3D PRINT A SIX-AXIS ROBOT ARM WITH 0.08MM PRECISION - FULL PLANS ARE FREE
A six-axis robot arm with 0.08mm repeatability that you print yourself, designed like the industrial ones but fully open-source.
by Petar Crnjak
RoboticsWorkshop
- difficulty
- ●●●●●
- time
- several weekends
- license
- GPL-3.0
- repo
- repo ACTIVE3,094 stars
●●●●● · several weekends · GPL-3.0 · 3,094 stars · repo ACTIVE
WHAT YOU’LL NEED
- 3D printer + filament — printable parts — files are in the repo
- Electronic parts — full list with part numbers in the repo BOM
- Dev board / microcontroller — runs the project firmware
- Soldering kit + basic tools — one-time buy, serves every future build
Partner
COMPAREE VERDICT
PAROL6 is a proper industrial-architecture robot arm shrunk to desktop scale. The specs are real: 0.08mm repeatability, 400mm reach, six axes with planetary gearboxes and a CAN bus linking custom stepper driver boards. Petar Crnjak documented it like a commercial product — assembly manuals, calibration spreadsheets, a Python GUI for both manual control and G-code. The single hardest part is not the print or the wiring, it is sourcing or making the planetary gearbox internals for each joint. The STLs include gearbox housings but the actual gears inside are either purchased units (Crnjak links suppliers) or printed from additional files, and backlash tuning will eat an afternoon per axis. If you have built a 3D printer from scratch or wired a CNC, this is the next tier up. If you have not, the BOM alone will be intimidating. Budget is genuinely three figures: motors, bearings, GT2 belts, custom PCBs, and those gearboxes. Most clones skip the gearboxes and lose the precision. This does not.
IN THE REPO
NOT IN THE REPO
- —STL files for all printed parts available on Printables (linked from repo)
- —Full firmware and control GUI in the GitHub repository
- —Detailed assembly documentation and calibration procedures included
- —Bill of materials lists every motor, bearing, fastener and PCB
- —GPL-3.0 license permits commercial use with source disclosure
- —Does NOT include pre-made planetary gearboxes — you source or print gearbox internals yourself
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Partner · KickstarterHeyGears G1: 10M+ colors and transparent parts in one print, plus UV printing on flat objects. Figures, parts and labels — no painting.
Videos
PAROL6 v1 - 3D printed 6 axis robot arm / Presentation
No official build video in repository or on a linked channel
Gallery
Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the full assembly guide and check the BOM (Decide whether to buy or print the planetary gearbox internals before ordering anything else)
- 2.Download STL files from Printables(Link provided in the README — all structural parts and housings)
- 3.Order or fabricate the custom stepper driver PCBs(Gerber files in the electronics folder — six identical boards required)
- 4.Install the Python control GUI and test CAN communication(Software folder in repo — requires Python environment and USB-CAN adapter)
Resources
Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.
KNOWN ISSUES
- Planetary gearbox internals are NOT printed by default in most builds — the STLs are housings only, and buying gearbox kits or printing the gears separately is a separate task that the BOM does not hand-hold you through
- CAN bus wiring has to be done correctly or the arm will not communicate — twisted pair, termination resistors, and correct pinout matter, and there is no plug-and-play harness
- Calibration is per-joint and manual — you will spend significant time with calipers and the calibration spreadsheet tuning each axis, this is not a flash-and-go firmware situation
- The custom PCBs require either soldering surface-mount components yourself or paying for assembly — if you have never ordered PCBs, budget time to learn JLCPCB or PCBWay workflows
- Print orientation and layer adhesion matter for the joint housings — a failed print halfway through a 12-hour part is common, and PETG or ABS is recommended over PLA for strength
- The repository assumes you understand robot kinematics and coordinate systems — if 'forward kinematics' is new terminology, start with the documentation and expect a learning curve
Can I skip the planetary gearboxes and still get decent precision?
No. The 0.08mm repeatability depends entirely on the gearbox reduction — without them you are back to direct-drive stepper slop and the arm will not hold position under load.
Do I need to design my own end effector or is one included?
The repository includes a basic gripper STL, but most builders design their own tool mount — the flange is standardised so swapping tools is straightforward once you have the arm running.
What is the actual payload capacity?
Approximately 1kg at full extension, more if the arm is not fully stretched — the exact figure depends on your gearbox choice and how well you tuned backlash.
Is there ROS support?
Not included in the base repository — the control is via the custom Python GUI or G-code, but several forks have added ROS wrappers if that is required.
Community builds
No community builds yet — be the first, we feature the best ones.
Discussion1
FROM THE COMPAREE TEAM
The repository lists 0.08mm repeatability and a 1kg payload — both depend heavily on gearbox choice and calibration effort. What would you actually use a desktop arm this precise for?
Petar Crnjak
Petar Crnjak runs Source Robotics and designed PAROL6 as an open-source desktop arm with industrial-grade architecture — planetary gearboxes, CAN bus, and proper kinematics — to prove that precision robotics could be DIY without compromising on specs. The project is fully documented and actively maintained.
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DISCLAIMER
- Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM27d agoedited
Practical notes from our verification: the repository is exceptionally well-documented with assembly manuals, calibration spreadsheets, and a working Python GUI, but the single biggest decision you make before ordering parts is whether to buy planetary gearbox kits or attempt to print the internals — most builders buy them, and that alone pushes the cost into three figures. The STL files are linked from the README to a Printables page (we confirmed the link works), and the custom PCB Gerbers are in the electronics folder. There is no official video walkthrough, so you are reading PDFs and following the bill of materials line by line. If you have never built anything with a CAN bus, expect to learn that before the arm moves.