DIY CNC Machine – Frame Build | Part 1/2

Building your own CNC can be a bit intimidating
at first, because you've got to deal with mechanics, electronics as well as the entire
software part to make the machine run. But there are so many great tutorials out
there and the parts are very easily available and affordable which makes building your own
machine a really fun project. In this video, I want to show you how I built my own machine which has really thought me a lot I want to share my experience with you and maybe I can inspire you to try it
on your own. I'm Roman, let's get started. The CNC has three axes and is 86cm long, 71cm
wide and 60cm tall and has a workable volume of 63 x 48 x 12.5cm. The machine is driven by four Nema 23 stepper
motors, one each for the X- and Z-axes and two for the Y-axis. Even though I wanted to keep the costs
down, the goal was to build a machine where all moving parts were going to run on ball
bearings. I therefore used linear rail guides with carriages
that run on ball bearings and ball screws. As always on my channel, I wanted to used
natural materials where possible.

That's why I chose a combination of birch
plywood and solid beech wood for the machine frame . The idea was that the relatively high
stiffness of beech wood in a combination with the U- and L-shaped cross sections of the
axels would provide a high enough stiffness for the frame. So first I needed to cut the plywood to
size and plane the beech wood to the needed dimensions. I have a good friend with an amazing wood
workshop and I'm fortunate to have the chance to go there and cut my own material.

With the frame materials cut, let's
have a look at the complete parts list: There are the parts for the frame, two linear rails
for each axis with two carriages each, the lead screws, four stepper motors, the motor
couplers and the motor drivers, two drag chains, a couple of switches and limit switches, an
Arduino Uno with CNC shield, a DC power supply, a router and various screws and cables. As always, the complete parts list can be
found in the video's description below. The square beech timbers had to be joint
with the plywood to build the frame for the three axes and I connected them with Lamellos. I made sure while planning that the dimensions
allowed for a perfectly flush surface of the linear rails with the ball screws. Back in my workshop, I gave the parts a
quick sanding and glued the parts together. Next I prepared the two mid-sections of the
frame. They are U-shaped which gives the frame stiffnes
but was also going to provide room for housing all the electronics.

In the same way I connected the axes I also
joint these parts and glued them together. Then I made all the necessary cutouts
and holes for mounting the electronics and for providing airflow for cooling. After making all the holes these two parts
looked like this. You're going to see later what all the cutous
are used for exactly. Now all that was left to do to finish the
main frame was to connect the two mid-sections with the sides.

These pieces I also glued togeter. I had previously pre-drilled all the holes
for the linear rails, and with this the machine was ready to get some color accents by spray
painting all the beech wood parts in my channels green signature color. Next I drew up the shape of the two sides
of the gantry and cut them out with the jig saw. I also drilled the holes that were needed
to screw the sides to the gantry as well as for for mounting the X-axis motor.

Finally, I also drilled the holes for the
connecting screws into the gantry. I then screwed the linear rails in place. When pre-drilling the holes I had already
made sure that the rails were going to be in a perfectly straight line. Now, while screwing the rails on I double
checked with a ruler that they were nicely aligned before finally tightening the screws. I was now able to work out the positioning
for the holes of the carriages to mount the Z to the X axis as well as for mounting the
gantry to the frame. These are the final pieces with the motor
mount on the left side. Next up I made the pieces to mount the
two Y- and the Z-axis stepper motors to the frame. They required the same drilling pattern that
I had drilled in the gantry side and were going to be mounted like so.

I first attached the coupler to the motor
before screwing the stepper motors to the plywood mounts. The parts could then be mounted to the back
of the frame with screws. From now on I didn't use any glue anymore
for the assembly of the machine to grant access to all parts in case I needed to dismantle
the machine for maintenance or trouble shooting.

In case of the Y-axis motor I had to insert
one connecting screw before because it would be blocked by the stepper motor. With the motors in place it was time to
mount the ball screws. They came as a set, including the ball nut,
a ball nut housing which allowed for easier connection to the sides in my case, two end
supports and the actual screw. Putting the parts together was very easy and
straight forward. With the assambled ball screws I could
now determine their position and mark the mounting holes and predrill them. Using the two set screws I connected the other
side of the motor coupler to the ball screw and fixed in into place.

The main frame and the X-axis were now
almost finished. So I joint the two sides with the gantry by
screwing them together with some very rigid flat head hex drive furniture screws which
allow for very strong and sturdy screw connections. One topic I haven't talked about yet are
the limit switches. But I had planned to install two per axis
to secure against over travel and having the option to use them as homing switches. I installed them right nex to the end supports
of the ball screws and routed a short length of cabel to the back of the gantry for an
easy connection later on. With round-head screws on the back of
the corresponding axes I was now going to be able to trigger them.

So I worked out the exact locations and put
in the screws. This turned out to be a practical and almost
invisible solution and worked really well. At this point I was now able to join the
Z- to the Y-axis. I could neither install the ball screw nor
the linear rails befor because they were going to cover up some the mounting holes.
The contact surface of the carriages was actually quite small. That's why I cut some aluminum spacers to
bridge the gap in the middle and increase the surface and avoid crushing the plywood
when tightening the screws. Next I put the ball screw in place and installed
the stepper motor. Then, I finally screwed the last two linear
rails in place and secured the ball screw and the motor coupler. The last missing piece now was the mount
for the router. The Makita router that I previousley owned
came with an angular bracket that I had never used before so I repurposed it as the router
mount for the CNC.

I had to take it apart and make some changes
to make it work for this application. For mounting the bracket to the frame
I made an adapter piece from two sections of beech wood that was also going to get the
green color accent. I simply had to cut out the same radius as
the aluminum bracket until I had a nice fit. Next, I drilled the mounting holes into
the base plate and then screwed the bracket to it. I had slightly tapered the bracket and the
base plate, simply for a more elegant look. I also put the screws to actuate the limit
switches in the back of the plate. Finally I attached the aluminum bracket,
and with that, the entire part was ready to be mounted to the gantry.

I put the cantry onto the main frame and very
carefully erected it to its final position and secured it with a screw. Then I inserted the rest of the screws. On the now almost complete machine frame
I installed the drag chains for the X- and Y-axes. I cut some plywood pieces to which I attached
the drag chains. I screwed one piece to the back of the vertical
axis, exactly below the hole thruogh which I had already routed the cables of the limit
switches. The other end was fixed as well. The other piece was screwed to the side
of the gantry with the drag chain running on top of the left side of the frame. The chain could be simply shortened to the
required length by removing some of the chain links and reattaching the end piece. The final missing frame piece was the
machine bed. The plan was to have a series of threaded
inserts that would allow to fix a spoil board or a work piece in place by using holding
down clamps. I therefore drilled a series of evenly spaced
holes in which I screwed threaded inserts for M6 screws.

When this was done, the machine bed could
be put in place and the machine frame was finished. Installing the electronics and software were
the next tasks. You can click on the link to see part two
of the build and also to watch the first run of the machine. Thank you for watching and see you in part
two. Bye for now..

As found on YouTube

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