Selecting a Material, step by step
Function, constraint, free variable, objective: then the index falls out.
- State function and constraintWhat must the part do, and what must it not exceed?
- Name the free variableUsually a dimension you are allowed to change.
- Write the objectiveMinimise mass, or cost, or deflection at a stated load.
- Derive the indexStiff light tie: E ÷ density. Strong light tie: yield ÷ density.
- Screen, rank, then checkRank on the index, then test process, supply and price.
An index ranks materials; it does not choose one. Corrosion, joining and availability decide in the end.
Questions about the Selecting a Material poster
- What’s on the Selecting a Material poster?
- 5 numbered steps. Function, constraint, free variable, objective: then the index falls out. State function and constraint — What must the part do, and what must it not exceed?; Name the free variable — Usually a dimension you are allowed to change.; Write the objective — Minimise mass, or cost, or deflection at a stated load.; Derive the index — Stiff light tie: E ÷ density. Strong light tie: yield ÷ density.; Screen, rank, then check — Rank on the index, then test process, supply and price.. An index ranks materials; it does not choose one. Corrosion, joining and availability decide in the end.
- Who is the Selecting a Material poster for?
- Selecting a Material belongs to the Mechanical Engineering section rather than to a school year, because engineering is not something one grade owns. Anyone learning manufacturing can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the Selecting a Material poster?
- Early design, when the material is still open and weight or cost matters. A wall chart earns its place by being glanceable from where the work is happening, so Selecting a Material belongs on the wall where that engineering work actually happens, within glancing distance, rather than filed away.
- What other posters go with Selecting a Material?
- Additive Processes, Casting Processes and Speed & Feed sit alongside Selecting a Material in the Mechanical Engineering section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.Additive ProcessesCasting ProcessesSpeed & Feed
- Is the Selecting a Material poster free to download and print?
- Yes. Selecting a Material downloads as a free PDF with no account, no email and no watermark, like everything else in the Mechanical Engineering section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the Selecting a Material poster print at?
- Selecting a Material is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Selecting a Material loses nothing.Printing guide
Related posters
Charts that sit alongside Selecting a Material on the same wall.
Additive Processes
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Casting Processes
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Speed & Feed
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Design for Manufacture
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Heat Treating Steel
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Designing for Moulding
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Process Families
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Process Capability
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