The Material Selection Scorecard: Performance, Cost, Risk, and Footprint

List the functions the material must perform: carry load, flex, insulate, conduct, seal, protect, transmit light, resist wear, feel comfortable, clean safely, or communicate quality. Add geometry, target process, expected life, user contact, environment, maintenance, regulatory questions, and failure consequence. A material that works in a thick machined block may fail in a thin molded wall.

Separate must-pass constraints from preferences. A maximum service temperature or required electrical insulation can eliminate candidates before scoring. Color, touch, and finish can be weighted after safety and function gates. If a target is unknown, mark it missing and assign a test rather than awarding every material an average score.

ABS, aluminum, wood, glass, and nylon are families, not complete specifications. Record exact grade or species, additives, recycled content if relevant, condition, thickness, orientation, finish, coating, joining, and process. Supplier data applies to named test methods and specimens; the final part can behave differently because of geometry, processing, aging, moisture, ultraviolet exposure, or assembly stress.

For additive prototypes, NIST notes that materials are built layer by layer and that measurements and standards matter. Do not copy a printed-part result onto a molded or machined production claim. Use representative processes when the decision depends on anisotropy, surface, porosity, residual stress, fiber orientation, knit lines, or process variation.

Choose criteria from actual requirements: stiffness, strength, impact, fatigue, creep, wear, friction, hardness, thermal range, expansion, conductivity, flammability, chemical resistance, moisture, ultraviolet exposure, dimensional stability, permeability, and cleanability. Add user perception only where it changes value. Weight each criterion before comparing candidates.

Record source, method, condition, confidence, and prototype implication for each score. Use disqualifying gates for severe safety or functional failures. A weighted average should not allow excellent color options to cancel an unacceptable heat or impact risk. Review failure modes and foreseeable misuse with appropriate engineering and safety specialists.

Compare compatible processes, tooling, minimum section, draft or tool access, tolerance, finish, secondary operations, joining, inspection, expected yield, rework, and production scale. Include supplier capability and alternate sources. A cheap raw material can become expensive when it needs slow machining, complex finishing, high scrap, or difficult joining.

Connect material selection to prototype choice. Use low-cost artifacts to narrow geometry and user questions, then representative materials and processes for performance questions. Define incoming and in-process checks. If appearance is critical, include color, gloss, texture, sink, grain, batch variation, and aging standards instead of approving one hero sample.

Include material price, conversion, scrap, finish, assembly, inspection, tooling, freight weight, packaging, maintenance, warranty, repair, and end-of-life obligations. Use low, base, and high ranges with price date, currency, volume, origin, MOQ, lead time, and supplier. Do not compare a spot price for one candidate with a production quote for another.

Add supply concentration, geopolitical or trade exposure, grade substitution difficulty, qualification work, storage life, and traceability. A slightly higher piece price may reduce schedule and continuity risk. Mark supplier claims that lack independent or lot-level evidence. Update volatile assumptions rather than changing only the article or spreadsheet date.

Consider extraction, manufacture, production, use, maintenance, expected life, repair, reuse, disassembly, recovery, and disposal. EPA guidance uses this lifecycle perspective. Record mass, durability, replaceability, material variety, separability, recycled-content evidence, hazardous constituents, and actual next-life infrastructure. Recyclable in theory is different from collected and recovered in the intended market.

The EU ecodesign framework is expanding attention to durability, repairability, circularity, and product information. Verify product-specific rules and timelines. Avoid unqualified sustainable, eco-friendly, or low-impact claims. Prefer measurable statements with boundaries: named recycled content under a named method, replaceable component with instructions, or documented reduction against a defined baseline.

Score both outcome and confidence. A candidate with strong published data under irrelevant conditions may have lower confidence than a modest candidate with representative test evidence. Highlight criteria where the winner changes under a plausible weight or value change. Those sensitivities show which requirement or test deserves attention before detailed design.

Shortlist at least two options and define prototype evidence for each. Record what would disqualify a material, who reviews the result, and how the final grade and process are controlled. ConjureAnything can propose material directions, but the scorecard must replace generic names with grade-level sources, representative tests, supplier evidence, and current safety review.