Project Logs

Collapse

• Adding the brains and... a problem

  AndyMac • 08/06/2015 at 03:23 • 0 comments

  Step 2: Motion. Time for a RAMPS board! After a lot of hunting around I decided on the "Ramps 1.4 Mini Set" from gadgets3d.com. For only $90 it came with RAMPS 1.4 board, 5x G3D stepper drivers, cooling fan, SD card reader, 2x thermistors, and wiring harnesses. Because this is a delta design, 5 stepper drivers gives me 1 for each axis, 1 for the extruder, and a bonus spare for a backup. If I manage to survive without needing the backup, it becomes a 2nd extruder driver. The kit even came with a ceramic screwdriver for stepper driver adjustments.

  A standard 9V wall power supply was used to power the Arduino Mega, and a salvaged 12V, 4.6A laptop power supply was stripped and used for the RAMPS board. The firmware is [jcrocholl]'s modified Marlin firmware, on github. For control software I opted for Repetier-Host.

  Installed, powered, and apparently running I tried to connect and... cannot. Once the firmware is uploaded to the Mega and the RAMPS board added, the device fails to show up on my computer. I have not had the time yet to troubleshoot this. My hope is that there is an address setting conflict that I can resolve. If there is an issue with the RAMPS board itself it will be much harder to diagnose.
  

• Steppers and Wiring

  AndyMac • 08/06/2015 at 03:04 • 0 comments

  Step 2: Motion.

  This post is actually a long time coming, as I did some of this assembly a year ago. I have added gears, steppers, end switches, and RAMPS board.

  LM8UU linear bearings are from vxb.com.
  

  I had the top bearings on-hand. They are standard skateboard bearings. Order of assembly is shown below. I needed a few spacers to keep the bearing spinning properly and lined up with the lower gear.

  Stepper motors and pulleys were added. Pulleys are GT2, 2mm pitch, 40 teeth, from sdp-si.com. Steppers are NEMA 14 from Adafruit.

  Another issue I found was with the end stop switch mountings. The lower mountings slide right onto the aluminum rods, but there is no way to keep them from spinning. This could be fixed with some sort of clamp, but should be okay for now as long as I keep them pointing inward.

  The print bed is a scrap piece of corkboard and the glass from an old printer. Holes were punched in the cork to offset the bolt heads.

  The 3 axes were labeled, as were the 6 end switch wiring harnesses and 3 stepper motor wiring harnesses.

  
  

• Mechanical Assembly

  AndyMac • 06/06/2014 at 18:22 • 0 comments

  Step one: put together the bare bones of the printer. The plastic parts were all printed from https://github.com/jcrocholl/rostock. I modified the BOM heavily and will post when it is closer to completion and not a total mess. The only missing info was dimensions for the top and bottom plate. Courtesy of a google search:

  A few missing dimensions were hole diameters and the location of 6 bolt holes. I used a 7/64 bit, but the hole diameter is not critical. The missing holes (red Xes) are easy to mark by lining up the motor_end with the 2 existing holes.

  Overall it was a straightforward assembly. There are some small issues I will have to fix later but are not crucial to operation. One of which is that the combined height of the endstop holders, bottom plate, and motor_end is FAR longer than a standard M3 screw. Countersinking the motor_end or bottom plate later on will fix that.

  The carriage and rod assembly takes a little bit of effort, since each side gets two bolts that face each other.

  Linear bearings were attached to the idler ends with zip ties. It is not my favorite method of assembly but it does hold pretty well. (Ignore the wires and belt for now)

  The final product looks something like this and moves smoothly with very little slop, which was my biggest concern with this step.

View all 3 project logs