📚 Year 9 OCR Engineering: Case Study Practical Exercise | Year 9 OCR 工程：案例分析实战演练
In Year 9 OCR Engineering, applying your knowledge to a practical case study is one of the best ways to develop real design and problem-solving skills. This article walks you through a complete engineering design process using the example of an adjustable phone stand for a classroom desk. You will see how user needs, material properties, making techniques and sustainability all come together in one authentic project.
在 Year 9 OCR 工程课程中，把所学知识应用到一个实际案例中是培养真实设计与解决问题能力的最佳方式之一。本文将通过一个可调节桌面手机支架的完整工程设计过程，带你走一遍真实的项目流程。你会看到用户需求、材料性能、制造工艺以及可持续性如何在一个真实项目中相互结合。
1. Understanding the Case Study | 理解案例背景
Our case study focuses on designing and prototyping a simple, adjustable phone stand that can hold a smartphone securely on a school desk. The stand must allow the user to tilt the phone to different viewing angles and fold flat for storage. It should be made from available workshop materials and be easy to manufacture with basic tools.
我们的案例重点是设计并制作一款简易可调节手机支架的原型，能稳固地将智能手机放在课桌上。支架需要让用户能够将手机倾斜到不同的观看角度，并且可以折叠平放以便收纳。它应当使用学校车间里常见的材料制作，并能用基本工具轻松加工出来。
2. Identifying User Needs | 识别用户需求
Before any design work begins, engineers must understand who will use the product and what they need. For this phone stand, the primary users are students who often watch educational videos or follow digital instructions during practical lessons. They need a stand that is stable, lightweight, and quick to adjust without distracting from their tasks.
在开始任何设计工作之前，工程师必须先了解谁会使用产品以及他们需要什么。针对这款手机支架，主要用户是学生，他们常常在实践课上观看教学视频或跟着电子说明操作。他们需要的支架必须稳定、轻便、调节迅速，并且不会分散他们做任务的注意力。
3. Writing a Design Specification | 撰写设计规格
A clear design specification turns user needs into measurable targets. For the adjustable phone stand, key specification points include: the stand must support a phone weighing up to 250 g, allow angle adjustment between 30° and 70° from the horizontal, have a footprint no larger than 150 mm × 100 mm, and be made from two or fewer different materials to simplify construction.
一份清晰的设计规格能将用户需求转化为可测量的目标。对于可调节手机支架，关键规格要点包括：支架必须能支撑重达 250 g 的手机，允许相对于水平面 30° 到 70° 的角度调节，底座占用面积不超过 150 mm × 100 mm，并且最多只使用两种不同材料以简化制作。
4. Generating Initial Design Concepts | 生成初步设计概念
At this stage, three different concepts were sketched: a simple wedge with a slot, a hinged folding frame, and a sliding track mechanism. Each concept was evaluated against the specification using a simple decision matrix. The hinged folding frame scored highest on stability, adjustability and ease of manufacture, so it was taken forward for development.
在这一阶段，我们绘制了三种不同的概念草图：带卡槽的简单楔形块、铰链折叠框架和滑轨机构。每个概念都用一个简单的决策矩阵对照设计规格进行评估。铰链折叠框架在稳定性、可调节性和制造便捷性上得分最高，因此被选中继续深入开发。
5. Selecting Suitable Materials | 选择合适的材料
Material choice in engineering is driven by properties such as strength, stiffness, weight and workability. For the hinged stand, the main body will be laser-cut from 3 mm birch plywood because it is light, reasonably strong and easy to shape. The hinge will be a simple metal bolt and nut, providing a firm pivot that can be tightened by hand.
工程中的材料选择由强度、刚度、重量和可加工性等性能驱动。针对铰链支架，主体将用 3 mm 桦木胶合板激光切割，因为它轻便、强度适中且易于成型。铰链处使用简单的金属螺栓和螺母，提供一个可以手动拧紧的稳固枢轴。
We also considered using acrylic, but plywood is more sustainable and provides better friction against the phone. A small non-slip rubber pad will be added to the base to prevent the stand from sliding on the desk.
我们也考虑过使用亚克力，但胶合板更具可持续性，而且能提供更好的摩擦力以固定手机。底座将增加一小块防滑橡胶垫，以防止支架在桌面上滑动。
6. Applying Basic Mechanical Principles | 应用基本力学原理
To ensure the stand does not tip over, we need to think about moments. The phone’s weight creates a clockwise moment about the front edge of the base. For stability, the anticlockwise moment from the stand’s own weight must be larger, or the centre of mass must stay within the base footprint. The moment balance can be written simply as:
为了确保支架不会翻倒，我们需要考虑力矩。手机的重力会对底座前边缘产生一个顺时针力矩。为了保证稳定，支架自身重力产生的逆时针力矩必须更大，或者整体重心必须保持在底座投影范围之内。力矩平衡可以简单表示为：
W_phone × d_phone = W_stand × d_stand
Where W_phone is the weight of the phone, d_phone is the horizontal distance from the pivot to the phone’s centre of mass, and W_stand, d_stand are the corresponding values for the stand. By keeping the base long enough, the stand remains stable even when the phone is tilted steeply.
其中 W_phone 是手机重量，d_phone 是枢轴到手机重心之间的水平距离，W_stand 和 d_stand 是支架自身的对应数值。只要底座足够长，即使手机倾斜角度很陡，支架也能保持稳定。
7. Planning the Manufacturing Process | 规划制造流程
A detailed production plan helps reduce errors and waste. The main steps for our phone stand are: (1) mark and cut the plywood pieces using a laser cutter or coping saw, (2) drill a hole for the M5 bolt in both the base and the tilting arm, (3) sand all edges smooth for safety, (4) assemble the hinge with a bolt, two washers and a wing nut, and (5) stick the rubber pad onto the base underside. A simple flow chart or numbered list like this keeps the workshop organised.
一份详细的生产计划有助于减少错误和浪费。我们手机支架的主要制作步骤为：(1) 用激光切割机或钢丝锯标记并切割胶合板件；(2) 在底座和倾斜臂上钻出 M5 螺栓孔；(3) 将所有边缘打磨光滑以保证安全；(4) 用螺栓、两个垫圈和一个蝶形螺母组装铰链；(5) 将橡胶垫粘贴到底座底面。像这样的简单流程图或编号列表能让车间工作保持有序。
8. Testing Against the Specification | 对照规格进行测试
Once the prototype is built, it must be tested rigorously. We placed phones of different sizes (from 5-inch to 6.7-inch screens) on the stand and checked stability at 30°, 45° and 70° angles. The stand successfully held all phones without tipping, and the hinge remained tight after ten adjustment cycles. However, at 70° the phone tended to slide forward slightly, indicating that extra grip was needed on the tilting arm.
原型制作完成后，必须进行严格测试。我们将不同尺寸的手机（从 5 英寸屏到 6.7 英寸屏）放在支架上，分别在 30°、45° 和 70° 角度下检查稳定性。支架成功地固定了所有手机而没有翻倒，铰链在十次调节循环后依然紧固。但是，在 70°时手机有轻微前滑的趋势，表明倾斜臂上需要增加额外的摩擦力。
9. Evaluation and Iteration | 评估与迭代改进
Engineering design is never a one-step process. Based on the test results, we decided to add two narrow strips of self-adhesive foam to the tilting arm to increase friction. We also noticed that the wing nut can be slightly difficult to turn for younger students, so we switched to a larger, ergonomic knob. This cycle of test, evaluate and improve is at the heart of real-world engineering.
工程设计从来不是一步到位的过程。根据测试结果，我们决定在倾斜臂上增加两条自粘泡沫窄条，以增加摩擦力。我们还注意到，蝶形螺母对低年级学生来说旋转略为费力，因此我们换成了更大、更符合人体工程学的旋钮。这种“测试、评估、改进”的循环正是现实世界工程的核心。
10. Considering Sustainability | 考虑可持续性
Good engineers always think about the environmental impact of their designs. Our plywood comes from FSC-certified sources, meaning it is harvested responsibly. The stand is designed so that the wooden parts can be separated from the metal bolt and rubber pad easily for recycling at the end of its life. We also minimised offcuts by nesting parts cleverly on the plywood sheet before cutting.
优秀的工程师总会思考其设计对环境的影响。我们使用的胶合板来自 FSC 认证来源，意味着其采伐是负责任的。支架设计使得木制部件能够在产品寿命结束时方便地与金属螺栓和橡胶垫分离，以便回收。我们还通过在切割前巧妙地在胶合板上嵌套排样，最大限度地减少了边角料。
11. Highlighting Safety in Design | 设计中强调安全
Safety must be built into a product, not added as an afterthought. All corners of the plywood pieces are rounded with a file, and any splinters are removed. The bolt length is chosen so that no more than two threads protrude beyond the nut, reducing the risk of scratches. The stand itself is stable enough to prevent accidental collapse, which could distract students and cause minor injuries.
安全必须被内建在产品中，而不能事后才去添加。所有胶合板件的角落都用锉刀磨圆，并清除了所有毛刺。螺栓长度经过选择，使得伸出螺母的螺纹不超过两圈，从而降低划伤风险。支架本身足够稳定，可防止意外倒塌，以免分散学生注意力或造成轻微伤害。
12. Reflection and Broader Engineering Links | 反思与更广泛的工程联系
This case study shows how even a simple product goes through the same engineering stages as a complex machine. By working through the project, you practised analysing a brief, developing specifications, selecting materials, applying moment calculations, manufacturing safely, testing, evaluating and considering sustainability. These skills are directly transferable to your OCR Engineering coursework and to any future design challenge you encounter.
这个案例表明，即使是一个简单的产品，也要经历与复杂机器相同的工程阶段。通过完成这个项目，你练习了分析设计纲要、制定规格、选择材料、应用力矩计算、安全制造、测试、评估以及考虑可持续性。这些技能可以直接迁移到你的 OCR 工程课程作业中，也可以应用于你今后遇到的任何设计挑战。
Published by TutorHao | Engineering Revision Series | aleveler.com
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