Faze4 Robotic arm open-source 6-DoF robot arm, 3D render from Final_light_assembly_URDF.urdf

Faze4 Robotic arm

3D-printed 6-axis stepper arm with printed cycloidal reducers and internal wiring.

Start the build

What it is

Faze4 is a 3D-printable 6-axis arm by Petar Crnjak, now published under Source Robotics, the maker of PAROL6. Six steppers (three NEMA 23, two NEMA 17 and a NEMA 14 with a 19:1 gearbox) drive printed cycloidal reducers on joints 1 to 5, with belts on joints 1, 4 and 5 and a planetary gearbox on joint 6, and all wiring runs inside an arm styled after the FANUC LR Mate 200iD. The repo holds zipped STLs, cycloidal-disc STEPs, a URDF with meshes, an xlsx BOM without prices, an 80-page assembly PDF, an electronics setup PDF, distribution PCB Gerbers and v2 board files, Teensy 3.5 Arduino code and Matlab kinematics; the full per-part STEP files are sold separately and are not open source. The LICENSE file was switched from MIT to CERN-OHL-S-2.0 in September 2025, while the README and the store page still describe the project as MIT. Upstream cost figures are rough (README under $1,000, docs around $1,000 to $1,500), hardware files were last changed between 2020 and 2023, and several docs pages are empty stubs.

Licenses

Hardware
CERN-OHL-S-2.0
Software
CERN-OHL-S-2.0
Docs
Not published

Degrees of freedom

6 DoF arm 6

Breakdown source

Serial armSpherical wristCycloidal reducerssource

Auto-assembled, not yet reviewed

Source record

Source
903 stars, last push 2025-12-28
HW license
CERN-OHL-S-2.0
Cost
$1,000estimate, Whole arm, rough upstream figure with no priced BOM behind it. README: 'It is cheap <1000 dollars.' Docs: 'Total cost of the arm is around 1000 - 1500 dollars.' Hackaday: 'The total cost of the arm is around 1000 dollars'
Lifecycle
Maintained
Engine
v3.1.1
Checked
Model
Final_light_assembly_URDF.urdf@674f46crendered 2026-10-02
Envelope
241 × 669 × 458 mmas modelled, default pose

Maintain Faze4 Robotic arm? Claim this page to correct it.

Parts and cost

21 rows

Cost to build

$1,000USDestimate
  • Whole arm, rough upstream figure with no priced BOM behind it. README: 'It is cheap <1000 dollars.' Docs: 'Total cost of the arm is around 1000 - 1500 dollars.' Hackaday: 'The total cost of the arm is around 1000 dollars'$1,000estimate

In the source currency, as read on 2026-09-30. Not converted, and not checked against current vendor prices: none of these is a Motari-verified checkout total.

Faze4 Robotic arm parts, as the source lists them. Prices are the source's, not checked against vendors.

Faze4 Robotic arm bill of materials
PartQtySpecSourceConfidence
Nema 23 Bipolar 1.5A 5.4V 57x57x56mmStepper used in the base assembly (assembly PDF, Base Assembly Step1)
1NEMA 23, 1.5 A, 5.4 V, 57x57x56 mm
StepperOnline (link from the project)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 58
high
Nema 23 Bipolar 4A 2.26V 57x57x84mmStepper used in the joint 2 cycloidal reducer (assembly PDF, Joint 2 cyclo Assembly Step1)
1NEMA 23, 4 A, 2.26 V, 57x57x84 mm; the source link points to a dual-shaft model
StepperOnline (link from the project)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 54
high
Nema 23 Bipolar 0.9deg 2.8A 2.5V 57x57x56mmStepper used in the elbow assembly (assembly PDF, Elbow Assembly Step4)
1NEMA 23, 0.9 deg, 2.8 A, 2.5 V, 57x57x56 mm
StepperOnline (link from the project)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 52
high
Nema 17 Bipolar 12V 42x42x40mmSteppers used in the elbow and forearm assemblies
2NEMA 17, 42x42x40 mm
StepperOnline (link from the project)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 46
high
Nema 14 L=33mm w/19:1 gearboxWrist stepper with planetary gearbox; the docs list joint 6 as a 19.19:1 planetary reducer
1NEMA 14, 33 mm body, 19:1 planetary gearbox
StepperOnline (link from the project)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 45
high
HTD 5M 490 mm timing belt 10 mm wideJoint 1 belt per the docs, tensioned with bearings
1HTD 5M, 490 mm, 10 mm wide
not linked in source BOMnot listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 59
high
HTD 5M 430 mm timing belt 10 mm wideJoint 4 belt per the docs
1HTD 5M, 430 mm, 10 mm wide
not linked in source BOMnot listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 51
high
J4 beltv = HTD belt 5M 285 10mm wideLabelled J4 in the BOM, while the docs assign the 285 mm belt to joint 5
1HTD 5M, 285 mm, 10 mm wide
not linked in source BOMnot listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 53
high
Inductive sensorHoming sensors; Hackaday says joints 1 and 6 home on inductive sensors
2inductive proximity sensor with M8 nuts
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 43
high
Micro limit switchHoming switches for the other joints
3micro limit switch
not linked in source BOMnot listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 50
high
Roller limit switchesHoming switches
2roller-lever limit switch
not linked in source BOMnot listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 57
high
Ball bearing 3x8x4Bearings section; the cycloidal reducers use many small bearings
2003x8x4 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 29
high
Ball bearing 3x10x4Bearings section
403x10x4 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 32
high
Ball bearing 5x10x4Bearings section
325x10x4 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 34
high
Ball bearing 5x16x5Bearings section
135x16x5 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 35
high
Ball bearing 35x47x7Bearings section
835x47x7 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 28
high
Ball bearing 50x65x7Bearings section
850x65x7 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 33
high
Ball baering 15x28x7Bearings section (spelling as in source); no vendor link
615x28x7 mm
not linked in source BOMnot listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 31
high
Ball bearing 17x23x4Bearings section
417x23x4 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 30
high
Ball bearing 20x27x4Bearings section
220x27x4 mm
AliExpress (source affiliate link)not listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 row 36
high
3D printed partsPrinted-parts column of the BOM (cases, cycloidal discs, eccentric shafts, spacers, pulleys, covers); STLs in STL_V2.zip. Screws, nuts, inserts and pneumatic fittings are listed upstream
197upstream printed-parts total; docs recommend PETG
3D print yourselfnot listed in source BOMSource-Robotics/Faze4-Robotic-arm BOM_7_11_2023.xlsx Sheet1 rows 7 to 66 and total row 65
high

Rows from the source's own parts list 23

BOM_7_11_2023.xlsx@674f46cxlsx

Source rowQtyPrice and vendorLine
Nema 23 Bipolar 1.5A 5.4V 57x57x56mm
1
vendor not listedno price listed
L58
Nema 23 Bipolar 4A 2.26V 57x57x84mm
1
vendor not listedno price listed
L54
Nema 23 Bipolar 0.9deg 2.8A 2.5V 57x57x56mm
1
vendor not listedno price listed
L52
Nema 17 Bipolar 12V 42x42x40mm
2
vendor not listedno price listed
L46
Nema 14 L=33mm w/19:1 gearbox
1
vendor not listedno price listed
L45
HTD 5M 490 mm timing belt 10 mm wide
1
vendor not listedno price listed
L59
HTD 5M 430 mm timing belt 10 mm wide
1
vendor not listedno price listed
L51
J4 beltv = HTD belt 5M 285 10mm wide
1
vendor not listedno price listed
L53

15 more rows in BOM_7_11_2023.xlsx

How to build

6 steps

Steps marked Motari summary condense the linked source; follow the source for exact instructions. Upstream step marks a step taken from the linked guide.

  1. Print the parts

    The docs recommend PETG and a printer with a 250x210x200 build volume (parts were designed for a Prusa MK2S). Upstream printed small parts at 0.15 mm and large parts at 0.35 mm layers, 25 to 30% infill, 3 perimeters, 7 top and 5 bottom layers; print large parts slowly.

    Upstream stepgithub.com/Source-Robotics/Faze4-Robotic-arm/blob/674f46cb60...

  2. Source the BOM

    Order the parts in BOM_7_11_2023.xlsx (the arm has around 1000 parts including screws and bearings); upstream suggests buying spare bearings and screws. Before starting, extend every wire by about 1.5 m (less for wires near the base).

    Motari summarygithub.com/Source-Robotics/Faze4-Robotic-arm/blob/674f46cb60...

  3. Build the arm segments

    Follow the assembly PDF in order: wrist, forearm, elbow and lower arm. The wrist uses a Nema 14 motor with a 19:1 gearbox; the forearm and elbow are built around printed cycloidal reducers (11:1 discs for joints 5 and 4, 15:1 for joint 3); the lower arm adds the joint 4 pulleys and belt. Cycloidal discs should be tight, but not so tight that they cannot be rotated.

    Upstream stepgithub.com/Source-Robotics/Faze4-Robotic-arm/blob/674f46cb60...

  4. Join the arm and base

    Continue with the arm, the joint 2 cycloidal reducer, the rotating base and the base, routing all wires through the arm and the joint 1 output shaft. If the 490 mm base belt is not tight enough, add ball bearings where the guide shows, then fit the lids.

    Upstream stepgithub.com/Source-Robotics/Faze4-Robotic-arm/blob/674f46cb60...

  5. Wire the electronics

    Wire the stepper drivers per the electronics setup PDF, which lists microstep, current, voltage, limit-switch direction and enable level for each joint. The docs describe the distribution PCB and warn that PCB v1 has errors.

    Motari summarygithub.com/Source-Robotics/Faze4-Robotic-arm/blob/674f46cb60...

  6. Load the control code

    Low-level code runs on a Teensy 3.5 (Arduino sketches in the repo); high-level kinematics and trajectories are Matlab live scripts.

    Motari summarygithub.com/Source-Robotics/Faze4-Robotic-arm/blob/674f46cb60...
Print timenot published
Assembly timenot published

Wiring, power and firmware are safety-relevant and shown for reference only. Check them against the source before building.

How reproducible

How confidently this design builds into a working robot, from what its sources publish: each criterion's points, quality tier and evidence.

70/100Partial source coverage, unverified

Engine v3.1.1 at 674f46c

How this score is computed

Files and sim

13 files

Files stay in the upstream repository under their own licenses; these links open them there. The 3D model on this page is Motari's conversion of the file named under Simulation.

Simulation

Robot description files a simulator or CAD tool can load, linked at the commit they were found.

The 3D specimen on this page is converted from URDF_FAZE4/urdf/Final_light_assembly_URDF.urdf at 674f46c.

Builds

0 reviewed

No reviewed builds of Faze4 Robotic arm yet.

A build log records the evidence (photos, a video, your repository), what the build cost, how long it took and what you changed. Each one is checked by Motari (until a maintainer claims this page) before it shows here, and reviewed builds count toward the reproducibility score.

Sources

Where the facts come from

Last push to Source-Robotics/Faze4-Robotic-arm: 2025-12-28 (checked 2026-10-02)

Related links

How this page was made

Assembled from public sources on 2026-09-30, not yet reviewed by the maintainer. Each figure links to where it is stated; a value the sources do not state reads "not published". Last source review: 2026-09-30 Source-Robotics/Faze4-Robotic-arm@674f46c README, LICENSE, tree.

Original files stay intact and separately licensed; Motari adds only the summary on this page. Maintainer? Request a correction or removal.

Badge for the README

Maintain Faze4 Robotic arm? Show its reproducibility score in the project's README. The badge links back to this page and updates with the score.

Badge: reproducibility 70/100

Markdown
[![Motari reproducibility score for Faze4 Robotic arm](https://motari.io/api/v1/badge/faze4)](https://motari.io/r/faze4)
HTML
<a href="https://motari.io/r/faze4"><img src="https://motari.io/api/v1/badge/faze4" alt="Motari reproducibility score for Faze4 Robotic arm" height="20"></a>

Not fully met yet: cad / mesh present (partial), bom evidence (partial). The score is read from the project's own sources, so publishing what is missing is what raises it. A score of 90 or more needs a reviewed build. How the score is computed