3D Printing vs MIM vs CNC for Humanoid Robots: Where Each Process Actually Wins

1. Where metal 3D printing wins: skeletons, joints, fingers and shells

Frames and brackets: light enough, and built to survive repeated motion

Torsos, shoulders, arms and legs are full of load-bearing structures. They connect motors, reducers and bearings while absorbing the repeated loads of walking, turning and lifting. Too heavy, and every joint pays the price. Too complex, and machining and assembly get harder. This is where metal 3D printing earns its keep.

At the 2026 World Robot Expo, Bright Laser Technologies (BLT) showcased shoulder brackets, torso structures and finger motor mounts made for humanoid robots. In its disclosed cases, the shoulder bracket lost 46% of its weight through part consolidation and structural optimization; the torso structure lost 49% through optimized load paths and multi-scale lattice structures.

In the collaboration BLT announced with UBTech in 2025, an upper-arm housing was produced in BLT-AlAM400 aluminum on a BLT-A320 machine, with a reported machine time of 16.5 hours. The partnership also developed the Photon Finger, described as the world's smallest six-axis force sensor.

Beifeng disclosed a lightweight robot bracket combining topology optimization, hollow design and its own GA520 high-strength aluminum alloy - 500 MPa tensile strength, more than 20% weight reduction and a delivery cycle of about 48 hours. Beifeng reports a fleet of more than 100 metal 3D printing machines, with parts installed on products from leading domestic robot makers.

Joints and actuators: print the housing, machine the drivetrain

A rotary joint typically contains a motor, reducer, bearings, an encoder, a housing and output structure. A linear joint may use a lead screw to convert rotation into linear motion.

Metal 3D printing is worth exploring for motor mounts, joint housings, reducer housings and structures with complex internal routing. Features that are difficult to machine in one piece can be consolidated into a single printed part; brackets that need weight reduction or multiple mounting features avoid excess material removal and assembly steps.

But the parts with the most demanding internal requirements - motors, reducers, lead screws - still go through five-axis CNC, followed by precision cutting and grinding.

Dexterous hands: complex finger structures are the interesting case

A dexterous hand is far more complex than a standard gripper. Fingers bend repeatedly and contain transmission parts, shaft holes, limit features, cable routing - and, in some designs, tendon cables or tactile sensors. Parts are small and dense, and assembly clearances directly affect performance.

In 2026, Farsoon showed titanium dexterous-hand components made with metal 3D printing: finger-joint housings, mounting structures and internal features consolidated into single printed parts, using a 20 µm powder layer, with a reported dimensional accuracy of ±0.05 mm and vertical surface roughness within Ra 3.2 µm.

The value is one-piece consolidation - routing channels, complex surfaces and internal cavities designed directly into the part and produced in a single step.

Shells and soft parts: more than wrapping the robot

Robot shells need to be judged by function. Head, chest and arm covers mainly protect, enclose and present; some housings also locate, support and dissipate heat. Flexible skins and foot buffers need elasticity, impact resistance and repeated deformation.

For covers, 3D printing makes it easy to change curvature, openings, snaps and internal mounting structures - genuinely useful when a robot has many variants, frequent revisions or small batches.

Yingpu 3D reported a robot development project using a P360 system with glass-fiber reinforced nylon: 52 limb structural parts printed in 32.5 hours, consuming 46.78 kg of powder, with a 20% new / 80% recycled powder blend.

For soft components, Farsoon demonstrated PEBA flexible material for cushioning and impact protection. After supercritical physical foaming, printed density falls to as low as 0.03 g/cm³ - about 70% lighter than conventional TPU - and the material survived 200,000 bend cycles without degradation. Boli, meanwhile, applies photopolymer elastomers to bionic skin and foot buffers, using flexible materials for cushioning, contact and controlled deformation.

2. Where MIM fits: the tiny, complex metal parts inside dexterous hands

Micro gears, connectors, limit parts and some transmission structures must be small - and also strong, wear-resistant and dimensionally consistent. At volume, machining them all by CNC inflates cost and lead time. MIM mixes metal powder with a binder, injection-molds the mixture, then debinds and sinters it - a good fit for complex, small metal parts with stable demand.

NBTM's MIM technology platform generated RMB 1.307 billion in revenue in the first half of 2026, up 8.25% year on year. The company is exploring MIM for precision dexterous-hand components and is pursuing powder metallurgy compaction routes for robot reducer parts.

Jingyan Technology - a MIM specialist that also makes transmission components - reported roughly RMB 337 million in embodied-intelligence equipment revenue in H1 2026, up 77.48%.

The read: MIM suits components that are mature, structurally complex and have genuine volume. If your robot is still changing weekly - many part numbers, low volume per part - CNC or 3D printing is the better call.