RUG/Pennsylvania/State College/Printers/BioFab@Home/About
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Contents
Project Summary
Background
This project was suggested by David Saint John in January 2014. The original intent was to convert the printer to RAMPS_1.4 allowing the use of typical RepRap software tool chains. Due to the syringe-based extruder, we thought it would be very useful for 3D bioprinting applications.
Current Work
Technical Information
Printer Hardware
The current printer used for this project is a modified Fab@Home platform. The original printer was built to Fab@Home Model 1 specifications. As of the summer of 2014, the printer was equipped with linear ball bearings on the X and Y axes in place of the bushings for reduced friction. The friction was causing the axes to lean in the desired direction before actual motion of the toolhead was achieved. This created inaccurate prints and sometimes bound the axes entirely.
Electronics
The printer had the original electronics installed, however they were never tested. Instead, RAMPS_1.4 electronics were installed due to the availability of the hardware and many open-sourced control methods. The tasks required for bioprinting can be very specific, therefore using hardware that allowed the use of custom G-Code was desirable. The current firmware is Marlin with modifications on the steps/mm settings and endstop booleans. See here for the current configuration file: File:Marlin-Marlin v1 Fab.zip. Note: The motors on the Fab@Home Model 1 seem to run best at 1/8 stepping ratio (determined by the jumpers under the drivers on the RAMPS board). They should also be driven slower, approx. <500 mm/min.
Extruders/Tool Heads
This particular Fab@Home was built with a single extruder and is fully operational. A dual extruder is currently in development using non-captive stepper motors from Sparkfun.