CNC Machine

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AllHandsActive has a CNC Machine! Use it to cut/mill/etch 2D/3D objects from wood, plastic and aluminum!

Contents

About

The Probotix Fireball V90 machine is on "permanent" loan from member. It's free to use after taking a class on proper operation. If you have not taken the CNC Class you may NOT use the machine.

What the class covers/funds

  • Safety
  • Using Vectric Cut3D
  • Using Vectric Vcarve Pro
  • Using Mach3 Mill
  • End mill discussion
  • Mounting your piece

Cost of class covers buying new end mills when they break and occasional upgrades of the machine.

Toolheads available

  • Dremel Mount + Dremel 300 series - Use this for harder materials where precision doesn't matter as much, fast passes! The runout is pretty big so this tool is really good for cutting out things instead of 3D, circuitry or fine cut work.
  • Paul Jones (CNC on a budget!) Spindle Mount + Spindle - Use this for intricate work. It is a pain to switch, but the bearing will wear out on this if we don't take care of it. The runout on this spindle is much less than on a Dremel.
  • Trim Router - _In process of acquiring_ (Est Aug 2012). Make fast cuts, high speed, high precision. Most wood work you will do.

End Mills

List and their usage is below. Bits for a milling machine are called end mills. They are designed to cut when moved parallel to the work piece as opposed to perpendicular to it like a drill bit. End mills can drill, but it will wear out the edges and damage them over time. End mills can break during use. Always, always, always wear safety goggles.

Run multiple passes to cut deep. Do not cut more depth than the width of the end mill per pass. If you are using an 1/8 inch thick end mill you should not cut more than 1/8 of an inch at a time.

Our slowest spindle is 2000rpm (max is about 30k rpm).

Many different types

  • Non Ferrous machining (aluminum)
  • Some for hardwoods / soft media
  • Drag etching (Great for glass)
  • Drag knife cutter (built by Henry Baughman) designed to move a knife for cutting as the CNC moves.
  • Etching bits 60 degree - only for circuit boards. Needs to just BARELY touch, use a multimeter to check continuity between surfaces
  • Etching bits 90 degree - can be used on glass

Deep Reach:

  • Must go slower
  • Must not push the CNC too fast to deflect this end mill
  • Expensive to replace

2 Flute vs. 3 flute:

  • 3 flute is smoother, 3 spirals going up the side, but ejects chips slower so you can't move it as fast
  • 2 flute isn't as smooth, ejects pieces faster, can move faster

Cutting edge:

  • Ball Nose mills leave a round edge and are best for 3D or sign work
  • Flat nose end mills leave a nice square cut and can be used for surfacing.
  • Fish Tail end mills are great for removing bulk material.

You can find more information on selecting the right end mill here: http://makezine.com/2014/09/10/endmills/

Accessories

  • Collet Care - Clean the collet when done to remove bits!
  • Collet - Used with Paul Jones spindle
  • Cutting Fluid - Mix with water before using!
  • Mount brackets - Use washers and T-Nut bolts to fasten your piece!

Jigs/Mounts

Need to fasten your work piece to the machine? We've built a T-SLOT board for the top of the machine to fasten things. This is temporary and will be replaced by a Spoil board with grid of T-Nuts in the near future (July 2012)

Mounting solutions

  • Machinist block kit
  • Metal hold downs for T Slot

Software

Vectric VCarve Pro

Vectric VCarve Pro 6.0 is licensed and installed on the rapid prototyping PC in the back. With VCarve you can import vector files, trace bitmaps, create design files and generate tool paths. VCarve is best used for 2D cut outs, engraving and sign type making. It will not work files created by newer versions of the software. VCarve is also not compatible with Aspire's file extension.

Generating a design

Create a .crv file with the tool. The first step is to open the program and setup your work piece. Tell vcarve how big your project is. This is important as it uses this information to know where to start the tool on the machine. Whatever you pick in the first step for tool placement is where you should line up the tool before use!

Tool paths

After creating a design in VCarve we need to create a file that tells the machine how to cut that path.

Select the paths you wish to make a tool path (one, all or multiple) for. Different tool paths can be created for each line on the board. They can use different settings and tools.

Once paths are selected, expand the side menu (right side) for tool paths. This will let you pick a type of tool path. Types of tool paths are discussed below in greater detail. Select the end mill for each path. This is the tool that you will use to cut the path. AHA has a bunch of end mills and they should all be configered in VCarve. Pick your path, pick your mill, configure and hit calculate tool path.

Once a tool path is generated, you can render a 3D view on simulated material. When you are happy with the path size and depth. Select save path the file and use the default Mach2/3 option. Do this for all your tool paths.

Tool Path Types
  • Profile - Cut out
  • Quick Engrave - DO NOT USE, SEEMS TO PLUNGE THE CNC INTO THE BOARD!
  • ETC

Vectric Cut3D

Vectric Cut3D can be used to slice a 3D model into pieces that can be run on a smaller machine or to cut a complete 3D model.

First, Import your model and then walk through the easy wizard following similar steps to VCarve Pro when you need to produce the GCODE and tool paths. The exported files can either be edited in VCarve pro or run right in the control software.

Eagle CAD

Eagle can be used to create a PCB trace file. PCB GCODE an add on for Eagle can generate tool paths for the CNC Machine.


Mach3 Mill

Mach3 is licensed and installed on the rapid prototyping computer. This software is required to control our CNC machine as it is the only piece of software which will work with our USB->Parallel port controller board inside the CNC case. Use Mach3 to run a tool path on the CNC Machine.

First ensure all USB cables from the CNC controller are plugged in. Turn on the CNC controller box and disengage the ESTOP button. Next start Mach3 mill with the V90 link on the desktop. The software is already configured for our machine.

On the left hand lower side of the screen pick load gcode, select your code file and open it. If the machine starts using the file it will lock it exclusively. You need to make sure the file is not open in any other program. If you stop the machine mid run, you need to rewind the file to back up the machine and start over. The functionality allows you to pause the mill, move it out of the way, change something, move it back and resume.

After loading the file, move the mill with the up, down, left, right, page up and page down keys. Put it in position to where you told your CAM toolpath to start. In Vectric Vcarve this is usually top and center. Put it right down against the work piece and then in Mach3 coordinates screen tell it to use the current position as home (zero-ing each axis).

Next, start the machine by pressing go. While the machine is running you may press the e-stop button in the software or on the controller at any time to stop the machine. After triggering the ESTOP you must clear it in the software and the hardware.

When the machine starts it will raise off the work piece and pause for a few seconds to wait for the spindle to get to speed. It will then start to cut the piece. DO NOT LEAVE THE ROOM AND BE SURE YOU ARE FOLLOWING ALL SAFETY PROCEDURES! YOU ARE USING THE MACHINE AT YOUR OWN RISK!

When the piece finishes, move the mill head away from the work piece, ENABLE THE ESTOP SWITCH and then approach the machine to move your piece. This ensures no one can start or move the machine while you are working by it without triggering the ESTOP. Alternatively switch off the controller box.

Configuration

Our machine sits sideways so the X and Y axis configs are flipped from stock Mach3. The settings below are used to configure the machine in Mach3. Mach3 is using metric mode so all values had to be converted.

Machine Travel:

  • X-Axis ~18"
  • Y-Axis ~12"
  • Z-Axis ~3"

Leadscrew Pitch:

  • X-Axis 5 Turns Per Inch (0.2in per rev/5.08mm per rev)
  • Y-Axis 5 Turns Per Inch (0.2in per rev/5.08mm per rev)
  • Z-Axis 12 Turns Per Inch (0.08334in per rev/2.1167mm per rev)

Resolution: (X & Y Axis)

  • Full Step 0.001"
  • Half Step 0.0005"
  • Quarter Step 0.00025"
  • Eighth Step 0.000125"
  • Sixteenth Step 0.0000625"

Step time 5000 ns

Step Space 5000 ns

Direction hold 20000 ns

Direction setup 20000 ns

Metric settings for Mach3 motor tunings X and Y in standard config (calcs below based on this):

  • x is pin 3 - Longer Axis
  • y is pin 5 - Shorter Axis

Steps

  • .1968503937007287 turns per mm (5.08 turns per mm)
  • 200 steps per revolution @ 1/2 stepping = 400 steps per rev
  • = 78.7401754803 X and Y Axis Steps per MM
  • Max vel is 4.2 in/s -> 106.68 mm/s
  • Max accel is 60 in/s^2 -> 1524 mm/s^2
  • max vel is 3.8 in/s -> 96.52 mm/s
  • Max accel is 60 in/s^2 -> 1524 mm/s^2


Z

Steps

  • 0.47243350498417347 turns per mm
  • 200 steps per revolution @ full stepping = 200 steps per rev
  • = 94.485 steps per mm
  • Max vel is .4 in/s -> 10.16 mm/s
  • Max accel is 64 in/s^2 -> 1625.6 mm/s^2

Z axis is currently running only at part of this speed to try to reduce problems at slower milling speeds. Might have to switch to partial stepping to get better resolution!

Ports and Pins:

  • X Axis Step Pin 2
  • X Axis Dir Pin 3
  • X Axis Step Low Active Yes
  • Y Axis Step Pin 4
  • Y Axis Dir Pin 5
  • Y Axis Step Low Active Yes
  • Z Axis Step Pin 6
  • Z Axis Dir Pin 7
  • Z Axis Step Low Active Yes
  • X Home Pin 10 (Active Low)
  • Y Home Pin 11 (Active Low)
  • Z Home Pin 12 (Active Low)
  • E Stop Pin 15 (Active HIGH)
  • Enable1 Pin 15
  • Enable2 Pin 16
  • Enable3 Pin 17
  • Output #1 Pin 1 (Spindle Enable)
  • Spindle Speed up 4 seconds CW Delay

Official Spec listing

Machine Specifications Machine Travel:

  • X-Axis ~18"
  • Y-Axis ~12"
  • Z-Axis ~3"

Leadscrew Pitch:

  • X-Axis 5 Turns Per Inch (0.2in per rev/5.08mm per rev)
  • Y-Axis 5 Turns Per Inch (0.2in per rev/5.08mm per rev)
  • Z-Axis 12 Turns Per Inch (0.08334in per rev/2.1167mm per rev)

Resolution: (X & Y Axis)

  • Full Step 0.001"
  • Half Step 0.0005"
  • Quarter Step 0.00025"
  • Eighth Step 0.000125"
  • Sixteenth Step 0.0000625"

Safety

  • Tie up hair
  • Wear safety glasses
  • Verify both USB cables are plugged into the PC (VERY IMPORTANT!)
  • Verify ESTOP is working!
  • Don't get close to a spindle when it is on!
  • Assume the machine is always live. Engage the ESTOP or unplug/turn off the CNC control box before approaching it.

Operation Steps

CNC Machine Operation Steps

Contact

Tyler W. Nate Y. Josh W.

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