SACE Stage 2 Design, Technology and Engineering common mistakes
SACE Stage 2 Design, Technology and Engineering · Understand the traps and how to avoid them.
Writing a chronological diary of what was built ("first I cut the timber, then I glued it") instead of explaining why each decision was made and what evidence justified it.
Students treat the folio as a record of activity and confuse effort with justification; they have never been shown the difference between describing a process and evaluating a decision.
What to do instead
For every process entry, force three sentences: the decision made, the alternative rejected, and the evidence or constraint that settled it. Delete any sentence that only reports an action with no reason attached.
Listing design criteria as vague aspirations ("must be strong", "should look good") with no measurable target, so later evaluation cannot be judged against anything.
Criteria are written early when the problem is still fuzzy, and students copy the language of the brief rather than converting needs into testable specifications.
What to do instead
Rewrite each criterion as a specification with a number, unit, and test method (for example a load target in newtons measured by a stated test rig). If a criterion cannot be measured, convert it to a ranked comparison against named reference products.
Naming a material or process without stating the property that drove the choice, e.g. "I used aluminium because it is a good material".
Students select on familiarity or availability and then retrofit a justification; they do not habitually link function to material properties.
What to do instead
Use a property-mapping sentence pattern: the function requires X, material Y delivers X at value Z, and the trade-off is W. Require at least one rejected material with the property that ruled it out.
Drawing freehand sketches with no dimensions, scale, projection convention, or labelling, so the drawing cannot be read by another person.
Students sketch to think, not to communicate, and are not in the habit of adding the conventions that make a drawing a technical document.
What to do instead
Impose a checklist on every submitted drawing: scale or stated not-to-scale, principal dimensions with units, view labels, and a parts or feature key. Practise redrawing one sketch to full convention standard each week.
Treating the evaluation as a pass/fail verdict at the end ("the product worked well and met the brief") rather than testing each criterion and reporting evidence.
Evaluation is left to the last days, so there is no time to test, and students believe a positive conclusion is what markers want.
What to do instead
Build an evaluation matrix at the start of the making phase with one row per criterion, a test method column, and an evidence column. Fill it as testing happens, and write conclusions only from the completed matrix.
Describing a manufacturing sequence that cannot actually be executed, such as finishing a surface before a joint is cut or assembling a part that blocks access to a fastener.
Sequences are written from memory of the finished object rather than simulated step by step, so hidden dependencies and access problems are missed.
What to do instead
Walk the plan backwards from final assembly, and at each step ask what must already be true and what access is still needed. Annotate the plan with clamping, access, and curing or drying waits.
Ignoring safety and risk as a design input, mentioning hazards only in a token sentence or not at all.
Students see safety as paperwork attached to the workshop rather than as a constraint that shapes the design and the process plan.
What to do instead
Add a hazard column to the process plan and a risk row to the design criteria. For each hazard, record the control (guard, extraction, PPE, procedure) and show where it changed a design or sequence decision.
Presenting research as undigested copied text or screenshots with no synthesis, so it is unclear what was learned or how it influenced the design.
Collecting feels like progress, and students lack a method for extracting and applying findings from sources.
What to do instead
After each source, write a fixed-format summary: the finding, its relevance to this project, and the specific design change it caused. Cite the source and keep the summary under a set word limit to force selection.
Using technical terminology loosely or incorrectly, for example swapping stress and strain, mass and weight, or tolerance and clearance.
Terms are absorbed from general reading rather than defined and used in context, and students do not check definitions against a reliable reference.
What to do instead
Keep a glossary in the folio where each term is defined in the student's own words plus one worked example from their project. When a term appears in a calculation, state the quantity, its symbol, and its unit explicitly.
Producing a design solution that ignores the stated constraints (budget, time, available equipment, client requirement) and never acknowledges the conflict.
Students design the ideal artefact first and treat constraints as an afterthought, or they hope the mismatch will not be noticed.
What to do instead
Maintain a constraints register alongside the concept sketches and check each concept against it before development. Where a constraint forces a compromise, document the trade-off explicitly and justify the priority order.