When a flap does not sit neutral, the assembly bench reaches for shims. The shims are usually correcting one of three things that were decided at the machine: ears that are not coplanar, so the bearing pin loads one ear first; bearing seats bored in two setups, so the two halves of the pair are not on one axis; or an ear gap that came out 0.15 mm over because the second ear was roughed, finished and coated separately.

This pair is machined to remove those three possibilities. Both brackets are cut from one plate and stay paired through every operation. The ears are finished together, the bearing seats are line bored through both ears in one setup, and the gap is measured after coating because conversion coating adds 1-3 µm per face.

• Line bored, not bored twice — 0.008 mm coaxiality across both ears.
• Coplanar ears — 0.01 mm, measured after the finish, not before.
• Gap held at the machine — 12.0 mm +0.05 / 0, so the shim pack stays thin.
• Pair matched by weight — within 0.3 g, so left and right react alike.

1. Hinge geometry review — bearing size, ear gap, shim allowance and flap neutral position confirmed against the assembly drawing before cutting.
2. Material verification — 7075-T6 plate received by heat number, ultrasonic checked, 3.1 certificate retained.
3. Pair routing — both brackets cut from the same plate and kept as a numbered pair through every operation.
4. Rough machining — ears, base and boss roughed with 0.6 mm allowance, symmetrical removal on both ears.
5. First stress relief — low-temperature relief before the ears are thinned, so they do not splay when released.
6. Semi-finish — ear faces and base semi-finished, ear thickness and gap measured in process.
7. Line boring — both bearing seats bored through the ear pair in one setup, 0.008 mm coaxiality, H7 Ø10.
8. Coating — chemical conversion coating per MIL-DTL-5541 Class 3 with bores and mating faces masked.
9. Final verification — CMM report on coplanarity, coaxiality and gap, weight matching, FAI shipped with the pair.

• Bearing interface — spherical bearing, plain bushing, or press-fit dowel with retaining compound.
• Ear configuration — symmetric clevis, offset clevis, or single ear with a mating block.
• Gap control — shim allowance set to your assembly procedure, from 0.05 mm up.
• Left and right hand — mirrored pairs machined from one program, delivered as a numbered set.
• Sampling — 1 pair for a fit trial on the airframe, then volume on the same program.

Wing geometry, hinge line and control-surface travel 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 photography inside.
• Codified routing — internal codes on travelers and labels instead of your part numbers.
• Data control — project folders on a permission server, files destroyed on request with a written 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 Europe, North America, Japan and Southeast Asia.

Machining, stress relief, coating and CMM inspection run on one site: 5-axis and 4-axis machining centers, turn-mill centers, surface grinders, wire EDM, CMM and 2.5D vision metrology. That is what keeps a line-bored pair on one axis — the parts never leave the building between boring and verification.

1. 01 Consumer Electronics — Phone, tablet and laptop housings · heat sinks · camera brackets · VR/AR headset structural parts · smart wearable housings
2. 02 Automation & Industrial Equipment — Automation jigs · fixtures · module frames · transmission sliders · motor mounts · sensor housings · conveyor line components
3. 03 Semiconductor & Vacuum Equipment — Vacuum chambers · vacuum fittings · semiconductor equipment precision bases · thermal insulation parts · inspection fixtures
4. 04 Medical Devices — Surgical instrument bases · medical device housings · endoscope components · aesthetic equipment structural parts (medical grade aluminum / stainless steel)
5. 05 Automotive — EV motor housings · battery end plates · sensor brackets · lamp structural parts · aftermarket parts · hydraulic valve blocks
6. 06 Aerospace & UAV — Aircraft structural parts · UAV frames · landing gear components · avionics instrument housings (lightweight precision parts)
7. 07 Optics & Photonics — Optical lens barrels · lens mounts · light source heat sinks · camera module brackets · inspection optical stages
8. 08 Telecommunications — 5G heat sink cavities · filter housings · signal adapter brackets · telecom equipment enclosures
9. 09 Robotics — Robotic arm joint parts · robot bases · reducer housings · AGV chassis structural parts
10. 10 Instruments & Meters — Inspection 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 pair never delays a scheduled batch.

• Samples — 7-10 days, trial-fitted 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.

Send STEP / IGES / DWG / PDF and receive DFM feedback plus a formal quotation within 24 hours.

Dongguan Changxinda Precision Technology Co., Ltd. · ISO 9001:2015 · Dongguan, Guangdong, China