{"id":4350,"date":"2026-05-07T06:46:21","date_gmt":"2026-05-07T06:46:21","guid":{"rendered":"https:\/\/xinyangmfg.com\/?p=4350"},"modified":"2026-05-11T05:24:28","modified_gmt":"2026-05-11T05:24:28","slug":"sheet-metal-fabrication-guide","status":"publish","type":"post","link":"https:\/\/xinyangmfg.com\/es\/sheet-metal-fabrication-guide\/","title":{"rendered":"Sheet Metal Fabrication: Processes, Tolerances, and How to Spec a Job"},"content":{"rendered":"

Sheet metal fabrication is the family of processes that converts flat metal stock into formed parts: laser cutting<\/a>, punching, bending, welding, and finishing. Standard tolerances are \u00b10.1 mm on cut edges and \u00b10.3 mm on bent dimensions, with material thickness typically 0.5\u20136 mm. A well-specified job ships in 5\u201310 days and avoids the three most common DFM errors: too-small bend radius, holes too close to bends, and overlooked stretch on long flanges.<\/p>\n\n\n\n

Sheet Metal Process Comparison<\/strong><\/h2>\n\n\n\n
Process<\/strong><\/th>Typical Material Range<\/strong><\/th>Tolerance<\/strong><\/th>Best For<\/strong><\/th>Setup Cost<\/strong><\/th><\/tr><\/thead>
Fiber Laser Cutting<\/td>0.5\u201325 mm steel, 0.5\u201312 mm SS, 0.5\u201310 mm Al<\/td>\u00b10.1 mm<\/td>Complex outlines, slots, tabs<\/td>Low<\/td><\/tr>
CO2 Laser Cutting<\/td>0.5\u201320 mm (slower than fiber)<\/td>\u00b10.15 mm<\/td>Older legacy parts<\/td>Low<\/td><\/tr>
CNC Punching<\/td>0.5\u20136 mm steel\/SS\/Al<\/td>\u00b10.1 mm<\/td>High-quantity, repetitive holes<\/td>Medium (tooling)<\/td><\/tr>
Press Brake Bending<\/td>0.5\u201310 mm typical<\/td>\u00b10.3 mm angle, \u00b10.5 mm length<\/td>Single-bend brackets, enclosures<\/td>Low<\/td><\/tr>
Robotic Welding<\/td>1\u201310 mm steel\/SS<\/td>\u00b10.5 mm position<\/td>Production weldments<\/td>Medium<\/td><\/tr>
Manual TIG\/MIG<\/td>0.5\u201325 mm<\/td>\u00b11.0 mm position<\/td>Prototype, repair, complex weldments<\/td>Low<\/td><\/tr>
Powder Coat Finishing<\/td>All \u2014 post-process<\/td>Coating 60\u2013120 \u00b5m<\/td>Durable, color-flexible finish<\/td>Medium<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The Five Core Sheet Metal Processes<\/strong><\/h2>\n\n\n\n

Sheet metal fabrication<\/a> runs on five process families, used in combination on almost every part:<\/p>\n\n\n\n

Laser Cutting<\/strong><\/h3>\n\n\n\n

Fiber lasers (1.5 kW to 30 kW resonators) dominate modern sheet metal cutting. A 6 kW fiber laser cuts 16-gauge mild steel at 8,000 mm\/min and 6 mm aluminum at 3,500 mm\/min with \u00b10.1 mm dimensional accuracy. Edge quality on the cut face is typically Ra 3.2\u20136.3 \u00b5m \u2014 clean enough for most applications without secondary grinding.<\/p>\n\n\n\n

Practical limits: minimum hole diameter equals roughly 1\u00d7 material thickness (a 3 mm thick sheet should have holes no smaller than 3 mm); minimum slot width 0.8\u00d7 thickness. Going below those limits forces more passes, higher heat input, and dross on the back side.<\/p>\n\n\n\n

CNC Punching and Nibbling<\/strong><\/h3>\n\n\n\n

Turret punch presses excel at high-quantity hole work. A modern Amada or Trumpf turret punch nibbles a 50 mm slot in 16-gauge steel in under 2 seconds and runs unattended for 4\u20138 hour shifts. Tolerance is comparable to laser at \u00b10.1 mm, but tooling cost (custom punches) and the per-part time advantage flips around quantity 200\u2013500.<\/p>\n\n\n\n

For quantities above 500 with repetitive hole patterns, CNC punching beats laser on cost<\/a>. Below 200, laser wins because there’s no tooling cost.<\/p>\n\n\n\n

Press Brake Bending<\/strong><\/h3>\n\n\n\n

Press brakes form the bend in sheet metal. The two practical methods are air bending (bottom of the V-die unsupported, angle controlled by ram depth) and bottoming (forced into the die, more consistent but more tonnage required).<\/p>\n\n\n\n

Standard bend tolerances are \u00b10.3\u00b0 on angle and \u00b10.5 mm on flange length. Tighter tolerances are achievable but require attention to:<\/p>\n\n\n\n