CNCCMV2

CAD of Mobile Bed Design (In Progress)

File:Cncubep2.stp

CAD of Mobile Gantry Design (In Progress)

Connexions Modules

What is a CNC Circuit Mill?

How to Use the CNC Circuit Mill

How to Design a CNC Circuit Mill

Getting Git on Linux

Getting Ruby on Linux

Getting Arduino IDE

Making the Arduino IDE Work on Linux

Getting and Using Kicad

Getting pcb2gcode

Key Performance Specifications

• X Axis Travel Range = 20cm

• Y Axis Travel Range = 20cm

• Z Axis Travel Range = 5cm

• Step Motor Torque at 12VDC = 3.2kg-cm

• Spindle Max Rotation Speed = 22600rpm no-load

• Spindle Motor Torque at 24VDC = 88.5g-cm at max efficiency

• Workpiece Holding Mechanism = Linear Bolt and Tensioning Nut

• For Prototype II, define goals based on study of industry standards. Include desired precision + accuracy + speed.
  • Minimum step size for each axis plus variance
  • Repeatability of motion (drift) (determined by going to certain locations a large number of times)
  • Minimum spacing between traces (determined by minimum allowable size of bit + precision)
  • Minimum trace size possible
  • Goal: repeatability is as good as step size - ie, all inaccuracy is negligible compared to step size, and zero backlash at all practical milling speeds.
  • Define practical milling speed range based on substrate

Key Design Specifications

• Step Motor Axis Drive

• Rotary-to-Linear Motion Converting Stainless Steel Leadscrew and Wear-compensating Leadscrew Nut

• Anti-friction Bronze Sleeve Bearings

• Precision Stainless Steel Axis-Supporting Shafts

• Versatile Holding Platform with Magnets

• Brushed DC Motor Spindle Drive

• Precision Stainless Steel Spindle Shaft

• Computer to Microcontroller to Stepper Driver Electronics Pathway

• Gcode Streamer to Gcode Interpreter Software Pathway

Cost

• Cost values in USD. In practice, some items must be purchased in greater quantity than necessary; the following values are equalized to the correct quantities. List excludes tools and shipping.

• Cube Frame Metal = 30

• Axes Structure Metal = 50

• Metal Shafts = 124

• Leadscrews and Leadscrew Nuts = 240

• Bearings = 65

• Fasteners = 70

• Control and Drive Electronics = 130

• Power Supply = 300

• Software = Open Source

• Total = 1009

X-Axis Frame Design Rationale

• Start by assuming that the x-axis frame needs to support a pair of precision shafts and allow mounting of the working platform and stepper motor with leadscrew.

• The working platform has to be some sort of flat sheet or plate.

• Some sort of rectangular support structure seems a good start, with a total part count of 5.

• Here is an visual example using 1 plate and 4 rectangular bars:

• This is rigid, but bulky. We notice that a lot of material is still being used despite the low part count. Keep in mind that part count and material volume and ease-of-manufacturing must all be considered separate, though interrelated factors in effective design.

• If we use only 2 rectangular bars (for supporting the precision shafts), then we can save on material volume by using 2 angles as structural supports.

• Here is an visual example using 1 plate, 2 rectangular bars, and 2 angles:

Sourcing

• Spreadsheet File

LINK HERE

• Prototyping Spreadsheet

• To edit or download the spreadsheet, click on the following link.

https://docs.google.com/spreadsheet/ccc?key=0AlpsBarfpPkzdFk5aDY3dHM0eEhfZHNkWVppdV9EelE

Structure

• 400mm x 1.5" x 1.5" x 0.125" Steel Angle (14)

• 140mm x 1.5" x 1.5" x 0.125 Aluminum Angle (12)

• 35mm x 1.5" x 1.5" x 0.125 Aluminum Angle (3)

• Single Point Template

• Double Point Template

• Frame Template

• Axis Template

• Mount Template

Soldering Stepper Driver Pins

• Insert the short end of the male headers into the stepper driver board from the bottom, then pressfit the headers into the small breadboard for holding.

• Apply flux to all header connections

• Apply solder to the tip of the soldering iron

• Solder header connections at opposite corners of the stepper driver board for stability, reapplying solder to and cleaning the soldering iron tip as necessary; repeat for the remaining header connections.

Wiring

Getting Git

• Open Terminal and type:

sudo apt-get install git-core

Getting Arduino Integrated Development Environment

• Go to this webpage:

http://arduino.cc/hu/Main/Software

• Download the Linux 32-bit version of Arduino IDE to a directory of your choosing

Compatibilizing Arduino IDE

• The following steps are a summary of the information in this webpage:

http://www.pluggy.me.uk/arduino-ubuntu/

• Open System>Administration>Synaptic Package Manager, then type your password

• In Synaptic Package Manager, search for jre, then mark for installation the item with the following name:

Openjdk-6-jre

• Note: marking these items will bring up other packages also to be marked. Click "mark" during these times.

• In Synaptic Package Manager, search for gcc-avr, then mark for installation the item with the following name:

gcc-avr

• In Synaptic Package Manager, search for avr-libc, then mark for installation the item with the following name:

avr-libc

• In Synaptic Package Manager, click "Apply"

• Restart your computer

Getting RUBY Programming Language

• Open Terminal and type:

sudo apt-get install ruby1.9.1

• Restart the computer for the changes to take place

Getting GRBL Files

• Open Terminal and type:

git clone https://github.com/damellis/grbl.git grbl

Getting Gctrl

• Open Terminal and type:

git clone https://github.com/damellis/gctrl.git gctrl

Getting Processing

• Go to this webpage:

http://processing.org/download/

• Download the latest version of Processing to a directory of your choosing

Moving RXTX files

• Navigate to the Arduino IDE folder>lib.

• Copy RXTXcomm.jar

• Navigate to the Processing folder>modes>java>libraries>serial>library

• Paste RXTXcomm.jar, replacing the existing version

• Navigate to the Arduino IDE folder>lib

• Copy librxtxSerial.so

• Navigate to the Processing folder>modes>java>libraries>serial>library>Linux32

• Paste librxtxSerial.so, replacing the existing version

Modifying Gctrl

• Open the Gctrl folder

• Open gctrl.pde in gedit

• Change a part of the code as annotated in the following:

Serial port = null; //change starts

String portname = "/dev/ttyACM0"; // Linux, Arduino Uno

//change ends

boolean streaming = false;

Modifying GRBL Files

• Navigate to the GRBL folder

• Open "Makefile" in gedit

• Edit the PROGRAMMER line as:

PROGRAMMER = -c stk500v1 -P /dev/ttyACM0 -b 115200

Flashing GRBL

• Open Terminal and navigate to the GRBL folder (ex. by using the "ls" and "cd" commands)

• In Terminal, type:

make clean

• In Terminal, type:

make

• Connect the Arduino Uno to the computer via USB cable

• In Terminal, type:

make flash

• Disconnect the Arduino Uno

Running Gctrl

• Navigate to the Processing folder

• Open and run Processing, setting the sketchbook folder as the folder in which the gctrl folder exists

• In Processing, open gctrl using File>Sketchbook>

• Connect the Arduino Uno to the computer via USB cable

• In Processing, run gctrl using Sketch>Run

• Now the Gctrl GUI window should pop up

• Note: For certain functions of gctrl, press and hold down the key for the popup windows to populate.

Determining GRBL Configuration Changes Required

• Go to the following webpage:

http://dank.bengler.no/-/page/show/5474_configuringgrbl?ref=mst

Modifying GRBL Settings

• Navigate to the Arduino IDE folder

• Double-click "Arduino" then click "run" in the popup window

• Note: you may want to create a quick launcher for the Arduino IDE

• Connect the Arduino Uno to the computer via USB cable

• In Arduino IDE, open Tools>Serial Monitor

• Note: the Serial Monitor window should pop up and you should see the following:

Grbl 0.6b

'$' to dump current settings

• In the Serial Monitor, change the left drop-down setting to the following:

Both NL & CR

• In the Serial Monitor, type the following in the command line:

$

• Note: you should now see the following:

$0 = 157.480 (steps/mm x)

$1 = 157.480 (steps/mm y)

$2 = 157.480 (steps/mm z)

$3 = 10 (microseconds step pulse)

$4 = 500.0 (mm/min default feed rate)

$5 = 600.0 (mm/min default seek rate)

$6 = 0.100 (mm/arc segment)

$7 = 0 (step port invert mask. binary = 0)

$8 = 25.0 (acceleration in mm/sec^2)

$9 = 225.0 (max instant cornering speed change in delta mm/min)

'$x=value' to set parameter or just '$' to dump current settings

• In the Serial Monitor, type commands as necessary in the following format, where "X" and "Y" are numbers:

$X = Y

Modularity

• Different step motors and drive mechanisms can be mounted onto the axis support angles via mounting holes

• Different frames can be used, provided they have precise mounting holes for the axis support angles

• Different holding platforms can be used, provided they have mounting holes for the X axis moving angles

• Different spindle setups can be used, provided they have mounting holes for the Z axis moving angles

• Different stepper driver boards and power supplies can be used, provided they have compatible performance specifications within the electronics system

Scaling

• Scaling mainly consists of changing the size of the frame (to affect travel ranges) and the type of step motors (to affect travel rates)

• Other discrete components such as fasteners, leadscrews, and shafts need only be scaled if necessary for functionality or certain desired performance specifications

• The travel range calculation for the X axis:

(X Travel Range) = (Distance Between 2 Parallel Frame Angles Along Horizontal Plane) - (Length of Platform Along Axis)

• The travel range calculation for the Y axis:

(Y Travel Range) = (Distance Between 2 Parallel Frame Angles Along Vertical Plane) - (Length of Z Support Angles Along Axis)

Usage

• Circuit Schematic to Gcode File Toolchain

• See following link for list of electronic design suites:

http://en.wikipedia.org/wiki/Comparison_of_EDA_software

• PCB-Gcode Optimizer

http://cnc.goodbits.net/wiki/index.php5/Pcb-gcode_optimizer

http://www.millpcbs.com/index.php?option=com_content&view=article&id=10&Itemid=44

GVCS Product Ecology

CNC Circuit Mill Product Ecology

Uses

• Induction Furnace - Steel

• Aluminum Extractor - Aluminum

• Metal Roller - Fasteners, Metal Angles, and Flats

• Rod and Wire Mill - Wires, Shafts

• CNC Multimachine - Bearings, Leadscrews, Leadscrew Nuts

• Motors - XYZ Movement

• CNC Circuit Mill - Control Circuit Boards

• Universal Power Supply - Power

Creates

• Milled Circuit Boards

See Product Ecologies for more information.