Engineering Graphics and CAD
Final-project brief
Create a small mechanical assembly and carry it from concept through modelling, drawings, verification, controlled change, and portfolio-ready evidence.
Purpose and learning outcomes
Project purpose
This project is the integrated evidence for the course. Your package should let another engineer understand the function, inspect the design decisions, manufacture the parts, assemble the product, and trace one controlled change.
By completion, you can
- Decompose a mechanical need into parts and interfaces.
- Build robust parametric parts and a correctly constrained assembly.
- Create complete part and assembly drawings.
- Specify tolerances, fits, and introductory geometric controls from function.
- Review manufacturability and document a design change.
- Present concise, verifiable portfolio evidence.
Mechanical design brief
Design an adjustable shaft-support assembly for a small bench-top mechanism. It must locate a 20 mm nominal shaft, allow at least 30 mm of vertical adjustment, lock at the selected height, attach to a flat base plate, and be serviceable with common hand tools. Use two to five original manufactured parts, plus standard fasteners or purchased items. Assume moderate workshop loads and state a defensible design load. This is a graphics and CAD project, so show sound interfaces and documentation without claiming structural certification.
Project options
- Option A, adjustable shaft support: use the brief above.
- Option B, compact toggle clamp: create a two-position linkage that holds a small workpiece and has a clear locked state.
- Option C, guided belt-tensioner bracket: create an adjustable idler support with a defined travel range and locking method.
Choose one option. You may propose an equivalent two-to-five-part mechanism if your instructor or reviewer confirms the scope before modelling.
Required CAD and drawing deliverables
Models and verification
- One-page concept and functional decomposition.
- Native parametric model for every original part, with named features and fully constrained functional sketches.
- Assembly model with mates that represent the real joints.
- Degrees-of-freedom statement, interference check, and clearance or fit check.
- Before-and-after evidence for one representative parameter edit.
Drawing package
- A separate part drawing for every original manufactured part.
- One assembly drawing with an exploded view, item balloons, and a matching bill of materials.
- A revision block and engineering-change record tied to the revised files.
- A short design review and reflection.
Part and assembly drawing requirements
Part drawings
- Use the minimum sufficient principal, section, detail, or auxiliary views.
- State projection method, scale, units, drawing title, part number, material, and revision.
- Define every manufactured feature once, without redundant or closed tolerance chains.
- Dimension from functional datums and interfaces.
- Include surface texture, thread, and standard-hole callouts where they affect function or manufacture.
Assembly drawing and bill of materials
- Show the assembled product and an exploded view with consistent item balloons.
- The bill of materials must include item number, part number, description, quantity, material or purchase specification, and revision where applicable.
- Part numbers, quantities, and revisions must agree across models, drawings, and the bill of materials.
Tolerances, fits, and geometric controls
- Identify at least two function-critical dimensions and justify their tolerances.
- Specify at least one shaft-hole or sliding interface as a clearance, transition, or interference fit, with a short functional reason.
- Define a datum reference frame for the most function-critical part.
- Apply at least two introductory geometric controls where size tolerance alone is insufficient, such as flatness, perpendicularity, parallelism, or position.
- Check values against function and manufacturing capability. State any standard or company convention used.
Engineering change and manufacturability
Controlled change
After the first review, make one meaningful engineering change, such as improving guidance, tool access, assembly access, mistake-proofing, clearance, or tolerance allocation. Record the problem, reason, affected files and parts, decision, verification performed, and new revision. Recheck the assembly, drawings, and bill of materials.
Manufacturability review
- Name the intended process for every original part.
- Check tool access, internal radii, hole depth, bend or print orientation where applicable.
- Avoid unjustified tight tolerances and finishes.
- Check assembly access, lead-ins, part orientation, and standard-tool clearance.
- State one cost or production risk and how the design addresses it.
Submission checklist
- Project choice, requirement statement, design load, and concept sketch.
- Functional decomposition, part list, and interface list.
- Native CAD files for all parts and the assembly.
- Model-health edit test, degrees-of-freedom result, interference result, and fit or clearance result.
- PDF part drawings for every original manufactured part.
- PDF assembly drawing, exploded view, item balloons, and bill of materials.
- Tolerance, fit, datum, geometric-control, and manufacturability rationale.
- Design-review findings with priorities and dispositions.
- Engineering-change record and updated revision identifiers.
- Final reflection and portfolio evidence summary.
- One index file that lists every submitted item and its revision.
Assessment rubric
| Criterion | Weight | Meets the standard |
|---|---|---|
| Requirements, concept, and decomposition | 10% | Function, scope, interfaces, and assumptions are clear and feasible. |
| Part modelling and design intent | 15% | Sketches are fully constrained, features are robust, and key parameters are named. |
| Assembly and verification | 15% | Mates match real joints, intended motion remains, and interference and clearances are checked. |
| Part drawings | 15% | Every part is completely and unambiguously defined for manufacture and inspection. |
| Assembly drawing and bill of materials | 10% | Views, balloons, quantities, part numbers, and revisions agree. |
| Tolerances, fits, and geometric controls | 10% | Controls follow function, use clear datums, and are feasible for the stated processes. |
| Manufacturability and assembly judgement | 10% | Process limits, tool access, assembly access, and cost risks are addressed. |
| Review and controlled change | 10% | Findings are actionable, one meaningful change is traceable, and affected artifacts are rechecked. |
| Reflection and portfolio evidence | 5% | The learner explains decisions, limits, evidence, and what improved. |
A submission cannot meet the completion standard if a required drawing is missing, the assembly has unexplained interference, or the engineering change is not traceable, regardless of the numerical score.
Reflection and portfolio evidence
Reflection questions
- Which interface drove the most important design decision?
- Which modelling choice made change easier or harder?
- What did the interference, clearance, or drawing review reveal?
- Why was your engineering change necessary, and what evidence shows it helped?
- What remains uncertain or would need physical testing?
Portfolio guidance
Prepare a concise case study with the need, constraints, one concept image, the assembly, one strong drawing excerpt, one verification result, the controlled change, and the final reflection. Remove personal, client, employer, or confidential information. Label assumptions and do not present an untested design as certified or production-ready.
Completion criteria
The project is complete when every checklist item is present, models and drawings agree, the intended motion and fit are verified, function-critical dimensions are toleranced, the assembly drawing and bill of materials agree, manufacturability has been reviewed, one change is documented and propagated, and the reflection states both evidence and limitations.