3D printers

FDM Printers

How FDM 3D Printing Works.

For this example we’ll use a Dimension ___ , manufactured by Stratasys. It is a Fused-Deposition Modeling system, and this is how it works: After a 3D model has been designed and exported to an STL, a special program slices it up into cross-sections thick. It looks at each cross-section and generates a set of instructions on how to build it. When this information is sent to the printer, it starts with the bottom-most layer, laying down plastic in the shape of the cross-section. When it finishes the first layer, it moves up a slice to start on the next layer. Take a close look at a 3D-printed model and you’ll notice that it is actually stepped. The machine consists of a moving bed (Z-axis) and a print head (X-axis and Y-axis). The print head has a heating element in it; thermoplastic is forced into the print head, melts, and is squeezed out, not unlike toothpaste. The print head is calibrated in such a way that the molten plastic coming out of it is almost always the same thickness. In order to form complex shapes, overhangs, and hinges/joints/free-moving objects, the plastic needs to be held up by something. The machine prints using a second material, which we call the ‘support.’ When the print is done, it is put in a bath of solution that dissolves away the support material, leaving only the finished model. Some machines do not have a second support material an instead have supports generated in the model material when sliced.

Two Material, FDM Printing, Extrusion System Diagram

Dimension

The Dimension SST 1200es I operated at UArts was a lemon. Material was the main culprit, but it was also an abused machine before I got to operate it.

Lulzbot

Overview

Great printers.

  • Lead Screws Lubricated (December 2019)
  • Need firmware updates.
  • Material Sample Test for Tolerance
  • Benchy off of each printer

Printer Quirks @ NVD

Printer 1

  • Y Belt Issues
  • Has some nozzle contact issues on calibration.
  • Needs new PEI.

Tolerances for 1x1x1 cube test: X Y Z

Printer 2

  • Y Belt Issues
  • Has some nozzle contact issues on calibration.
  • Needs new PEI.

Tolerances for 1x1x1 cube test: X Y Z

Printer 3

  • Y Belt Issues
  • Has some nozzle contact issues on calibration.
  • Needs new PEI.

Tolerances for 1x1x1 cube test: X Y Z

Printer 4

  • Y Belt Issues
  • Has some nozzle contact issues on calibration.
  • Needs new PEI.

Tolerances for 1x1x1 cube test: X Y Z

Monoprice Maker Mini V2

Decent printer that I use at home directly off my PC with CURA. May set up Octoprint once I have a good location for the printer.

Monoprice Maker Select

Run away from these fire-hazards. Even after fixing the thermistor…

Makerbot

Replicator

Solid machine, likes loose extrusion, hard to keep consistent temp. Once it gets gremlins they stay.

Replicator 2

Horrible machine, all I have interacted with have had ribbon cable gremlins. Run away.

Replicator 2X

Really decent when they work. Can be very temper-mental. Does two materials well.

Plastic Recycling Research

  • Recycle Bot
  • Precious Plastics

Materials Review

  • NGEN is great, but fractures, super shiny.
  • PLA, good-old standard. Watch for moisture and dust.
  • ABS, only for enclosed dimension, very susceptible to moisture damage.
  • Ninjaflex, only used once. Can’t use at home.
  • TPU, want to try.

SLA Printing

Form 2?

Super interesting printer, not student friendly. I spent 2 months servicing one that a student almost broke the year before I got to NVD. Definitely get a good UV box or clean sunny space.

  • Inventory Material
  • Write up checklist for proper handling

Shapeways Printing

Sandstone Printing

Done through shape-ways, link image from minecraft!

Ceramic Printing

Done through shape-ways, link image from Ryans gift!

Notes that need to get added into above or gcode…

Working with Tolerance and Support Material.

There are a few basic guidelines to follow when developing a model for printing. These won’t help you edit a model; these are things to keep in mind when designing it.

Wall Thickness - The printer can print walls as thin as ~0.01”, however these will not be structurally sound. Keep walls to a minimum of 0.04” for rigid structure.

Suspended Parts - It is possible to make joints by leaving some space between two interlocking parts; leave at least 0.02” or the printer may connect the two parts. If a part is threaded or must fit snugly, it is best to print it separately (when possible).

Model Interior settings:

Solid: fills any interior space with 100% plastic. Strongest and most expensive option.

Sparse High Density: fills interior space with a grid pattern. Very strong and cheaper than Solid fill.

Sparse Low Density: fills interior space with a grid pattern using less plastic than Sparse High Density. Uses the least plastic and is therefore the cheapest.

Support Fill settings:

Minimal: uses the least amount of material and is therefore the cheapest option.

Sparse: uses more material than Minimal. Only necessary when printing complex overhangs or objects that require a high tolerance.

Printer Capabilities: