Lecture notes

docs/Assignments/week_7_computer_controlled_cutting/lecute_notes.md

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+# Lecture Notes
+
+## Wednesday - Neil time!
+
+Press F in KiCad during tracing to `automaticly` finish the trace
+
+
+Open loop cnc machine
+
+Closed loop cnc machine
+
+
+### Materials
+Tri fold cardboard - Doesn't machine well
+Ridgit foam insulations
+MDF - machines smoothly - can be very toxic
+MDO - better MDF
+OSB "constructieplaat - recycled wood - eco friendly
+
+### Flute
+2 than one flute mills 
+The more flutes to smaller the bites the drill takes so the smoother the result is.
+
+fewer flutes when removing a lot of material.
+
+Flutes can have different coatings. Coatings can significantly extend the lifetime of the `end mill`
+
+Different bits for center cutting and not center cutting
+
+center cutting lets you directly go into the material
+Non center cutting is to clean the cuts.
+
+
+Need to watch which way you're drilling it will have impact on the holes and cuts
+
+### Cutting materials
+Down cut leaves loose material around the hole
+up cut destroys the bottom if you're going through the entire material at once
+
+doing a combination can give you the benefit of both and leave a clean hole.
+
+
+
+Machineries handbook
+
+Chip load - how fast you let the tool spin/cut while moving. Too fast is bad too slow is bad. There is a sweetspot
+
+
+For heavy metal machinery you need lubricants. For other stuff not really
+
+
+
+### locking the material in place
+machining vise - good
+bar clamps - need a lot and to distribute the holding force
+vacuum bed - The vacuum hold the material down - need periodic maintenance because the holes can get clogged
+
+
+### Sacrificial layer
+Set to Z=0 
+
+Bolts can get loose on the shopbot.
+
+### Dust
+You need a dust collector because the cnc machine will create a lot of dust. If there's dust around the lab something is wrong.
+
+
+### Modification
+flexible designs - Flexure
+Steam bending - Big box of steam to soften wood and shape it.
+
+
+Japanese wood joints
+https://www.thingiverse.com/thing:169723
+
+
+### Tool paths
+Kerf - Offset by tool diameter
+
+Runout - The tool may not be attached straight to the machine so it will create sloped cuts
+
+
+klein machining - cleaner cut but harder on machine - for finishing
+Conventional - To start out with is easier on the machine. Is more rough
+
+2d top down
+3d
+4d Can curve the tool during cutting
+5d all degrees of freedom
+
+
+
+
+prototype by 3d printing or laser cut before you do the cnc job
+
+
+Shopbot - Vcarve
+
+
+### Safety
+Sharp material can fly out
+Material can get very hot - Fires
+Splinters
+
+
+Always wear safety glasses
+Shoes no crocks or sandals
+Hair in a knot
+Ear protection
+
+
+Never reach into a running machine
+Never do large format machining alone
+You want a second pair of eyes and ears always check each other
+Need to be well prepared
+
+Know how to turn the machine off before turning it on