Author: Lawrence Jongi
Objective of the project: Was to design a sustainable packaging system for medicine for Sierra Leone for areas with little internet coverage. The packaging should be moist proof, dust proof, temper proof, easily foldable, which can maintain temperatures below room temperature, can sustain shocks during transportation, with a durability of at least 2 years and with unit cost of 12USD/year.
Design for sustainability in terms of heat transfer:
Trapped air is the best insulator, hence trapping air within two leaves (inner leaf and outer leaf) of the container for the four parts excluding the lower and upper part, since these are the load bearing part. This will maintain optimum temperature within the box. The temperature warning functionality will be discussed later, but for now we will expose the engineering calculations of heat transfer which will help the solver in determining the appropriate leaf thickness for both inner and outer section and the thickness of the upper and lower section for the box.
Design for dust proof:
Since the container is air tight, their will be no room for inflow and outflow of air, hence foreign particles will not enter the container, because the top cover will mesh (overlap) with the box over a length of 37 mm and the sealant temper proof tape around this meshing region will enhance dust proof as discussed further in the section below.
Designing for temper-proof and waterproof: the solver proposes to use a tamper-evident seal tape with security labels or features that leaves a hidden pattern or mark once removed, the mark will be having Stock Keeping Unit which is only known in the dispatch and receiving documents. This Stock Keeping Unit can only be authenticated by stores person, either through confirming the numeric or through scanning the barcode or the QR code. The seal is positioned between places where the two parts of the box meet (the top cover and the box), this also reinforces waterproof action. Water-proof property will be enhanced by making a compound material of pulp with organic resin which will be discussed in more detail. The box can be used for 2 years, the only thing that can be changed is the tamper evident seal whenever a new use is initiated.
Remember that no tamper-evident solution is entirely foolproof, but by using a combination of these methods and regularly inspecting boxes for signs of tampering, the solver proposes using thermochromic material or dye (Ultraviolet activated pigment) to significantly enhance the security of the packaging and provide peace of mind to customers. Placing a small pigment inside the box under controlled lighting conditions. When implementing colour-changing materials for security purposes, you can control the lighting conditions during verification or inspection. This typically involves using specific, controlled light sources to trigger the colour change. For example, UV or infrared light sources can be used in controlled environments. Hence if the box has been opened the pigment marking will be exposed to light settings which to not match the control setting, hence giving out a permanent colour. It's important to note that the specific chemical composition of photochromic pigments can vary widely among different manufacturers and products. Some common photochromic compounds include spiropyrans, spirooxazines, diarylethenes, and fulgides. The choice of photochromic molecule and the formulation details are often proprietary and can vary to achieve specific color changes, response times, and durability.
Authentication Process: The security feature may involve an authentication process where trained personnel or specialized equipment (monochromic light emitter) are used to inspect the item under controlled lighting conditions upon dispatch of the payload. This process can be part of a security protocol to verify the authenticity of the box, together with the sealant inspection.
Design for impact and impulse: 3D printed pulp has the capability to act as a custion from external force impulses for the payload. Also, due to 3D printing, the medicine can also be individually separated within the box, making it less likely for the medicine bottles to damage each other, this comes with individualised payload as demanded. Since madicine industrial does not constantly change, it means, these separators can be predesigned and manufactured for specific medicine bottles. Since during transportation most of the impact is vertical, hence the bottom layer of the box will have a thicker layer, not only for impact but also to add extra strength for bearing weight loads. For storage impacts and load bearing capacity, the top part of the box should have an extra layer and should not have an enclosed air pockets for insulation for this will weaken structural integrity of the box.
Design for functionality:
Track and Trace and temperature monitoring In Sierra Leone, mobile internet continues to be the main source of access to the internet, with mobile penetration estimated to be at around 74.7 percent. The solution that the solver is proposing is a data logger for both real time position and temperature, which can easily be accessed when transport system is in reach of internet, even all the data that includes when it was not in coverage can be retrieved, because the RTLS will store this data with its own battery power. The data can be uploaded when the vehicle is now in the range of the Long Range Wide Area Network (LoRaWAN), of which with the percentage of mobile internet in Sierra Leone its feasible for realtime monitoring.
Logistics and supply chain network visibility and collaboration through information sharing, both internal and external to the organization, have been the drivers to give an organization and its network the following benefits and competitive advantages: risk management, decision making support, safety, quality, customer-service, agility, lead time management, demand management, access to information and inventory management. This has been seen as the development of visibility enabling technologies from SKU (Stock Keeping Unit), Bar Code, and QR Codes which needs a line of sight without sensors, to Cyber Physical Systems (CPS) that collects data using sensor technologies, wireless technology communication systems and transmit data to Industrial Internet of Things (IIoT) with no line of sight such technologies include Radio Frequency Identification (RFID tags), Smart Label (Real Time Locating System/RLTS), Geographic Information System (GIS), Global Positioning System (GPS). However, these technologies present the following challenges: budget constraints, risk of losing business, reluctant to provide data, conflict of interest, disparate sources of information, lack of standardization, lack of skills and knowledge, and supply chain complexity. The solver is proposing to integrate real position and temperature monitoring in one sensor, which most either RFID and RTLS sensors come with. The solver is proposing to leverage such kind of technologies, with proper design can yield cost effective designs.
Because of cost issues, it is not cost effective to monitor every box and position in a truck full of payload, but can have one sensor per 10 cubic meters, each sensor monitoring both variables, position and temperature. The issue is choosing the correct technology that fits the situation requirements at a cost effective price. The solver has done a practical research on RTLS technology which uses bluetooth and another which uses WiFi technology respectively, these technologies differ in functionality and effectiveness. These technologies are afffected by electromagnetic waves, from electrical cables, and other inductive machines, however, the WiFi technology performed better. In this situation, the solver would choose the WiFi technology.
Internet of Things Design:
Realtime location monitoring gives away the location if the boxes move to an unsuctioned location, either during transportation or at a cross docking fascility or distribution center or at the company premise. The solver propose to use Node-Red IoT platform which is a free open source. The Node-Red flow is as shown in figure below. Node-Red will request a query from the RTLS of both geo-location and temperature within the box. The primary objective of the IoT is to give notification to emails, mobile sms and dashboard if the box move out of its boundary or path or the temperature within the box has exceeded the threshold. Hence, more boxes with tracking devices for places with historical theft incidences, high theft risk, cross docking, distribution centres or places with less experienced personnel in material handling will be very much wise.
Even if the payload is a milkrun, each RTLS will be given a specific name which respond to the type of medicine in its group, because it will not make financial and technological sense to encoporate sensors in all the boxes. Not giving an visible stock keeping unit number externally makes the box anonymous making it difficulty for thieves to identify the particular medicine they want to steal. All this information can then be stored in the data base (realtime location data, any deviation from the path or boundary and temperature data and any threshold exceeds data). This data is date stamped, and is send as notifications to the key stakeholder on email, sms and on dashboard of the logistic operator. Since temperature data and location comes in pair, the 3PL company can also do data analytics, through mapping of places with the risk of places with the risk of temperature overshooting above 30 degrees celcius. This data will also have time stamp making it also easy to analyse the data over the entire year. This information is important to avoid movement of payload during worst weather days, identified in prediction and recommender systems.
Node-RED can be used to integrate with the geolocation data from Real-Time Location Systems (RTLS) and display the movement of tracked objects or assets on a map. Node-RED is a flow-based development tool that is well-suited for IoT (Internet of Things) applications and data integration tasks, including real-time tracking and mapping, which is what the solver will use in this case. Choosing the practical communication protocol is important as this will ensure efficiency, although the choice can be affected by integrating various technologies from various ventors (for RTLS, database servers, network servers) who use different communication protocol. For this case the solver chooses Message Queueing Telemetric Transport (MQTT) because the case is handling light weight data and the case needs efficient realtime monitoring.
The geolocation conversion node converts RTLS data into appropriete longitude and latitude coordinate system which is appropriete for the maping system, but appropriete nodes should be installed in the Node-Red flow (node-red-contrib-web-worldmap). The function node will process also the payload name, latitude, longtude, icon type and colour, circle and black rspectively if this is the preference. This will be followed by node-red-contrib-web-worldmap node which will display location on google maps. To trace and monitor the object we might need to install geolib and geofence nodes to give boundaries, and it is at this point that installation of all the boundaries that the payload goes through. After this node the solver develops a function or code that ensured notification if the payload is beyond practical distance from the distance, taking note of posible google map error, RTLS technology errors and the noise from inductive machines within the vicinity. For the code the solver assumes anything beyond 20meters from the path or boundary will cause concern and send notifications. The next node is the doployement of notification nodes, email, and mobile sms, followes by a function to manupulate the message content send to the receiptient. Use the MQTT out node to POST to the SMS gatway Application Programming Interface (API) it is at this point that the solver needs API key from the API service provider. The nodes for temperature monitoring are simble, the solver will only add the function that process how threshold are determined i.e above 30 degrees celcius then give notifications to both sms, emails and map dashboard to designated receiptient.
Joining the two temperature and geolocation variables can be joined using the ‘join node based on common identifier, timestamp. Add the timestamp in the function code. Joining the two parameters is critical for analysis and development of reliable and useful database. The solver will choose to present the paired sets of variables as an array in a csv file. Which will be further processed for database storage. After the split node use the split node to replicate the combined variable for various purpose like database and various notifications or even further processing. The last step is to send the joined message to a database using a specific node, it is here that interoperability is important as the database server communication protocol should be integrateble. For this case the solver chooses Mysql, this is done using the function node, that is to configure the joined data with the database. Configure the catch node to handle errors in the flow and send email notifications to IoT engineer. Add the complete node to close the flow at the end of the database. Although, the solver shows the overall flow in Node-Red there is intensive coding in the background. The detailed Node-Red IoT flow for the project is shown below.
By leveraging Node-RED's flexibility and the available mapping and geospatial nodes and libraries, it is possible to create a customized solution for tracking and visualizing the movement of assets and other sensor variables in real-time using RTLS data. Additionally, Node-RED's extensibility allows for integration with various mapping services and tailor the solution to the specific requirements, not mensioning that it is a free platform.
Design for interconnectivity: To avoid use of so many gateways in the workplace for the two technologies they can utilize Long Range Low Power Wide Area Network (LoRaWAN) gateways. It is an upper layer protocol that defines the network’s communication infrastructure for limited network traffic but for a longer range LoRaWAN goes to sleep if not in use which mean it saves battery life of the system, it works with a frequency of 1GHz, which is not impressive for complex networks. It is more applicable in rural areas with less noise and disturbances LoRaWAN can have a range of 10km. This is enough radius to cover those areas with limited or unstable connectivity from the growth point. One interoperability challenge, is making sure before purchase of the RTLS technology, the coordinate system is the same with system people who will be using are familiar with. Installing this system means each vehicle will have a gateway to provide access point for all the sensors in the payload to the LoRaWAN and then the LoRaWAN gives the payload of both the position and temperature to the Internet of Things flow. This flow will then take the sensor payload to the dashboard. The solver proposes use of Node-Red Internet of Things platform which is for free. The flow which will support the IoT is as shown in figure 1.
Human-centric design (ergonomics)
Making solution that is financially viable that makes business sense. The economic sustainability of the packaging is critical for environmental and social decoupling.
Identify and develop what is technically feasible to achieve. Development of the value creation network for the entire supply chain and logistics is important, to understand how this design affects production systems of other actors. Actors should be participants in value creation for success, issues to do with performance, costs, environmental issues, demand will be collaboratively decided to avoid bullwhip effects, reduce costs, poor quality and other issues.
Weight: The package should weight less, for easy of handling during logistics and storage of empty box. The weight of the empty package is 8.87kg.
Foldeability: The design has some hinges at specific points and planes that makes it easy for folding without much thinking. To reduce complexity of the design the box will come in squares, if otherwise certain geometric modifications will be done on the box and also the pulp pressing machine to allow flexibility at the hinges. The process of folding is shown in the working drawings below. The vertical corners for foldeability should allow for at least 50mm expansion at the exterior corners and 28mm at the interior corners, as shown in the diagram below. The external corners (16mmX16mm) remain rigid whilst the interior corners (5mmX5mm) remain also rigid (for manufacturebility however, adjacent faces will be waivy to allow for foldeability. The corners has a stretch capability, enabled by the wavy design.
Ergonomics: The box should have human package interraction that makes it easy for the handler to move the package from point A to point B. The solver will display the scenario with a 450mm X 450mm X 450mm packaging box.
For excellent design it is important to work with people who work with packaging and the IT department for the feasibility and interoperability of the track and trace, how technology ready are the personnel. Desireable for the human users. This stage is stakeholder interraction of value creation collaboration, the key user requirement are always ‘ease of handling’, hence a human product interface is necessary. This is ensured by making the five finger prints at the four sides at the bottom in the middle, and these should be rough enough to ensure grip, for this reason the outer wall leaf should have an extra 2mm for the placement of the thumb engraving, refer to figure below:
Costing
The costing is as in the table below:
No. | Item | Unit Cost/usd | Quantity | SubTotal | Description |
1 | Dry Pulp | 624/ton | 3.88kg | 2.42 | |
2 | Resin | 4.2/kg | 0.005kg | 0.02 | |
3 | Colour Pigment | 1.5/kg | 0.005 | 0.01 | |
4 | Sealing Tape | 16/5m | 1.35m | 4.32 | |
5 | Photochromatic Pigment | 5/gram | 0.1g | 0.5 | The pigment will just be placed as small dot inside the box |
6 | RLTS (location and temp) | 45 | unit | 1.96 | 1 RTLS will be in one box but monitoring 23 boxes |
7 | WiFi Gateway | 49.99 | unit | 2.15 | 4 routers in one truck that caries 93 boxes |
8 | Water | 3.65/m^3 | 0.0277m^3 | 0.11 | |
9 | Catalyst Hardener | 4.5/kg | 0.0001 | 0.01 | |
10 | Energy | 0.28/kWhr | 0.65kWhr | 0.182 | |
11 | Internet coverage | 1.26/GigaByte | 0.3GigaByte | 0.378 | |
12 | SubTotal | 12.06 | |||
13 | Labour (20%) | 2.42 | |||
14 | Adminstration Cost (15%) | 1.81 | |||
15 | Profit (12%) | 1.45 | The implementing organization will demand profit | ||
16 | Total Cost | 17.74 | The total cost is spread over at least two years |
Design for Circularity
By adopting circularity in the design process will increase competitiveness of the enterprise and environmental decoupling through innovative strategies such as Reuse, Recycle, Repair, and Recondition. This is enabled by use of renewable resources and avoid non-renewable resources in production of the box. This is imperative as transparent Environmental Social and Governance issues attract impact investment as product and production systems becomes more sustainable through-out the integrated product and production overall lifecycle. The solver is adopting paper pulp as the primary material for the design
Design the Box:
Start by designing the box with collapsibility in mind. Consider using a hinged or folding design that allows the box to reduce its volume when not in use. Locate hinges places. Using the sample size provided by thy the client, it makes practical sense for the 450cm 450cm and 450cm be the dimensions defining the horizontal plan that seats on the floor or that other subsequent boxes seats on. This optimization choice reduce the volume when the box is folded, as the only foldeable side is the one with the shortest distance, 20cm.
Design Hinges or Folding Mechanisms:
Incorporate hinges or folding mechanisms into the design. These components will allow the box to collapse and expand. Be mindful of the 3D printing limitations, such as layer adhesion, when designing moving parts like hinges. You may need to design and print these components separately and assemble them later.
Designing for Sustainability:
In case when the box is not in use, for optimum use of volume during storage and transportation, the box should be foldeable and the process the solver is proposing is fool proof. This means, the box can be folded along the width or length as shown in the diagram. 3D printing is an additive manufacturing process which reduces elliminates material waste usage throughout the product life cycle. Consumers are increasingly basing their purchasing or use of services decisions on their perception of a company’s sustainability performance, and the SDGs may further strengthen this trend. Understanding the sustainable business case consumers are increasingly basing their acceptance decisions on their perception of a company’s sustainability performance. Although Rescue is mainly focused on social impact investment it is not exempted from this scrutiny, hence they are liable to what happens in the value chain which posses reputational risks which affects intangible assets which weakens trust among stakeholders. This is the main reason why the solver is focusing on the green and sustainable product and production development. Building resilience to costs and sustainability requirements imposed by current and future regional and global legislation is a milestone on environmental decoupling because business cannot succeed in societies that fails.
Design of the 3D Production System:
The production of the box starts with production of detailed engineering drawings, for the box first and then for the specific die. For the 3D printing machine, it is appropriete to choose the one that aligns with the production capacity, as required in capacity planning and requirement engineering. The solver will give details of the drawings for the box when produced and when folded, to show volume utilization after the box utilization.
Heat Transfer Calculations
The solver want to do calculations for design of container box made from paper pulp with air gapes between the four vertical walls (with outer and inner leaf with enclosed airgap) but the bottom and the top sides do not have an air gape. The box has to maintain temperature below 30 degrees celcius and should carry 25 kgs. The outside dimension for the horizontal plan is 450 cm by 450 cm and the height is defined by 450 cm. Hence, the four sides with air gaps are define by an equilateral triangle in geometric sense as shown in the working drawings. Designing a container box made from paper pulp with air gaps for thermal insulation and structural integrity involves considering both heat transfer calculations and strength calculations.
Percentage of binding material by volume
Assumptions in calculations:
Volume Assumptions: Although the percentage of additive materials ranges from 5% to 30%, in this case the total percentage that the solver is going to assumme is 15.25%. This percentage will consitute, bioresin, accelerator agent, starch, alumium sulphate, and if need be colouring pigment. The percentage for alum is less than 1%, for starch the solver will adopt 4%. To attain design levels of structural integrity and moisture resistance, the solver will assumme the bioresin percentage to be 10%. For organic colouring pigment, the solver will assumme 0.2% although this will depend with the level of colour contrast. The accelerant is negligly of small volume and can be as low as 0.05%. The remaining percentage will be assumed by paper pulp which is 84.75%. These constituence will vary with size of the box and the dead load, but in this case this is for a 20cm by 40cm by 60cm to carry 25kg.
Environmental Temperature Assumptions: The highest temperature in Sierra Leone is 35.1 degree celcius although some extreme and rare temperature can be 37 degree celcius which might be for one day per year. Therefore it is practical for 3PL to avoid movement of the payload during specific days with forecasted elevated temperatures. For practical calculation purpose the solver will assume environmental temperature to be 37 degrees celsius to design for the worst case scenario.
Density Assumptions: The approximate density of aluminum sulfate (Al2(SO4)3) at room temperature is typically around 2.67 grams per cubic centimeter (g/cm³) or 2670 kilograms per cubic meter (kg/m³). The approximate density of starch at room temperature is typically in the range of 1.4 to 1.5 grams per cubic centimeter (g/cm³) or 1400 to 1500 kilograms per cubic meter (kg/m³). Here are some general density ranges for common types of bioresins at room temperature (around 25 degrees Celsius or 77 degrees Fahrenheit):
Polylactic Acid (PLA): PLA is a biodegradable bioresin commonly made from cornstarch or sugarcane. Its density is approximately 1.24 to 1.27 grams per cubic centimeter (g/cm³) or 1240 to 1270 kilograms per cubic meter (kg/m³).
Polyhydroxyalkanoates (PHA): PHA is a family of biodegradable bioresins produced by certain microorganisms. The density of PHA can vary depending on the specific type, but it is typically in the range of 1.2 to 1.4 g/cm³ or 1200 to 1400 kg/m³.
Polybutylene Succinate (PBS): PBS is a biodegradable bioresin derived from renewable resources. Its density is approximately 1.27 to 1.33 g/cm³ or 1270 to 1330 kg/m³.
Polycaprolactone (PCL): PCL is a biodegradable bioresin often used for various applications, including 3D printing. Its density is approximately 1.1 to 1.2 g/cm³ or 1100 to 1200 kg/m³.
The solver will definately choose Polycaprolactone, because it is most practical for the case and that it has a lower density, which reduces weight and gives a trade-off in insulation.
Organic Pigments: Organic pigments, which include a wide range of synthetic colorants, tend to have lower densities compared to inorganic pigments. Their densities can vary but are generally in the range of 1.0 to 1.5 g/cm³ or 1000 to 1500 kg/m³.
The solver has already chosen organic colouring pigment because of green design issues.
When seligna wood pulp is compressed into a densified form without additives, the resulting density can increase significantly. Compressed seligna wood pulp densities can fall within the range of 1.0 to 1.3 g/cm³ or 1000 to 1300 kg/m³, depending on the compression process and the desired final density.
Powdered Accelerants: Accelerants in powder form, such as certain types of catalysts or initiators used in resin systems, can have densities typically ranging from 0.5 to 2.0 grams per cubic centimeter (g/cm³) or 500 to 2000 kilograms per cubic meter (kg/m³).
Liquid Accelerants: Some accelerants are in liquid form, and their densities can vary significantly depending on the specific chemical composition. Liquid accelerants may have densities ranging from 0.6 to 2.0 g/cm³ or 600 to 2000 kg/m³.
Solid Accelerants: Solid accelerants, such as certain types of curing agents, may have densities in the range of 1.0 to 2.5 g/cm³ or 1000 to 2500 kg/m³.
Although these densities are subject to change according to the chemical composition from the specific manufacturer, but in this case the solver will choose liquid accelerant because it will yield less throughput time during production, because it is easier to mix all the materials with a liquid accelerant in a short space of time.
Heat Transfer Calculations:
A research by Elia Harb et al shows that more holes in a dry pulp gives a higher thermal resistance and consiquently lowers the thermal conductivity. The research done on dry pulp with air holes for insulation purpose in calculation showed that the the thermal conductivity of dry pulp ranges from 0.0693 to 0.075W/m.K which is not bad compared to superior insulators such as glass wool which seats at a range from 0.03 to 0.05W/m.K. The thermal resistance ranged from 1.1m^2.K/W to 1.218m^2.K/W.
Assimming a homogenous mixture the effective thermal conductivity: Thermal conductivity of dry pulp the solver is assumming to be Keq= 0.0693 W/m.K based on Elia Harb et al research, since this variable can not be derived theoretically but through a series of laboratory test of the finished dry pulp with all its composite materials. Thermal conductivity for air will be 0.0257 W/m.K,. The equivalent thermal resistances were obtained equal to 1.180 -1.218 - 1.10 m2.K/W, 1.218 m. K/W, from there research. Aaumming conduction resistance of the wall or convection heat transfere in a steady state, h, to be 15 for outside the box and 10 W/m2.K for inside the box.
Using simulation tools to optimize the the thickness of the walls as shown below:
The heat transfer according to design hinges on many variables especially on the manufacturing method and materials composites, hence in the value creation network it is critical for the actors to be made aware of this, although the thickness of the leafs plays a key role, its not the primary intervention to enhance insulation. The two wall thickness for the dry pulp on four sides will be at least 6 + 2mm, and the air gap will be 11mm giving a total of 25mm, and the top and the bottom section will be (11 + 2) 13mm thick. With this design the box will last at least 5 years.
Appendix
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