3D Printing

Many parts on the Colorado Front Range Railroad are 3D printed either commercially or at home. The fabrication shop has two 3D printers; the FDM Printer and the SLA resin printer.

FDM 3D Printer

SLA Resin Printer

The Fused Deposition Modeling (FDM) 3D printer uses a 1.75 mm plastics filament to printer parts by laying down layers of melted plastic. In this the plastic is ABS for its chemical properties. Typical plastic cement can chemically weld it to other ABS or Styrene parts. The level of detail for this type of printer is limited. This printer is used more to make prototypes and structural components for models rather than detail parts. Example include interior seats for cabooses, protoboard mounts, speaker enclosures for sound locomotives and drilling jigs.

The Stereo Lithography Apparatus (SLA) 3D printer uses a UV-cured liquid resin to 3D print models. The advantage of this printing style is very high layer resolution and ultimately very high detail. This is useful to making hard-to-find or non-existent detail parts for models. In this case the SLA printer has been used to make detail parts for models such as ladders, insulated hatches, Fan blades for a cooling tower, and other very intricate model details.

The disadvantage of the SLA printer is there is much more post-processing require to get a good turnout. The model is required to be cleaning with Rubbing alcohol and then cured using a UV light. A UV light curing chamber was made using a paint bucket and a strip of UV LED's mounted inside the paint can. A 12VDC 3 amp power supply drives the LED's. A solar power rotary table ensures the parts get full exposure the UV light from the LEDs

An example print from the SLA printer. Unfortunately this model is not usable due to post processing errors.