computer-controlled machining

• Assignment
  make something big

History of repairing a chair

• Actually, this is not the first repair of this chair.
  ▼ It used to be this originally. The cloth was worn out.
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• ▼ And it was repaired to be this,
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• ▼ then this (the right one).
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• But, again, some of the wooden bars were broken.
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• 
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• (▼ For your information, its sizes were this. The material was shina-plywood.)
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• Plus, this was not comfortable..
  Then I decided to repair it again for this week assignment.

Design on Rhinoceros and Illustrator

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• I decided to make a reclining chair with using the original metalic armrest and base part.

Generate a path data (G code) on VCarve Pro

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• We use VCarve Pro
• Tutorials on Youtube

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• ▲ Diameter: the diameter of your endmill
  Pass Depth: the depth your router mills at once (The router will mill the same path for plural times to cut the material)
  Stepover: ?
  Spindle Speed: how many times the endmill rotates per minute. rpm means rotation per minute. Check your router spec.
  Feed Rate: how fast your router moves in X and Y axis.
  Plunge Rate: how fast your router moves in Z axis.
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• ▲ When you cut/drill throught the material, the cut depth should be a bit longer than the thickness of your material.
  
  So don't forget to put another board under the material you want to mill.
  Or the endmill will mill the machine.
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• ▲ Choose your Post Processor.
  Then it generates a path data (G code) according to your CAM.
  

Machining with Rockler CNC Shark

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• ▲ We use this machine in our lab. This is named Rockler CNC Shark.
  I found a playlist on how to use it on youtube.

• ▼ Put double-sided tapes on the back of your board.
  They hold the material on the machine and hold cut parts on the machine, also. Or cut parts will move around.
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• ▼ Use cramps to fix the material. Try to make it move by hands and make sure it never does.
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• Then, you need to be careful about the cutting order.
  It should be INSIDE-OUT.
• ▼ Firstly, inside.
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• ▼ Then, outside.
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• This is what a lasercutter does automatically.
  When you use a CNC router, you need to make separate path data according whether each of them should be cut inside the line or outside the line.
  This is why you need to select the order manually.

Errors and a Result

• ▼ This was the first result.
  The cutting itself was good but I found my design error then.
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• ▼ This was the second result.
• Maybe one of the holes was too small for the endmill, VCarve Pro didn't make the path data for the hole line and I found that after cutting.

• ▼ This was the third result.
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• The side got burned a lot and the edge was not sharp.
• ▼ Actually, other parts' sides milled before this third trial also turned blacker than the firstly milled one.
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• I guess this is because the endmill got wax and resin included in MDF boards then became dull.

• So, the works is still in progress this week.
  I uploaded a video of the structual test on youtube.