HydraFabber

Note: document all progress here, and start Leo Log. See Marcin Log as an example.

HydraFabber - after HydraRaptor - is a portable, multi-headed CNC fabrication machine that can do 3D printing, circuit milling, and laser cutting. It is intended to be a portable machine that can be brought to OSE Design Sprints for prototyping. During the sprints, we design machines in Sketchup, and then prototype them by printing out modular parts with a 3D printer and laser cutter. The laser cutter cuts out flat sheets that are folded to make 3D beams and other parts, and these beams form 3D frames and other 3D parts. Then the circuit mill functionality can be used to prototype circuit boards, such as controllers for automated machines.

Specifications

Functional Spec

• 200x200x120mm mininimum build volume
• Quick change heads with accurate repeatable alignment
• Complete system includes robust carry case
• At most 10 minutes for a competent user to set up or prepare for travel

• Printer
  • One material at a time
  • heated bed to at least 140C
  • reliable extruder
  • hot end to at least 245C
  • Glass print surface for flatness
    • Optional tape over glass for ABS adhesion
  • Fan to cool print
  • at least 60mm/s practical print speed (more is better)

• Laser
  • 1.5W laser cutter diode

• Circuit mill
  • depth of cut control relative to surface of PCB
  • easy tool change
  • effective quick change PCB holddown

• Folds up into a portable suitcase so it can be brought to design sprints and other events

Functional Spec Questions

• Is 1.5w optimum?
• What wavelength?
• What laser radiation safety measures (1.5w is plenty to blind)?
• Fixed laser + moving optics or moving laser?
• What feed rates would be ideal?

• How accurate do we need to be for circuit milling?
• What is our target track pitch?
  • Are we aiming for through hole or SMT? If SMT, then how small (just SOICs or QFNs and BGAs)?
• Is a dremmel type spindle good enough?
  • Noise?
  • Speed (RPM)?
  • Accuracy (TIR)?
  • Mass - is it too heavy?
  • Size - is it too big?
• Are there any reasonable off the shelf alternatives to the dremmel?
• How hard/expensive would it be to make a good small open source spindle?
• What feed rates would be ideal?
• What cutting forces are we going to get?
• How do we hold down the PCB?

• Will the dust from the PCB milling interfere with the 3D printing?

Process

Start with Window 7, presentation page 2 - concept design.

1. Do Systems Engineering Breakdown Diagram

Diagram to follow.

1. Potentially do an interface design that shows how modules fit together
2. Then embed the original i3 RepRap STL via an STL Viewer in the wiki

Printer Reliability

• Leo's RepRap Kit had at best 4/5 print success on 8 hour overnight prints. Drift in mechanical calibration, failure of print adhesion, nozzle blockage, filament feed slip, and filament spool tangles are the main cause of failures in long prints.
• For short prints, once print parameters are established for a particular object for a particular printer with a particular material. Once you are dialed in, ~1% failure rate for prints of 1 hour. This is for unambitious - ie, safe zone - prints. Wall thickness safe, fairly thick layers, not too fast, etc.

Links

• Leo Dearden
• Opencreators Korean printer - [1]
• Suitcase 3D Printer
• Lulzbot
• RepRap Kit
• [RepRap Prusa i3|http://reprap.org/wiki/Prusa_i3]