Stainless steel laser cutting

Thickness and grade both matter: 316L cuts a little slower than 304 at the same power because of its alloy content. Reflective, thin stainless distorts if the nest is too dense, so heat input per unit area is part of nesting, not a post-process correction.

The commercial consequence is that stainless is priced on its own material line, not blended into a steel rate. Material grade, thickness, tolerance and finish are quoted separately from conversion, so a change of specification is visible in the price.

Ganesh quotes to the drawing first and to ISO 2768 general tolerances where the drawing is silent. For stainless laser cutting, the practical starting points are in the table below. They are starting points, not a guarantee: the part geometry, thickness and fixturing decide what can actually be held, and the quotation states the tolerance offered.

Cut quality depends on assist gas, focus position and nozzle condition more than on the headline power; nitrogen gives an oxide-free edge on stainless and aluminium. Stainless must be cut with high-pressure nitrogen to keep the edge oxide-free; that is the difference between a weldable edge and one that has to be pickled. The route is quoted as one sequence so the customer does not have to coordinate a cutter, a former, a welder and a coater.

Laser cutting leaves a heat-affected zone at the edge. Where the specification forbids any thermal effect, waterjet or a machined edge is the right process.

A manufacturability review before quotation is the cheapest place to find this out. Send the drawing, material, finish and annual quantity and the review comes back in writing.

• Hygienic brackets and covers
• Architectural trim
• Railway fittings
• Enclosure panels

Use laser cutting when the design is still moving, when the volume does not justify a tool, or when the part is large enough that a press tool would be uneconomic. It is also the right first operation for a part that will be formed and welded, because a nest can carry several different parts at once. It stops being the cheapest route when a flat part with stable geometry runs in high volume, at which point a blanking die wins on piece price and generally on edge quality too. For stainless the practical constraint is contamination: carbon steel tooling, brushes and blast media transfer free iron, so stainless work is kept on dedicated tooling and its own handling. Stainless raises the stakes on the decision: tool wear, gas cost and slower forming mean the volume needed to justify a tool is higher than for CRCA, and the wrong early choice is expensive to reverse once a die has been cut.

Send a DXF with the cut contour on its own layer, no duplicate or open entities, and a drawing that states material grade, thickness, tolerance and finish. State which edges are cosmetic and which are weld prep, because the assist gas and the deburring requirement follow from that. If the part is long, say the maximum length: a 4,450 mm panel that fits the 40 ft bed in one piece does not need a joint.

Inspection covers the cut contour against the DXF, overall size, hole position, squareness and edge condition. Burr is checked visually and by touch on cosmetic edges. Material is traceable to the mill certificate where the customer requires it. First article parts are inspected before a repeat run.

Cost splits into material, machine time, handling, deburring and any secondary operation. Material is quoted at the prevailing rate for the grade and thickness, on the nest area consumed rather than the finished part area. Machine time is set by cut length, thickness, pierce count and nesting density. Deburring is a separate operation and is often the line that surprises a buyer. On stainless steel, material is quoted as its own line at the prevailing rate for the grade and thickness, so a change of specification is visible rather than hidden in a blended rate.