Aluminum Extrusion in China: Profiles, Dies, and Lead Times

Aluminum extrusion in China is one of the most cost-effective ways to get custom profiles made: new dies often cost a few hundred dollars, minimum orders start around 300–500 kg per profile, and most factories run extrusion, finishing, and CNC machining under one roof. Guangdong's Foshan region alone hosts hundreds of extrusion plants, making it one of the densest extrusion clusters anywhere.

This guide covers how the process works, what custom dies cost, which alloy and finish to specify, what MOQs and lead times to expect, and how to separate real extruders from trading companies before you pay for a die. One thing worth sorting out early: finding factories is easy; verifying them is the hard part. If you'd rather not do that legwork yourself, CN Ally identifies and vets extrusion suppliers for foreign buyers, so your first quote request goes to the right kind of factory.

How does aluminum extrusion actually work?

A heated aluminum billet is forced through a shaped steel die under high pressure, producing a continuous length of metal with a constant cross-section. That's the process in one sentence — everything else is preparation and finishing around that push.

The sequence at a typical Chinese plant:

1. Billet preheating. Aluminum billets are heated to roughly 400–500°C — hot enough to flow under pressure, still solid.
2. Extrusion. A ram pushes the billet through the die in a hydraulic press. Chinese plants run presses from around 500 tons up to 10,000+ tons.
3. Quench, stretch, age. The profile is cooled to lock in temper, stretched to straighten it, then artificially aged to the specified T5 or T6 temper.
4. Cut and finish. Lengths are cut to size, then anodized, powder coated, or machined as ordered.

One concept buyers run into constantly is solid vs. hollow dies. A solid profile (angles, channels, bars) uses a relatively simple flat die. A hollow profile (tubes, enclosed shapes) needs a porthole die — the metal flow splits and welds back together inside the die. Hollow dies cost more and take more skill to get right, which is why tube quotes always carry a higher tooling line.

Suppliers also talk about the circumscribing circle diameter (CCD) — the smallest circle enclosing the profile's cross-section. It's the standard measure of profile size and determines which press your order needs.

Which alloy should you specify: 6063, 6061, or 7075?

For most buyers, this choice is simpler than it looks: 6063 for visible, architectural parts; 6061 for structural work; 7075 only for specialized high-stress components.

Alloy · Typical temper · Approx. tensile strength · Extrudability · Weldability · Best for

• 6063: T5 / T6 · ~215 MPa (T5) · Excellent · Good · Window/door frames, architectural trim
• 6061: T6 · ~310 MPa · Good · Good · Structural frames, machine parts, heat sinks
• 6082: T6 · ~325 MPa · Good · Good · Heavier structural and transport profiles
• 6005A: T5 / T6 · ~260 MPa · Good · Good · Rail and automotive structural profiles
• 7075: T6 · ~570 MPa · Difficult · Poor · Aerospace and high-stress components

A few practical notes. Strength figures are typical published values for the listed tempers; actual results vary with section thickness (see this 6061/6063/7075 comparison). 6063 takes an anodized finish noticeably better than 6061, which matters if the part will be visible. 6061's edge is strength and weldability — the reason it dominates industrial extrusions. 7075 extrusions exist, but few Chinese extruders run them routinely; expect fewer capable factories and higher prices.

About tempers: T5 is cooled from the extrusion process, then artificially aged — the standard for 6063 architectural profiles. T6 is solution heat-treated separately before aging, producing higher strength. T5 and T6 cover the vast majority of orders.

What do custom extrusion dies cost in China?

This is where China has its biggest advantage. Current marketplace listings for extrusion dies from Chinese makers run roughly US$200–1,000 for standard dies, with complex multi-cavity or large hollow dies reaching US$2,000–3,000 (Made-in-China die listings) — typically well below what equivalent tooling costs in Europe or North America. Some factories waive or refund the die fee once your orders pass an agreed volume. Worth asking about.

What moves the price within that range:

Cost driver · Lower cost · Higher cost

• Profile type: Solid (flat die) · Hollow (porthole die)
• Complexity: Simple angle or channel · Multi-void, thin walls, tight radii
• Size (CCD): Small profiles · Large profiles needing a bigger press
• Tolerances: Standard EN 755 / ASTM B221 · Tighter-than-standard dimensions
• Cavities: Single cavity · Multi-cavity dies for high-volume runs

Die lead time is short: factories typically quote 7–10 days to make a new die, with first-article samples following in another week or so.

Two commercial points buyers often miss. First, die ownership: if you pay for the die, get in writing that it's your property and can't be used for other customers' orders. Second, die correction (the trial-and-error tweaking after the first extrusion) is where experienced die shops earn their money. A factory with an in-house die workshop iterates in days; one that outsources dies adds weeks every time something needs adjusting.

Standard profiles vs. custom profiles: which route should you take?

If your design can use a catalog profile, do that. If it can't, the custom route in China is cheap enough that it rarely blocks a project.

Factor · Standard (catalog) profile · Custom profile

• Tooling cost: None — die already exists · US$200–3,000 for a new die
• MOQ: Often 1 kg to a few hundred kg · Typically 300–500 kg per profile
• Lead time: 10–15 days after order confirmation · Die (7–10 days) + samples + 15–30 days production
• Unit price: Lowest — amortized tooling, high volume · Slightly higher on small runs
• Fit: Compromise on dimensions · Exact to your drawing

China's extrusion industry runs on enormous die libraries. Factories in Foshan commonly advertise thousands of existing dies, and standard industrial profiles — T-slot framing extrusions in the 2020/3030/4040/5050 series, angles, channels, tubes — are stocked or produced continuously. For machine framing, enclosures, or LED housings, check catalogs first; some suppliers accept orders as small as a kilogram.

Go custom when the profile is visible and branded, when it must interface with your own parts, or when a catalog profile forces design compromises that cost more than the die. A few hundred dollars of tooling is a small price for an exact-fit profile.

What tolerances can Chinese extruders realistically hold?

Most established Chinese extruders work to EN 755 or ASTM B221 — the standards their export customers require, and reputable factories name the standard on the quote without being asked. Tolerances scale with geometry: a simple solid bar holds tighter tolerances than a complex thin-walled hollow section. Wall thicknesses down to around 0.3 mm are advertised by some factories, though thin walls in complex shapes are where dimensional problems start.

What this means in practice:

• For architectural and general industrial profiles, standard extrusion tolerances are fine. Ask the factory to confirm which standard applies to your quote.
• For mating surfaces, press fits, or machined interfaces, don't rely on as-extruded tolerances. Specify the critical dimensions for post-extrusion CNC machining — extrusion gets you close, machining gets you exact.
• Get tolerances in writing before production. Most extrusion disputes aren't about alloy or finish — they're about a dimension nobody specified.

If you're ordering tight-tolerance profiles from a new factory, an independent quality control inspection on the first run is cheap insurance: dimensional checks, alloy verification, and finish thickness measurements catch problems while they're still fixable.

Anodizing, powder coating, or mill finish?

Surface finish is the second-biggest decision after alloy — it affects price, lead time, and how the part ages. Chinese extrusion plants almost always finish in-house, with anodizing and powder-coating lines in the same industrial parks as the presses.

Finish · Typical film thickness · Look · Corrosion protection · Notes

• Mill finish: — · Dull metallic, extrusion lines visible · Minimal · Cheapest; fine for hidden parts
• Anodizing: 8–25 µm · Satin metallic, dyeable · Good · Best on 6063; hard integral oxide layer
• Powder coating: 40–100 µm · Any RAL color, matte to gloss · Very good · Hides minor surface flaws
• Electrophoresis: Thin, clear · Glossy clear or tinted · Good · Common on Chinese window/door profiles
• Brushed / polished: — · Decorative metallic texture · Low · Often followed by anodizing

Anodizing deserves a note because buyers misunderstand it. It's not a coating: it's an electrochemical process that grows the aluminum's own oxide layer, so it can't chip or peel the way paint can. Architectural specs usually call for 10–25 µm, and 6063 anodizes to a smoother, more consistent finish than 6061, one more reason it's the default for visible parts.

Powder coating is the workhorse for colored profiles: any RAL color, excellent coverage, and the thick film hides minor die lines. It's a coating, though — it can chip on sharp edges if pretreatment is poor. For outdoor use, ask whether the powder is a super-durable polyester formulation; standard polyester chalks faster in strong UV.

What are typical MOQs and lead times?

Minimum order quantities for custom extrusions in China cluster in a narrow band: 300–500 kg per profile is the norm, with some factories quoting 1 ton and window/door specialists asking for 2 tons per item. Standard catalog profiles can go much lower. The MOQ exists because each profile change means a die change, press setup, and a minimum billet run — below a few hundred kilos, setup cost swamps the material.

Lead times, from deposit to shipment:

Stage · Typical time

• New die manufacturing: 7–10 days
• Die development + first samples: ~15 days (combined, some factories)
• Sample approval and revisions: 1–2 weeks
• Mass production (custom): 20–30 days after deposit
• Mass production (standard profiles): 10–15 days after order confirmation

All in, a new custom profile runs roughly 6–8 weeks from drawing approval to shipment; reorders of an existing die run in 2–4 weeks.

Payment terms are standardized: 30% deposit by wire transfer (T/T) to start production, 70% balance before shipment. Factories pack profiles in protective PE film with kraft paper or shrink wrap, usually on pallets — and if you're consolidating extrusions with other goods, plan the shipping and logistics early, because 6-meter lengths need proper container planning.

What secondary operations can factories handle in-house?

One of the practical advantages of sourcing extrusions in China is how much happens under one roof. A typical mid-size extrusion plant offers:

• Cutting to exact length, including angle cuts
• CNC machining — drilling, tapping, milling, punching
• Bending and roll forming
• Welding (TIG/MIG, mainly on 6xxx alloys)
• Assembly of multi-part kits

Every handoff between factories adds cost, lead time, and a chance for damage. A profile that arrives cut, drilled, anodized, and ready to assemble is worth more than the sum of its operations done separately.

The caveat: in-house CNC quality varies widely. Extrusion and precision machining are different disciplines. If your part has machined features tighter than about ±0.1 mm, vet the machining separately — ask for sample parts and check what machines they run. Same for anodizing consistency on visible parts: get finish samples before committing to volume.

How do you vet an aluminum extrusion supplier in China?

The extrusion market has a specific trap: trading companies that present themselves as factories. They quote low, then subcontract your order to whichever plant has press time — and you lose control over dies, alloy, and quality. Here's how to tell them apart:

1. Ask for press details. A real extruder will tell you how many presses they run and the tonnage range. Vague answers are a red flag.
2. Ask about the die shop. In-house die design means faster corrections and better profiles. Outsourced dies mean delays.
3. Check certifications. ISO 9001 is the baseline for export-oriented plants. Ask for the certificate, not just the claim.
4. Request the tolerance standard. A factory that names EN 755 or ASTM B221 unprompted understands export work.
5. Insist on first-article samples. Reputable factories provide pre-production samples for approval — many free, with you covering freight.
6. Verify alloy and temper. Ask for mill certificates on billet stock and confirm temper testing is part of in-process QC.
7. Visit or audit. For significant orders, a factory audit before production (presses, die shop, aging furnaces, QC lab) is the single most effective risk control available.

When quotes look similar on paper, the differentiator is process control: in-house dies, documented tolerances, real QC records, and a working sample process.

Frequently asked questions

Who owns the extrusion die if I pay for it?

You should — but only if it's in writing. Standard practice is that the buyer-funded die remains the buyer's property, stored at the factory for reorders. Get a simple agreement stating the die is yours and won't be used for other customers.

Can I order less than 300 kg of a custom profile?

Sometimes, with a surcharge. The 300–500 kg norm reflects real setup costs: die installation, press warmup, minimum billet quantities. Below MOQ, factories may agree for a setup fee or suggest a standard profile close to your design.

What's the difference between T5 and T6 temper?

Both are artificially aged for strength. T5 is cooled from the extrusion process itself, then aged — the standard temper for 6063 architectural profiles. T6 goes through a separate solution heat treatment before aging, producing higher strength. Specify T5 for visible profiles, T6 when the design needs maximum strength.

Which aluminum alloy is best for outdoor use?

For most outdoor applications (facades, railings, window frames), 6063 with anodizing or quality powder coating is the standard answer. The finish provides the real long-term protection. In marine environments, 6061 or 6082 with a heavier anodized film (20–25 µm) or marine-grade powder coating performs better. Avoid mill finish outdoors.

Can extruded aluminum profiles be welded or bent?

Yes, with the right alloy. The 6xxx series (6061, 6063, 6082) welds well with TIG or MIG, though welding locally anneals the heat-affected zone. 7075 is generally not considered weldable. Bending works on most 6xxx extrusions; tight radii on thin walls may need mandrel support.

A simple decision rule before you request quotes

Start with the profile, not the factory. If a catalog profile does the job, buy standard: no tooling, lower MOQ, faster delivery. If the design needs a custom cross-section, the math in China almost always favors going custom: a few hundred dollars of tooling buys an exact-fit profile at near-commodity unit prices. The risk isn't the die cost — it's choosing the wrong supplier. Verify the factory is a real extruder, lock down tolerances and die ownership in writing, approve first-article samples, and inspect the first production run.

If you'd like help with any of that — finding extruders with the right press capacity, auditing a factory before you pay for tooling, or running QC on first production — email hi@cnally.com.