WHAT IT IS

A box of parts that becomes a 1.2-metre humanoid

Asimov 1 comes from Menlo Research, headquartered in Singapore (Menlo company page). The official specification is 1.2 m tall and 35 kg, with 25 actuated joints: six in each leg, five in each arm, one at the waist and two in the neck. Each arm is rated for 5 kg, with a 15 kg peak, in curls and front raises (official design documentation).

Buyers receive the parts unassembled, together with an assembly manual and build videos (official manual). Menlo estimates around 20 hours of total assembly time, and its assembly and servicing partners are in the US and Singapore (Menlo FAQ).

What sets it apart from commercial robots is the licence: CERN-OHL-S-2.0 for the hardware and GPL-2.0 for the software in the same GitHub project. Anyone who does not want the kit can source the parts from the published bill of materials and have them made locally.

TEARDOWN

Of 100 custom part numbers, 57 are already 3D printed

We downloaded the published mechanical design files for Asimov 1 and counted them by the project's own naming convention, one part number each. There are 100 part numbers to make: 39 MJF-printed PA12 nylon parts, 18 SLM-printed (laser powder-bed) 316L stainless parts, and 43 machined parts (39 in 7075 aluminium, 4 in stainless steel), plus 67 bought-in items such as motors.

The list is, in effect, a manufacturing work order. The parts are published as 3D files, so the buyer chooses who makes them and where. The team already sends close to six in ten parts to 3D printing, including 18 metal parts, which tells you they see no need for tooling on those parts.

We also estimated the bounding box of each nylon part from the 3D files. 38 of the 39 have a longest side within 330 mm; the largest, the torso shell, is about 38 × 25 × 22 cm.

Up close, the division of labour shows. The shells, full of curves that must look good and hold the wiring, and the feet are MJF nylon; the brackets that hold the motors inside the joints are machined aluminium or SLM-printed stainless steel.

STRENGTH

A new head is easy. The load-bearing parts are the test

The printed head in the video is a cosmetic part; any material will do. On Asimov 1 the nylon parts are mostly shells, but they include the feet, which carry the whole robot; the aluminium and SLM stainless parts hold the motors and take the load. If you make these parts in your own plant, printing the shape is only the start; the part has to hold, and moving from MJF to extrusion printing means rethinking orientation and supports.

Markforged works in two steps. The base material, Onyx, is a micro carbon fibre filled nylon: in strength it is in the same range as engineering nylons, and against Markforged's plain nylon it is far stiffer and more heat resistant, with a tensile modulus of 2.4 versus 1.7 GPa and a heat deflection temperature of 145 versus 41°C. Where a part carries load, continuous carbon fibre is laid along the load path; on Markforged's published datasheet, unidirectional, fully filled continuous carbon fibre test specimens reach 800 MPa tensile strength and a 60 GPa tensile modulus (ASTM D3039, Markforged composites datasheet).

For a robot like Asimov 1, the first suits shells and general brackets; the second makes some of the brackets now machined from aluminium worth a test. Whether a printed part can replace one is settled under real load, not on a datasheet.

On size, most of the nylon parts fit the X7 (build volume 330 × 270 × 200 mm); a large part such as the torso shell fits the FX20 (build volume 525 × 400 × 400 mm single-nozzle, 500 × 400 × 400 mm multi-nozzle). A design change needs no new mould and no new machining set-up, only a new file.

For an open robot that people are building and modifying all over the world, the same file producing the same part wherever it is printed matters as much as the cost per part. Markforged's Eiger software manages part files and print settings centrally, so the same printer model and material can repeat the same settings.

There is a route for the metal parts too. The FX10 with the Metal Kit prints 316L stainless steel (washed and sintered after printing), so the 18 stainless parts Asimov makes by SLM can be evaluated in house as well; the two processes differ, so strength and dimensions need their own validation.

X7

The core continuous-fibre composite printer

• Build volume 330 × 270 × 200 mm
• For: most nylon parts, brackets, fixtures

Product page →

FX20

Large-format composite printer with a heated chamber

• Build volume 525 × 400 × 400 mm (single nozzle)
• For: large parts such as the torso shell

Product page →

CASE

Kojima Industries: printed robot hands, part cost down 67%

Kojima Industries is a Japanese automotive parts manufacturer. The robot hands on its production lines used to be made of metal, and the heavier the hand, the larger the robot it needed, which pushed up equipment cost.

After moving to Markforged printing, the cost of making the hand parts fell 67% compared with conventional machining, and lead time went from 14 days with an outside machine shop to 1 day printed in house. Design hours also fell by about 30% for some parts, because outsourced machining needs 2D drawings while printing works straight from the 3D file (Markforged case study).

−67%

hand part cost

versus conventional machining

14 → 1

days, part lead time

outside machine shop vs. in house

~−30%

design hours

for some parts

Akira Kashima, Assistant Manager, Equipment Engineering Division, Kojima Industries (image: Markforged case study)

A humanoid's arm and a production-line robot hand run the same arithmetic: every gram taken off the end is load the motors and structure no longer carry.