The BreepBroop (nickname) is a standard RepRap Mendel. It's the original design, and was printed during the main build rush after the Mendel came out. Chorca printed the parts on Mack's MakerBot over a period of about a month. It is all ABS aside from the frame vertexes which were purchased from the RepRap Forums, from Joshua Updyke in particular. This style of Mendel is rarely made anymore due to it's complexity. The much simpler Prusa Mendel is more commonly built, due to the large reduction of printed parts and hardware, and the simpler pulley and bearing systems used. Digitalman2112's RepRap is a Prusa.
The BreepBroop originally used a Techzone Gen3 electronics set, which needed a good amount of touch-up and had some issues. Chorca replaced some of these boards:
- Two Techzone Stepper Controllers were replaced with self-etched Stepper Driver v3.0 (link goes to the 3.3, which is the released version)
- The Extruder controller was removed as it's function was replaced by one of the stepper drivers, and the heaters (bed and extruder) are driven by two Omron E5GN Temperature Process Controllers
- Endstops are not used.
- Temperature is controlled by thermocouple, which is why there are Omron controllers as opposed to a simple RepRap heater control (The Extruder Controller had issues maintaining accurate temps with thermocouples, later traced to a noisy power supply)
Most mechanical functions of the BreepBroop are according to the original build specifications. Few have been made:
- Using a Wade's extruder on the X carriage
- Wade's extruder is using a Herringbone gear set from Thingiverse
- Hot end is a MakerGear Power Resistor heater and BigHead nozzle.
- Bed has been modified to a 1/8" thick copper plate, using a 110v silicone mat heater from McMaster Carr (Part number: 35765K482)
Chorca is currently using the following:
- Latest version of Sprinter firmware
- Host software is Pronterface, using SFACT to interface with Skeinforge
The printer is not printing. After a total rebuild of the hot end and reassembly, we are still having major issues. It was able to successfully print a Wade's extruder gear, however, the PLA was burning and oozing out of the top of the nozzle slightly. The X axis is cracked near the belt clamp area and binding badly. The Y axis also has a lot of wobble due to the weight of the copper plate. There are no endstops so homing is a major issue. The extruder constantly strips because of the shallow hobbing and due to the fact that the thermocouples are difficult to use in getting an accurate temperature reading, it is hard to figure out what the temperature currently is.
The electronics system is a mess, and is very hard to operate. There have been great strides in ease of use, mainly with the RAMPS platform. This integrates all components onto one shield for the Arduino MEGA, reducing footprint and making everything a lot easier to run. The following are current plans for work:
- Replace all electronics with RAMPS board (Digitalman2112 has graciously donated a complete RAMPS kit with Pololus to my cause. I have assembled it and am borrowing an Arduino MEGA from him to use for testing)
- Swap thermocouples for thermistors to use with RAMPS (Digitalman2112 has a set of thermistors which we will attempt to use for this)
- Purchase small SSR to handle the tiny load of the heated bed, and soon the extruder heater
The hotend needs to be replaced and the Wade's upgraded. The X axis needs to be redone, preferably with a Prusa-style carriage to reduce weight and complexity. The following are current plans for work:
- Replace hot end with LulzBot pre-built Budaschnozzle
- Replace X carriage with Prusa-style carriage
- Swap smooth rods for smoother rods on X axis and use oil-impregnated bushings to ride along the rails for greater accuracy
- Replace copper bed with aluminum bed to lower stress on Y axis and prevent wobble
- Fix hobbed bolt on Wade's extruder (Run tap on bolt for longer, cut deeper grooves to get better traction on filament)
- Replace herringbone gears with original gears OR print new extruder such as Greg's Accessible Extruder and use it instead