Robot joints use a split design so a bearing can be serviced without removing half an arm. But splitting turns precision into a fit problem:

• Bore Only After Clamping — boring the halves separately always leaves a step and misalignment after assembly. We clamp the halves together and bore through, holding 0.01 mm roundness with no step at the joint.
• Locating Pins Decide Repeatability — reamed locating pins (Ø6 H7/m6); after three assembly cycles the bore roundness changes by ≤ 0.003 mm.
• Joint face flatness — joint face 0.005 mm, Ra 0.8; otherwise the halves deflect elastically after tightening and crush the bore.
• Pair numbering — top and bottom halves are marked with the same set number to prevent mixing batches; this is where maintenance sites most often go wrong.
• Lightweighting — 6061-T6 cuts weight by about 60% versus cast iron, with a clear effect on end joint inertia.

The split direction is tied closely to disassembly space, so it is almost always custom to the joint structure.

• Split Direction — horizontal, angled or stepped split, decided by disassembly path and tool access.
• Bearing matching — bore, shoulder and preload method customized for deep groove, angular contact or crossed roller bearings.
• Pin and Screw Layout — locating pins and screw groups arranged to suit stiffness and sealing requirements.
• Material Options — aluminum for weight, ductile iron for damping, cast aluminum for cost, with weight and cost comparison.

The drawings of a complete humanoid robot are often the core competitiveness of the next machine generation. We apply both physical and data isolation on a per-project basis.

• NDA First — mutual NDA and non-circumvention agreement signed before drawings are received.
• Isolated Secure Area — dedicated machines and staff, no photography and no phones inside the area.
• Not displayed — drawings, part photos and customer logos never enter sample cabinets, catalogs, the website or social media.
• Data Isolation — programs and models sit on an access-controlled server, destroyed at project end with a written record.
• Code-named — traveler cards and packaging labels use internal codes instead of customer part numbers.
• Pair Management — top and bottom halves are recorded as a numbered pair, so rework and spares trace back to the same pair.

Dongguan Changxinda Precision Technology Co., Ltd.Founded in 2008, with a team of 90-102 staff, serving 200+ Customers, export share 50-60%, annual sales of USD 10-20 million, ISO 9001:2015 certified.

What matters in a split part is not machining capability but whether you dare clamp the halves and bore afterwards. That sequence complicates each individual operation, but it means the joint still turns freely after three disassembly cycles in the field.

• Reserved Capacity — machine time is locked weekly for volume programs, so rush orders never displace batch schedules.
• Two shifts, six days a week — production runs 07:30-22:00, with weekend shifts added in peak season.
• Buffer Stock — semi-finished stock is held for repeat specifications, cutting repeat order lead time by about 30%.
• Visible Progress — weekly progress sheet plus shop floor photos, tracking number issued at shipment.
• Shipping — samples by express in 3-5 days, volume by air or sea, EXW / FOB Shenzhen / CIF.