📚 Case Study Practical Drill: Designing a Portable Phone Stand | 案例分析实战演练：设计便携式手机支架
In this article, you will follow a step-by-step engineering case study built around a familiar product – a portable phone stand. The goal is to practise the complete design cycle, from understanding a brief to testing a prototype, strengthening your skills for CCEA Year 9 Engineering and beyond.
在这篇文章中，你将跟随一项围绕熟悉产品——便携式手机支架——展开的工程案例分析步骤。目标是实践从理解设计任务到测试原型的完整设计循环，为 CCEA Year 9 工程学及更高年级的学习夯实技能。
1. Introduction to Engineering Case Studies | 工程案例分析简介
Engineering case studies bridge the gap between theory and practice. They require you to think like an engineer, applying scientific principles and workshop skills to solve a specific problem. This drill places you in the role of a design engineer tasked with creating a real-world product.
工程案例分析架起了理论与实践的桥梁。它们要求你像工程师一样思考，应用科学原理和车间技能来解决具体问题。这次演练将你放在设计工程师的角色里，负责创造一款真实的产品。
2. The Design Brief: A Portable Phone Stand | 设计任务书：便携式手机支架
Your brief reads: "Design and manufacture a prototype portable phone stand. It must hold a smartphone securely at an optimum viewing angle for watching videos. The stand should be lightweight (under 100 g), foldable to pocket size, stable on uneven surfaces, and cheap to produce in batch quantities. The target user is a student who uses public transport."
你的任务书写道：“设计并制造一个便携式手机支架原型。它必须稳固地支撑智能手机，以最佳角度观看视频。支架应轻便（低于 100 克），可折叠至口袋大小，在不平整表面上保持稳定，并且批量生产成本低廉。目标用户是乘坐公共交通的学生。”
You must work within several constraints: maximum material cost £0.50 per unit, recyclable or biodegradable materials preferred, and manufacturing time under 15 minutes per unit in a school workshop.
你必须在若干约束条件下工作：每单位最大材料成本 0.50 英镑，优先使用可回收或可生物降解的材料，以及在学校车间内每单位的制造时间少于 15 分钟。
3. Research and Investigation | 调查与研究
Begin by examining existing phone stands on the market – from simple cardboard cut-outs to injection-moulded plastic stands. Take notes on their folding mechanisms, materials, and weaknesses. Use a disassembly table to record findings. Measure typical smartphone dimensions: many modern phones are about 160 mm tall, 75 mm wide and 8 mm thick, with a mass around 200 g.
从市场上现有的手机支架开始调研——从简单的纸板剪裁到注塑成型的塑料支架。记录它们的折叠机构、材料和不足之处。使用拆卸表格记录发现。测量典型的智能手机尺寸：许多现代手机高度约 160 毫米，宽 75 毫米，厚 8 毫米，质量约为 200 克。
Carry out user observations: watch videos of people using stands on trains and buses. Notice that many users prop their phones against a bag or use a ring grip. A successful stand must be quick to deploy and stable on a lap or tray table. Research material data sheets for plywood, PLA, and cardboard.
进行用户观察：观看人们在火车和公交车上使用支架的视频。注意到许多用户把手机靠在包上或使用指环扣。成功的支架必须能够快速展开，并在膝上或小桌板上保持稳定。查阅胶合板、PLA 和卡纸的材料数据表。
4. Generating Initial Design Ideas | 初步设计构思
Sketch at least three distinct concepts using isometric projection and orthographic views. Annotate each sketch with notes on how it meets the brief. Concept A could be a simple folding wedge made from a single piece of scored cardboard. Concept B might use a laser-cut plywood folding frame with interlocking slots. Concept C could be a collapsible PLA tripod with a threaded ball joint for angle adjustment.
使用等轴测投影和正交视图绘制至少三种不同的概念草图。在每幅草图上标注它如何满足任务书。概念 A 可以是一个由单片刻痕卡纸制成的简单折叠楔形。概念 B 或许采用激光切割胶合板折叠框架，带有联锁插槽。概念 C 可以是一个可折叠的 PLA 三脚架，带有一个用于调节角度的螺纹球头关节。
A design matrix helps you compare ideas against criteria such as weight, cost, stability, ease of manufacture, and portability. Score each concept on a scale of 1 to 5. The plywood frame might score highest due to its balance of strength and simplicity.
设计矩阵帮助你根据重量、成本、稳定性、制造便捷性和便携性等标准比较方案。用 1 到 5 分对每项概念打分。胶合板框架可能因其强度与简便性的平衡而得分最高。
5. Material Selection and Properties | 材料选择与性能
Selecting the right material is critical. Below is a comparison table for candidate materials suitable for a school workshop. The aim is to minimise mass, cost and environmental impact while maintaining adequate strength.
选择正确的材料至关重要。下面是一份适用于学校车间候选材料的对比表。目标是在保持足够强度的同时，尽量降低质量、成本和环境影响。
| Material | Density (kg/m³) | Tensile Strength (MPa) | Cost per unit (£) | Workability | Recyclability |
|---|---|---|---|---|---|
| 3 mm Plywood (Birch) | 650 | 30 | 0.15 | Laser cut, sand, glue | Biodegradable, compostable |
| PLA (3D printed) | 1240 | 50 | 0.40 | 3D print, minimal finishing | Industrially compostable |
| Cardboard (1.5 mm) | 400 | 2 | 0.05 | Cut, score, fold | Recyclable, biodegradable |
| Aluminium sheet (1 mm) | 2700 | 200 | 0.60 | Shear, bend, file | 100% recyclable |
Plywood offers the best balance of low cost, light weight, ease of use with laser cutters, and acceptable strength. The biodegradable nature also aligns with the sustainability requirement.
胶合板在低成本、轻重量、便于激光切割以及可接受的强度之间取得了最佳平衡。其可生物降解的特性也符合可持续性要求。
6. Detailed Design and Technical Drawing | 详细设计与技术图纸
Choose Concept B – the folding plywood stand – and produce a detailed technical drawing. The stand consists of two main pieces: a base plate with a slot and a support arm that slots in to create a variable angle. The drawing must include front, side and plan views, using third-angle projection. Add dimensions in millimetres: base 80 x 60 mm, thickness 3 mm, slot width 3.2 mm, and support arm length 110 mm with a 30° cut at the contact edge.
选择概念 B —— 折叠胶合板支架——并绘制详细的技术图纸。支架由两块主要部件组成：一块带槽的底板和一个可插入以形成不同角度的支撑臂。图纸必须包含使用第三角投影的前视图、侧视图和俯视图。标注毫米尺寸：底板 80 x 60 毫米，厚度 3 毫米，槽宽 3.2 毫米，支撑臂长度 110 毫米，接触边缘处有 30° 切角。
r cutting. Indicate that the two parts fit together with a friction fit; no adhesives necessary. Add a material note: "3 mm Birch Plywood, BS EN 636-2." Complete a parts list with item numbers, part names, quantity and material.
规定公差：激光切割为 ±0.5 毫米。指明两个部件采用摩擦配合组装，无需粘合剂。添加材料注释：“3 毫米桦木胶合板，BS EN 636-2。”完成包含项目编号、零件名称、数量和材料的零件清单。
7. Planning the Manufacturing Process | 规划制造过程
Write a step-by-step process map for producing one unit in a school workshop using a laser cutter. Step 1: Design the CAD model in software like 2D Design or Fusion 360, creating the base outline and slot. Step 2: Export the file as a DXF for the laser cutter. Step 3: Set the laser cutter to the correct speed and power for 3 mm plywood; run a test cut on scrap material. Step 4: Cut the parts, then use fine-grit sandpaper to smooth edges and remove any charring. Step 5: Check that the support arm fits snugly in the slot; if too tight, sand slightly. Step 6: Apply a light finish of food-safe mineral oil if needed. Step 7: Assemble and test.
编写在校园车间使用激光切割机制造一台产品的分步流程图。步骤 1：在 2D Design 或 Fusion 360 等软件中设计 CAD 模型，绘制底板轮廓和槽口。步骤 2：导出为激光切割机可用的 DXF 文件。步骤 3：设定适合 3 毫米胶合板的激光切割机速度与功率；在边角料上试切。步骤 4：切割零件，然后用细砂纸打磨边缘并去除任何炭化痕迹。步骤 5：检查支撑臂是否紧密地插入槽中；如果太紧，轻微打磨。步骤 6：如有需要，涂一层食品级矿物油的轻薄保护层。步骤 7：组装并测试。
min), packaging (2 min). Total ≈ 20 minutes per unit, slightly above the 15-minute target – an improvement could be to batch-cut multiple units and omit finishing.
估算总制造时间：CAD（10 分钟），激光切割（3 分钟），打磨与表面处理（5 分钟），包装（2 分钟）。每台总计约 20 分钟，略高于 15 分钟的目标——改进措施可以是批量切割多个单元并省略表面处理。
8. Safety Considerations in the Workshop | 车间安全注意事项
Prioritise safety at every stage. When using the laser cutter, ensure the extraction system is on to remove fumes. Never leave the laser cutter unattended during operation. Wear safety glasses when sanding. If applying oil finish, work in a well-ventilated area and use disposable gloves. Tie back any loose clothing, remove dangling jewellery, and secure long hair. Know the location of the nearest fire extinguisher and the emergency stop button before starting work.
在每个阶段都要把安全放在首位。使用激光切割机时，确保排风系统已开启以排除烟雾。激光切割机运行期间切勿无人看管。进行打磨时佩戴安全眼镜。如果涂敷油性保护层，请在通风良好的区域操作并戴上一次性手套。束好宽松衣物，摘掉悬垂的首饰，并束起长发。开始工作前，知道最近灭火器和紧急停止按钮的位置。
Conduct a risk assessment for each process: identify hazards such as burns from hot material, inhalation of wood dust, and cuts from sharp edges. Record the severity and likelihood, and list control measures. For example, to control dust, use a vacuum attachment on the sander and wear a dust mask rated FFP2.
为每道工序进行风险评估：识别灼伤、吸入木屑、锋利边缘割伤等危险。记录严重程度与发生概率，并列出控制措施。例如，为控制粉尘，在打磨机上使用吸尘附件并佩戴 FFP2 级防尘口罩。
9. Prototyping and Testing | 原型制作与测试
Build a first prototype according to the manufacturing plan. Once assembled, perform a series of tests. Stability test: place the stand with a 200 g smartphone (or equivalent weight) on a flat surface, and on a surface tilted 10°. Observe if it tips over. Measure the viewing angle using a protractor – the target range is 30° to 45° from horizontal. Durability test: fold and unfold the stand 50 times and inspect the slot for wear. Portability test: measure its folded dimensions and mass; aim for less than 120 x 80 x 15 mm and under 100 g.
根据制造计划制作第一个原型。组装完成后，进行一系列测试。稳定性测试：将支架与 200 克重的智能手机（或等效重物）放在平面上，以及倾斜 10° 的表面上。观察是否会翻倒。使用量角器测量观看角度——目标范围是与水平面成 30° 至 45°。耐久性测试：将支架折叠和展开 50 次，检查槽口的磨损情况。便携性测试：测量其折叠尺寸和质量；目标是小于 120 x 80 x 15 毫米且低于 100 克。
A simple moment calculation confirms the stand' entre of gravity of the phone sits 40 mm behind the pivot edge, the overturning moment is:
简单的力矩计算可以确认支架的稳定性。手机重量 W = m × g = 0.2 kg × 10 N/kg = 2 N。如果手机的重心位于转轴边缘后方 40 毫米处，倾覆力矩为：
Moment = W × d = 2 N × 0.04 m = 0.08 N·m
The restoring moment provided by the stand' ng moment is larger, the base must be extended or a non-slip material added to prevent sliding. This analysis leads to a design improvement: widening the base footprint to 100 mm.
由支架自身质量（0.05 kg，重心位于边缘前方 30 毫米处）提供的恢复力矩为 0.05 × 10 × 0.03 = 0.015 N·m。由于倾覆力矩更大，必须加长底座或添加防滑材料以防止滑动。这一分析引出一项设计改进：将底座尺寸拓宽到 100 毫米。
10. Evaluation and Iterative Improvement | 评估与迭代改进
Compare the test results against the original brief. The prototype achieves a viewing angle of 38°, folds to 115 x 80 x 12 mm, and weighs 48 g – all within targets. However, on a 10° slope, the phone slid when nudged, indicating insufficient friction. The assembly time still exceeds 15 minutes per unit. Gather peer feedback using a questionnaire: 80% of testers found it easy to set up, but some noted the slot loosened after repeated folding.
将测试结果与原始任务书进行对比。原型达到了 38° 的观看角度，折叠尺寸为 115 x 80 x 12 毫米，重量 48 克——均在目标范围内。然而，在 10° 斜坡上受到轻碰时，手机会滑动，表明摩擦力不足。装配时间仍超过每台 15 分钟。使用问卷收集同伴反馈：80% 的测试者认为它易于搭建，但有些反馈提到多次折叠后槽口变松。
Based on evaluation, propose three improvements: (1) apply self-adhesive rubber pads to the base contact points to increase friction; (2) redesign the slot to a keyhole shape with a slight interference fit to maintain tension; (3) streamline the finishing step by using a pre-sanded plywood supplier. Document these changes in the design log.
基于评估提出三项改进：(1) 在底座的接触点上粘贴自粘橡胶垫以增加摩擦力；(2) 将槽口重新设计为键孔形状，并采用轻微过盈配合以维持张力；(3) 通过使用预打磨的胶合板供应商来精简表面处理步骤。将这些变更记录在设计日志中。
11. Case Study Reflection: Skills for GCSE | 案例反思：面向GCSE的技能
This practical drill develops the core competencies assessed in GCSE Engineering. You have practised interpreting a design brief, carrying out research, generating and communicating design ideas, selecting and justifying materials, using technical drawings, planning manufacturing, conducting risk assessments, and iteratively improving a prototype. These stages mirror the iterative design process used in industry.
这次实战演练培养了 GCSE 工程学评估的核心能力。你已练习了解读设计任务书、开展调研、生成并传达设计想法、选择并论证材料、使用技术图纸、规划制造过程、进行风险评估以及迭代改进原型。这些阶段与工业中使用的迭代设计流程相呼应。
Maintain a project portfolio that includes sketches, research notes, CAD screenshots, test data and evaluation records. Learning to document your work clearly is just as important as making the product. This will form excellent evidence for controlled assessment tasks later.
维护一本项目作品集，包含草图、调研笔记、CAD 截图、测试数据和评估记录。学会清晰地记录你的工作与制作产品同样重要。这将为日后控制性评估任务提供极好的证据。
12. Conclusion: Becoming an Engineering Problem Solver | 结论：成为工程问题解决者
Through this case study, you have experienced the complete engineering design cycle – from identifying a need to refining a solution. Engineering is not a straight line; it requires curiosity, critical thinking and a willingness to learn from failure. A simple phone stand is just the beginning. The same principles apply to designing bridges, medical devices or renewable energy systems.
通过这次案例分析，你已体验了完整的工程设计循环——从识别需求到完善解决方案。工程学并非直线；它需要好奇心、批判性思维以及从失败中学习的意愿。一个简单的手机支架仅仅是开始。同样的原理适用于设计桥梁、医疗设备或可再生能源系统。
Keep asking "how could this be better?" and use your engineering notebook to capture ideas. As you move into GCSE and beyond, these problem-solving habits will set you apart as a true engineer.
不断追问“如何能做得更好？”，并用工程笔记本记录想法。当你进入 GCSE 及更高阶段时，这些解决问题的习惯将使你成为真正的工程师。
Published by TutorHao | Engineering Revision Series | aleveler.com
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