What This Heatsink Is and the Hard Numbers Behind It This is a folded fin aluminum heatsink built by CNC machining the base and fin slots to a flatness of 0.05 mm across the entire mounting surface.
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What This Heatsink Is and the Hard Numbers Behind It This is a folded fin aluminum heatsink built by CNC machining the base and fin slots to a flatness of 0.05 mm across the entire mounting surface.
This is a folded fin aluminum heatsink built by CNC machining the base and fin slots to a flatness of 0.05 mm across the entire mounting surface. You get a thermal interface that sits flush against your IGBT or CPU, with a fin density of up to 10 fins per inch and a base thickness from 3 mm to 25 mm, all held to a tolerance of ±0.05 mm. Typical lead time is 7 days for prototypes, and we run 100% inspection on critical dimensions before any unit ships.
Extruded heatsinks hit a wall at a fin aspect ratio of about 10:1. Our folded fin design uses a separate aluminum sheet, bent into a U-shape and then mechanically or adhesively bonded to a CNC-machined base plate. This lets us reach fin heights of 100 mm with a fin thickness of just 0.2 mm—something no extruder can do. The result is a surface area increase of up to 40% over an equivalent extruded profile, which translates directly into lower thermal resistance for forced convection applications.
The folded fin block is the thermal heart, but the base is where your assembly lives or dies. We machine the base from 6061-T6 or 6063-T5 aluminum plate on 3-axis and 4-axis CNC mills. Mounting hole positions are held to ±0.05 mm, and the countersink depths are controlled within 0.1 mm. We also offer tapped holes from M2 to M12 with thread depth verified by go/no-go gauges on every part. If you need a stepped base or a custom channel for a heat pipe, we cut those features directly into the plate before the fins are attached.
We stock 6061-T6 (yield strength 276 MPa) and 6063-T5 (yield strength 145 MPa) for the base. The fin stock is typically 1100 aluminum or 3003 alloy, chosen for its high thermal conductivity (222 W/m·K) and excellent bendability. After forming, the folded fin block can be annealed or left as-formed depending on your vibration requirements. For military or automotive grade, we apply a hard anodize coating (MIL-A-8625 Type III) of 25 µm thickness, which raises surface hardness to 60 HRC equivalent and prevents galvanic corrosion.
Every batch, regardless of size, goes through a coordinate measuring machine (CMM) check on the base flatness and hole pattern. We also run a surface profilometer on the base mating face to confirm an Ra of 1.6 µm or better. For high-volume orders, we keep a first article report (FAIR) with actual measured values—not just a pass/fail stamp. If you need a material certificate or a RoHS/REACH declaration, we issue it with the packing list, no extra charge.
We do not sell vague thermal numbers. For a standard 100 mm x 100 mm base with 25 mm fins at 10 FPI, we can provide measured pressure drop and thermal resistance curves from our in-house wind tunnel. Typical values are 0.45 °C/W at 2 m/s airflow for a natural convection setup and 0.18 °C/W at 4 m/s with a fan. If you need a specific fin pitch or height, we run a quick CFD check on our side to confirm the geometry is thermally sensible before we quote you a price.
Folded fins are fragile—a dropped box can bend 10 fins and ruin your thermal performance. We pack each heatsink in a corrugated tray with individual slots for every fin row. The base is wrapped in anti-static foam, and the whole unit goes into a double-wall carton with a minimum edge crush strength of 9.5 kg/cm². For orders over 100 pieces, we use custom wooden pallets with fixtured layers. No loose packing peanuts, ever.
| Parameter | Value / Range |
|---|---|
| Base Material | 6061-T6 or 6063-T5 aluminum |
| Fin Material | 1100 or 3003 aluminum sheet |
| Base Thickness | 3 mm to 25 mm |
| Fin Height | 10 mm to 100 mm |
| Fin Thickness | 0.2 mm to 0.8 mm |
| Fin Density (FPI) | 4 to 10 fins per inch |
| Base Flatness Tolerance | 0.05 mm over 100 mm length |
| Hole Position Tolerance | ±0.05 mm |
| Surface Finish (Base) | Ra 1.6 µm (32 µin) |
| Hardness After Anodize | 60 HRC equivalent (Type III) |
| Runout (base to fin tip) | 0.05 mm total indicator reading |
| Lead Time (Prototype) | 7 days |
| Lead Time (Production) | 15-20 days |
| MOQ | No MOQ (1 piece accepted) |
We do not charge a separate tooling fee for folded fin heatsinks because the fins are formed on a simple press brake with a custom die that we own. For a prototype order of 1 to 5 pieces, we use a manual folding fixture and CNC-machine the base from solid plate. For production runs above 500 pieces, we switch to a pneumatic press with a quick-change die, which cuts unit cost by about 30%. Our factory runs 24/5, and we can push a 1000-piece order through in 10 days if you need it.
There is no MOQ—we accept single-piece prototypes and scale up to 10,000+ units per month without changing your per-unit price logic.
Yes, we adjust the fin folding die and CNC program to match your exact fin pitch, height, and base cutouts, as long as the geometry stays within our 0.2 mm fin thickness limit.
We inspect the first article on a CMM, then check base flatness and hole positions on every 10th piece using a height gauge and pin gauges, and we photograph all out-of-tolerance parts for your review.
We can ship 50 pieces in 5 days if you approve a simple 2D PDF drawing, but a fully custom design with CMM inspection will take the standard 7 days.
We ship via DHL, FedEx, or UPS from our Dongguan factory, with typical transit times of 3-5 days to the US and Europe. The price for a standard 100x100x50 mm folded fin heatsink with 10 FPI starts at $4.20 per piece for a quantity of 100, and drops to $2.80 at 1000 pieces. We are a precision manufacturing partner with 20 years of experience in CNC machining and stamping, and we are proud to be a made in China supplier that does not cut corners on tolerance or finish. For a firm quote within 12 hours, email your STEP or IGES file to sc@bquq.com, or send it via WhatsApp at +86 13713157787. You can also read our CNC cutting tool selection guide to understand how we achieve tight slots, and check our CNC machining tolerances guide for the limits of our process. Send your drawing today, and we will respond with a DFM comment and a price—no obligation.
| Parameter | Capability |
|---|---|
| Materials | AL6063/6061/5052, pure copper C1100, copper-aluminum composite |
| Process | Extrusion, CNC machining, skiving, forging, die casting, stamping fins |
| Fin Types | Extruded, pin fin, skived, folded, bonded, heat pipe, vapor chamber |
| Surface | Black anodizing, clear anodizing, nickel plating, powder coating |
| Size Range | Max 1500 x 400 x 300 mm |
| Thermal Test | Thermal resistance and heat dissipation data per batch |
| Prototype | 5-7 days, no MOQ on samples |
| Inspection | CMM, thermal resistance tester, full report per batch |
