The short answer Start with thickness: it sets every other limit. Keep holes at least one thickness across and 2.5 thicknesses plus the bend radius away from a bend line, keep the inside bend radius at one thickness for mild steel, and tolerance to ISO 2768-m except where a feature actually mates. That removes most avoidable cost before a quote is issued. Thickness first, because it sets every...

The short answer For bare steel outdoors, hot-dip galvanizing lasts longest: an 85 micron coating gives roughly 20 to 40 years in a C4 coastal or industrial site, and it keeps protecting scratched edges. Where colour is needed, powder over galvanizing adds a second barrier; 316L stainless needs no coating in marine air. Why there is no single best finish Corrosion is a rate, not a property of ...

The short answer A bend relief is a small notch cut at the end of a bend line, where the bend meets an edge or another flange. Without it the material has nowhere to flow, so it tears or bulges. Cut it at least one material thickness wide and as deep as the bend radius plus one thickness. Why a bend with no relief tears When sheet metal is formed, the outside of the bend stretches and the insi...

The short answer Consistent weld quality comes from process control, not from inspection alone. Write the welding procedure and qualify welders to it, control joint preparation, gap and parameters, then inspect in three phases: before, during and after the arc. Inspect 100 percent visually and add NDT in proportion to what the joint carries. Consistency is a process property, not something you...

The short answer Use TIG for thin, cosmetic work in stainless or aluminium from 0.5 to 3.0 mm, MIG for structural steel from about 1.2 to 6.0 mm, fiber laser for thin enclosures where distortion and finish matter, and resistance spot welding for lap joints in high volume. Thinnest wall and joint type decide, not preference. There is no best process, only a best fit Every welding argument on a ...

The short answer Bend allowance is the arc length of the neutral axis through a bend, so it is the material that bend consumes. On two millimetre mild steel with a two millimetre inside radius, one 90 degree bend takes about 4.3 mm, so add each allowance to the flat legs to size the blank. Bend allowance is the arc length of the neutral axis When sheet metal bends, the outside surface stretche...

The short answer Air bending is the default and covers most custom sheet metal work, holding roughly 0.5 to 1.0 degrees with one tool set. Bottoming and coining tighten that to about 0.1 to 0.5 degrees on angle-specific tooling, roll bending forms large curves, and hemming folds an edge for safety and stiffness. Five techniques cover almost all press-brake work Bending looks like one operation...

The short answer Industrial fiber laser cutting holds about ±0.1 mm on sheet under 3 mm, ±0.15 to 0.2 mm on 3 to 10 mm plate and ±0.3 to 0.5 mm on plate over 10 mm, with repeatability near ±0.05 mm across a run. Kerf is 0.1 to 0.3 mm. Bending and welding then add their own error. Accuracy and repeatability are two different numbers Laser cutting tolerances get misquoted because two different m...

The short answer Industrial fiber laser cutting handles roughly 0.5 to 20 mm across common metals: about 20 mm carbon steel, 15 mm stainless and 12 mm aluminium on a 6 kW machine, rising to 60, 40 and 30 mm at 20 kW. Copper and brass stay under 10 mm. Thickness is set by power, and power alone does not promise a clean cut Every laser cutting capacity table is really two numbers, not one. The f...

The short answer Professional sheet metal fabrication runs six stages: design and flat pattern, material selection, cutting, forming, welding and assembly, then surface finishing and inspection. Cutting and forming set the tolerance, finishing is the largest single cost line at 25 to 40 percent, and the first part carries all the setup. Six stages, and the one number each stage controls The pr...

The short answer Choose sheet metal fabrication when the part is a thin-walled enclosure, panel or bracket between 0.5 and 6 mm and you expect volume: material use of 70 to 85 percent makes it 30 to 60 percent cheaper above roughly 50 units. Choose CNC for solid bodies, tight tolerances and complex 3D features. Geometry decides before cost does The question is not which process is better but w...

The short answer Choose a sheet metal fabricator on process fit, not price. Confirm the material, thickness and tolerance your part needs, ask for a line-item quote and an engineering reply, audit inspection and capacity, then approve a sample and a small pilot before volume. A weak reply to a technical question is the strongest warning sign. Four gates before volume Supplier selection is a se...

The short answer Powder coating is the default for steel and mixed metal, giving 60 to 120 micrometres of colour and impact protection. Type II anodising suits aluminium where a metallic look and wear resistance matter, hard anodising where sliding wear dominates, and passivation is a low-cost step for stainless. Finishing can reach 25 to 40 percent of part cost. Five finishes cover most sheet...

The short answer Common sheet metal grades are cold-rolled SPCC or Q235 carbon steel, SGCC galvanised steel, 304 and 316 stainless, 5052-H32 and 6061-T6 aluminium, and copper or brass. Thickness runs about 0.5 to 6 mm, and grade choice is driven by corrosion, formability, weight and weldability rather than price alone. Specify the decimal thickness, not the gauge The single most common specifi...