This guide covers Unit 45 Additive Manufacturing Processes in the Pearson BTEC Level 3 Nationals in Engineering, an internally assessed optional unit on 3D printing in industry. It explains the three learning aims, what Pass, Merit and Distinction work looks like, and gives model paragraphs plus a worked costing example for a printed component so you can plan each assignment with confidence.
What the Unit 45 assignments ask you to do
A typical scenario places you as an apprentice in a company that makes small prototype parts using CNC machining and CAM, and is considering additive manufacturing (AM). You are asked to investigate AM, then design and make a component. The unit is usually split into three assignments:
- Learning aim A – report: investigate the technology and characteristics of at least two AM processes used in industry, including sustainability and safe working practices.
- Learning aim B – report: investigate design considerations and finishing processes, usually by looking at how components currently made by traditional methods could be adapted for AM.
- Learning aim C – practical: design and manufacture a component using an AM process safely, supported by a development log book, set-up notes, quality control records, annotated photographs and observation records.
Learning aims for Unit 45
| Learning aim | What it covers |
|---|---|
| A: Examine the technology and characteristics of additive manufacturing processes as used in industry | A1 AM processes; A2 safe working practices for AM processes |
| B: Investigate component design considerations and finishing processes required to effectively use additive manufacturing processes | B1 design considerations for AM; B2 component finishing processes after AM |
| C: Develop a component using additive manufacturing processes safely | C1 component design for additive manufacture; C2 manufacture of a component using an AM process |
Pass, Merit and Distinction criteria explained
Codes shown below are those confirmed from centre assignment briefs. For criteria without a code, follow the exact wording in your own brief.
| Criterion | What it asks | How to evidence it |
|---|---|---|
| A.P1 | Explain the technology and characteristics of AM processes | At least two processes, with materials, applications, accuracy, finish, build speed and safety |
| A.M1 | Compare the technology and characteristics of AM processes | Side-by-side comparison with similarities and differences, not two separate descriptions |
| A.D1 | Justify the use of AM processes | Argue which process suits each product, with reasons drawn from your comparison, sustainability and safety |
| B – Pass (design) | Explain design considerations for components made by AM | Orientation, supports, overhangs, wall thickness, tolerances, material properties |
| B.P3 | Explain finishing processes that could be applied to two components if made by AM instead of traditional methods | Support removal, sanding, bead blasting, vapour smoothing, machining, heat treatment |
| B – Merit | Analyse how the designs and finishes would need to change for AM | Explain cause and effect for each design change |
| B.D2 | Evaluate how the design of at least two components made by traditional processes could be improved and adapted for AM | Weigh benefits (weight, part count) against drawbacks (cost, strength, finish) and conclude |
| C – Pass | Produce a design and manufacture a component safely using AM | Log book, CAD files, slicer settings, risk assessment, finished part |
| C – Merit/Distinction | Optimise the design and manufacture, then evaluate the outcome | Iterations, quality checks against the specification, reasoned improvements |
How to answer Learning aim A: AM technology and characteristics
Choose two contrasting processes and two real engineered products made by them – for example a polymer prototype housing made by material extrusion (FDM) and a titanium aerospace bracket made by laser powder bed fusion.
- Use the seven process categories from ISO/ASTM 52900: vat photopolymerisation, material extrusion, material jetting, binder jetting, powder bed fusion, directed energy deposition and sheet lamination.
- For each process cover: how it builds a part, materials, layer thickness and accuracy, surface finish, build volume, speed, cost and typical applications.
- Sustainability: material waste, powder reuse, energy use per part, reduced tooling and lighter parts in service.
- Safe working: fine powders and fumes (Control of Substances Hazardous to Health Regulations 2002), explosive metal powders (Dangerous Substances and Explosive Atmospheres Regulations 2002), lasers and UV light, hot surfaces, resin skin contact, and machine guarding under the Provision and Use of Work Equipment Regulations 1998.
- For A.M1, use a comparison table and then discuss it; for A.D1, justify which process is right for each product.
Example paragraph (A.M1): Both FDM and laser powder bed fusion build parts layer by layer from a CAD model, but they differ greatly in capability. FDM extrudes a thermoplastic filament, typically at 0.1–0.3 mm layers, so parts show visible layer lines and are weaker across the layers. Laser powder bed fusion melts metal powder with a laser in an inert atmosphere, producing dense parts with mechanical properties close to wrought metal. However, the metal process needs controlled powder handling, explosion precautions and stress-relief heat treatment, so it is far more expensive and is only justified for high-value components such as aerospace brackets.
How to answer Learning aim B: design and finishing
Pick two components your company currently makes by machining, casting or fabrication. For each, explain how the design would change for AM and what finishing would be needed.
- Describe the current component, material and manufacturing route.
- Explain AM design considerations: build orientation, overhangs (around 45° as a common guide for many polymer processes), support structures, minimum wall thickness, hole orientation, shrinkage and anisotropy.
- Explain AM opportunities: part consolidation, internal channels, lattice structures and topology optimisation.
- Explain finishing: support removal, sanding, bead blasting, vapour smoothing, UV post-curing for resin parts, machining critical faces, heat treatment for metal parts, painting or plating.
- For B.D2, evaluate whether the redesigned component is actually better, considering strength, cost, lead time and finish.
Example paragraph (B.P3): The aluminium sensor bracket is currently machined from solid bar, giving a smooth finish straight from the machine. If it were made by powder bed fusion in aluminium alloy, it would need supports removing by wire cutting, stress-relief heat treatment, and bead blasting to give an even surface. The two mounting holes would also need reaming, because as-printed holes are not accurate enough for a precision fit.
How to answer Learning aim C: designing and making a component
Learning aim C is assessed largely on evidence of your practical process, so keep your log book up to date at every session.
- Write a short design specification: function, dimensions, tolerances, material and quantity.
- Produce CAD models and record design iterations, with reasons for each change.
- Record printer set-up: material, nozzle and bed temperature, layer height, infill, orientation and supports.
- Complete a risk assessment before printing and follow it during manufacture.
- Check the finished part against the specification with measured dimensions in a quality control sheet.
- Add annotated photographs of each stage and ask your tutor to complete an observation record.
Example log entry: First print of the cable clip failed at the hook because the overhang was printed without support. I rotated the part 90° so the hook was built vertically, which removed the need for supports and also aligned the layers with the bending load. The second print measured 24.8 mm against a target of 25.0 mm, which is within the ±0.3 mm tolerance in my specification.
Worked example: costing an FDM component
Costing your part gives strong evidence for evaluation criteria. Suppose your slicer reports that a bracket uses 18 cm³ of PLA, is 30 mm tall, printed at 0.2 mm layers, and takes 3 hours.
- Number of layers = 30 mm ÷ 0.2 mm = 150 layers.
- Material mass = volume × density = 18 cm³ × 1.24 g/cm³ = 22.3 g.
- Filament length (1.75 mm diameter): cross-sectional area = π × (0.0875 cm)² ≈ 0.0241 cm², so length = 18 ÷ 0.0241 ≈ 750 cm ≈ 7.5 m.
- Material cost at £20 per kg = 0.0223 kg × £20 = £0.45.
- Machine cost at an assumed £1.50 per hour = 3 × £1.50 = £4.50.
- Total cost per part ≈ £4.95, excluding labour and finishing.
Judgement: for a one-off prototype this is far cheaper than setting up a CNC job, but for 500 parts per month the three-hour cycle time becomes a bottleneck, so injection moulding or machining might be better for volume production. This kind of reasoned comparison is what assessors look for at Merit and Distinction.
Common mistakes that cost marks
- Describing “3D printing” in general instead of specific, named AM processes and real products.
- Writing two separate descriptions for A.M1 rather than a true comparison.
- Ignoring sustainability or safe working practices, which are named in learning aim A.
- Listing finishing processes without linking them to a specific component and material.
- Missing log book entries, set-up notes or quality control records for learning aim C.
- Presenting only a successful final print – failed prints and fixes are valuable evidence.
How to move from Merit to Distinction
At Distinction you must justify and evaluate. For A.D1, explain why a chosen AM process is the best fit for a product, using evidence from your comparison and stating what you would lose by choosing another process. For B.D2, judge whether redesigning each component for AM genuinely improves it, balancing weight saving and part consolidation against cost, strength and finishing time. In learning aim C, show how you optimised the design or settings through testing and evaluate the final part against your specification with measured data.
FAQs
Is Unit 45 Additive Manufacturing internally assessed?
Yes. It is assessed through assignments set and marked by your centre and checked by Pearson’s standards verification.
Which two AM processes should I compare?
Choose contrasting ones, such as material extrusion (FDM) and powder bed fusion or vat photopolymerisation (SLA), so there are clear differences in materials, accuracy and cost to discuss.
Do I have to print the component myself?
Learning aim C requires you to develop and manufacture a component, so you need practical evidence. If your centre has limited equipment, your tutor will explain how manufacture and observation will be arranged.
What regulations should I mention for AM safety?
The Health and Safety at Work etc. Act 1974, COSHH 2002 for powders, resins and fumes, DSEAR 2002 for combustible metal powders, PUWER 1998 for machinery and the Personal Protective Equipment at Work Regulations 1992.
How long should the learning aim A report be?
There is no set word count. Aim for enough detail to explain, compare and justify two processes fully – quality of comparison matters more than length.
Need one-to-one support from a subject specialist? Our BTEC Level 3 Engineering assignment help service covers planning, feedback on drafts and referencing.
For related engineering help, see our Unit 3 Engineering Product Design and Manufacture guide and Unit 5 Specialist Engineering Project guide. If you need support with your report or log book, get expert help with your BTEC assignment.
