Difference between revisions of "CNC plasma cutter"

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{{Project
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|Name= CNC plasma cutter
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|Status=Initializing
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|Contact= Walter, [[User:Smeding|Smeding]], [[User:Gori|Gori]], [[User:Yotson|Yotson]], [[User:Semafoor|Semafoor]]
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}}
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After acquiring a [[Plasmasnijder|plasma cutter]] at the space, it seemed only logical to try and fabricate a CNC version eventually.
 
After acquiring a [[Plasmasnijder|plasma cutter]] at the space, it seemed only logical to try and fabricate a CNC version eventually.
  
 
This goal is still a while away for now, but as always, we are full of Ideas and this is a convenient place to put them.
 
This goal is still a while away for now, but as always, we are full of Ideas and this is a convenient place to put them.
  
== Specs ==
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== System overview ==
* 3x3 m working area
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The diagram below shows the proposed system setup.
* movement speed of 1000mm/s
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* Calibrated accuracy and precision of +/- 0.1mm
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[[File:plasmacnc.svg]]
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 +
From left to right:
 +
* design software (like inkscape) is used to design the shape to be cut and to export it as svg.
 +
* job setup software (unknown, but something like visicut) is used to position the shape and convert it to g-code.
 +
* linuxcnc (or possibly grbl) is used to "execute" the g-code through the control hardware.
 +
* the control hardware powers the motors of the cutting table and controls the plasma torch
 +
 
 +
We're basing this project on an old X-Z traversing unit originally made for measuring air velocity distributions in wind tunnels at a metrology institute. The current motor controllers, however, seem to be made for a fixed speed and it's probably easiest to replace the electronics altogether.
 +
 
 +
<gallery>
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File:X-Z_traverseerunit_front.jpg|X-Z traversing unit before any modifications
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File:X-Z_traverseerunit_stuurelektronika.jpg|Current control electronics with DC-motor controllers and Mitsubishi PLC
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</gallery>
 +
 
 +
A Z-axis seems required to control the torch height. It won't need to move very far, quickly or precisely, though.
 +
 
 +
== To-do list ==
 +
# Decide how to control the machine. There seem to be two basic options: GRBL and LinuxCNC
 +
#* [[User:Smeding|Smeding]] knows a little bit about LinuxCNC and is willing to do some of the work
 +
# Design and build interface/driver hardware for motors and encoders
 +
#* [[User:Smeding|Smeding]] is willing to help with this
 +
#* [[Benadski]] has motor controller hardware that takes PWM as input.
 +
# Set up a PC that can withstand the general environment of the SparkShack (EMI, humidity, temperature)
 +
# Get basic motion control working so that the machine moves
 +
# Design and build interface hardware for the plasma torch, so it can be turned on and off. Will probably want voltage sensing for torch height control.
 +
#* [[User:Smeding|Smeding]] is willing to help with this, too
 +
# Add a third axis to the machine for torch height control
 +
# Put everything together -- implement the software side of things for torch height control and reading e.g. SVG files
 +
 
 +
 
 +
connection diagram:
 +
<br>
 +
[[File:XY-tafel connection diagram bewerkt.JPG|1024px]]
 +
<br>
  
== Axis motors ==
 
[[User:Smeding|smeding]] is going to design and build a proof of concept linear (synchronous) motor for use in the X- and Y-axes. This test rig will be used to determine whether a DIY LSM is at all useful for our application and to finalize the design if we choose to go with the concept. Specifically, this involves figuring out:
 
* How the attainable accuracy compares to the wanted specifications
 
* How the attainable movement speed compares to the wanted specifications
 
* A final design for the drive electronics
 
* Coil and armature geometries
 
* Rail geometries (magnet size, spacing and orientation pattern and any backing)
 
* Optimal control schemes
 
  
After this, we'll be ready to construct the three rails (2x X and 1x Y) that make up the bulk of the CNC machine.
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blokdiagram sturing plasmasnijder<br>
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<br>
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[[File:Blockdiagram sturing rev 2.1.PNG|1280px]]
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<br>

Latest revision as of 02:43, 21 October 2015

Project CNC plasma cutter
Status Initializing
Contact [[Project Contact::Walter, Smeding, Gori, Yotson, Semafoor]]
Last Update 2015-10-21

After acquiring a plasma cutter at the space, it seemed only logical to try and fabricate a CNC version eventually.

This goal is still a while away for now, but as always, we are full of Ideas and this is a convenient place to put them.

System overview

The diagram below shows the proposed system setup.

Plasmacnc.svg

From left to right:

  • design software (like inkscape) is used to design the shape to be cut and to export it as svg.
  • job setup software (unknown, but something like visicut) is used to position the shape and convert it to g-code.
  • linuxcnc (or possibly grbl) is used to "execute" the g-code through the control hardware.
  • the control hardware powers the motors of the cutting table and controls the plasma torch

We're basing this project on an old X-Z traversing unit originally made for measuring air velocity distributions in wind tunnels at a metrology institute. The current motor controllers, however, seem to be made for a fixed speed and it's probably easiest to replace the electronics altogether.

A Z-axis seems required to control the torch height. It won't need to move very far, quickly or precisely, though.

To-do list

  1. Decide how to control the machine. There seem to be two basic options: GRBL and LinuxCNC
    • Smeding knows a little bit about LinuxCNC and is willing to do some of the work
  2. Design and build interface/driver hardware for motors and encoders
    • Smeding is willing to help with this
    • Benadski has motor controller hardware that takes PWM as input.
  3. Set up a PC that can withstand the general environment of the SparkShack (EMI, humidity, temperature)
  4. Get basic motion control working so that the machine moves
  5. Design and build interface hardware for the plasma torch, so it can be turned on and off. Will probably want voltage sensing for torch height control.
    • Smeding is willing to help with this, too
  6. Add a third axis to the machine for torch height control
  7. Put everything together -- implement the software side of things for torch height control and reading e.g. SVG files


connection diagram:
XY-tafel connection diagram bewerkt.JPG


blokdiagram sturing plasmasnijder

Blockdiagram sturing rev 2.1.PNG