Can you turn an old 3D printer into
a CNC machine?  Well yes...
but there are issues!
this video is once again sponsored by Banggood who have
given me this hundred dollar CNC spindle
and some tooling to try and make my old
3D printer, a Prusa i3 into a
CNC machine
the 3D printer I've had a few years now just sitting in the shed
and I have my nice lulzbot Taz 3
now so it's about time I gave this thing
a new lease of life
it was a good printer for its time and has I built it myself I'm very familiar with the design
so I thought it would lend itself
perfectly to this project
now my first thought as I'm sure many of you have considered before there isn't much
difference between a 3d printer and a
small CNC machine that typically both
have small stepper motors that drive a
tool end of some kind along several axis to reproduce a digital file
3d printers to addative manufacturing using a plastic extruder usually
a CNC machine typically use a rotary cutting tool to do subtractive manufacturing
carving away the unwanted material
so surely it's as simple as swapping out
the extruder over the spindle right
on both the CNC and 3d printer something needs to tell the motors exactly what to
do now in this case I'm using an old
ramped border that was on the machine
with an Arduino mega and it controls the
various different motor directions as
well as telling the extruder how much
plastic to squirt out and where and when
this would probably work fine with a bit
of reconfiguration
let's look at the spindle first comes well packaged it has two short wires with bare ends as well
as a nice aluminium mounting block a pop a link and discount code in the video description if you want to check it out
you also get a power supply and a variable speed controller
allowing the spindle to be run at anywhere between 1 and 3,000 rpm
I knew immediately the
cables would not be long enough so I
soldered on some additional length and
then set about testing the spindle to
make sure it worked well
and it did!  amazingly well in fact I did have some
trouble with the connections partly
because the PSU labels were in Chinese
but this was nothing a quick google
couldn't fix
I needed to know if the old 3D printer still worked after all it had been an damp shed for a few years
brilliant!
It sort of works and the print that recognizable
It's the old logo from my old makerspace so make it probably needs
recalibrating but I didn't bother with
all that because I'm about to completely
reconfigure this machine plus I admit I
was a little intimidated by the tiny
whirring of that I'd need to deal with
*Captain America* It seem to run on some form of electricity...
for now I'm gonna run the spindle in isolation at a set speed
using the provided power supply and the
speed controller rather than doing
anything clever like letting the
electronics handle the speed just one
less thing that can go wrong the glass
print bed is great for holding down a 3D
prints but the idea of a rotating
carbide end mill crashing down on it
scared me a little so I knew this had to
go look at that it's just an Ikea mirror
tile this thing is pretty sophisticated
now I got rid of it and replaced it with
a bit of plywood where so it's cheap
enough to cope with a few holes and be
replaced if necessary as well as being
fairly dimensionally stable
the extruder also had to be removed as
well as all the associated wiring like
the heater cables the temperature probes
which made things a little bit easier to
deal with now with the wiring
now the banggood spindle comes with a
nice mounting bracket which means I just
need to drill a few extra holes in the existing mounting plate
but I'm impatient and a bodger so I used some of
this awesome gorilla tape to make a
temporary mounting there looks proper good that
The firmware on this controller board is currently Marlin
As awesome as Marlin is it was designed
to run 3D printers and not CNC Mills
Ordinarily you would expect something on
a machine like this to be GRBL, GRRBAL, GERBIL...
Whatever!  As there is no
longer in the extruder or hot bed as
well as all the temperature probes that
come with that I removed any references
to them in the code I used repetier to
drive the machine as that's what I've
used before on the 3D printer and I know
it works it's free and it's fairly easy
to use and for the first cut I inserted
a three millimeter end mill piece also from Banggood
I've not used any of their tool bits before but I have found
them to be great value on other stuff if
you don't mind waiting a little bit longer for them to arrive
So I've got high hopes
Some scrap pine was stuck down to the bed with carpet tape
and I love this stuff; carpet tape
I mean it's double-sided cheap grips
really well not so well that you can't
remove the stuff afterwards
okay what could go wrong I thought
what happened there?!
What happened there was my steps per inch was off easy to
fix in the code let's try that again...
Seems to work okay
I used a ESTLcam to generate the
toolpaths as this can generate some
Marlin compatible G-code and again it's
free and easy to use now let's cut out an actual design
Oh No!
oh dear oh!
Okay I'm giving up on the ramps
I really wanted to make this work
with the printers existing electronics
and it kind of does it's not easy to
reconfigure however and the software
I've got loaded is about five years out
of date
I could probably muddle through but
there's an easier way
I ditched the ramps board and the Arduino and switched
to this it's a dedicated CNC board that
runs the latest builds of GRBL it
runs 3 axis and of course it's
available from Banggood so again I
popped a link of where you can get it in
the video description below I made a
simple plywood mount for the new board
wired on some standard connectors then
it was just a simple job of wiring it
yeah bear with me okay I'll try this
later easy this connector just goes here....
there we go
the flex in my tape mounted spindle was
pretty bad during that though so I
should probably make a more serious
mounting bracket now that's a bit of
walnut so just suffice just measure it
up cut it to size and drill some holes
fantastic that looks a little bit more
professional
I could almost give this thing a fancy
name and launch a Kickstarter!  Brilliant!
let's see if I can cut out a
recognizable shape it made sense to use
a shape I'm familiar with so I used the
makerspace logo again but I scaled it up
a bit so you can see the detail with a
3 millimeter bit because I didn't
have anything smaller than that at the
time I thought some line wood would be
ideal for the first cuts because it's
fairly soft and I made sure it was a
little bit extra secure in the bed this
time
wow we have a recognizable cut that's
not bad at all I switched from ESTLcam
to the Inventables Easel as it's
free and really easy to use I mean look
at this, I just picked what material I'm
using tell it how big it is add a
pattern or something I want to cut to
the depth and it just generates my tool path
I also switched to something
that's designed to run the CNC;
The open build control software again this is free and really easy to use
oh and you can control your machine with your phone
too which is pretty cool
I just move my spindle to a reference
point say the bottom left corner of what
I want to cut just at the top set this
to my home position and then start our cut.
I tried something a little bit deeper
this time a simple smiley face
brilliant!  Time to take it up a notch and do a stamp now I use this rubber that's
specifically designed for laser cutting
stamps and stuff... and ...
oh well that might have been the problem
It's for laser cutting and too soft so I tried
something a little harder; linoleum and
that seemed to work great for making a
working stamp
next on the list is acrylic not bad I
mean the bit sort of melted its way
around rather than removing chips that's
because I was using a cheapy dremel bit
and that you know I needed something a
bit more suitable
Happy snowman!
now the final test aluminium or aluminum if you can't spell it the proper British way
wow that's cut a bit of a weird step
feature there not sure what happened
it's not missteps or slip belt surely as
it's not replicated over here if you
have any other ideas of what happened
there let me know in the comments but it
cuts so I learned loads of making this
thing for like cats and Engraving it's
actually a really useful machine but you
can see from the wobble it's not
suitable as a serious CNC now I can say
the spindle does not need to be changed
this thing's pretty good for a small
machine banger do more powerful ones as
well if you need it I bet I could make
this thing better
I mean maybe just add some more powerful
motors change out some of the plastic
parts for something more rigid change
the belts for lead screws and maybe just
design the structure redesign a
structure overall to make it more rigid
but no I'm not even that crazy when you
can just go and buy a fairly well design
little machine for about 150 pounds or
200 dollars
so big thanks again Banggood for all the gear I've really enjoyed this project and I have a useful
machine to show for it and thanks to all
my patreons Lily Allison, Jamie reader
Peter Millard and if you want to support
this channel consider signing up there's
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and the more people who sign up the more videos I can do
Thanks all!
