This phase of the build is the fabrication. This section consists of more pictures and videos since the bulk of the build is its construction. Now that I have the general design figured out, I have moved on to making the frame for the X & Y axis. I began with 3/4" angle iron, ground the edges at an angle where the weld will go, and clamped everything down square to the table.
After the frame is squared up I tack weld it in case anything moves on me. I take my time here, measuring and remeasuring. If this is rushed, the whole foundation of the 3D printer will be warped and everything else will be an attempt to fix this. Once I am happy with where everything is, I finish welding it up. I weld small areas at a time, moving around the entire frame as to not overheat and warp the frame. At this point, I mark all my holes and drill them out for the Y axis.
Now that the Y axis is started, I can refine my 3D models of the X axis. I have been using a Makerbot 2x to print most of the plastic parts and then joining them with metal hardware.
I am using smooth drill rod from McMasterCarr for the rails. Once cut to size, I use my 1941 Logan lathe to sand down the rods before using the buffer. The linear bearings and pulleys are kind of tight out of the box so the rods need some sanding and buffing. I also use the smooth rod as a shaft for a skate bearing that is used in the extruder.
The extruder is set up to print in 3mm filament. However I want to use 1.75mm so I need to change out the PTFE tube that guides the filament. I took apart the extruder and drilled out a piece of PTFE solid stock I bought off Amazon. After I cut it to length with a jeweler's tube cutter I simply replaced the old tube.
Some of the 3D printed parts for the hot end were pretty rough from the support material so after filing them down, I put them on the buffer and then cleaned them up with some dish soap and a toothbrush.
Now that I have some 3D printed parts, some hardware and the frame, I can begin some initial assembly.
For the bed I used two pieces of aluminum. The top sheet will be the print bed and will be supported by 4 springs that are attached to a piece of aluminum below that. I used my 1930's Delta bandsaw to cut them out and my early Hamilton and Delta drill presses for the mounts. To make sure all the holes lined up, I used a divider to mark the holes at an equal distance. I then taped both sheets together and drilled them at the same time.
After the bottom platform is drilled, I use the drill press to assist in manually tapping the holes (3mm).
Now it is time to move onto the Z axis. I go through a similar process as I did with the X/Y frame. I start with 3/4" angle iron and everything is welded together. Afterwards, I will end up marking the holes for the Z-axis' and drill them out.
During fabrication, the tool box goes through a few modifications itself. However, since I am preserving its current finish, I often use some painters tape to protect the surface around where I am grinding. In addition, I also use welding leathers to keep out sparks and metal dust.
Once the Z frame is constructed it is then squared up and welded to the X/Y frame in a similar way as the frame sections. After I am sure everything is accurately laid out and welded up, I then cut out the middle support that I welded in earlier.
Now it is time to get the Z axis made and moving. For the main frame and some of the mounting brackets, I used scrap aluminum extrusions that were salvaged from a shower door guide rail. Everything is bolted together and moves along drill rod and threaded rod.
Four out of 3 of the motors have shortened shafts due to the tight space. To avoid dust contaminating the motors, I use blue tape. The top end of the threaded rod is machined so that it fits into a couple of Boca bearings. The bottom end is coupled together with the Z motor using some re-purposed motorcycle fuel line from another project and crimped with zip ties.
Now that the X & Z motors are mounted, I need to fabricate a Y motor mount. I used some of the aluminum extrusion but I still need a way to mount it to the frame. I decided to weld on some studs but need them flush because the weld will get in the way. I used similar techniques of a "V" slot so that I could grind the weld flat.
At this point, the main fabrication is done. I have to button up a few fabrication details but I will be moving onto the wiring. Below is one more video and a few still shots of the final construction. I still need to do some finish work and testing but that will be in Phase III.
June 29, 2015
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