This build will attempt a large 3D printer (nominal 2ft by 2ft by 2ft build volume) using primarily v-slot components for all three axis of motion (X,Y,Z). This configuration is that of a gantry robot.
About 4 years ago I purchased a Solidoodle 3 3D printer to hop on the 3D printer bandwagon or perhaps more appropriately join the stream of lemmings headed for the nearest cliff. My real interest was modeling (not the run way kind) a cartesian 3d printer's errors. Towards this end I wrote 2 Matlab programs recycled to some extent from my Applied Mathematics graduate project titled "Master's Project 2009 Error Analysis of Robot Arm Kinematics". The first was a Print-Test driver and the second one was a Monte Carlo simulation of the printer errors. The Print-Test driver provided the ability to run 30 tests of escalating build volume and error estimate assumptions. Test-30 was for a 609mm cube and the results are provided here. This was the genesis for the idea for a 2ft=609mm cube 3D printer.
Officially my build started April 1,2017 but the frame shown was put together about 8 months prior. The frame is made from rail, that is , actual aluminum stair railing from my back yard that was replaced with recycled wrought ironing from my sister's front porch remodeling. On top is fixed Makerslide rail primarily trying to use up the Makerslide rail before I start using my preferred V-slot rail.
Over the last several years I purchased V-slot rails and a smaller number of Makerslide rails and their respective required wheels and a few large plates. I 3D printed many Openbuild connectors and such in anticipation of starting the build. I purchased both Nema 17 and 23 stepper motors and a Ramps 1.4 kit and of course a large assortment of metric nuts and bolts required for the V-slot rails. Submmiting a "build in progress" has given me the impetus to take the build seriously and devote a lot of time to it.
This is more like a design in progress. Since v-slot components make it easy to assemble components into subassemblies such as the x-carriage it is just as easy to disassemble if a better design seems evident.
I recently assembled a carriage with a x-axis stepper and a z-axis stepper to control the 20 by 20 mm z-axis hot-end arm. I'm designing this on the go so it's no surprise that it's "better" i.e. more build volume will be available if I use 80 by 20 mm V-slot on the x-axis ends. This will elevate the x-axis rail so that the carriage assembly will clear the aluminum railing frame as depicted here. Before I go any further I'm going to step back and look at the mass of the different axis and what size Nema stepper motors are required. I have been assuming that the z-axis can be handled by a Nema-17. My trial x-z carriage uses a Nema-17 which must lift up and down without gearing the 20x20 hot-end arm which at present I am questioning. It should be noted that a Bowden extruder will be used to eliminate a stepper motor on the z-axis. My plan was to use a single Nema-23 stepper to drive the y-axis. I would set it up the way Solidoodle 3 did it. If you think about it the Solidoodle 3 is close to a Gantry design at least for the x and y axis. I need to establish my stepper motor torque requirements and do some testing prior to committing to a final design. I googled the specs for my Nema-17 and Nema-23.
Comparing the Nema-17 holding torque specs with information from Question: how much weight can my stepping motor lift? and Understanding Torque it became questionable if the Nema-17 was powerful enough to lift and hold the current z-axis of length 108 cm. A python program was written to determine the force available at the pulley for Nema-17 and Nema-23 steppers. Additionally, calculations were performed to determine the effective loads as seen by each z,x and y stepper motors. The results indicate z-axis Nema-17 can handle the 1.27 lb gravity load . The load for the x-axis is 3.64 lb and 5.59 lb for the y-axis but these are the weights that must be moved by the steppers in a horizontal plane. Further analysis is required to determine if the steppers can meet the acceleration requirements expected at the hotend. I discovered an excellent document i.e. "Step Motor Basics Guide" to assist me in validating the viability of the planned Nema 17 and Nema 23 stepper selection usage in this design. This guide ......
Large cartesian gantry style 3D printer
This will be a fixed bed, v-slot implemented X,Y,Z axis gantry style 3D printer.
- Build License:
- CC - Attribution - CC BY
Reason for this BuildThis build is to attempt a build without rods, acme screws. I will use just v-slot (and some makerslide) rails and components.