The most common mistake in an extrusion press investment is selecting capacity by looking at the width of the largest profile. The correct order is the reverse: define the product family and alloys first, derive container diameter and extrusion ratio from them, and let capacity follow as the result.
1. Which alloys will you extrude?
The alloy directly determines the specific pressure required. Soft architectural alloys such as 6063 flow at comparatively low pressure, while 6082 and especially the 7000 series demand markedly higher pressure. A press sized only for 6063 becomes an obstacle the moment you want to enter automotive or structural work a few years later.
A practical approach: size the press for your three-to-five-year product target, not today’s mix. The economic life of a press exceeds twenty years; your portfolio will not stay still that long.
2. Container diameter and extrusion ratio
The extrusion ratio is the container cross-section divided by the profile cross-section. If the ratio is too low the metal is not sufficiently worked and both mechanical properties and surface quality suffer; if it is too high, the required pressure and frictional heat push the press and the die towards their limits.
In aluminium extrusion the working range is generally kept between roughly 20:1 and 60:1, and thin-walled architectural profiles can sit higher. These ranges are indicative and not binding — the final value depends on alloy, profile geometry and die design.
The consequence is that a larger container is not automatically better. In a plant producing small profiles, an oversized container drives the extrusion ratio too high and increases both scrap and energy consumption.
3. Circumscribing circle diameter (CCD)
The smallest circle enclosing the profile determines die size and therefore container size. As a general rule the CCD should not exceed about three quarters of the container diameter; enough margin must remain at the edge for the metal to distribute across the die face.
Writing only "maximum profile width" into a specification is insufficient. CCD, wall thickness and profile weight (kg/m) must be given together.
4. In which unit are you discussing capacity?
Quotations state capacity sometimes in MN, sometimes in US tons, sometimes in metric tonnes. A 2,500 US ton press is not the same machine as a 2,500 metric tonne press. Convert every quotation to a single unit — preferably MN — before comparing.
Also clarify whether the stated figure is nominal or maximum capacity; the difference changes the real capacity available to you in continuous production.
5. Never evaluate the press in isolation
The output of an extrusion line is limited not by the press but by its slowest link. A correctly sized press will never deliver the target tonnage if the billet heating furnace is undersized, the handling line is slow, or the stretcher capacity is low.
Capacity must therefore be calculated across the whole line: furnace feed rate, dead cycle time, run-out and cooling capacity, stretcher and saw speed, ageing oven cycle. If any one of these is undersized, the return on the entire investment suffers.
What belongs in the specification
- Target alloy list and temper conditions
- CCD, wall thickness and kg/m for the largest and smallest profile
- Target annual tonnage and shift pattern
- Container diameter and billet length range
- The unit of capacity and the nominal/maximum distinction
- Target dead cycle time across the whole line
The ADA TRUSTAR approach
Rather than leaving capacity selection to the manufacturer, we recommend preparing an independent technical specification before the investment. Once the specification is clear, offers from different manufacturers become genuinely comparable; without it, every offer simply sells its own assumptions.
Frequently asked
Can I select press capacity from profile width alone?
No. Width by itself is insufficient. Capacity is calculated from alloy, CCD, wall thickness and the target extrusion ratio.
Does the US ton versus metric tonne difference matter?
Yes. 2,500 US tons is roughly 2,268 metric tonnes. Convert all quotations to one unit, preferably MN, before comparing.
Is a larger container always an advantage?
No. For small profiles an oversized container drives the extrusion ratio too high, increasing scrap and energy consumption.
Last reviewed: 08.2026