Most of the cost in a sheet metal part is committed before the first cut, and most of it is committed by geometry rather than by material. This cluster is the manufacturing side of the site: what each process can hold, what it cannot, and which lines on the drawing move the quote.
What this cluster covers
The process map shows where each decision lands across the nine steps from drawing to assembly. The DFM and tolerance articles deal with the two things that cause most arguments at goods-in: geometry the process cannot produce, and a tolerance that nobody agreed how to measure. Cutting and piercing are covered by material and by method — laser edge condition and kerf, punching and turret limits, and the choice between laser, stamping and hard tooling. Forming covers bending maths, the press brake calculator, hems, bend reliefs and corner joints, plus deburring and edge break. Joining covers process selection, distortion control, what an appearance criterion actually says, and welded against modular construction. The last group is programme control: reverse engineering a part from a sample, revision and cut-in discipline, and when tooling pays for itself.
Where to start
- New to sheet metal: start with the process map, then the DFM rules, then tolerances. Read them in that order — the first explains what happens, the second what to change, the third what to write on the print.
- Changing a part that already runs: go to the article for the specific feature you want to change rather than reading the cluster end to end.
- Arguing about whether a part is acceptable: the tolerance, laser edge quality and weld appearance articles are all about what 'acceptable' means when it is written down.
- Comparing laser, turret and stamping for one part: the three process articles plus the laser-versus-stamping comparison will settle it on features and volume, not on opinion.
The process map, DFM rules and tolerances
Sheet Metal Fabrication Process: 9 Steps to Assembly
A complete guide to the sheet metal fabrication process — from DFM design and laser cutting to bending, welding, powder coating and final assembly.
Sheet Metal DFM: Design for Manufacturability Guide
Sheet metal DFM design guide: 12 rules that cut cost on enclosures, brackets and chassis, from hole-to-edge spacing to bend relief and fastener selection.
Sheet Metal Tolerance Guide: ISO 2768 & GD&T
Sheet metal tolerance explained: ISO 2768 medium class limits, GD&T vs traditional tolerances, and how to balance cost vs precision on custom enclosures.
Sheet Metal DFM: Where a 30% Cost Cut Really Comes From
A cost-driver breakdown of a sheet metal quote: nesting yield, bend radius standardisation, weld-length reduction and tolerance allocation, with a worked before-and-after example.
Cutting and piercing
Laser Cut Edge Quality: Kerf, Dross & Tolerance Guide
What a laser cut edge really specifies: kerf width, dross types, assist gas choice, tolerance by thickness and HAZ. Plus a paste-ready drawing callout.
Sheet Metal Punching: Turret Press Limits & DFM Rules
How to design for sheet metal punching: minimum hole diameter, punch and die clearance, web and bend distances, turret forms, burr direction and tonnage.
Laser Cutting vs Stamping for Sheet Metal | SanJun Hardware
Laser cutting vs stamping — compare cost, volume, accuracy and lead time to choose the right sheet metal fabrication process for your parts.
Precision Metal Stamping Service: Process & Dies
Progressive vs. compound dies, tolerances, materials and tooling costs for precision metal stamping — and when to choose stamping over laser cutting.
Forming and edges
Sheet Metal Bending Guide: Radius, K-Factor & Allowance
Sheet metal bending explained: K-factor, bend allowance, minimum flange and springback compensation, plus press brake tooling rules for repeatable enclosures.
Press Brake Bending Calculator: Bend Force & Allowance
Press brake bending calculator: bend force, bend allowance, bend deduction and K-factor, with a worked 2 mm steel example, V-die rules and what to verify.
Sheet Metal Hems, Bend Reliefs & Corner Joints Guide 2026
Sheet metal hem, bend relief and corner joint design rules: 4xT return, relief width and depth, 4 corner joints, Z-bend limits, K-factor, 9 DFM checks.
Sheet Metal Deburring & Edge Break: ISO 13715 Burr Limits
Sheet metal deburring explained: ISO 13715 + and - edge values, how much burr is allowed, 5 methods, edge break vs radius, and how to write it on a PO.
Oil Canning in Sheet Metal: Causes and Flatness Fixes
Why a large thin panel buckles under residual stress, what gloss and raking light do to it, how to measure flatness in free state without disputes, and the design and process levers that keep a wide face flat.
Joining: process, distortion, appearance, construction
Sheet Metal Welding: MIG, TIG, Spot & Laser Guide
Sheet metal welding guide: MIG, TIG, spot and laser welding compared, with process selection, starting parameters, distortion control and AWS/ISO weld symbols.
Sheet Metal Weld Distortion Control: Heat Input & Fixes
Control sheet metal weld distortion with heat input maths, five distortion modes, weld sequence, fixtures and post-weld acceptance criteria you can specify.
Weld Appearance Acceptance Criteria: Levels & Defects
How to write weld appearance acceptance criteria: the three ISO 5817 quality levels, nine defects buyers reject, cosmetic vs structural, and limit samples.
Welded vs Modular Enclosures: Cost Crossover & Sealing
Compare welded vs modular enclosures on cost crossover, sealing, EMC, vibration, freight and service, plus the hybrid structure and RFQ fields to lock.
Yield and programme control
Sheet Metal Nesting & Material Yield: Cost Guide 2026
Sheet metal nesting and material yield: where scrap goes, six levers that add 5-14 points, sheet vs coil economics, fair utilisation bands, seven DFM rules.
Sketch or Sample to Production-Ready Sheet Metal CAD
Turn a hand sketch or sample part into production-ready sheet metal drawings: 3D scanning, K-factor calibration, DFM, BOM and a 7-10 day prototype run.
Sheet Metal Drawing Revisions: ECN, Cut-In & Disposition
Run sheet metal engineering changes without mixed stock: impact on tooling, nesting, coil and FAIR, cut-in by lot, old-revision disposition, three-way match.
Sheet Metal Tooling Investment: When to Buy Fixtures
When to invest in sheet metal tooling: what each fixture buys, the payback arithmetic, hidden lifecycle costs, ownership clauses, and the right build sequence.
Sheet Metal vs Injection Molding: Enclosure Process Route Decision
Where the two cost curves cross, given as a formula rather than a published number; envelope, load path and feature integration as filters that come before any cost term; why revision risk is asymmetric between the routes; and the conditions under which sheet metal is simply the wrong answer.