Alloys: 6061, 6063, 6005
How the common 6000-series extrusion alloys differ in strength, extrudability and finish.
Sourcing Repository guide
Aluminium Extrusion Guide for Custom Profiles
This aluminium extrusion guide explains how profiles are made, which alloys and tolerances apply, what drives cost, and how to qualify a supplier before you release a custom die.
- Processes
- Alloys
- Tolerances
- Cost drivers
Guide chapters
Extrusion finishes: anodize, powder coat
What anodizing and powder coating change in appearance, durability and handling.
Extrusion process and die design
How a billet becomes a profile, and how die layout affects section quality.
Standard vs custom profiles
When an existing die is enough and when a new die pays for itself.
T-slot / 80/20 framing system guide
How modular T-slot framing is specified, cut and assembled.
Guides hub
The full library of Sourcing Repository sourcing and manufacturing guides.
Request a quote
Send a drawing and requirements to start a custom profile quotation.
Quick answer
Aluminium extrusion is a process in which a heated aluminium billet is forced through a shaped die to produce a continuous profile with a fixed cross-section. This aluminium extrusion guide covers extrusion routes, 6000-series alloys, dimensional tolerances, cost drivers, supplier checks, and the information needed for a custom profile RFQ.
Overview: What This Aluminium Extrusion Guide Covers
This aluminium extrusion guide is written for engineers, procurement managers and founders who need to buy or specify extruded aluminium profiles. It moves from process selection through alloy choice, tolerances, cost and supplier qualification, and it ends with the inputs an RFQ needs.
Aluminium extrusion is a process in which a heated aluminium billet is forced through a shaped die to produce a continuous profile with a fixed cross-section. Profiles may be standard or custom, solid, semi-hollow, or hollow, and may receive heat treatment, finishing, cutting, machining, or fabrication.
The guide is deliberately practical. Every tolerance figure is stated as a typical rule of thumb, because real limits vary by dimension, alloy, temper, section and the standard named on your drawing. Where a value depends on your purchase specification, the guide says so rather than quoting a universal number.
aluminium extrusion guide
Primary keyword
Informational intent, automotive-first audience
About 11 minutes
Reading time
Eight chapters plus FAQs
Process, alloys, tolerances, cost, sourcing
Scope
Standard and custom profiles
RFQ-ready specification
Output
Drawing, alloy, temper, finish, quantities
Use this guide as a checklist, not a substitute for the applicable standard. Dimensional acceptance for extruded profiles is normally taken from EN 755-3 through EN 755-9, EN 12020, or ASTM B221/B221M, together with your own drawing.
Chapter Map: Every Section of the Aluminium Extrusion Guide
The chapter map below lists each section of this aluminium extrusion guide with a one-line summary, so you can jump straight to the decision you are making. Each linked chapter goes deeper on a single topic.
| Chapter | One-line summary | Link |
|---|---|---|
| Alloys: 6061, 6063, 6005 | How the common 6000-series extrusion alloys differ in strength, extrudability and finish. | /resources/guides/aluminum-extrusion-guide/alloys-6061-6063-6005/ |
| Extrusion finishes: anodize, powder coat | What anodizing and powder coating change in appearance, durability and handling. | /resources/guides/aluminum-extrusion-guide/extrusion-finishes-anodize-powder-coat/ |
| Extrusion process and die design | How a billet becomes a profile, and how die layout affects section quality. | /resources/guides/aluminum-extrusion-guide/extrusion-process-and-die-design/ |
| Standard vs custom profiles | When an existing die is enough and when a new die pays for itself. | /resources/guides/aluminum-extrusion-guide/standard-vs-custom-profiles/ |
| T-slot / 80/20 framing system guide | How modular T-slot framing is specified, cut and assembled. | /resources/guides/aluminum-extrusion-guide/t-slot-80-20-framing-system-guide/ |
| Guides hub | The full library of Sourcing Repository sourcing and manufacturing guides. | /resources/guides/ |
| Request a quote | Send a drawing and requirements to start a custom profile quotation. | /get-a-quote/ |
Read the process and alloy chapters first if you are still selecting a route. Read the tolerance and cost chapters first if the design is fixed and you are preparing to buy.
Processes: Extrusion Routes at a Glance
Hot extrusion is the standard route for long aluminium profiles; the other routes exist for specific shapes, sizes and surface requirements. The table below compares the main routes with their advantages and limitations.
| Route | Process | Pros | Cons |
|---|---|---|---|
| Direct extrusion | A billet is heated and pushed through a stationary die by a ram. | Broad alloy and profile capability; suitable for solid and hollow sections. | Billet-to-die friction increases force, heat, wear, and scrap. |
| Indirect extrusion | The die moves through a relatively stationary billet. | Lower friction and improved dimensional consistency for suitable profiles. | More specialized equipment and limitations on profile size and handling. |
| Hot extrusion | Billet temperature is raised enough to reduce flow stress before extrusion. | Most common route; enables complex profiles and production rates. | Requires temperature control, quenching, stretching, and possible aging. |
| Cold extrusion | Aluminium is formed below its hot-working temperature. | Good surface finish and dimensional accuracy for smaller sections. | Higher forming forces; less suitable for large or highly complex profiles. |
| Impact extrusion | A slug is rapidly forced around or through a punch to form a short hollow part. | Efficient for seamless cups, cans, and small housings. | Not generally suitable for long continuous architectural profiles. |
What happens after the press
Hot extrusion is followed by cooling or quenching, stretching, and often aging to reach the specified temper. The profile is then cut to length and may be finished, machined or fabricated. Each of these steps can change dimensions, so acceptance limits should be agreed before production.
Choosing between direct and indirect extrusion
Direct extrusion pushes the billet through a stationary die; indirect extrusion moves the die through the billet, reducing friction but requiring specialized equipment. For most architectural and general-purpose profiles, direct hot extrusion is the practical default.
Materials: Aluminium Extrusion Alloy Overview
Most extruded profiles are made from 6000-series alloys, and the choice usually comes down to strength versus extrudability and finish. The table below summarises the common options; exact properties depend on temper and product form.
| Alloy | Typical temper | Properties | Typical uses |
|---|---|---|---|
| Aluminium alloy 6063 | 6063-T5 or 6063-T6 | Excellent extrudability, surface finish, corrosion resistance, and moderate strength. Exact properties depend on temper and product form. | Architectural frames, trim, furniture, lighting, heat sinks, and general-purpose profiles. |
| Aluminium alloy 6061 | 6061-T6 | Higher strength and good corrosion resistance, with lower extrudability and finish quality than 6063. | Structural frames, machine components, transport parts, brackets, and machined extrusions. |
| Aluminium alloy 6005A | 6005A-T5 or 6005A-T6 | Intermediate-to-high strength with useful extrudability for structural sections. | Transport structures, platforms, ladders, frames, and load-bearing profiles. |
| Aluminium alloy 6082 | 6082-T6 | High strength among common 6000-series extrusion alloys; generally less suited to very complex thin-wall shapes. | Structural, automotive, marine, transport, and heavy-duty machined profiles. |
| Aluminium alloy 6005 | 6005-T5 | Good strength and extrudability for medium-duty structural applications. | Frames, rails, ladders, and structural extrusions. |
6063 versus 6061 in one line
6063 generally extrudes and finishes better; 6061 generally provides higher strength and is often selected for structural or machined parts. If a profile must be both visually clean and load-bearing, confirm the alloy and temper against the design loads rather than assuming either will do.
Verify alloy and temper using mill certificates and, when required, positive material identification. Certificates are the practical evidence that the delivered profile matches the alloy and temper you specified.
Design and Tolerances: Core Rules for Extruded Profiles
Dimensional acceptance for extruded profiles comes from the applicable standard and your drawing, not from a single universal figure. The values below are typical rules of thumb used for early design; confirm final limits against EN 755, EN 12020 or ASTM B221/B221M for your section.
| Parameter | Typical range | Standard or source |
|---|---|---|
| Linear dimensions | Often approximately ±1% as a rule of thumb; actual limits vary by dimension, alloy, temper, section, and standard. | European Aluminium, Extruded Products |
| Wall thickness | Often approximately ±5–10% as a rule of thumb; thinner walls generally require greater percentage allowance. | European Aluminium, Extruded Products |
| Angular geometry | Approximately ±2 degrees as a general rule of thumb. | European Aluminium, Extruded Products |
| Straightness, flatness, twist, and corner radii | Profile- and size-dependent; specify acceptance limits using the applicable product standard. | EN 755-3 through EN 755-9; EN 12020 |
| Profile length | Cut-length tolerance is supplier- and order-specific; do not assume a universal value. | Applicable purchase specification and supplier drawing |
| Outside dimensions | Unverified: approximately ±0.006–0.020 inch [±0.15–0.50 mm] is reported by a non-standards source. | Unverified secondary technical source; confirm against EN 755 or ASTM B221 |
Design rules that reduce risk
- Keep wall thickness as uniform as practical; abrupt thickness changes concentrate flow and distort the section.
- Allow generous corner radii and avoid sharp internal corners, which are difficult to fill and hard to inspect.
- Design symmetrical sections where possible; asymmetry increases twist and straightness risk.
- Avoid very thin walls unless the alloy and section have been reviewed by the extruder.
- State the reference standard and the critical dimensions on the drawing rather than relying on general tolerances.
- Agree cut-length tolerance, end condition and surface finish before the die is cut.
Inspection and first-article approval
Require first-article approval for new custom dies or materially changed processes. First-article approval confirms that the die produces the intended section before volume production, and it is the point at which tolerance disputes are cheapest to resolve.
Cost: What Drives Aluminium Extrusion Pricing
Extrusion cost is built from metal, conversion and finishing, with tooling and secondary operations added on top. The largest single input is the aluminium itself, so weight and alloy choice move the price more than most design details.
Primary cost drivers
- Aluminium alloy, billet price, conversion charge, and applicable market premium.
- Profile weight per metre, which follows from the cross-section and the alloy density.
- Die and tooling cost for custom profiles, plus any die maintenance or replacement.
- Order quantity and the number of releases, since setup and press time are spread across the run.
- Finishing such as anodizing or powder coating, including batch size and colour changes.
- Secondary operations such as sawing, drilling, tapping, milling, punching, bending and assembly.
- Inspection requirements, packaging and freight to the delivery location.
Published price estimates and their limits
No universal price is reliable without a specification. Supplier-published estimates report approximately $2.50–$8.00 per kilogram [$1.13–$3.63 per pound], but these figures are unverified and should not replace quotations. Reported die costs of $400–$3,000+ are likewise supplier estimates, not standards-based values.
Treat any published extrusion price as a planning range only. A quotation based on your drawing, alloy, temper, finish and quantities is the only figure you should budget against.
Choosing a Supplier: Checklist for Aluminium Extruders
A capable extruder is one that can hold your tolerances, document the alloy and deliver on schedule. Use the checklist below before you commit a custom die to a supplier.
- Press capability matched to your section size, alloy and annual volume.
- Experience with your profile type: solid, semi-hollow or hollow, and with your wall thickness range.
- Documented alloy and temper control, with mill certificates supplied per lot.
- First-article approval process for new dies and materially changed processes.
- Dimensional inspection capability against the standard named on your drawing.
- Finishing and secondary operation capacity, or a controlled subcontract route.
- Written confirmation of the minimum chargeable quantity and the die ownership position.
- Packaging, labelling and delivery performance you can audit.
- Quality system appropriate to your industry, such as IATF 16949 or PPAP where automotive work requires it.
Questions worth asking before the die is cut
- Which standard will govern dimensional acceptance for this section?
- How will straightness, twist and flatness be measured and reported?
- What is the first-article timeline, and who approves it?
- How are alloy and temper verified, and what documentation accompanies each shipment?
- What happens if the first article does not meet the drawing?
Sourcing Repository does not own factories or machines. It collects quotes from a vetted supplier network, manages quality and inspection, and delivers parts, which is useful when you want several extrusion quotes compared against one specification.
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FAQ
Common questions
Are standard aluminum extrusion profiles cheaper than custom profiles?
Yes, standard profiles are usually cheaper than custom aluminum profiles, because an existing die avoids new tooling and typically shortens lead time. Unit cost still depends on alloy, weight, quantity, finish, cutting, machining, and freight. This aluminium extrusion guide recommends quoting both options with each aluminum extruder.
How much do aluminum extrusions cost?
No universal price is reliable without a specification. Supplier-published estimates report approximately $2.50–$8.00 per kilogram [$1.13–$3.63 per pound], but these figures are unverified and should not replace quotations.
What is the difference between aluminium and aluminum extrusion?
There is no difference in process or material. "Aluminium" is the common spelling internationally, and "aluminum" is common in United States usage. In this aluminium extrusion guide, both spellings cover extruded aluminum profiles and aluminium extrusion profiles made by forcing a heated billet through a shaped die.
Can aluminium extrusions be machined?
Yes. Custom aluminum extrusions and extruded aluminum profiles can receive secondary operations such as sawing, drilling, tapping, milling, punching, bending, and assembly. Agree machining allowances and distortion controls with the aluminum extruder before production starts, and confirm them on the drawing.
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