What "manufacturable" means
Given the sensor-mount CAD part, identify at least 3 manufacturability problems and state why each is a problem — each mapped to the correct defect class on a fixed grader seed.
Try this first — before any explanation.
This part passed every check in the Design course — it's geometrically valid and simulates fine. But a factory can't build it as drawn. Find at least 3 places this part will fight the tools that have to make it, tag the offending feature, and pick the reason. You haven't been taught what to look for — inspect, guess, and tag. Distractors (wrong color, not symmetric) are in the list, so tagging isn't free.
The full Bench runs the WebGL inspector; here you re-implement its deterministic geometry tests in numpy — measure each feature, classify the defect, and tag it.
What "manufacturable" means
The full Bench runs the WebGL inspector; here you re-implement its deterministic geometry tests in numpy — measure each feature, classify the defect, and tag it.
The idea, built visually.
In CAD you are a god: you draw a shape and it exists — a wall one molecule thick, a pocket sealed inside solid metal, the screen never says no. But a real part isn't drawn, it's reached: a spinning cutter, molten plastic, a jet of metal has to physically get to every surface, and physical things have size, direction, and limits.
Manufacturable means a real process can reach it, form it, and have it survive. Four ways geometry fights the tool: a wall too thin to survive being made, a side with no draft so a mold grips it forever, a sharp inside corner a round tool can't cut, a feature too deep and narrow for anything to reach.
▣ Stage animation: Bracket morphs from a perfect glowing wireframe to a 'MADE' view where an end-mill stalls in a sharp corner and four problem zones halo in blue — thin wall, no draft, sharp corner, unreachable rib.
Build it up, step by step.
- Pass A (worked): confirm the pre-placed tag on the barrel wall — Wall probe reads 0.80 mm; reason = too thin to survive the process.
- Pass B (hint): Section the boss; its side walls rise at 90.000°. Ask 'how does this come OUT of a mold?' Tag
no draft. - Pass C (independent): find the remaining two unaided — the sharp internal corner (
FILLET_R = 0) and the deep narrow unreachable rib (RIB_GAP = 3.0, ~24 mm deep).
How the Bench grades your run.
PASS WHEN At least 3 distinct true defects tagged, each with the reason class that matches its failed test (survive/form/reach), and zero distractors accepted on seed 1101.
- Tag on the barrel wall is right, but reason 'hole too small' doesn't fit — the probe reads wall = 0.80 mm; the problem is thickness (SURVIVE). Re-pick the reason.
- 'wrong color' isn't a manufacturability defect — color never changes whether a tool can reach or form the part. Remove it and check the side-wall angles instead.
- 2 of 3 found. One real defect is still untagged — run Draft check on the barrel: a face at 0.00° off the pull direction can't release from a mold.
- Reason 'no draft' is correct, but the draft problem is on the boss side-wall, not the base plate. Move the tag onto the vertical wall.
Bring back what you've already mastered.
- From Design M1/M2: in the part script, name the variable that sets barrel wall thickness (WALL) and state its value.
- From Design M2: which manufacturability test (reach/form/survive) does a minimum-wall constraint protect? → survive.
- Within-lesson: for four mini-parts, pick which of reach/form/survive each most violates — discrimination, not pattern-matching one part.
What you must demonstrate to advance.
In sim, tag ≥3 distinct true defects on the sensor-mount part, each mapped to the correct defect class, with zero distractor tags accepted, on held-out grader seed 1101.
How this feeds your build.
Produces the defect ledger for the carried part: 1.2 chooses a process knowing these problems, 1.3 clears them, and the M5 capstone's yield is only achievable because the part was made manufacturable here.