Custom profiles: dies, costs and development

When it makes sense

Your own profile makes sense when it replaces several parts or several operations (cutting, welding, drilling), when you need a shape that does not exist, or when the volume justifies optimising down to the last gram. If a standard profile solves the problem, it is almost always cheaper and faster.

The steps

1. Cross-section drawing. A DXF, STEP or PDF with the dimensions, plus the alloy, temper, finish and estimated quantity.
2. Feasibility review. The die shop checks wall thicknesses, hollows, tongues and size, and suggests adjustments if needed.
3. Die design and manufacture. The die is made from tool steel (typically H13), then hardened and nitrided for durability.
4. Die trial. The first lengths are extruded and measured against the drawing.
5. Sample approval. You review the samples and, if they are right, the profile is approved.
6. Production. From then on, it is produced with the same die every time you order it.

What drives the cost

• The die: it is paid for only once. It costs more if the profile is large, has closed hollows (bridge die) or a lot of detail.
• The minimum per run: each extruder sets a minimum quantity in kilos per production run, because setting up the press has a fixed cost.
• Material and finish: they are priced per kilo; a better-designed profile uses fewer kilos per metre.

Designing for extrusion

• Even wall thicknesses: walls of very different thickness cool at different rates and distort the profile.
• Rounded corners: a radius of 0.5 to 1 mm where walls meet helps the metal flow and extends die life.
• No long, thin tongues: the parts of the die that form deep, narrow channels break under the pressure.
• Symmetry: a balanced profile comes out straighter.
• Compact size: a small circumscribing circle allows smaller, cheaper presses to be used.