Advanced geometric pattern development
The four layout methods and the surfaces they unfold, the allowances, seams and sheet limits a pattern must respect, parallel line, radial line and triangulation worked on real parts, and the checks that catch a bad pattern before it is cut.
4 lessons · about 42 min · 11 diagrams · 0 videos
Version 1.0.0
Lessons
0 of 4 complete
Lesson 1 · 10 min · 10 slides · 7 questions
Advanced geometric pattern development: principles and terminology
Why a pattern comes first, the four layout methods and what each one is used for, which surfaces unfold exactly, the words a pattern drawing uses, how true length is found, and the hazards of cut edges.
You will be able to: Name the four layout methods and the fittings each one suits, tell developable from non-developable surfaces, define element, stretch-out, apex, slant height, true length and allowance, and state the safety boundaries.
Not startedStart →Lesson 2 · 10 min · 10 slides · 7 questions
Advanced geometric pattern development: materials, standards and design constraints
Which documents govern a pattern, the allowances added outside a development and how to calculate them, where seams go, and how sheet size, thickness, AFS's limits and the number of divisions constrain a pattern.
You will be able to: Identify who sets the rules for a pattern on a job, add seam and edge allowances to a development, place seams, and check a pattern against sheet size, thickness and AFS's published limits.
Not startedStart →Lesson 3 · 12 min · 11 slides · 8 questions
Advanced geometric pattern development: methods and worked application
The parallel line, radial line and triangulation procedures step by step, each worked through on a real part with every number shown, elbow cut angles, and how one manufacturer laps a pipe flashing into a shingle roof.
You will be able to: Develop a sloped-cut pipe sleeve by parallel line, a cone frustum by radial line and a square-to-round by triangulation, recording every input, unit and check point.
Not startedStart →Lesson 4 · 10 min · 11 slides · 7 questions
Advanced geometric pattern development: defects, verification and case study
The errors that ruin a pattern and how each one is caught, the checks to make before cutting, a case study of a sleeve pattern that came up short, and the evidence to hand over for review.
You will be able to: Diagnose common pattern development errors, verify a pattern with arithmetic and construction checks before it is cut, and document the evidence for review.
Not startedStart →
Practical task
Develop, check and document a parallel line pattern for a 4 in diameter pipe sleeve whose lower end is cut to a 6:12 roof, then lay it out full size on paper or scrap and confirm it before any metal is cut.
Hand in
- A plan and elevation of the sleeve with the half circle divided into six equal parts and the elements numbered.
- A stretch-out calculated as pi x D (12.566 in), divided into twelve, with each element's height above the shortest element tabulated in inches.
- The full-size pattern with the curve joined, the seam on the shortest element, the allowance band drawn outside the curve and the allowance rule named.
- A note of the base hole: 4 in across the slope and 4.472 in down it, with the true-length factor used.
- A one-page check sheet: every input with its unit and source, the checks made, and the pieces labelled.
Rubric
| Criterion | Meets the standard when |
|---|---|
| Method and views | Parallel line is chosen and justified; plan and elevation are drawn and the elements are numbered consistently on both. |
| Stretch-out | The stretch-out is calculated as pi x D, not stepped off in chords, and equals 12.566 in before allowances. |
| Ordinates | Each element height is shown with its unit, runs from 0 at the shortest element to the diameter x rise/12 at the longest and back, and the curve passes through every point. |
| Allowances and seam | The allowance is drawn outside the developed curve and its rule is named; the seam is on the shortest element. |
| Evidence and safety | Inputs, units, sources and check results are recorded; example values are marked as examples; gloves are worn and edges deburred when the scrap is cut. |