EaseBrainACADEMYDesign a small part, compare 3D printing with machining and fabrication, and make a production plan with measurable acceptance checks.
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If one item feels unfamiliar, revisit these foundation missions:
The Builder is designing a tabletop display base. Fictional dimensions: Base: 60 mm long x 40 mm wide x 12 mm thick Through-hole at the centre: 10.4 +/- 0.1 mm Removable round peg: 10.0 +/- 0.1 mm diameter Minimum diametral clearance = 10.3 - 10.1 = 0.2 mm Maximum diametral clearance = 10.5 - 9.9 = 0.6 mm This is a geometric fit exercise, not a load-bearing design. Batch costing assumptions, in fictional currency units: Printing: setup 10 + 6 per part Machining: setup 100 + 3 per part
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A part specification describes the job, interfaces and acceptance criteria before selecting a machine. A visually attractive model can still be impossible to assemble or inspect.
The Builder needs a removable peg for a tabletop sign. Sketch the user, the base and the peg. State three requirements: removable by hand, fits the intended space, and inspectable dimensions. Use paper, a ruler and the starter values.
Your brief separates measured dimensions from untested assumptions about strength, grip and wear.
A drawing communicates geometry with units and a common reference. In parametric CAD, dimensions and constraints govern a sketch; an extrusion adds depth. A rendered image alone does not specify a part.
Draw top and front views of the base, locate the hole at 30 mm by 20 mm and label its through depth. Optionally use a local CAD tool: constrain a 60 x 40 mm rectangle, extrude 12 mm, then cut the centred circle through it. Keep the editable model and a labelled drawing.
A reviewer can reconstruct the shape from your views and dimensions. Changing the base length does not silently leave the hole off-centre.
3D printing adds material; machining removes it; fabrication assembles or forms components. Shape, quantity, material, finishing and inspection influence the choice. A machine preview does not establish physical quality.
Compare printing the base, machining it from stock, and assembling a simple layered mock-up. For each, name setup, waste, difficult features, finishing and inspection needs. If using a slicer or CAM preview, inspect orientation or tool access without running equipment.
Your chosen route follows the brief. You identify one reason another process could be better at a different quantity. Powered machining, welding, lasers and printing require suitable facilities and competent supervision; they are not required for this project.
Nominal dimensions are targets. Tolerances define allowed variation. For a hole and peg, minimum diametral clearance uses the smallest hole minus the largest peg; maximum clearance uses the opposite extremes. Measurement uncertainty matters near a limit.
Reproduce the starter range of 0.2 to 0.6 mm. Then change the hole to 10.2 +/- 0.1 mm: minimum clearance becomes zero. Explain why an ideal boundary fit does not assure easy assembly. Record which dimensions an inspector would measure.
You show both extremes, use diameter rather than radius, and do not treat a ruler sketch as a precision measurement.
Setup and unit costs affect process choice. Rejects, labour, finishing and delivery may change the comparison. Inspection needs an acceptance rule, not a statement that a part looks fine.
Using the fictional costs, compare 10 and 40 parts: printing costs 70 and 250; machining costs 130 and 220. The totals match at 30 parts. Create a five-row inspection log for fictional hole diameters 10.28, 10.32, 10.41, 10.49 and 10.55 mm against the 10.3-10.5 mm interval.
Ignoring measurement uncertainty for this numerical exercise, only the middle three readings meet the dimensional requirement. Your cost model labels exclusions and explains why a quote would still be needed.
An engineering handover lets someone reproduce the design and check a change. Revision control preserves what was tested and what remains a prediction.
Design a new non-load-bearing desk organiser or display part. Supply its brief, drawing/model, tolerances, process choice, fictional cost model and inspection plan. Revise one feature after a paper assembly check or supervised feedback. Keep the first version.
Your portfolio contains a traceable change, a checkable acceptance rule and a clear distinction between a design, a simulation and a manufactured/tested part.
Choose a twist. Use paper, a sketch or a conversation.
Optional practice. Copy useful observations into your workbook; choosing a twist does not record completion.
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