A heat sink is only as good as the surface that touches the component. If the base is not flat, the thermal interface material cannot bridge the gap and the whole fin area is wasted. We machine these cold plates from 6061-T6 aluminum with fin walls down to 1.0mm, hold base flatness to 0.02mm and fin thickness to ±0.05mm, then lap and inspect the contact face so the plate performs as designed in the customer's thermal stack.

• Fin-first sequence: the fin field is cut before the base is finished, so the base is machined last on a solid, supported part and cannot be pushed out of flat by fin machining forces.
• Progressive depth passes: fins are cut in shallow stepped passes with a small radial engagement, keeping side load low so 1.0mm walls do not bend or taper toward the tip.
• Sharp, dedicated tooling: fin slots use sharp end mills reserved for aluminum, replaced on a fixed count so the wall stays straight instead of rubbing and work hardening.
• Support and clamping: the plate sits on a machined fixture face with even support; clamps act on the outer margin, never on the fin field or the contact face.
• Base finishing last: the contact face is fly cut, then lapped where the thermal budget requires it, giving a flatness figure that survives anodizing and packing.

1. Thermal and mechanical review: fin geometry, base thickness, mounting pattern and flatness requirement are checked against machining capability.
2. 6061-T6 plate sawed with allowance, faced and squared.
3. Rough milling of the outer profile, flange and fin field boundary.
4. Stress relief pause to let the plate settle before thin features are cut.
5. Fin slot machining in progressive passes with controlled radial engagement.
6. Base face fly cutting and lapping where required; mounting holes drilled, counterbored and tapped.
7. Deburring of fin edges and hole break-out, ultrasonic cleaning to remove aluminum dust from fin roots.
8. Clear anodizing or black anodizing with masking of the thermal contact face when specified.
9. Flatness, fin and hole verification, protective packing with the contact face shielded.

Power module and IGBT cold plates, LED driver and street light heat sinks, inverter and motor controller cooling plates, server and telecom equipment heat sinks, laser diode and optical module heat spreaders, battery module cooling plates, medical imaging electronics cooling and industrial power supply heat sinks. Options include copper inserts, embedded heat pipes, sealed liquid channels and customer-specific mounting patterns.

Dongguan Changxinda Precision Technology Co., Ltd has produced custom CNC machined parts since 2008 and exports 50–60% of output to more than 200 customers in power electronics, telecom, medical, automation, robotics, automotive, aerospace and instrument industries. The plant operates 4-axis and 5-axis CNC machining centers, turn-mill compound lathes, CNC lathes and milling machines with about 100 employees, and takes on any non-standard aluminum part and complex cavity work in 5-axis or 3-axis machining.

Prototypes ship in 7–10 days and production batches in 15–25 days. Aluminum plate stock is kept on hand so a repeat order does not wait for material, and each confirmed order is booked into a fixed production slot with a written delivery date. Capacity is planned around repeat programs rather than single jobs, which is what keeps the second shipment as predictable as the first.

Each lot ships with a flatness and fin dimension report, material certificate and anodizing thickness record. First article inspection reports and process capability data are available for thermal programs that require supplier qualification.