Encoder End Cap and Motor End Cap with 0.01mm Pocket Position, H7 22mm Encoder Pocket in 7075-T5 Aluminum

On an encoder-equipped drone motor, the air gap between the magnetic ring and the sensor is set by the end cap, not by the electronics. A pocket that is 0.05 mm deep or 0.03 mm off centre changes the signal before anyone touches a firmware setting. This CNC machining parts end cap holds the pocket position to 0.01 mm, the depth to ±0.02 mm and the O-ring groove to a controlled squeeze.

Two caps from the same drawing can give different encoder signals. The magnetic ring sits in the pocket, the sensor sits on the PCB, and the air gap between them is the sum of the pocket depth and the PCB stack. If the pocket is 0.03 mm deep and the O-ring groove was turned in a second setup, the cap tilts when the screws are tightened and the gap varies around the circumference.

Here the pocket, the bearing seat, the O-ring groove and the sealing face are turned and milled from one datum in one clamping. The groove depth is measured after anodizing, because coating on the sealing face would change the squeeze, and the pocket is masked so the ring seat keeps its bore tolerance.

• Pocket on axis — positioned to 0.01 mm from the bearing seat, not from the OD.
• Depth after coating — ±0.02 mm measured once anodizing is done.
• Groove squeeze controlled — 1.0 mm deep to ±0.02 mm, sealing face flat to 0.02 mm.
• No tilt on assembly — seating face and pocket machined in one clamping, so tightening screws does not skew the gap.

1. Sensor stack review — magnetic ring, PCB thickness, sensor height and required air gap confirmed before machining.
2. Material verification — 7075-T5 received by heat number with ultrasonic check and 3.1 material certificate.
3. Rough turning — OD, bearing spigot and pocket roughed with 0.5 mm allowance.
4. First stress relief — low-temperature relief before the cap is thinned to 10 mm.
5. Semi-finish — spigot, pocket and sealing face semi-finished in one clamping.
6. Finish machining — pocket bored to H7, sealing face and O-ring groove turned, sensor window and connector cutout milled from the same datum.
7. Second stress relief — a short cycle before the final depth pass on the groove.
8. Anodizing — 15-20 µm anodizing, pocket, groove and sealing face masked.
9. Verification — pocket position and depth, groove depth, sealing face flatness on CMM, FAI shipped with the parts.

Encoder type, PCB outline, connector and sealing class differ by motor, so the cap is built from your electronics stack. Send the sensor and PCB drawings or a sample cap and we return a DFM note on air gap, pocket masking, groove squeeze and connector clearance within 24 hours.

• Encoder interface — magnetic ring pocket, optical disc window, or a resolver mounting boss.
• Sealing — O-ring groove, gasket land, or IP67 connector with a moulded seal.
• Connectors — M8/M12 panel mount, JST header opening, or a flying-lead grommet.
• Material — 7075-T5 for stiffness, 6061-T6 for cost, stainless for marine duty.
• Sampling — 1 pc built onto a sample motor for an air-gap and signal 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.

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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.