Three facts that decide this page
- 5052 is the usual choice for formed covers and brackets because it forms better than 6061 at the same thickness, while 6061 is specified where strength or machinability matters more than formability.
- The 200 T, 4,450 mm, 5-axis CNC press brake with Delem control stores bend programs per part, so a repeat order runs the approved setup instead of a new interpretation of the drawing.
- 5052 H32 will take a radius close to its thickness; 6061 T6 needs a larger radius or it will tear on the outside of the bend. Springback is lower than steel, so a program written for CRCA will overbend aluminium. Soft aluminium also marks easily, so tooling and handling need protection.
What changes when you bend aluminium
5052 H32 will take a radius close to its thickness; 6061 T6 needs a larger radius or it will tear on the outside of the bend. Springback is lower than steel, so a program written for CRCA will overbend aluminium. Soft aluminium also marks easily, so tooling and handling need protection.
The commercial consequence is that aluminium 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.
Tolerance, edge and finish
Ganesh quotes to the drawing first and to ISO 2768 general tolerances where the drawing is silent. For aluminium CNC bending, 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.
How Ganesh runs this route
Flat length is calculated from bend allowance, not outside dimensions; a K-factor taken from a table rather than the actual material and die is the most common cause of a part that is 1 mm short across a box. Aluminium needs a dedicated pretreatment; a phosphate line built for steel will not give the same adhesion, and chromate-free conversion is the practical route for a mixed-material shop. The route is quoted as one sequence so the customer does not have to coordinate a cutter, a former, a welder and a coater.
When CNC bending is the wrong route for aluminium
Press brake bending is the wrong route where the radius demanded by the design is below what the alloy can take. Change the alloy or change the design rather than forcing the bend.
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.
Typical parts
- Heat sink shrouds
- Enclosure bodies
- Mounting brackets
- Trim sections
Decision rule: when to choose CNC bending
Use press brake bending for almost every formed sheet part, including production parts, because the brake stores a program per part and needs no tool beyond standard punches and dies. A dedicated forming tool only makes sense when the geometry needs a feature a brake cannot produce: a coining operation, a closed hem, a very short flange on a high-volume part, or a form that must be identical across a million cycles. For aluminium the practical constraint is the oxide layer and the alloy temper: pretreatment, bend radius and weld procedure all change relative to steel, and the drawing needs to name the alloy, not just the word aluminium. Aluminium is where the alloy decision matters as much as the process decision: a part specified in 6061 T6 that really needs 5052 will be quoted twice and made badly once.
What to put on the drawing
Give the inside radius, the bend angle and its tolerance, the bend line dimensions and whether they are to the outside or the inside of the form. State the flat pattern expectation if the customer owns it, and the bend sequence if the part is boxed and the order matters. Mark the cosmetic faces. On a 4,450 mm panel, say whether the full length is a single bend or a stepped form.
Quality evidence and inspection
Angular tolerance is checked with a protractor or against a fixture, and linear dimensions against the drawing. The stored program is the setup record. First article approval covers the first part off the program, not the drawing review.
What drives the cost
Cost splits into setup, handling and stroke time. Setup is amortised across the batch, which is why 50 parts cost more per part than 500 off the same program. The number of bends, the part size and whether a second operator is needed to handle a long panel all move the price more than the tonnage does. On aluminium, 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.
| Specification | aluminium CNC bending | Ganesh limit or note |
|---|---|---|
| Grades | 1050, 5052 and 6061 to ASTM B209 / IS 737 | Grade per drawing |
| Thickness | 0.8–6 mm sheet; cut to 10 mm plate | 200 T, 5-axis, 4,450 mm, Delem control |
| Tensile / property | 110–310 MPa depending on alloy and temper | 2.70 g/cm³ density |
| Alloy and temper | 1050 H14, 5052 H32, 6061 T6 | 5052 for forming, 6061 for strength |
| Bend radius | 0.8–1.5 × thickness typical | Tight radii crack on 6061 T6 |
| Laser cutting | Fast, high reflectivity | Clean nozzle and correct pierce height |
| CNC bending | 200 T, 5-axis, 4,450 mm, Delem control | Bends to 10 mm |
| Tolerance basis | ISO 2768-m unless drawing states otherwise | Critical features inspected |
| Finish | Etch or conversion pretreatment, then powder coat where specified | Specified per part |
Sources and review
- ASTM B209 — Aluminium and aluminium-alloy sheet and plate · reviewed 2026-11-03
- IS 737 — Wrought aluminium and aluminium alloy sheet and strip · reviewed 2026-11-03
- ISO 2768-1 — General tolerances · reviewed 2026-11-03
- ASTM B209 temper and minimum bend radius · reviewed 2026-11-03
Combines Ganesh machine limits (200 T, 5-axis, 4,450 mm, Delem control) with aluminium grade and property data. The "what changes" section is written for this material–process pair and is not reused on another page.
Send the drawing and we will check the route
Material, thickness, tolerance, finish and annual quantity are enough for a manufacturability review. Tooling is quoted separately from the piece price.
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