I've been working on the DM2800
milling machine rebuild, creating 3D printed plastic parts, to replace metal
parts that were either broken, missing, or in need of a redesign. I'm gonna go over
some of that process in this video Hey it's Pete welcome back to the workshop. I do a lot of 3d printing, but it's rarely anything that's purely decorative. Most of what I 3d print are parts that are useful to actually solve problems
here in the shop or very limited run production pieces. I've printed various tool holders, and organizers
and, in an earlier video, I even designed and printed
some enhancements to my Harbor Freight storage cases. I also manufacture a small
air valve controller here in the shop that has an entirely
3D printed case. So I started to see what I thought were some opportunities with
this CNC mill retrofit, to use 3D printing for some
of the various parts I needed. In a previous video I showed the adapter plate I had designed, to mount
the DMM AC servo motor in place of the original brushless DC motor. After several design revisions, I
had a piece that looked great, but as I went to put more
of the mill back together, I realized I had not taken into
account this motor shroud. It's designed to cover the spindle motor, hiding all the motor connections, and provide a cooling fan. The original adapter plate had separate
mounting brackets and rather than just screwing those
brackets onto my adapter, I thought it would be better to integrate
them into the adapter design and began modifying my model in fusion 360. I added provisions for mounting the
cover, and while I was at it, I threw in some scoops to allow the fan to
suck in air from the bottom. I followed a tip from John over at the
JohnSL YouTube channel. In a recent video he suggested that
when doing prototype parts, only print enough of the
part to check the fit before committing the time and
filament, to printing the entire part. in fusion 360 I temporarily removed most
of the base of the adapter, and just focused on printing enough of the part to check
the fit with the shroud. After making some adjustments to the design, I did
another abbreviated test print to check my screw hole locations- and then went on
to print the entire new adapter plate. Trying to cut, or even print threads in a
3D printed part is not usually a great option. One or two uses and the threads
usually strip out. To get around this problem you can either
leave a recess for a nut in the print, or in the case of blind holes, use
these brass heat insert nuts. These can be installed by placing them
on the end of a hot soldering iron and pushing them in place. They even make
special soldering iron tips for this purpose one of the common issues I've
heard is that a typical soldering iron can get too hot, so in doing multiple
inserts you need to repeatedly unplug the iron, allowing it time to cool down
between inserts. There are also ultrasonic tools for
doing this sort of work but I've never seen one made for home shop use. I'm gonna try a slightly different approach. I'm gonna screw the insert onto a
stainless steel machine screw, then heat it up with my hot air gun. I've got the air set to 300 degrees
Celsius on my hot air gun, this should be about right. The key to installing these is
to get them just hot enough so that they slide into place,
without liquefying it to the point where it flows away from the
insert and distorts the part. Once installed it's important to disturb the
inserts as little as possible while the plastic cools and re solidifies. These are really reasonably
priced and add what I think is a super finished look to the part. Iwill leave a link to these as well as some of the other tools I used in the
video description below. The next item I wanted to address was
this motor cove. These cover the stepper motors on all three axes. Similar to the spindle motor cover, they provide a place to make all the electrical connections
for the motors, as well as containing a cooling fan. They are also the connection
point for the axes limit switches. One of these covers was missing when I
received the machine and I do not have the equipment or the skill level to
recreate this in metal I took some measurements and headed back
to fusion 360 to model the part. This was a fairly faithful reproduction
of the original piece, with the only major change being an
increase of the wall thickness The original metal version is
about 1 millimeter thick, while the plastic version I
created is 2-1/2 millimeters. And that's just to give it a better
chance of standing up to the job my plan is to put
this up on the z-axis where it really won't be disturbed. I typically print with ABS filament and
acetone is a solvent for ABS. There's a technique called cold vapor smoothing
that allows you to remove some of the layer lines from the printing process
and leaving behind a smooth shiny finish. Basically you subject the part to an
environment with a lot of acetone fumes and the acetone condenses on the surface
of the part, microscopically melting it and leaving it with a smooth surface.
I want to try that on this part I cut a piece of window screening that fits
the perimeter of a plastic container I use that screen to trap a layer of paper
towels up against the wall of the container Acetone was poured in and swirled around
until it was completely absorbed by the paper towels The 3d printed motor shroud was placed
on a platform in a shallow pan of water and the plastic container was
inverted over it. The water helps to trap the fumes in place. This was allowed to sit for about 20 minutes
and I ran it through the process several times In the end I was never really happy with the results. This technique does work but I
don't think this particular part is well-suited for the process. With only a
2-1/2 millimeter wall thickness this part started to soften to the point
I was concerned about it losing its shape The side walls started to bow in a bit
and I pulled the plug on the whole operation. After it regained its firmness
I broke out the sandpaper primer and paint. And I'm really happy
with how it came out. Matter of fact I thought this piece turned out so nice that I had to go back and sand and
paint the original metal covers as well I also replaced the fans
with all-new 24 volt ones while I was at it I wanted to degrease and clean up the
flexible conduit that runs to each axis before putting
them back on the machine. I soaked these for a few days
in a container of purple power, occasionally scrubbing the tubing
with a brush as I walked by After removing the tubing from the container, I let them hang and drip dry
for another few days I wasn't really in a hurry for these parts
as I was working on other things during this time And just a quick shoutout
for this hand pump - it's super cheap and works surprisingly well for
this job. Once you start the flow with a few pumps, it will continue to siphon on its own. Again I will have a link down below
where you can check this out Once the conduit was dry
I went back with a brush and removed the powdery residue
that was left behind The y-axis conduit had a crack in it. Based on where it was located
on the machine, I'm guessing at some point in the past something
fell on it and cracked it I looked around for replacement conduit and fittings but then started to think maybe I could just create a splint to cover this crack. I envisioned a two-piece tube that would close around the conduit in a clamshell
fashion - supporting the cracked area while not looking out a place on the
machine I sketched up a design that could be
printed in two identical pieces and then pinned together with pieces of filament I think it came out really well. One quick change I wanted to mention here in the previous video where I went
over the electrical panel, I had originally installed a 24 volt 100 watt power
supply. Based on some comments from Marty's CNC garage, I swapped that out
for two 60 watt 24 volt power supplies . one of these power supplies is going to be
dedicated to powering the Acorn and the Ether1616, while the other power
supply will be used for external loads such as solenoid valves and relays-
things like that that might make noise if you want to follow along with this
milling machine rebuild from the very beginning or any spot along the way, click that playlist and I will see you over there
