FABO ACADEMY X_6

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FABO ACADEMY X

CLASS 6

Introduction 2 Subtractive Manufacturing

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ZZZZZZZZZZZZZZZZZZiiiiiiiiiiii….Here comes MILLING MACHINE!

So this week we have learnt what is Subtractive Manufacturing especially CNC Milling and, most importantly, how to use Milling Machine - Roland SRM-20. And we will cut a PCB as pre-work for Shanghaino!

MILLING WORKFLOW

  • 3D model.

  • Tool path generation - Gcode or .rml file.

  • Setting up the machine including flating.

  • Milling.

ABOUT Tools

  • Drill Bit : to make holes.

  • End Mill : to cut in horizontal direction.

mills

ABOUT End Mill

  • More flutes more smoother surface.

  • Fewer flutes are easier to clear up.

  • one, two or four flute are most common.

mills

mills

MAKING PCB

  • Use fabmodules to generate .rml file from .png. Be careful about the setting of machine ( SRM-20 ), process ( ‘PCB traces(1/64)’ for circuit traces and ‘PCB outline(1/32)’ for circuit pin holes and outline ), x0 y0 z0 ( all should be zero ), tool diameter ( 0.4mm for traces and 0.8mm for pin holes and outline ), number of offsets ( in this case is 3) and offsets overlap ( in this case is 25% to reduce leftover ).

  • Setting the X/Y and Z origin at first part. Then only set the Z origin after changing the milling.

  • At any case after setting Z origin remember UP the milling.

  • My settings are as follows:

p1

p1s

p2

p2s

p3

p3s

  • Mistake 1: Choosing Wrong Machine ( I choose MDX-20 instead of SRM-20) the output became much smaller…

mt1

  • Mistake 2: Broken one milling!!! Maybe because I have make Mistake 1 for 3 or 4 times so the milling just reached the end of its life. orz

mt2

  • Finally I finish my PCB.

pcb

  • Found that even 25% offsets overlap could still have thin leftover.

leftover