Elongated Cavity Aluminum Thermal Partition with 0.01mm Cavity Depth and One-Setup CNC Machining for Battery Modules

This elongated cavity aluminum partition separates and thermally links battery cells inside a module. Two numbers decide its performance: how flat the contact face is against the thermal pad, and how uniform the cavity depth is under each cell. A contact face that is out of flat by 0.02 mm leaves an air gap that behaves like extra thermal resistance, and a cavity that is 0.03 mm shallow holds the cell off the pad on one side.

The part is machined from 6061-T6, 6082-T6 or 7075-T6 plate, with the cavity, contact face, counterbored holes and outer profile completed in one clamping. Cavity depth is held to ±0.01 mm, contact face flatness to 0.01 mm, and parallelism between the face and the cavity floor to 0.015 mm, so the thermal path is consistent from the first cell to the last.

1. 1Drawing review and DFM. We check cavity depth and width, wall thickness, pad area, bolt pattern and sealing requirement, then return a marked drawing and quotation within one working day.
2. 2Material verification. Plate is checked against the mill certificate for grade and temper, and the block is faced square before cavity work starts.
3. 3Stress relief. Blanks are stress relieved so the long thin floor does not bow after the cavity removes most of the section.
4. 4Cavity roughing. The cavity is roughed with 0.5 mm allowance using a trochoidal path, keeping heat out of the floor and the side walls.
5. 5Finishing in one clamping. Contact face, cavity floor, cavity walls and outer profile are finished without releasing the part, which is how parallelism stays at 0.015 mm.
6. 6Holes and counterbores. Mounting holes and counterbores are drilled from the same datum, with depth checked so a bolt head cannot stand proud of the face.
7. 7Deburr and surface treatment. Edges are broken, the part is cleaned, then clear, black or hard anodizing is applied with the contact face masked where thermal contact must be bare metal.
8. 8Final inspection and packing. CMM for cavity depth and parallelism, flatness gauge for the contact face, air decay test on request, then foam-separated packing with a first article report.

A polished surface that is 0.03 mm out of flat performs worse than a machined surface that is flat to 0.01 mm, because the gap dominates the thermal resistance. We fly-cut the contact face with a large-diameter cutter at a controlled feed so the surface is flat and free of steps, check it on a surface plate or flatness gauge, and leave the face uncoated when the customer uses a thermal pad or gap filler. Where the part also carries a coolant channel, we air-decay test the sealed volume before shipment.

Every partition is built to your drawing: cavity length, width and depth, wall thickness, contact face area, bolt pattern, counterbore size, material grade, anodizing type and masking. One piece is a normal order with no tooling charge and no setup fee, and the prototype uses the same programme and inspection plan as the batch. If a feature would add cost without improving the thermal path, our engineer returns a DFM note with a practical alternative and waits for written approval before cutting metal.

• NDA before files. A mutual non-disclosure agreement is signed before drawings, models or samples are released, covering geometry, volume, end use and customer identity.
• No public reference. Confidential partitions are never used as samples, catalogue items, website photos or trade show parts; photos need written release.
• Separated production. Sensitive jobs run in a designated cell with named operators, and programmes and fixtures are stored under a project code.
• Controlled data. Files stay on an access-controlled server, and anodizing partners receive the process specification only, never the assembly drawing.

Dongguan Changxinda Precision Technology Co., Ltd has produced custom machined parts since 2008. The plant operates four-axis and five-axis machining centres, turn-mill combined lathes, CNC lathes and milling machines, with 90 to 102 employees and an ISO 9001:2015 quality system. More than 200 customers are served, 50 to 60 percent of output is exported, and annual sales are between USD 10 million and 20 million. Every custom project has a named engineer, every batch ships with a first article report, and every delivery date is confirmed before the order is accepted.

• Confirmed dates. Prototypes in 5 to 8 working days, batch orders in 15 to 22 working days after drawing approval.
• Repeat orders skip setup. Programmes, fixtures and gauge sets stay on file, so the second order starts in production.
• Reserved capacity. Blanket orders are booked into fixed monthly machine time, keeping the same part arriving in the same week.
• Early warning. If material, anodizing or leak testing threatens the date, you are told before the date is missed, with a partial shipment option.
• Dispatch evidence. Production photos, inspection report and packing list before shipment, tracking number on the day of dispatch.

• Consumer ElectronicsPhone, tablet and laptop housings, heat sinks, camera brackets, VR/AR headset structural parts, smart wearable shells
• Automation & Industrial EquipmentAutomation fixtures, jigs, module frames, transmission sliders, motor mounts, sensor housings, conveyor line parts
• Semiconductor & Vacuum EquipmentVacuum chambers, vacuum fittings, precision equipment bases, thermal isolation and insulation parts, inspection fixtures
• Medical DevicesSurgical instrument bases, diagnostic instrument housings, endoscope components, aesthetic device structural parts (medical-grade aluminum and stainless steel)
• AutomotiveNew energy motor housings, battery end plates, sensor brackets, lamp structural parts, tuning parts, hydraulic valve blocks
• Aerospace & UAVAircraft structural parts, drone frames, landing gear parts, avionics instrument housings (lightweight precision parts)
• Optics & PhotonicsOptical lens barrels, lens mounts, light source heat sinks, camera module brackets, inspection optical benches
• Communications5G heat dissipation cavities, filter parts, signal adapter structural parts, telecom equipment housings
• RoboticsRobot arm joint parts, robot bases, reducer housings, AGV structural parts
• InstrumentationTest equipment housings, precision gauge bases, flow meter parts, laboratory equipment accessories

Each partition is bagged with a desiccant sachet, separated by EPE foam so anodized faces and the contact surface cannot rub, and packed in a five-layer export carton marked with part number, quantity and batch code. Sea freight goes on a fumigation-free plywood pallet with strapping and stretch film; air freight uses a reinforced carton with edge protectors. Neutral packing is available for distributors selling under their own brand.