us with immeasurable and unconditional support and for providing the unique opportunity of working on this sustainability initiative. Specifically, we would like to thank Katherine and Yu Liong for introducing us to the warehouse facilities and for providing the waste plastic pallets that form the basis of our project. Without their support and eagerness to participate in this project, we will not have the chance to try our hand at such an exciting capstone project that has the potential to bring about real impact in sustainability.

Plastify

We would also like to thank our external partner, Plastify, particularly Paul and Yew Jin, for their partnership and hands-on mentorship. Their passion and expertise in plastic recycling is evident through their willingness to collaborate for this project, and has been instrumental in realizing our design goals. Their guidance and tips have also been crucial to the design process of our final product, and they have imparted real-world practical advice that we consider invaluable.

SUTD

We would also like to thank our SUTD Staff: Dr Massimiliano Colla, Dr Zheng Kai, Dr Susan Wong, Dr Dominic Edmund Kim San Quah, Ken, Andy, Mr Goh. Their unconditional support was extremely helpful especially during times when we faced immense difficulty and confusion. Their help was critical in finishing this project from start to end.