Wednesday, January 2, 2013

RepRapPro Mendel (Part 2)

There’s been quite a few changes made in the x and y-axis assemblies in comparison to the Prusa Mendel model. The most intriguing modification (and one of the reasons why I chose this particular model) is the design of the x carriage.

Presently, it carries one hot end, but it's designed to hold a total of 3. This will allow for a multi-color print in 2 or 3 colors, or 2 hot ends can be employed to print with different materials for the purpose of printing with a dissolvable support material. According to the RepRapPro website, the multiple hot end assembly is still in a testing stage and will be available sometime in 2013 (if the multi-head upgrade isn't available by April, I plan to make my own modifications and experiment using KISSlicer).

Other notable changes:

The Prusa Mendel uses either printed PLA bushings for the smooth z-axis rod or LM8UU bearings. This printer is designed using plastic IGUS bushings.

The design difference in the z-axis assembly is the use of a smaller diameter threaded rod (5M studding) instead of the 8mm rod. This makes more sense since it matches the diameter of the stepper motor’s shaft. The coupler is a piece of poly tube, allowing for slight flexibility.

The belt installation for the x carriage was a joy. I recently made a belt adjustment on my Prusa Mendel and it’s always been a point of frustration. Not with this design. It was very quickly applied.

One of the most welcomed features on this printer is the addition of an adjustable Z endstop. This is another frustrating point in using the Prusa Mendel model. Instead of having to slide the Z stop clamp up and down for adjustment, now a precise homing can be made by turning a knob.

The heat bed is nicely designed by sandwiching the pcb heatbed between an aluminum plate and a MDF insulator creating a nice low-profile print platform.