MVP v2: Manufacturing Cost Estimation¶

Source files: Architechture & Research/RapidDraft/Product Scope & PRDs/MVP Scopes and Problems.md (lines 320-625) Last synthesized: March 2026 Purpose: Specification of v2 extension: rough cost estimation for design trade-off analysis.

One-Liner¶

RapidDraft v2 adds rough manufacturing cost estimation tied to design parameters, helping engineers make smarter material/tolerance/process choices during design iteration.

What v2 Does¶

v2 is not a quoting replacement. It's an early warning system and design trade-off tool that answers: "If I change this, what happens to cost?"

Before you send a design to purchasing/suppliers, you want to know whether you're designing a €20 part or a €200 part—and why. v2 helps you see:

"This feature is driving cost"
"This tolerance/finish is the real killer"
"This looks like it forces a different process / extra setups"

Real Designer Use Cases¶

1. Cost Sanity Check During Design Iterations¶

You change a wall thickness, add a pocket, tighten a tolerance, add a coating… and suddenly the part gets expensive. v2 helps you spot it:

See cost impact immediately as you design
Understand what's driving the cost
Make informed trade-offs between function and manufacturing

2. Compare Options Quickly¶

CNC vs casting + machining — which is cheaper for this geometry?
Sheet metal vs machined plate — what's the break-even batch size?
Injection molding (high tooling, low per-piece) vs CNC (low tooling, high per-piece) — for what quantities does each win?

3. DFM + Cost in One Place¶

DFM warnings become more actionable when tied to money:

"Sharp internal corners → likely EDM / special tooling → time ↑ → cost ↑"
"Tight positional tolerance → inspection ↑ → cost ↑"
"Deep pocket → multiple setups / long tool → time ↑ → cost ↑"

Scope Details¶

Inputs (What the Engineer Tells the Tool)¶

Required: - Manufacturing process (e.g., CNC machining, sheet metal, injection molding — start with 1–2) - Material (e.g., Al 6061, steel, stainless) - Batch size (prototype 1–5, low 10–100, series 1000+)

Optional but high impact: - Tolerance class ("standard", "tight", "very tight") - Surface finish requirement (raw / as-machined / polished / anodized) - Secondary operations (heat treat, anodize, paint, weld, thread inserts) - Inspection level (basic vs CMM-heavy)

What the Tool Reads Automatically¶

From CAD model (3D): - Overall size / bounding box - Material volume and weight - Surface area (rough proxy for finishing) - Feature complexity proxies (e.g., lots of small faces, deep cavities, thin walls — even if imperfect)

From drawing (2D): - Tolerances called out (tight tolerances drive cost via inspection and process limits) - Surface finish notes - Hole/thread callout density (drilling/tapping time + tool changes) - Special processes called out (coating, heat treat, deburr) - GD&T presence (often implies more inspection and fixturing discipline)

Outputs (What the Engineer Gets)¶

Cost Estimate: - Cost range, not a single number (e.g., "€35–€70/part at qty 10") - Always shows explicit assumptions on screen (process, material, batch size, tolerance class, finish)

Cost Driver Breakdown (in engineer terms): - Material cost - Machine time (setup + cutting) - Tool changes / complexity penalty - Finishing / secondary operations - Inspection / tolerance penalty - Scrap risk (optional)

Top 3 Cost Drivers + Reduction Suggestions: - "Relax this tolerance" - "Increase this fillet" - "Avoid this deep slot" - "Remove cosmetic finish on non-visible surfaces"

Output Format: - Interactive view showing cost breakdown by component - Sensitivity analysis (what if I change this parameter?) - Export for design documentation

Why This Is Hard (The Ground Truth)¶

Cost estimation is difficult because cost is not geometry alone. It depends on:

Shop rates and region — labor costs vary 5x globally
Fixturing approach — 1 setup vs 3 setups changes time dramatically
Tool library and preferred processes — what machines are available
Tolerance and inspection culture — some shops inspect everything, others spot-check
Batch size realities — learning curve, amortization of setup time
Supplier relationships — what they want to make

v2 behaves like a design-side estimator, not purchasing. The right promise: "directionally correct + highlights the cost drivers," not "accurate quote."

Key Risks and Credibility Mitigation¶

Risk 1: Wrong Assumptions = Useless Number¶

Mitigation: Force explicit assumptions on screen: - Process, material, batch size, tolerance class, finish - Show them in the output so nobody treats it as gospel - Allow easy "what if" variations

Demo test: Take 10 parts with known supplier quotes, run v2 with matching assumptions. Target "within ±30–50%" to start, but with correct ranking of cheapest→most expensive.

Risk 2: Overconfidence ("Tool Says €40, So It Must Be €40")¶

Mitigation: - Always output range + confidence (not point estimates) - Show the drivers so users understand what drives cost - Require "reviewer sign-off" if it's saved to PLM

Demo test: Take same part, vary batch size (1 vs 100 vs 1000). Output should shift in intuitive way (setup amortization, tooling impact).

Risk 3: Tolerance/Inspection Underweighted (Common Failure)¶

Mitigation: Treat drawing tolerances and GD&T as a major multiplier (inspection/fixturing penalty), not a footnote.

Demo test: Identical geometry, two drawings: - One with standard tolerances - One with tight GD&T

The tight one must estimate significantly higher and explicitly say "inspection drives this."

Where to Start (So It Doesn't Become a Science Project)¶

Pick one process first: CNC machining.

Why? Cost drivers map well to what designers change: - Setups (geometry complexity) - Deep features (tool time) - Tool access (special tooling → cost) - Tolerances (inspection) - Finish (secondary ops)

Then later, add: - Sheet metal (bends, flanges, secondary ops) - Injection molding (but only if ready to handle tooling vs piece cost properly — complex)

Implementation Strategy for v2¶

Phase 1: CNC Machining Foundation¶

Simple cost model: material + machine time + tool penalty + finish
Fixed reference shop rate (start with European SMB average)
Configurable tolerance and finish multipliers
Demo on 20 test parts with known quotes

Phase 2: Accuracy Improvement¶

Calibrate against 50+ supplier quotes
Refine feature complexity detection
Add setup/fixturing penalties
Validate ±30% on new part set

Phase 3: Expansion¶

Sheet metal process model
Batch size optimization analysis
Cost-driver sensitivity reports

Success Criteria for v2¶

Accuracy targets: - Within ±30–50% of supplier quotes for CNC machining on test set - Correct ranking of cheap→expensive parts (does budgeting/prioritization work?) - Cost drivers accurately identified (does engineer find root causes?)

Usability targets: - Engineer can set assumptions and run estimate in <2 minutes - Report is understood without training (clear cost driver explanations) - "What if I tighten this tolerance?" takes <30 seconds to rerun

Pilot validation: - Design team uses v2 to make ≥3 documented design trade-offs per project - Pilot team confirms estimates were "directionally useful" for budgeting - No cases where v2 estimate was wildly wrong (>50% off repeated)

What v2 Is NOT¶

Not a formal quoting engine — that's what suppliers do
Not gospel truth — it's educated guessing for iteration
Not a substitute for supplier feedback — real costs come from suppliers
Not a replacement for manufacturing expertise — cost drivers are domain knowledge

Data Flow for v2¶

CAD Model + Drawing
        ↓
Extract cost-relevant features:
  - geometry complexity
  - hole/pocket count
  - surface area
  - tolerances, GD&T, finish
        ↓
Apply cost model:
  - process rules (machining/sheet-metal)
  - material rates
  - batch size scaling
  - tolerance penalties
        ↓
Estimate cost + breakdown
        ↓
Show range + assumptions + drivers
        ↓
Enable "what if" variations

Example Cost Breakdown (CNC Machining)¶

For a small aluminum bracket at quantity 10:

Component	Cost	% of Total
Material (Al 6061)	€5	12%
Machine time (setup + cutting)	€18	43%
Tool wear penalty (complex geom)	€8	19%
Anodize finish	€8	19%
Inspection (GD&T)	€3	7%
Total estimated range	€35–€55/part	—

Top cost driver: Machine time (complex geometry = multiple setups)

How to reduce cost: - Reduce feature count (simplify pockets) - Increase bend radii (faster tooling) - Relax positional tolerance from ±0.1 to ±0.2 mm (reduces inspection)

Transition Beyond v2¶

Once v2 is proven, future extensions could include: - Supplier cost database — learn from quotes to improve estimates - Assembly cost roll-up — estimate full product from component estimates - Design for cost — AI suggestions for cost-optimal geometry - Supply chain risk — material cost volatility, lead time impacts