DFM Reference

Minimum internal corner radii, wall thickness, pocket depth-to-width ratios, and achievable tolerances by operation. Workholding considerations and feature accessibility.

Length-to-diameter ratios, internal feature access, undercut geometry, and live tooling limitations. Turned feature tolerance expectations by operation type.

Minimum corner radii (wire diameter dependent), taper limits, surface finish achievable by number of passes, and start hole requirements. When wire EDM beats CNC.

Surface finish specifications (Ra, Rz), grinding stock allowances, hardness requirements for grinding, and when to specify lapping, honing, or superfinishing.

Minimum bend radius by material and thickness. Minimum flange length, bend relief geometry, and grain direction. When to specify air bend vs bottom vs coining.

Hole-to-edge and hole-to-bend minimums. PEM hardware requirements and installation clearances. Countersink and dimple limits by gauge. Louver and lance geometry.

Joint types, weld symbol interpretation, access requirements, distortion control, and designing for weldability. When to weld vs fasten mechanically.

Sheet metal gauge charts (steel, aluminum, stainless). Standard sheet sizes. Common material tempers and their formability. Minimum order quantities and lead time expectations.

Uniform wall thickness rules, rib-to-wall ratios to avoid sink, boss design, and coring strategies. Minimum and maximum wall by material family.

Minimum draft angles by surface finish and depth. Side actions, lifters, collapsible cores, and when to redesign instead. Texture depth vs draft requirements.

Gate types (edge, sub, hot tip, valve), placement strategy, weld line management, and runner sizing. How gate location affects fill, pack, and cosmetics.

Cantilever snap fit geometry, allowable strain by material, insertion force estimation, and living hinge design. When snap fits replace fasteners.

Draft requirements, wall thickness limits, parting line placement, and ejector pin marks. Porosity management, die life by alloy, and as-cast tolerance expectations.

Wax pattern limitations, minimum feature size, achievable tolerances and surface finish. When investment casting beats machining from billet. Shell thickness and gating.

Layer orientation strategy, support minimization, minimum wall and feature sizes, bridging limits, and tolerance expectations. Infill vs shell strength trade-offs.

Powder bed processes — minimum wall, escape holes for trapped powder, accuracy by axis, and surface finish expectations. When SLS/MJF beats FDM for functional parts.

Resin processes — minimum feature size, drain holes, support removal strategy, and UV post-cure requirements. Dimensional accuracy vs part size.

Decision framework for choosing between AM processes. Cost vs volume, material availability, accuracy requirements, and when to 3D print vs machine vs mold.