Documents.
Every step from printing to first motion is documented. You can download the documents as PDFs; the assembly guide is included with the purchased package.
Draft content: measurements and settings will be updated as they are verified on the arm.
The system’s three layers, which package to start with and the tools you need.
Material choice, slicer settings, part orientations and the list of parts to print.
Six steps with photos, from seating the bearings to mounting the motor.
Control board, driver bus, power supply and emergency stop wiring.
Installing Reachbotics Studio, connecting to the robot, updating firmware and homing.
Purchased packages include measured, illustrated guides; for questions, email reachbotics@gmail.com.
Draft content: measurements and settings will be updated as they are verified on the arm.
Getting started
The system has three layers: mechanics (cycloidal reducer and arm parts), electronics (a control board that sits on an Arduino Mega) and software (kinematics and motion control running on the PC). The package to start with depends on your goal:
| Printing the reducer | Cycloidal Reducer 33:1 · Files |
| Changing dimensions | The STL + STEP option of the same product |
| Building the robot arm | RB-6 Robot Arm · Full STL (price coming soon) + 6 reducers |
Tools you need
- A desktop FDM printer; PETG (discs) and PLA (other parts) filament
- A metric hex key set (2.5 mm for M3)
- A vise or a flat block for pressing in bearings
- A soldering iron, a multimeter and a 24 V power supply for the electronics
Printing guide
Download PDF ↓All parts are designed for desktop FDM printers. The cycloidal discs are printed in PETG, the other parts in PLA. Bearing seats are dimension-sensitive; before printing the full set, check the bearing fit with a single test part.
| Material | Cycloidal discs in PETG; housing, cover and other parts in PLA |
| Layer height | 0.2 mm (0.12–0.16 mm is better for bearing seats) |
| Infill | 30% gyroid; 60%+ for the eccentric shaft |
| Walls | 4 perimeters |
| Supports | Not needed; parts are oriented with flat faces on the bed |
Reducer parts list
- Housing and cover
- Cycloidal disc × 2 (PETG)
- Eccentric shaft
- Bearing support
- NEMA17 motor flange
Reducer assembly
Assembly takes six steps: seating the bearings, preparing the eccentric shaft, fitting the discs out of phase, inserting the output bushings, closing the cover and mounting the motor. It takes about an hour in total; no special tools are required.
The measured, illustrated step-by-step guide is provided as a PDF with the reducer package.
The sequence below applies to all reducer packages.
- Seat the bearings. Press the 6808 output bearing into the housing and the 6700 bearing into the cover evenly with a flat block.
- Prepare the eccentric shaft. Fit two 6701 bearings onto the eccentric sections of the shaft.
- Fit the discs 180° out of phase. Slide the first disc onto the shaft and place the second one rotated half a turn; this way the discs balance each other.
- Insert the output bushings. Pass the purchased bushings through the disc holes and seat them in the bearing support.
- Close the cover. Align the cover and tighten the M3 screws in a cross pattern.
- Mount the motor. Attach the NEMA17 flange and slide the motor shaft into the eccentric shaft; turn it by hand to confirm that nothing binds.
Electronics
Download PDF ↓Kinematics are computed on the PC; the Arduino Mega only generates steps and reads position feedback. Six MKS SERVO42C drivers share a single addressed UART bus through the control board.
| Controller | Arduino Mega 2560 + RB-6 shield v2 (200 × 130 mm, 2 layers) |
| Drivers | 6 × MKS SERVO42C, closed-loop |
| Motor | NEMA17 + 33:1 cycloidal reducer |
| Driver bus | Addressed UART · Mega Serial2 (D16/D17) · addresses 0xE0–0xE5 |
| PC connection | USB → Mega Serial0 |
| Power | 24 V / 15 A, TVS-protected input |
| Emergency stop | Hardware NC relay; cuts power independently of the software |
Control software
Download PDF ↓Reachbotics Studio is a desktop app for Windows. Kinematics and motion control run on the PC; the robot works without internet, which is only used for updates. The software is introduced on its product page and is not on sale yet. Buyers receive updates free of charge.
The interface is currently in Turkish. The button names below are written as they appear in the app, followed by their meaning in English.
Installation
- Run the installer.
ReachboticsStudio-<version>-setup.exe· Windows 10/11, 64-bit. No administrator rights, Python or other software required. - Open the app. Reachbotics Studio opens in its own window; your settings are stored on your computer.
- Connect to the robot. Plug the control board in via USB, open the Sürücü (Driver) panel in the top bar, choose the port and press Bağlan (Connect).
- Update the firmware. If the firmware on the board is out of date, the app warns you; install it with one click from the Firmware section of the connection panel.
- Home the arm. Move the arm to the green park pose shown on screen and press Parkı onayla (Confirm park); motion commands are enabled after that.