CNC mill JarBeRi

CNC Mill by Jarni, Benedik, Richard

Checklist:

Workflow:

Links:

https://cloud.tu-ilmenau.de/apps/files/files/104312242?dir=/Benutzer/CNC%20JarBeRi

3D modeling:

Design decisions:

General

Standart PCB Sizes:

Material Goals:

  1. PCB milling very precise
    • 0,4mm traces
  2. Engrave stone
    • soft limestone

Work Table (fixed)

Outer Dimensions: (might change based on final design)

https://service-manual.ons.gov.uk/content/language/nouns

Mechanical:

Y-Axis: (Jarni)
X-Axis: (Benedikt)
Z-Axis:
Machine Bed (work table):
Spindle and Spindle Mount:
Frame:

Electric:

Software:

Project Progress / Documentation:

First Idea to Sketch:

On Thursday, the day after the Mechanical Design and Machine Building lecture we decided to form groups in our local lab. It wasn't easy to form a group in the first place but after longer discussion we formed a group of three: Jarni, Benedikt and Richard.

We wanted to build a use full tool for our lab and get some redundancy for our existing CNC the Carvera Makera. Machines often have issues or have downtime due to maintenance thats why it is use full to have a backup if something goes wrong with the Carvera mill. For us building a X-Y-Z computer controlled coordinate system was a completely new topic, what made this project exiting in the first place. We took our existing machines in the lab as a reference and did some research online about homemade CNC's. We checked the following:

We did our Idea sketches patially in CAD software (Autodesk Inventro) and partially in 2D sketching software (Goodnotes). IMG_6BBC0691DA5E-1.jpegIMG_7208EF404562-1.jpegcad_draft_2.pngcad_draft_1.png

Idea Sketch to Mechanical design:

First Design:

cad_frame_w_axis.png

This is the first 3D Design Jarni and Benedikt made. It features already the main two Axis X and Y with the T8 screw nuts, sleds, rods and stepper motors. Now it was time to test some parts of the design with the 3D printer!
The test print showed some assembly issues we had If we wanted to use threaded inserts.

IMG_1105.jpg (V1)

In the second iteration Jarni added some more material and the ability to add threaded inserts.

-> instert picture here

(V2)

right screws for version V3: M3 20mm or 30mm

Cutting the Extrusion

Cutting the extrusions did not turn out to be easy because they needed to be exact in length and right-angled. The tool we used for cutting was the plunge saw with a blade for aluminium. After measuring, marking and setting everything up the actual cutting process was very quick!

IMG_1111.jpeg

Y-Axis: (Jarni)

Electrical and Software Design:

For the electronic components we relied on the RapRep parts.

What ist RapRep? RepRap is humanity's first general-purpose self-replicating manufacturing machine.

RepRap is openSource software and hardware framework that has many derivitives and versions. For our project we used the standart RAMPS 1.4 board and a Arduino Mega.

RAMPS board

We used the official documentation of the RapRep

Functions we need:

Functions we do not need:

Endstops

official Wiki RepRap - Endstops

RAMPS 1.4 offers no pull-up circuits, current limiting resistors or other protections.

Wiring improperly an endstop that uses **5V** may damage an IO port on the ATmega 2560 or the Arduino itself, this is a particular issue with clones of the Arduino ATmega2560.

In firmwares a setting is available to enable or disable built-in pull-ups, for example in Marlin you have the ENDSTOPPULLUPS constant in configuration.h, this option is enabled by default.

Motors are a common source of noise. Keep endstop wiring away from motors or use strategies like twisted cables or or used screened cables to reduce the noise.

Ferdi recomendend to use the simple endstop design without pull up because it is simple and just works.

Stepper:

The stepper cables should not be disconnected from the boards while powered on.

Firmware:

idea list:

component list: mechanical structural: - alu extrusion 20*20 moving: - 2x 8mm leadscrews with brass nuts - 4x 8mm guide rails - electrical: mechatronic: manufacturing methods:

Links:


Revision #16
Created 11 April 2025 08:17:28 by Richard
Updated 16 April 2025 18:13:07 by Richard