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8. Computer controlled machining

This week I worked on defining my final project idea and started to getting used to the documentation process.

Group assignment


Listen to the sound from the machine Always wear glasses, shoes, fitting clothes and gloves Ensure cut pieces do not block path of mill.

Different Mills

Down cuts, centre cuts, up cuts shallow cuts with down cut deep cuts with up cuts hybrid mills upcut with HDPE is beautiful unlike wood Flat vs ball end mill bits Ball end for smoother finishes in in curved projects Flat end gives more accurate cuts in flat surface with 3 axis movement and to remove debris

Kerf offset

Tool diameter is not = to kerf. There is a runout. Climb vs conventional machining Trochoidal milling

Different materials

MDF & its expensive cousin- Valchromat OSB- oriented strand board- to look into HDPE- Cuts well and flexes well Garolite- PCB material safe material to work with carbon fiber Aluminium composite panel

Speeds & Feeds

Listen to the sound of the machine Chip load: amount of wood each spin take out: between one and ten thousands of an inch Work depth should ideally be= Diameter of tool Stepover= half or more of tool diameter for cleaner cuts


Wood screws to hold stock board into sacrifice board or glue guns Our CNC has vacuum suction to help hold the board in place while cutting.


  1. Cut air before cutting stock
  2. Do test cuts before cutting large cuts
  3. Check cutting a square
  4. Test speeds & feeds

Design & Make something big

sketch vwx dxf cut cut cut cut cut


The structure did not stand upright, I have to revise the design.

Illustrator file