MAS.865 > Additive Manufacturing > FFF

Fused Deposition Modeling

A spool of thermoplastic filament is first loaded into the printer. Once the nozzle has reached the desired temperature, the filament is fed to the extrusion head and in the nozzle where it was heated to its well above glass temperature and around its melting point(click click sound and blobs) . The extrusion head is attached to a 3-axis system that allows it to move in the X, Y and Z directions. The melted material is extruded in thin strands and is deposited layer-by-layer in predetermined locations, where it cools and solidifies. Sometimes the cooling of the material is accelerated through the use of cooling fans attached on the extrusion head. To fill an area, multiple passes are required (similar to coloring a rectangle with a marker). When a layer is finished, the build platform moves down (or in other machine setups, the extrusion head moves up) and a new layer is deposited. This process is repeated until the part is complete.

XYZ Motion Machanism

• Cartesian
• Delta
  
  • motor hidden at the bottom instead of being attached to the printhead, faster speed, less chance of machanical parts flexing due to shifts in momentum
  • inversed kinemaitics required precise length of the arm and distance between carriages and better computation power than Cartesian Printer

     
• Polar
  • Small footprint large print volume
• Robotics
  • MiniBuilder
  • Mataerial (fast-curing two-component thermosetting polymer, preferably polyurethane required)Patent

Failure and Solution Mechanism

• Warping
  • solution:
    • full enclosure to provide homogeneous temperature within the printer
    • heated print platform with perforated plate
• Bad Layer Adhesion
  • on first layer solution:
    • glue stick
    • z leveling of the plate 
  • not on first layer solution: fine tune cooling fan on extruder head
• Leveling
  • Mesh Bed Leveling: Virtualy create a 3d virtual plate to allow computing compensation of flex and curve on the print platform on the fly, traditional z level adjustment,grid-based adjustment presume print platform to be a perfectly even and sometimes tilted surface, which is engineering wise difficult in reality. Manual leveling, automated leveling with probe (prusa i3 MK3)
• Collision
  
  • extremely vicious for printers with 2 nozzles, especially when z is not leveled. 
  • solution: auto head lift on retraction through firmware, spring on extruder head, print head lift switch on Ultimaker 3
• Curious Fingers

Fun Things to do:

• Whole Part with Kinematic linkage (dual nozzle with resolvable filament recommended, SLS even better) clearance
• Air Tight / Water Tight part  (over-extruding)
• Direct casting on plastic mold (mechanical lock can be easily formed, destroyable and flexible filament recommended)

Materials

• safety
• Interesting CompositePLA :
  
  • Matelfill PLA
    
    • Rust iron PLA
    • Copper
    • Stainless Steel
  • Woodfill PLA
  • Conductive PLA (stylus tip)
  • Carbon Fiber PLA (just for shimmers look and feel)
• ABS (legos,injection molding, compare to pla: better strength, better ductility, higher heat resistance 105°C glass transition. However easier to warp)
• PLA (biodegradable, 60°C glass transition)
• HIPS & PVA (disolvable support for ABS and PLA)
• TPU (flexible, low accuracy)
• Nylon(PA) (strenghth, adherance problem)
• PETG (food safe)
• PEI (fire and chemical resistance)
• PEEK (dental, 500°C, 230°C)

• UnderDevelopment:
  • Glass
  • Glass Fiber/ Carbon Fiber (Stiffness and weight, here prints were composed with multiple Nylon layers and reinforced with Carbon Fiber layers together, sole Carbon Fiber have extreme layer adherance difficulty, the machanism is when carbon fiber printed out it will melt its way into the part below it. ) Markforged 
  • Metal FDM (In Thermoplastic FDM, printed layers are heated to its glass transition temperature, which makes it soft and fusible when next layer is added. Metal doesn't do that, it is either hard and collide the print head or imaging what happent when you use a soldering gun on solder)

• Sanding
• Cold Wedling (Aceton)
• Gap Filling (Cotton swab Aceton, fill the gap with epoxy XCT-3D, autobody filler, Aceton with ABS, and sand)
• Polishing Priming & Painting (hang it, airbrush recommended)
• Vapor Smoothing (Spray Aceton Poison)
• Dipping (Acetone should be used for dipping ABS, and MEK or THF can be used to dip PLA, matte or glazed spray afterwards)
• Epoxy Coating
• Metal Plating (Spray Acetone+graphite 1:1, or conductive spray and electro-plate it)
• Just Don't Expected them looks like below result, and spend more time with your friends and family and bed, and save the world by using less Acetone, Designers...

Comparison

FDM/FFF Machines: