Cnc 3018 Upgrade with a 500 W Spindle Motor

Hello, welcome to Techydiy. In today’s video, I am going to upgrade the spindle
motor on a 3018 cnc machine, with a more powerful
Machifit 500w model. The 3018 machine that I am using
is a basic model from Banggood that I reviewed in a previous video It has a grbl controller and a 24 volt dc spindle motor. The new spindle motor cost $70 It was delivered packed in foam and it was supplied with a power supply and an aluminium clamp.

The spindle is air cooled
with an external fan It has an ER11a chuck and a 3.175mm or 1/8” collet. The spindle motor body is
52mm in diameter 208 mm in length. And it weighs 920 grams. Its considerably larger than
the existing spindle motor, so, the z axis on the 3018 machine will
need to be modified to accommodate it. The power supply is a chassis type. It has an input of 110 – 220v ac and a variable output of 0 – 100v dc.

A potentiometer sets
the output voltage and this in turn determines the
speed of the spindle motor. These are the connections
on the power supply, but before we wire it up,
let’s have a look inside The mains ac power is connected
to the top two terminals with the live input
protected by a fuse The ac is rectified by
a full wave bridge And the dc smoothed with
an electrolytic capacitor. There are two components
bolted to the chassis, which acts as a heatsink Firstly a UF460L, which is a 500 volt, 21 amp N channel power mosfet and secondly an U860G,
600 volt, 8 amp power rectifier. Plastic film is used to electrically
insulate them from the chassis. The rest of the components make up
a switched mode power supply circuit. The dc output is available from
the third and fourth terminals The fifth and sixth terminals are used
to switch the output on or off The little blue preset pot sets
the maximum output voltage And the green connector is used
to connect the potentiometer,
which controls the output voltage.

The back of the pcb has some flux residue,
which I am going to clean off
before reassembling the power supply. Next, I am going to test the spindle motor, A power cable is wired up
to the power supply terminals. There isn’t an earth terminal,
so I am connecting the earth
directly to the chassis. The spindle motor is temporarily
mounted on a piece of wood and connected to the motor terminals
on the power supply. I have got a multimeter
measuring the output voltage And with the power turned on, the potentiometer is turned
to the maximum setting As expected,
the maximum is 100 volts. The way that I am going to connect
the spindle motor to the grbl controller
is with a relay. This will allow the spindle motor
to be automatically turned on or off
under program control. The coil of the relay will be connected
to the spindle motor output socket
in place of the existing spindle motor.

The relays switch contacts are connected
to the power supplies terminals and this allows the grbl controller
to switch on or off the new spindle motor. To mount the relay, I have designed
a simple printed circuit board using eagle, which I am going to mill
later in the video. Next, I am going to remove the
spindle holder and dismantle it so that I can take
some measurements. The new spindle holder
is going to consist of a pair of 6mm acrylic plates bolted together with spacers. I created the design for
the plates in easel and you can find a link to it in
the video description. The new holder also uses
four flanged linear bearings and a leadscrew with
an anti-backlash nut. Next, I am going to reassemble
the 3018 machine and while I am doing that, I am
going to make some improvements. The first is to install thrust bearings
on the stepper motor shafts.

When I previously reviewed
the machine, I found that the stepper motors
had quite a lot of play which affected the
machines accuracy. To fix this I am installing
a penny washer and a thrust bearing on
each stepper motor shaft, sandwiching them between
the stepper motor body and the blue shaft coupler. The penny washer is there
to stop the thrust bearing falling into the wide shaft opening. The second is to turn the
spindle holder upside down. The reason for this is that the spring in
the z axis anti-backlash mechanism normally pushes the
spindle holder downwards. When the end mill hits
a hard surface the spring compresses and takes up the play
from the leadscrew, a little bit like
a shock absorber and that makes it quite difficult
to accurately set the z axis height.

By turning the spindle holder
upside down the spring now pushes
the spindle upwards and eliminates the small amount
of play from the leadscrew. I am also adding a very simple
air-cooling attachment which is just a pipe and a tube
connected to a compressor. This is attached to the
mounting threads on the bottom of
the spindle motor. Ok so now let’s mill
the printed circuit board. I have loaded
the jpadie workspace from the Chilipeppr website And run a serial port
json server Drop the eagle file
into the workspace and after a few changes we
are ready to run an autolevel I am using mitre adhesive
and painters tape to attach the blank pcb material
to the spoil board The probe leads are connected to
pin A5 and ground on the controller Then I run the autolevel, which uses the probe to measure
the surface height in a grid and modify the gcode to account
for surface height variations Next the pcb is milled
using a v bit And the holes are drilled.

Now we can cut
the acrylic plates. I am using a two
flute 3mm bit, With a 200 mm per minute
feed rate 120mm per minute
plunge rate And 0.5mm
depth per pass. I am using 6mm thick
cast acrylic sheet, leaving the protective
backing in place and attaching it
to the spoil board with mitre adhesive
and painters tape. It’s important to
use cast acrylic, as extruded acrylic
is difficult to mill. To send the gcode
to the machine I am using candle. Next, I am going
to manually countersink the four mounting holes
for the anti-backlash nut. The countersink bit requires
a larger 6mm collet And I am just using
the jog keys to find the right depth. The next job is to remove and dismantle the spindle holder I am going to make
a new spring to replace the one supplied with
the anti-backlash nut. This will allow me to adjust
the strength of the spring to properly support the weight of
the new spindle motor.

Now, we can assemble
the new spindle holder. Now we can install the
spindle holder into the carriage Reinstall the stepper motor Slide the whole assembly
back onto the rails Plug in the stepper motor cable And check that the
axes operate correctly. The power supply and
the spindle motor are connected with a cable And then the spindle motor
is tested by turning on the power and changing the
potentiometer setting. Next, the components are
soldered onto the pcb. A length of cable is soldered to
a dc barrel connector, And the other end is connected to
the pcb input terminals.

The cable is plugged into
the controller And the operation of
the relay checked, by turning the spindle
on and off from candle. A second cable, connects
the output terminals of the pcb, to the on/off terminals of
the power supply. And finally, with the
power supply switched on, the spindle motor is tested. Ok, let’s try it out. I am going to cut out
a hose adapter from mdf using a 3mm 2 flute end mill. Next, I am going to cut out
a bracket from 1.5mm aluminium sheet using the same 3mm
2 flute endmill.

And finally, I am going to resurface
the spoil board using a 22mm surfacing bit. Overall this has been a very
worthwhile upgrade to the 3018, it now cuts much quicker
than it did before. I will leave a link to the parts and
the design in the video description. Thanks for watching and
I will see you again next time..

As found on YouTube

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