8. Computer controlled machining

Class

Assignment

group assignment:
test runout, alignment, speeds, feeds, and toolpaths for your machine
individual assignment:
make (design+mill+assemble) something big

Previous year

Assesment

Learning outcomes

  • Demonstrate 2D design development for CNC production
  • Describe workflows for CNC production

Have you?

  • Explained how you made your files for machining (2D or 3D)
  • Shown how you made something BIG (setting up the machine, using fixings, testing joints, adjusting feeds and speeds, depth of cut etc)
  • Described problems and how you fixed them
  • Included your design files and ‘hero shot’ photos of final object

FAQ

  • How big is big?
  • Answer: Big enough to show you understand many of the possibilities of CNC machining - drill, pocket, dogbones, nesting, etc.
  • Does it have to be wood or wood products?
  • Answer: No. But the lab is only responsible for providing you with a full size wood board.

Schedule

Endmill

種類


※写真は左から「アップカット」「ダウンカット」「アップ+ダウンカット」
ref.BTMT - Upcut - Downcut - Compression(Up and Down cut)
- compression
- CONVENTIONAL MILLING VS. CLIMB MILLING - Climb Milling Vs. Conventional Milling: 12 Key Differences Machinists Must Know - COMPRESSION CUTTER FOR COMPOSITES

- ref.[THE CORRECT WAY TO SETUP A COMPRESSION END MILL](https://www.stepcraft.us/blog/blog-1/post/the-correct-way-to-setup-a-compression-end-mill-8)

形状


ref.misumi - Monotaro:コーティング

my endmill

corret

材料

  • 3x6板 910mmx1820mm
  • Group Assignment 1枚、individual Assignment 1枚
  • 個体差がある（2枚が同じ厚みとは限らない）購入時に測る？ノギス持参？

To Do

Safety

  • glasses, shoes, clothes, hair, gloves
  • 関内にあるものは持っていく

group assignment

  • CNCの特性を知る
  • ref.fablabtrivandrum 2018
  • ref.oshanghai 2019
  • runout
    • 回転体の半径方向の振れ > エンドミルの振れ
    • 刃径6mm vs 削り跡の幅
    • 軸がぶれていると大きくなる
  • alignment
    • 度、向き、位置など機械構造の歪み
    • 四角を切って、対辺が平行か、直角かを測る
  • speeds
    • 主軸速度(rpm)
    • ディフォルト:12,000rpm(TechShop)
    • 10,000-12,000-14,000 rpm
    • 深さ(刃径と同じ)、速度固定で、rpmを変えて比較する
  • feed rate
    • 送り速度(mm/s)
    • ディフォルト:1in/s(TechShop)
    • 17-25-50? mm/s
    • 深さ(刃径と同じ)、rpm固定（上記）で速度を変える
  • toolpath
    • climb, conversional
  • Tolerance
    • 交差 > kerf, offset
    • comb
    • 板厚：パラメトリック（測定値、カタログ値は参考のみ）
    • スリット：オフセットを求める

individual assignment

  • Design
  • 2D, 2.5D
  • parametric
  • joint
    • Dogbone Filets
    • pocket
  • V-bit engrave
  • Prototyping
  • laser cut
    • 設計15mm厚 > 3mm厚(=1/5 Scale)
  • Cut
  • Air cut
  • Assemble
  • sanding

(# Useful Links

- opendesk

Next week

  • Monday Recitation 23:00-24:00
  • debugging
  • Tuesday Asian Regional Review 12:00 & 21:00
  • 12:00-: zoon http://fab.academany.org/2020/video.html
  • 21:00-: zoom or bluejeans Bluejeans.com/u/fablab/1248
  • Wendnesday Class 22:00-1:00
  • Embedded Programming
  • assignment
    group assignment:
    read a microcontroller data sheet program your board to do something,
    with as many different programming languages
    and programming environments as possible
    individual assignment:
    compare the performance and development workflows for other architectures