The ten-point checklist to run before you upload a part for quoting

Design for Manufacturing (DFM) is a pre-flight checklist: ten questions that catch most quoting surprises before they cost money — walls, draft, radii, threads, tolerances, text, depth, overhangs, material and finish. Running it before upload takes five minutes and typically cuts cost 20–50% while eliminating schedule risk.

1. The ten checks

1. Walls: above process minimums (0.8 mm metal, 1.0 mm plastic, 1.0–4.0 mm molded) and uniform. 2. Draft: 1–2° on molded faces. 3. Radii: internal fillets ≥ 0.5 mm. 4. Depth: pockets ≤ 4:1. 5. Threads: standard sizes ≥ M1.6, engagement 1.5–2×.

6. Tolerances: general ±0.127 mm unless function demands; tight only on mating features. 7. Text: ≥ 0.8 mm or laser mark. 8. Overhangs: ≤ 45° for printing or oriented to supports. 9. Material: cheapest grade meeting service conditions. 10. Finish: match spec to function, one pass per operation.

2. Before you upload

Export STEP (AP214) from native CAD; check units (mm) and scale; set the coordinate system to the datum scheme; remove reference bodies and sketches; verify the part is a solid (watertight).

Decide the process by quantity and geometry (see Manufacturing Methods); enter or confirm L/W/H; choose material from the library; state finish, tolerance class and lead time. The engine flags residual issues on upload.

3. Red flags on the quote

A quote with DFM notes means risk: read them (deep pockets, thin walls, tight tolerances) and fix before ordering. Unexpectedly high per-unit cost on small simple parts usually means setup/minimums — order the tier or consolidate.

If the engine’s volume/bounding box differs from your model, correct it — the whole quote is built on it.

4. The habit

DFM is iterative: quote, review, redesign, re-quote. The live calculator makes each iteration instant, so tighten the loop until the price matches the function — then freeze and order.

Keep the checklist with your CAD template; teams that run it mechanically quote 20–50% cheaper and hit schedules.

Quick reference

#	Check	Pass condition
1	Wall thickness	Above process minimum, uniform
2	Draft	1–2° on molded faces
3	Internal radii	≥ 0.5 mm fillets
4	Pocket depth	≤ 4:1 depth:width
5	Threads	≥ M1.6, standard, engaged 1.5–2×
6	Tolerances	General unless functional
7	Text	≥ 0.8 mm or laser mark
8	Overhangs	≤ 45° or supported
9	Material	Minimum adequate grade
10	Finish	Matched to function

Sources & references

• ISO 2768-1 — General tolerances
• DIN 16742 — Plastic tolerances
• Xometry Learning Center — DFM Checklist (public engineering reference)

Subtractive, additive, formative and joining — the four families and when each wins

All manufacturing is one of four families: subtractive (machining removes material), additive (printing adds material), formative (molding/stamping/forming shapes material under pressure) and joining/assembly (fastening, welding, adhesives). A part’s geometry, quantity and material decide the family; within a family, the specific process is an economic choice. Engineers who think in families select processes in seconds.

1. Subtractive: machining

CNC milling, turning, drilling and EDM remove stock from solid billets. Strengths: tightest tolerances (±0.025–0.127 mm), best surface control, any solid metal/plastic, no minimum quantity beyond setup. Weaknesses: material waste, cost scales with part complexity, and internal cavities need tool access.

Best for: precision components, low-to-mid volume, parts needing exact tolerances or specific metal tempers.

2. Additive: 3D printing

FDM, SLA, SLS/MJF and DMLS build parts layer by layer. Strengths: unlimited geometric freedom (channels, lattices, undercuts), no tooling, fast iteration, near-net metal via DMLS. Weaknesses: layered surfaces, anisotropic strength, tolerances ±0.2–0.5 mm, cost scales with volume not quantity.

Best for: complex geometry, prototypes, low volume, design iteration, internal channels.

3. Formative: molding, stamping, casting

Injection molding, sheet stamping, die casting, forging and extrusion shape material against a tool. Strengths: lowest unit cost at volume, fast cycle times, repeatability, excellent surfaces (molded). Weaknesses: tooling investment ($2k–100k+), design constraints (draft, wall, parting), long tooling lead.

Best for: production volumes above the tooling crossover (typically 500–5,000 for molding), identical parts in quantity, metals and plastics at scale.

4. Joining and assembly

Fasteners, welding, brazing, adhesives and interference fits combine subparts. Design for assembly (DFA) minimizes part count and fastener types; welding integrates strength but adds distortion; adhesives distribute load and seal. Assembly is where most product cost actually hides.

Best for: multi-material products, serviceable designs, large structures, and integrating printed/machined/molded parts into one product.

Quick reference

Family	Example processes	Tolerance	Volume sweet spot	Unit cost
Subtractive	CNC mill/turn, EDM	±0.025–0.127 mm	1–5,000	Medium
Additive	FDM, SLA, SLS, DMLS	±0.2–0.5 mm	1–100	High (flat)
Formative	Molding, stamping, die-cast	±0.3% / ±0.1 mm	500–1M+	Low
Joining	Weld, fastener, adhesive	assembly ±	varies	varies

Sources & references

• ISO/ASTM 52900:2021 — Additive terms
• ASM Handbook — Vol 16 Machining
• Xometry Learning Center — Manufacturing Overview (public engineering reference)

Thin walls, deep pockets, sharp corners, unsupported text — and the redesigns that fix them

Most quoting and manufacturing failures come from a short list of avoidable features: walls below the process minimum, deep narrow pockets, sharp internal corners, unsupported overhangs, tiny text, and zero-draft vertical faces in molding. Each has a simple redesign that preserves function while cutting cost and risk dramatically.

1. Walls, ribs and thickness

Avoid walls thinner than the process floor: CNC metal 0.8 mm, plastic 1.0 mm; printed 0.7–1.0 mm (process-dependent); molded 1.0–4.0 mm uniform. Thin walls vibrate (machining), warp (printing), or sink/fill poorly (molding). Fix: thicken, or add ribs/bosses to stiffen.

Avoid abrupt thickness changes — they create stress concentrations and differential cooling (sink marks in molding). Transition gradually or add a fillet.

2. Pockets, corners and depth

Deep narrow pockets force long tools that deflect: keep depth:width ≤ 4:1 for milling; beyond that, EDM or redesign. Internal corners should be filleted ≥ 0.5 mm (tool radius); sharp internal corners are simply unmachinable by round tools.

Undercuts in molding need side actions ($$$): rotate the feature into the pull direction or accept the tooling cost. Printing: overhangs beyond 45° need supports — orient or redesign the face.

3. Text, threads and small features

Text smaller than 0.5 mm depth is unreliable in machining and molding; use ≥ 0.8 mm or switch to laser marking. Threads below M1.6 break taps — use M2+ or insert hardware. Holes below 0.8 mm need EDM or laser drilling — resize or post-machine.

Features that invite failure: razor edges (break them), blind fine threads (through-hole or enlarge), unsupported long spans (rib them), and tight tolerances on cosmetic faces (loosen them).

4. The redesign-first habit

Before quoting, run the DFM checklist: walls, draft, radii, threads, tolerance, text, overhangs, depth ratios. The platform flags violations on upload with suggested fixes — most are 30-minute redesigns that cut cost 20–50%.

When a feature is genuinely required (thin wall for weight, sharp corner for function), say so: the quote and DFM notes will confirm the process cost, and you decide if it is worth it.

Quick reference

Feature	Problem	Fix
Wall < 1 mm (plastic)	Warp, break, sink	Thicken or rib
Deep pocket > 4:1	Tool deflection	EDM, or widen
Sharp internal corner	Unmachinable	Fillet ≥ 0.5 mm
Overhang > 45° (print)	Supports needed	Orient/redesign
Zero draft (mold)	Part sticks	Add 1–2° draft
Text < 0.5 mm	Unreadable	Enlarge or laser mark
Thread < M1.6	Tap breakage	M2+ or insert

Sources & references

• ISO 2768 / DIN 16742 — Feature limits
• Xometry Learning Center — Features to Avoid (public engineering reference)

The eight levers of part price: material, volume, tolerance, finish, quantity and more

Part cost is a product of eight levers: material choice, part volume, geometric complexity, tolerance, surface finish, quantity, lead time and tooling. Most cost reduction is design-led — a 30-minute geometry change beats weeks of supplier negotiation. This article ranks the levers by their typical impact and shows where to look first.

1. Material and volume

Material is volume × density × price/kg: aluminum ≈1 index, steel ≈1.2, stainless ≈3–4, titanium ≈8–12, PEEK ≈30–60. On machined parts, you pay for the stock removed too — design near-net and expect 2–5× finished volume in waste.

Part volume also sets machine time, print height and mold size: every cubic millimeter of unnecessary material adds cost across the whole process chain. Lightening cores, reducing envelope and cutting non-functional material is the highest-leverage move.

2. Complexity and tolerance

Feature count drives machining minutes: deep pockets, fine threads, tight GD&T, multiple setups. Complexity is multiplicative with quantity — a complex part at 500 units is very expensive. Simplify by consolidation, standard sizes and looser non-critical tolerances.

Tolerance bands: general ±0.127 mm is free; ±0.025 mm roughly doubles time; ±0.005 mm is 5–10× and usually unnecessary. Surface finish similarly: as-machined is free; fine polish is premium; anodize/powder is a modest area-based cost.

3. Quantity, lead time and tooling

Quantity tiers discount setup and amortize programming: 100 parts can cost 60–70% per unit of a 1-off. Lead time is a multiplier: expediting adds 20–40%. Tooling (molds/dies) is a separate line that pays off only above the crossover quantity.

Overhead and margin add 15–30% on top — the platform’s transparent lines show these; they are not negotiable but they are visible.

4. The 80/20 of cost reduction

Check in order: (1) material grade — can a cheaper alloy/plastic do it? (2) volume — lighten non-functional mass; (3) tolerance/finish — loosen what does not mate; (4) features — remove deep pockets and fine threads; (5) quantity — buy to the tier; (6) lead — plan standard, not expedite.

Every redesign that removes material or complexity compounds across all other levers; the quoting engine’s live calculator shows the price impact of each change instantly.

Quick reference

Lever	Typical impact	Action
Material grade	2–60× between families	Choose the minimum adequate
Part volume	Scales material + time	Lighten, core, reduce envelope
Complexity	Multiplies machine time	Consolidate, standardize
Tolerance	1–10× on features	Loosen non-critical
Finish	+5–40% by spec	Match finish to function
Quantity	−30–50% per tier	Buy to the tier
Lead time	+20–40% expedite	Plan standard
Tooling	Amortized per part	Cross above crossover

Sources & references

• Xometry Learning Center — Cost Drivers (public engineering reference)
• Protolabs — Design for Manufacturing Cost Guide (public engineering reference)
• ISO 9001:2015 — Quality management systems (prevention & appraisal cost context)