A story about a small CNC millingmachine.

I always wanted to build a computer controlled milling machine.
Just to make some small stuff. So I started off last week.
Procedure one, was searching internet and discovered that there are a lot off people into CNC !
And a lot of problems too !
Still  found some nice looking machines.  Loved the site of mr Kleinbauer , because he uses low cost stuff .
Getting some cheap steppermotors was  the hardest part.
Finally found a few very old HP printers, you know, the ones that have some real steel parts!
Then looking for some scrap in my workshop and  the dimension of  the machine was a fact.
So  it bacame a small one, thats ok. because I build one first then optimize it.
After that we are going for the real thing!



Ok first  some bearings.
found a pair of old inline skates supplying me with 20 of them.

bearings

To adjust the guiding rails I used a piece of corian, a material that is
easy to work on.

corian

The main parts are made of  MDF.
I soaked the parts in  thin epoxy so they became
very hard. If  used in the right way its pretty strong material.

mdf1              mdf2
parts


The anti backlashscrew is made of a piece delrin.

delrin                 delrin2

For this first machine I used  metric standard threaded rod.
Not the best but it was in stock and  it works

rod

Now putting it together.
Actually the thing  is running very smoothly !
I made a little corian handwheel to play a little around.


wheel               portal
assembly               base

Then came the Z-axis.  found a  pair of  smal slides
from a drawer. With al little bit of aluminium, delrin and
a few hours fooling around I came up with this.
Not perfect, I know, but it will do the job.



To get the whole thing a bit accurate  I decided to
make the working table (Y-axis) mobile.
So the X-axis portal screwed to base constuction, the
whole thing is quite rigid.

z1           z2
z3           z4

Then spraypainted everything, and put it together.

In two days  the hardware was finished.
A friend is now working on the drivers for
steppers.


m1             m2
m3              m4

For converting DXF to G -codes  I'm thinking of
using K-cam. Now thats a nice little program.k


 Ok so far step 1..... the making of




Now step 2.... getting it running!

First I have to say that it was impossible for me to do the job without the help
of two of my friends.
They get all the credits for the  electronic side of the job!
And of course the overall  research and survey




I bought a stepperdrivercard at CONRAD electronics.  The SMC800 board.





Three weeks have passed, stepperdriving realised and some minor adjustemts have been done.

After the fiirst testrun the y-axis steppermotor overheated.
To small!!
Searching the internet I found some cheap motors and decided to take the chance and bought them.



They were only 2.5 euro a piece.
After they came in  we found out they were unipolar, fortunatly  they could be opened and we rewired them.!


Now I had some reconstruction to do .
Refitting the motors, making some new couplers.      
Again a frew hours of work, but with a good result.            




Moment of truth arrived, milling a few rectangles and circles in a piece of MDF.  Eureka it worked !!!



A little scaling and some other minor adjustments and we dicided to jump into deep water!
We took a .dxf file from our logo converted it into G-code ............
The whole thing is running very smooth,  take a look at the first results.




some more pics.



           
Here we are trying to make a circuitboard, but we did not have the right routerbits to do
the job.
We first have to cover up the electronics!
Motors and electronics do not produce very much heat.
After an hour of milling the motor  remains slightly above roomtemperature.



 

   
First attempts for some inlay work.
pocketmilling the letter H, then the inlay in another material.



         
   It fits!
Here is a little video.
I started working on the second machine upgrading some  weak points from the first.
Remember, the first one was entirely made off scrap material !

The second machine must be a reliable one and easy to work with.
The main occupation will be simple engraving- and inlay work.


To be continued........

OK here is the second machine !!


questions?   mail me at  emey@wxs.nl
last update: march. 30   2006

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