CNC Drone Parts Drone Structural Bracket with Lapped Mating Face 0.005mm Flatness in 7075-T6 Aluminum

Most brackets stop at milling. When a structural bracket also carries an optical reference — a laser module, a camera datum, an alignment rail — 0.01 mm flatness is not enough, because contact only happens at the high spots. This CNC machining parts bracket adds a lapped mating face at 0.005 mm flatness and Ra 0.05, with the opposite mounting face parallel to 0.01 mm.

A milled face at 0.01 mm flatness touches its mating part at the high points only. On a structural joint that is fine, because the bolts clamp it down. On an optical datum it is not: the module sits on a few spots, the gap is a wedge, and the alignment moves when the screws are torqued in a different order.

This bracket gets a lapped face after milling: 0.005 mm flatness with a contact ratio above 90% checked on blue marking compound, finished to Ra 0.05. The lapped face and the mounting face are held parallel to 0.01 mm so the module does not tilt relative to the airframe, and both are masked through anodizing because 25 µm of coating would undo the lapping.

• Lapped, not just milled — 0.005 mm flatness, 90%+ contact on blue check.
• Ra 0.05 finish — no high spots left by the cutter to distort the joint.
• Parallel to 0.01 mm — the datumed module cannot tilt against the airframe.
• Masked through coating — anodizing stays off the lapped face and the holes.

1. Datum review — which face carries the optical or alignment reference, and the tolerated tilt, confirmed before machining.
2. Material verification — 7075-T6 received by heat number with ultrasonic check and 3.1 certificate.
3. Rough machining — body, datum pad and mounting face roughed with 0.6 mm allowance, symmetric removal.
4. First stress relief — low-temperature relief, then semi-finish, because a lapped face cannot be corrected later.
5. Second stress relief — a second cycle before finishing, so the pad stays flat once the mass is removed.
6. Finish milling — datum pad and mounting face milled to 0.01 mm, mounting holes drilled and reamed in the same clamping.
7. Lapping — datum pad lapped to 0.005 mm flatness and Ra 0.05, contact ratio verified on blue marking compound.
8. Hard anodizing — 25 µm with the lapped face, holes and pad masked.
9. Verification — CMM on flatness and parallelism, blue-check contact record, roughness measurement, FAI shipped.

Datum size, lapped area, hole pattern and body shape follow the module you are mounting, so the bracket is designed around a reference rather than a profile. Send the module drawing and the alignment budget and we return a DFM note on lapped area, parallelism, masking and clamping within 24 hours.

• Datum — lapped pad, lapped rail, or three lapped points for kinematic contact.
• Surface spec — 0.005 mm standard, 0.003 mm on request with longer lead time.
• Body — solid, ribbed, or truss-lightened to a stiffness target.
• Finish — hard anodized body with masked datum, or chromate conversion for conductivity.
• Sampling — 1 pc with your module fitted for an alignment repeatability check.

Motor geometry, stator stack and winding data are competitive information, so access is limited from the drawing stage onward.

• NDA first — mutual NDA and non-circumvention signed before any file is exchanged.
• Isolated area — dedicated machines and authorized staff, no phones or photography inside.
• Codified routing — internal codes on travelers and labels instead of your part numbers.
• Data control — per-project folders on a permission server, destroyed on request with a record.
• No display — no drawings, part photos or logos in samples, catalogs, the website or social media.

Dongguan Changxinda Precision Technology Co., Ltd. — founded in 2008, 90–102 staff, ISO 9001:2015 certified, annual sales USD 10–20 million, export share 50–60%, serving customers in Europe, North America, Japan and Southeast Asia.

Machining, stress relief, anodizing and metrology run in one plant: 5-axis and 4-axis machining centers, turn-mill centers, surface grinders, wire EDM, CMM, 2.5D vision metrology and automated anodizing lines. About 12,000 aluminum parts ship each month, most of them small precision parts where the fixture and the boring sequence decide the result.

• 01 Consumer ElectronicsPhone, tablet and laptop housings · heat sinks · camera brackets · VR/AR headset structural parts · smart wearable housings
• 02 Automation & Industrial EquipmentAutomation jigs · fixtures · module frames · transmission sliders · motor mounts · sensor housings · conveyor line components
• 03 Semiconductor & Vacuum EquipmentVacuum chambers · vacuum fittings · semiconductor equipment precision bases · thermal insulation parts · inspection fixtures
• 04 Medical DevicesSurgical instrument bases · medical device housings · endoscope components · aesthetic equipment structural parts (medical grade aluminum / stainless steel)
• 05 AutomotiveEV motor housings · battery end plates · sensor brackets · lamp structural parts · aftermarket parts · hydraulic valve blocks
• 06 Aerospace & UAVAircraft structural parts · UAV frames · landing gear components · avionics instrument housings (lightweight precision parts)
• 07 Optics & PhotonicsOptical lens barrels · lens mounts · light source heat sinks · camera module brackets · inspection optical stages
• 08 Telecommunications5G heat sink cavities · filter housings · signal adapter brackets · telecom equipment enclosures
• 09 RoboticsRobotic arm joint parts · robot bases · reducer housings · AGV chassis structural parts
• 10 Instruments & MetersInspection equipment housings · precision gauge bases · flow meter parts · laboratory equipment components

Two shifts 07:30–22:00, six days a week, with weekend shifts in peak season. Capacity is locked weekly for volume programs, so a rush order never displaces a scheduled batch.

• Samples — 7–10 days, checked on your stator or bearing set before the batch is released.
• Batch — 15–20 days from deposit and drawing approval.
• Buffer stock — semi-finished stock for repeat models, cutting repeat lead time by about 30%.
• Shipping — DHL/FedEx/UPS in 3–5 days for samples; air or sea for volume; EXW Dongguan, FOB Shenzhen or CIF.
• Documents — FAI, 3.1 material certificate, CMM report and packing list with every shipment.