📚 Case Study in Action: Designing a Sustainable Desk Organiser | 案例分析实战演练：设计可持续桌面收纳盒
In this article, we will walk through a complete engineering case study focused on designing a sustainable desk organiser for students. The aim is to demonstrate how engineers apply a structured design process to solve real-world problems, from identifying needs to evaluating the final prototype. All steps align with the Edexcel Year 9 Engineering curriculum, highlighting materials, manufacturing, costs, and environmental impact.
在本文中，我们将完成一个完整的工程案例分析，重点是为学生设计一款可持续的桌面收纳盒。目的是展示工程师如何应用结构化设计流程来解决现实问题，从识别需求到评估最终原型。所有步骤均与 Edexcel 九年级工程课程大纲保持一致，突出材料、制造工艺、成本以及环境影响。
1. Understanding the Problem | 理解问题
ity and causes stress. The challenge is to design a desk organiser that is affordable, durable, and environmentally friendly. It must hold pens, pencils, a ruler, an eraser, and a small notebook, while fitting within a space of 25 cm × 15 cm × 10 cm.
任何工程项目的第一步都是明确定义问题。学生常遇到的一个问题是桌面杂乱，这会降低学习效率并造成压力。我们的挑战是设计一款价格合理、耐用且环保的桌面收纳盒。它需要容纳钢笔、铅笔、一把尺子、一块橡皮和一个小的笔记本，同时其尺寸需控制在 25 cm × 15 cm × 10 cm 的空间内。
Target users are secondary school students aged 13–15, who may carry the organiser between home and school. The design must therefore be lightweight (under 500 g) and easy to clean. This problem statement guides all subsequent decisions.
目标用户是 13 至 15 岁的中学生，他们可能会在家和学校之间携带收纳盒。因此，设计必须轻便（低于 500 g）且易于清洁。这一问题陈述将指导后续所有决策。
2. Research and Analysis | 研究与分析
Before generating ideas, engineers research existing products and user needs. We surveyed 30 students and found that 80% preferred a modular organiser over a fixed single-compartment box. They also valued a pen holder that prevents tipping and a dedicated slot for a smartphone.
在产生创意之前，工程师需要对现有产品及用户需求展开调研。我们调查了 30 名学生，发现 80% 的人更倾向于模块化收纳盒而非固定单隔间盒子。他们还看重能防止笔筒倾倒的设计以及一个专用的智能手机插槽。
An analysis of existing desk organisers revealed that most are made from injection-moulded polypropylene, a petroleum-based plastic. While cheap, they have a high carbon footprint and are rarely recycled. Bamboo and recycled cardboard alternatives exist but often lack durability or moisture resistance. This research pointed towards a hybrid design using a natural material for structure and minimal plastic for functional components.
对现有桌面收纳盒的分析显示，大多数产品由注塑聚丙烯制成，这是一种石油基塑料。虽然价格便宜，但其碳足迹高且很少被回收。市面上也存在竹子和再生纸板替代品，但它们往往缺乏耐用性或防潮性。这项研究指向了一种混合设计，即使用天然材料作为结构主体，而仅用少量塑料制作功能部件。
3. Design Specification | 设计规格
A clear design specification translates the problem and research findings into measurable criteria. Our specification includes:
- Dimensions: ≤ 25 cm (length) × 15 cm (width) × 10 cm (height).
- Mass: ≤ 500 g.
- Material: body made from bamboo plywood; connectors 3D-printed from PLA bioplastic.
- Compartments: minimum 3 separate sections for pens, small items, and a phone.
- Stability: base must have a non-slip pad; centre of gravity below 5 cm when loaded.
- Cost: raw material cost under £3 per unit.
- Sustainability: at least 70% of the material by weight must be renewable or recycled.
一份清晰的设计规格将问题陈述和研究成果转化为可衡量的标准。我们的规格包括：
- 尺寸：≤ 25 cm（长）× 15 cm（宽）× 10 cm（高）。
- 质量：≤ 500 g。
- 材料：主体由竹胶合板制成；连接件采用 PLA 生物塑料 3D 打印。
- 隔间：至少 3 个独立区域，分别用于放置笔、小物件和手机。
- 稳定性：底座必须带有防滑垫；加载后重心低于 5 cm。
- 成本：每件原材料成本低于 3 英镑。
- 可持续性：按重量计至少 70% 的材料必须为可再生或回收材料。
These specifications will be used to test the final design against user requirements.
这些规格将用于对照用户需求检验最终设计。
4. Material Selection | 材料选择
Choosing the right material is crucial for meeting the specification. Bamboo plywood was selected for the main body because it is a fast-growing grass with high strength-to-weight ratio, comparable to hardwood. It can be laser-cut with precision and requires no toxic finishes. Bamboo is biodegradable and has a low embodied energy of about 2.5 MJ/kg, compared to 80 MJ/kg for aluminium.
选择合适的材料对于满足规格至关重要。选择竹胶合板作为主体材料，因为它是一种生长迅速的草本植物，具有与硬木相当的高强度重量比。它可以被激光精确切割，且无需使用有毒涂料。竹子是可生物降解的，其内含能约 2.5 MJ/kg，而铝则为 80 MJ/kg。
For connectors and hinges, polylactic acid (PLA) was chosen – a bioplastic derived from corn starch. It prints at a low temperature (around 200 °C) and, although its biodegradability requires industrial composting conditions, it avoids fossil fuel usage. Non-slip pads can be made from recycled silicone offcuts. All materials comply with the 70% renewable content rule.
对于连接件和铰链，选择了聚乳酸 (PLA)——一种来源于玉米淀粉的生物塑料。它可在较低温度（约 200 °C）下打印，尽管其生物降解性需要工业堆肥条件，但它避免了化石燃料的使用。防滑垫可以采用回收的硅胶边角料制作。所有材料均符合 70% 可再生含量规则。
5. Manufacturing Processes | 制造工艺
The manufacturing plan must balance precision, speed, and cost. The bamboo sheets (3 mm thick) will be laser-cut using a CO₂ laser cutter, producing smooth edges that require minimal sanding. This subtractive process generates digital files from CAD software, enabling rapid prototyping and easy design changes.
制造计划必须平衡精度、速度与成本。厚度为 3 mm 的竹板将使用 CO₂ 激光切割机进行切割，产生的光滑边缘几乎无需打磨。这种减材制造工艺利用 CAD 软件生成的数字文件，能够实现快速原型制作及轻松的设计变更。
PLA connectors will be 3D-printed using fused deposition modelling (FDM). This additive process minimises waste, as unused filament can be retained on the spool. Printing time for all connectors is approximately 45 minutes per unit. Assembly is done without glue; the parts snap-fit together using tapered dovetail joints, which can be designed in Fusion 360. This design for assembly reduces labour and allows disassembly for repair or recycling.
PLA 连接件将采用熔融沉积成型 (FDM) 进行 3D 打印。这种增材工艺能最大限度减少浪费，因为未使用的丝材可保留在卷轴上。每件所有连接件的打印时间约为 45 分钟。组装无需胶水；部件通过锥形燕尾榫接头卡合在一起，这些可在 Fusion 360 中设计。这种面向装配的设计减少了劳动力，并允许拆卸维修或回收。
6. Cost Analysis | 成本分析
A detailed cost breakdown ensures the product stays within the £3 raw material budget. For one unit:
- Bamboo sheet (300 mm × 200 mm × 3 mm): £0.80 (bulk purchase reduces unit price).
- PLA filament (15 g): £0.45 (assuming £30/kg spool).
- Recycled silicone pad: £0.10.
- Total material cost: £1.35, well under the limit.
详细的成本细目确保产品能维持在 3 英镑的原材料预算内。对于单件产品：
- 竹板（300 mm × 200 mm × 3 mm）：0.80 英镑（批量购买降低了单价）。
- PLA 丝材（15 g）：0.45 英镑（假设卷材价格为 30 英镑/kg）。
- 回收硅胶垫：0.10 英镑。
- 原材料总成本：1.35 英镑，远低于上限。
7. Prototyping and CAD Modelling | 原型制作与 CAD 建模
A virtual prototype was created in Autodesk Fusion 360 to check fit and aesthetics before physical cutting. The CAD model allows stress simulation: simple finite element analysis (FEA) showed that the bamboo base deflects less than 0.2 mm under a 1 kg load, which is perfectly acceptable. The dovetail joints were parameterised so that dimensions can be updated automatically if manufacturing tolerances change.
在物理切割之前，我们使用 Autodesk Fusion 360 创建了虚拟原型，以检查装配和美观性。CAD 模型可进行应力模拟：简单的有限元分析 (FEA) 显示，竹底板在 1 kg 载荷下的挠度小于 0.2 mm，完全可接受。燕尾榫接头被参数化，这样当制造公差变化时，尺寸可以自动更新。
An initial cardboard mock-up was built to test ergonomics. This low-fidelity prototype revealed that the phone slot needed to be angled at 15° for better viewing. That change was immediately reflected in the CAD design. After one iteration, the final design was sent to the laser cutter and 3D printer.
我们制作了一个初步纸板模型来测试人体工程学。这个低保真度原型显示，手机插槽需要倾斜 15° 以获得更好的观看角度。这一更改立刻反映在 CAD 设计中。经过一轮迭代后，最终设计被发送至激光切割机和 3D 打印机。
8. Testing and Evaluation | 测试与评估
Testing was performed against the original specification. The organiser weighed 480 g, within the limit. The base’s non-slip pad kept it stable on a smooth desk inclined at 10°. A drop test from 0.5 m onto a carpeted floor showed no cracks or joint separation, indicating good impact resistance. Users rated ease of access and appearance 4.5 out of 5 in a survey of 20 peers.
我们依据原始规格进行了测试。收纳盒重量为 480 g，符合限制要求。底座防滑垫使其在倾斜 10° 的光滑桌面上保持稳定。从 0.5 m 高度跌落到铺有地毯的地板上的测试未出现裂纹或接头分离，表明良好的抗冲击性。在对 20 名同龄人的调查中，用户对取用便捷性和外观评分为 4.5 分（满分 5 分）。
However, one failure was noted: the central divider in the bamboo body warped slightly after exposure to high humidity (85% RH for 24 hours). A design revision added a thin layer of natural beeswax as a moisture barrier, which solved the problem without adding harmful chemicals.
然而，发现了一个缺陷：在暴露于高湿度环境（85% RH，24 小时）后，竹体中的中央隔板出现了轻微翘曲。设计修订增加了一层薄薄的天然蜂蜡作为防潮层，这在不添加有害化学物质的情况下解决了问题。
9. Environmental Impact Assessment | 环境影响评估
A simplified life cycle assessment (LCA) was carried out to quantify the organiser's ecological footprint. The raw material stage accounts for 0.35 kg CO₂ equivalent per unit, dominated by bamboo cultivation and PLA production. Manufacturing energy (laser + 3D printing) contributes 0.20 kg CO₂e. Transportation and end-of-life are negligible because bamboo can be composted and PLA can be industrially composted, though current infrastructure is limited.
我们进行了一项简化的生命周期评估 (LCA)，以量化收纳盒的生态足迹。在原材料阶段，每件产品产生 0.35 kg 二氧化碳当量，主要来自竹子的种植和 PLA 的生产。制造能耗（激光 + 3D 打印）贡献了 0.20 kg CO₂e。运输和报废处理的影响可忽略不计，因为竹子可堆肥，PLA 理论上可工业堆肥，尽管目前基础设施有限。
Compared to an equivalent injection-moulded polypropylene organiser (1.2 kg CO₂e per unit), our design reduces carbon emissions by approximately 54%. This aligns with UN Sustainable Development Goal 12, responsible consumption and production.
与同等的注塑聚丙烯收纳盒（每件 1.2 kg CO₂e）相比，我们的设计减少了约 54% 的碳排放。这符合联合国可持续发展目标 12——负责任的消费和生产。
10. Final Design and Conclusion | 最终方案与结论
The final design is a modular desk organiser with a bamboo plywood base and vertical dividers, connected by bioplastic snap-fit joints. It features three compartments: a cylindrical pen holder (8 cm diameter), a rectangular tray for erasers and clips, and an angled smartphone dock. The warm bamboo finish is visually appealing and resists scratches better than painted surfaces.
最终设计是一个模块化桌面收纳盒，采用竹胶合板底座和垂直隔板，通过生物塑料卡扣连接件组装。它设有三个隔间：一个直径 8 cm 的圆柱形笔筒、一个用于放置橡皮和回形针的矩形托盘，以及一个倾斜式智能手机底座。温暖竹材饰面富有视觉吸引力，且比涂漆表面更耐刮擦。
This case study illustrates that by following a systematic engineering design process – defining the problem, researching, specifying, selecting materials, prototyping, and testing – students can create a product that meets real user needs while respecting environmental constraints. The iterative nature of engineering is clearly demonstrated: the warp issue taught us the importance of moisture testing and informed a sustainable solution.
本案例研究表明，遵循系统化的工程设计流程——定义问题、调研、制定规格、选择材料、制作原型以及测试——学生能够创造出既满足真实用户需求又尊重环境约束的产品。工程的迭代本质在此得到清晰展现：翘曲问题让我们认识到湿度测试的重要性，并启发了一个可持续的解决方案。
Further improvements could include integrating a solar-powered LED light or using a biodegradable adhesive for permanent joints if snap-fit proves insufficient over time. Through this practical exercise, Year 9 engineers gain hands-on experience that mirrors real-world product development.
进一步的改进可能包括集成太阳能 LED 灯，或者当卡扣连接长期来看证明不足时，使用可生物降解的胶粘剂进行永久连接。通过这次实践演练，九年级工程学生获得了模拟真实产品开发的亲身体验。
Published by TutorHao | Engineering Revision Series | aleveler.com
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