Key takeaways
- A laser-cut edge runs Ra 1.5–15 µm depending on gas and thickness; a linished edge runs Ra 0.8–1.6 µm and a tumbled edge Ra 0.4–1.0 µm, and only the last two are measurable specifications.
- Powder film on a sharp 90° edge measures 40–60% of the flat-face thickness, so a 0.3–0.5 mm edge radius is a coating decision before it is a cosmetic one.
- Hand deburring a 2,000 mm perimeter takes 3–5 minutes; linishing the same part takes 40–60 seconds per metre on a belt, and tumbling 200 parts takes one 30–45 minute cycle.
- Finish before bending on aluminium and above 3 mm, and before pretreatment on everything, because a burr compressed into a bend cannot be removed afterwards.
A laser-cut bracket comes off the bed with an edge that passes a visual check and fails a hand check. The cut face carries a burr under 0.1 mm on thin sheet, a sharp 90° corner and, on stainless, a tint that no amount of wiping removes. Whether that matters is not a question about the edge. It is a question about what happens next.
Sheet metal finishing after cutting is a choice between four outcomes: leave the edge, break it, linish it, or tumble it. Each has a surface value, a handling time and a place in the sequence, and choosing by habit rather than by next operation is how parts get a finish they do not need or miss one they do.
The decision rule is short. Leave the edge when it will be coated and never touched. Break it when it will be handled, welded or coated on a visible face. Linish it when it will be seen. Tumble it when there are hundreds of small parts and every edge matters equally.
Which edge finish does the part need?
Match the finish to the next operation, not to the material. A part that goes straight into a weld fixture needs a clean faying face and nothing else. A part that goes to powder coating needs an edge break, because film pulls back from a sharp corner. A part that is the visible face of a lift door needs a grain that runs in one direction and a radius that catches light evenly.
That gives four tiers:
Leave as cut. Acceptable on 1.5–3 mm CRCA that will be coated, on internal brackets and on parts where the edge is buried in an assembly. The burr must still be under about 0.1 mm, or it holds the part off a fixture and shows through the coating.
Edge break. A 0.2–0.5 mm radius on named edges. This is the default for anything handled, anything coated on a visible face, and anything that will be welded near the edge, because a sharp corner concentrates coating stress and a burr holds a faying surface apart.
Linish. A belt or brush pass that removes the cut striations and leaves a directional grain, typically Ra 0.8–1.6 µm. This is the finish for visible stainless, painted aluminium that will be inspected under grazing light, and any face where the cut edge would show through a thin coat.
Tumble or vibratory finish. Every edge at once, Ra 0.4–1.0 µm, with a radius set by the media. This is the economic choice above a few hundred small parts, and the wrong choice for a large panel or a part with a location feature that must stay sharp.
Edge finish options and what each one costs
The table is for 1.5–3 mm sheet, which is where most of the volume sits. Times are per part or per metre and exclude loading and inspection. The Ganesh column describes what the shop actually applies, not what a catalogue offers.
| Finish | Typical Ra | Edge radius | Time | Where it belongs | Ganesh limit or note |
|---|---|---|---|---|---|
| Leave as cut | 1.5–15 µm | None, sharp | 0 s | Coated internal brackets | Burr kept under 0.1 mm on thin sheet |
| Hand edge break | 1.5–6 µm | 0.2–0.5 mm | 3–5 min per 2,000 mm | Welded frames, hand contact | File or scraper, operator dependent |
| Belt linish | 0.8–1.6 µm | 0.3–0.8 mm | 40–60 s per metre | Visible panels, door edges | Grain direction must be specified |
| Brush or Scotch-Brite | 0.6–1.2 µm | 0.2–0.4 mm | 30–50 s per metre | Stainless, painted aluminium | Blends scratches, does not remove them |
| Vibratory tumble | 0.4–1.0 µm | 0.2–0.6 mm | 30–45 min per 200 parts | Small brackets, spacers | Media sets the radius; threads need plugging |
| Coating only | 3–15 µm | None | 0 s | Outdoor enclosures, long panels | Edge film 40–60% of face value |
The first and last rows are the same edge with different downstream consequences, which is why the finish cannot be decided at the cutter. A bracket left as cut and then powder coated has an edge film of 40–60% of the face thickness, and that thin band is where corrosion starts on an outdoor part.
The tumble row is the one that changes the economics. At 200 parts per 45-minute cycle, the per-part time is about 13 seconds, which is less than a hand deburr on a single edge. The catch is that the whole batch waits for the cycle and every part in it gets the same radius, whether or not it needs one.
The sequence matters more than the method
Finishing after cutting is not one operation. It sits between cutting and bending, between welding and coating, and sometimes after coating, and the order changes what the finish can achieve.
Before bending
Deburr the edges that meet the bend line before forming on aluminium, on 3 mm and above, and on any part where the burr would sit on the outside of the bend. A burr on the tension face is a notch at the point of maximum strain, and on 3 mm CRCA or 2 mm aluminium it is where the first crack starts.
On thin CRCA bent in one direction, the burr can stay if it is on the inside face. Specify which face the burr is permitted on rather than assuming the shop will choose. A part with bends in both directions will put one set of burrs on a tension face no matter what, and that part needs a deburr before forming.
After welding, before coating
A welded frame needs its spatter removed before anything else. A grinding disc that cuts into the parent metal leaves a gouge that shows through powder, so the sequence is chisel or grind the weld, then blend with a 120-grit disc, then finish the whole face if it is visible.
Do not linish a face that will be masked. The mask needs a flat, clean surface to seal, and a brushed finish with a directional grain gives powder a path under the tape edge. Mask boundaries belong on an as-cut or lightly prepped face.
Stainless after cutting
Laser cutting leaves a chromium-depleted layer a few micrometres deep at the cut edge, plus a heat tint that ranges from pale straw to dark blue depending on the gas. On 304 or 316L in a wash-down or coastal application, that edge is where tea staining appears first.
Mechanical finishing removes the tint and the depleted layer together if it removes 5–10 µm of material. Passivation, per ASTM A967, restores the oxide film but does not remove tint. The practical order is mechanical finish first, passivation second, and never passivation alone on a visible edge.
What finishing adds to a part
Take a 1.5 mm CRCA bracket with a 2,000 mm cut perimeter, 500 per month, powder coated and visible on one face.
Left as cut, it has zero finishing time and an edge film that measures 40–60% of the face. On an indoor bracket that is acceptable. On an outdoor one it is the start of rust creep at the edge, typically within two monsoon seasons.
Hand deburred, it takes 3–5 minutes per part. At 500 parts that is 25–42 hours a month, which is a person and a half on one part number, and the result depends on who held the file.
Linished on a belt, the same perimeter takes 40–60 seconds per metre, so 1.3–2 minutes per part, and the edge gets a consistent 0.3–0.8 mm radius. The finish is measurable, the time is predictable and the part coats better because the edge geometry is no longer a knife.
Tumbled, 200 parts go into a cycle and come out in 30–45 minutes. That is 9–13 seconds per part, the cheapest option by an order of magnitude, and it is only available if the part fits the bowl and can tolerate a radius on every edge, including the ones that locate it.
The cost ranking is therefore tumble, linish, hand deburr, leave. The quality ranking is linish, tumble, hand deburr, leave. The right choice depends on which ranking the part is actually judged by, and a visible lift panel is judged by the second.
The edge and the coating
Powder and wet paint both pull back from a sharp edge through surface tension. Measured with a DFT gauge per ISO 2808, a coated 90° edge typically reads 40–60% of the flat-face value, and on a 70 µm face that is 28–42 µm at the edge.
That is not a coating defect. It is the geometry doing what geometry does. The fix is a radius, not a second coat: a 0.3–0.5 mm edge break lets the film wrap without thinning as sharply, and on a part rated for a C3 or C4 environment under ISO 12944-2, the edge is the first place the specification is tested.
A burr makes it worse than a sharp corner. The burr is a lump that shields the edge from the spray on one side and creates a shadow on the other, so the film steps from 70 µm to 30 µm to zero over a couple of millimetres. That step is where blistering starts.
What Ganesh runs for cut edges
Cut blanks come off the 12 kW fibre laser or the 6 kW and 3 kW machines, and the edge route is chosen per part rather than per customer. Hand deburring is used on heavy plate, on small batches and on edges next to a feature that must stay sharp. Belt linishing handles visible enclosure and door edges. Tumbling is used for small brackets and spacers where the batch justifies it.
The finishing step is quoted, not assumed. A part that arrives with "deburr all edges" gets a query at review, because the note cannot be priced without deciding what it means. Where the drawing names a radius and the faces, the operation goes on the route card and the first article measures it.
Parts for TKE and Godrej & Boyce include visible door and panel work where the edge is part of the finish, and the paint shop page covers what happens after the edge is prepared. The custom parts page shows the range of thicknesses the route covers.
What to put on the drawing
- A radius or burr limit on named edges, not a general note. "0.3 mm radius on edges A, B and C, burr 0.1 mm maximum elsewhere" is inspectable.
- The side the burr is permitted on, especially on a part bent in two directions.
- The surface texture where a finish is visible, as a Ra value per ISO 4287 and the direction of the grain.
- Whether the finish applies before or after welding, and which faces are faying faces that must stay unfinished.
- The coating and the environment class, so the edge break can be matched to the film and the corrosion requirement.
- Whether the part may be tumbled, which is a question about the location features as much as the finish.
When finishing is a waste
Four cases where the operation adds cost and nothing else.
Edges buried in a weld. A faying face that will be welded and sealed does not need a cosmetic finish. It needs to be clean, flat and free of burr, which is a different requirement and a much cheaper one.
Parts that will be machined. A blank that goes to a mill for its final dimensions does not need a linished edge. The machining removes it, and the finish is paid for twice.
Over-specified stainless. A 320-grit grain on an internal bracket is not a finish, it is a habit. Match the grain to the visible faces and leave the rest as cut.
Tumbling a part with a datum. A vibratory cycle rounds every edge, including the one that locates the part in a fixture. If the datum is an edge, tumble before the datum is formed, or do not tumble at all.
Send the drawing with the visible faces, weld faces and hand-contact edges marked to request a quote. The finishing route, the radius and the coating sequence are confirmed together, so the edge is priced as part of the part rather than as a surprise at first article. The laser cutting and fabrication hub indexes the cutting, tolerance and edge guides that sit either side of this step.
Related reading: the Aluminium sheet laser cutting: process, gas and edge quality and the Deburring and edge quality after laser cutting take the same problem further.
Frequently asked questions
Do I need to deburr laser-cut parts?
Only where the burr affects the next operation. On 1.5–2 mm CRCA cut with nitrogen, the burr is usually under 0.1 mm and does not need removal before bending or coating. Above 6 mm, or on any part that will be handled, a 0.2–0.5 mm edge break is worth specifying.
What is the difference between deburring and edge breaking?
Deburring removes the raised metal left by the cut. Edge breaking removes the sharp corner itself, typically to a 0.2–0.5 mm radius. A part can be deburred and still be sharp, which is why a drawing that says deburr has not specified what the operator's hand will feel.
Which finish should stainless steel get after laser cutting?
A mechanical finish followed by passivation if the part is visible or will see moisture. Laser cutting leaves a chromium-depleted layer a few micrometres deep at the edge, and on 304 or 316L a wash-down or coastal part will show tea staining at that edge first. Passivation restores the oxide film; it does not remove heat tint.
Can I tumble parts that have threaded holes?
Yes, with the right media and a short cycle, but the thread entry will be deburred and slightly rounded. For M8 and below, plug the thread or tumble before tapping. Tumbling after tapping changes the thread class and is not recoverable.
How much does finishing add to a laser-cut part?
Hand deburring a 2,000 mm perimeter adds 3–5 minutes per part. Linishing adds 40–60 seconds per metre, so 1.5–2 minutes on the same part. Tumbling is 30–45 minutes per batch of 200, which is 9–13 seconds per part once the batch is loaded.
Sources and further reading
- ISO 4287:1997 — Geometrical product specifications: surface texture, profile method, terms and definitions of roughness parameters · reviewed 3 Nov 2026
- ISO 2768-1 — General tolerances for linear and angular dimensions without individual tolerance indications · reviewed 3 Nov 2026
- ISO 2808:2019 — Paints and varnishes: determination of film thickness, including measurement on edges · reviewed 3 Nov 2026
Send the drawing with the edges that matter
Mark the visible edges, the weld faces and the hand-contact edges. We will confirm which finish each one needs and what it adds to the piece.
Request a quote