CNCMV1a

Computer Numerical Control or as abbreviated to CNC has been an interest of mine since my youth.

To simplify what it relay is, a computer driving a machine doing something that requires accuracy. The device could be a router, a laser or the most recent popular, a device melting plastic to build something (= known now as 3d printing).  

For a guy of my age that grew up while the first PCs were made available to affordable prices, it was a dream to be able to do things with a computer that now are considered for granted.

There were no internet back then, only a a few BBSs (Bulletin Board Systems) that you had to call by dialing a phone line. The speeds of downloading whatever you could find at the time (shareware) were down to 300 bps (my first modem that later was replaced by a 1200 one, then 2400, then 13600 and last before the internet era to 33600 bps).  A 20MB hard disk was enormous data saving space (and I paid for my first one a month's salary!).     

To stop my ranting, I have been trying for ever to build myself an affordable device that would help me in my scale modelling and here are my adventures!

The beginning

CNC Router

My early stages with CNC were to create a router so as to be able to cut balsa strips for my radio controlled scale planes. 

Back then in the 90's, parts were not that easily available, they were extremely expensive and knowledge around them was safeguarded as a state secret. Gradually on-line discussion groups related to CNC and CNC routers started sharing plans, technical information and programs to drive step motors with the accuracy that the hardware could provide. 

On the picture on the left you can see a CNC router very similar to the one I built with mdf on the balcony of my house in Athens! Photos of the original probably not saved or not yet found. 

Building the router

This is how I built the rouher in the balcony of my house in Athens. Mdf sheet was cut with a circular saw to size and then the hardware was installed with stainless steel bolts and nylocs.

Needles to say that to accurately square the damn thing was almost impossible and hours were spent in minor adjustments...

That was even more difficult since you has to do it three times (each for the three axis X,Y,Z that define a point in space) with all of these one over to another. 

I did manage to build the machine and install electronics bought through internet from one of the pioneers of the time who was called Routout CNC and still trading at http://www.routoutcnc.com/

After getting there, then the difficult next step arose which is still a challenge for many: design what the machine you want to produce which simply is the Computer Aided Design or CAD. 

Different programs, a lot of different schools of thinking, all of them requiring devotion and endless hours of learning. I still try to improve my skills to CAD having still not fully committed to one program... 

This is the X axis module and on the sliders you see on the two rails the module of the Y axis was standing. The movement on the axis was achieved with the lead screw in the center which was driving the brass nut that you see to move the complete Y axis module (oh that terminology - note to myself: I have to find the proper terms for these parts and replace them here).

Similarly built but smaller were the Y and X axis modules with the last having a cradle that was keeping a pencil when I wanted to draw something or test the device or my handheld router to cut the balsa wood.

When we moved to UK I had to scrap the device so as to save all the valuable parts to be used in my next device... 

2018: Next device

In May 2018 I took the plunge and bought myself from ebay a cheap diy kit of a Prusa I3 clone 3d printer. The kit is from CTC and I bought it for 95 £.  The reason for that was simple: I had to update myself on all of the developments in the field and enrich my collection of parts for my own designed device to follow. The risk of buying a cheap Chinese clone was affordable and a challenge at the same time.

The basic frame that forms the device

Immediately after opening the box, the first problem was apparent. The laser cut notches where the mdf parts of the frame hold together, were not true and a lot of filling was required in order to square them up. At least the file was provided in the kit...(sarcasm).

The frame is made from 6 mm mdf and then sprayed black. It has notches where bolts and nuts fasten it together but since it is soft wood, you have to be careful not to over tighten.

Anyway after some trial and error, the frame was assembled to a satisfactory result.

Problems already with the assembly
The screen module was installed
The step motors of the Y axis
The lead screws for the Z axis
Then the power supply and the ready made X axis module were installed
and the Z axis module

This is where all the fun started! In order to connect the step motors to the lead screws that move the Z axis module you are provided with pieces of pvc hose to use as couplers. In principle they are ok but of course there are two problems here. They are soft so they bend and get easily deformed, they stick and they are difficult to adjust in height. The later is not really a problem as you can square the Z axis module in height, but the softness of the material is a problem as you can get as I did the lead screws to sit of center the step motor shafts. And that moves the lead screws in an unbalanced way so when the module moves up or down, the lead screw touches abnormally the guiding holes of the top end and creates friction. A lot of, which stalls the movement of the module. A little research over Youtube found a temporary solution which was to cut off the part of the top end with the hole for the lead screw. I preferred to keep the originals and make copies on my scrollsaw without that part. Most likely I'll order some proper couplers to use instead.

Scrollsaw copy
A part missing here...
The top
It is working!

Now it is time to start calibrating and making fail-safe before actually trying to print and start designing my new machine with parts from my inventory... It will take some time but then again this is a hobby to be used for my other hobbies!

And with that,...until next time!

Update 21 May 2018

I have finished the initial adjustments to a satisfactory level although there are minor micro adjustments need to be made on the Z axis. I have had actually also my first two prints.

Ho track ballasting tool

As all my 3d printing involvement began after my model trains, it was only fair for the first time to be used for printing something relevant. If you google out there, there are dozens of banks offering free downloadable designs and I picked this one from thingiverse.com.

It went pretty well and the only thing to tell that it is not perfect, is the fact that I was absent after the first hour of printing and I run out of PLA filament as can be observed on the top sides of the device which are not closed.

Other than this, the device has been tested and works perfectly for what it was designed to do (=spread scale ballast the the rails of my model trains).

Ballasting tool top side
Ballasting tool - Front side

Side servo mount

This side servo mount is an useful device both for my RC planes and for my model train layout. I found it to the 3d print repository of rcscalebuilder.com and I have had it for some time in my downloads.

For this print I started trying different settings though Cura software and I settled to 60 degrees Celsius for the heating bed, 210 degrees for the printing temperature and 30 mm/sec for the printing speed.

As it has a big unsupported gap where the servo sits in, there were several sagging print lines to be cleared at the end of the print but the final result is fit for purpose.

The side servo mount
Start of print. Need to improve the first layers.
Print completed, now cooling off
Almost there

And with that,...until next time!

Update 27 May 2018

Again today I had a few hours available to play in my garage and of course it was 3d printing and model trains.

Today's project was to print a HO scale bus stop that I downloaded free from thingiverse.com . Well I did try a couple of times before I have a had an adequate result mainly because the heatbed was not properly leveled.

 

A deformation can be seen on the left side quite early on the print
This print ended early as the moving head detached it freom the heatbed.
On the top the first trial, below the second. It is immediately evident that something is wrong with the left side of the printing in both occassions.

After the second failure even earlier than the first, I realized that the heatbed was not properly leveled. After I made sure that the place the machine it self was sitting was level enough, I readjusted the heatbed and the third print was a success.!

Same settings: 210 Celsius in the nozle, 60 on the heatbed, 30mm/sec speed.
Happy with the result, just a small sprue.
Just a few sprues. Need to see how to eliminate them too.
The end product. Happy to have on my layout.

And with that,...until next time!

Update 15 July 2018

Oh, I did not realize how long it has been since my last update. Anything excited since? Not really. Having said that, I have been printing a few things, I have been trying to learn a few more things on designing, I have been experimenting with my printer. If only a day have had a few more hours...

Ho Scale container. The inside printing support can be seen removed.
Ho scale chairs and round table (to be assembled)
Ho scale Med type house and extension.
Tortoise key ring

All of these are free royalty designed parts mostly downloaded from Thingiverse.com and used on my learning experience by doing it, failing and redoing it!

Sometimes of course you get to learn the hard way some things like never - ever take out the filament from the spool and putting it back. It is more than certain that it will block itself and ruin your printing.

I have bought now a set of filler gauges and trying to achieve a better leveling of the hot bed. I have come to realize though that the soft wood used for the printers frame flexes enough to drive you crazy when you try to level it. Probably when I get the chance I'll try making up an aluminium frame to stiffen it up!

I have already started printing some parts to be used in future upgrades although I have discovered that PLA is not that hard to break! Possibly I need to try some ABS that I have been postponing to do due to the poisonous smell it emits when melt.

Y axis base and motor holder for a Prussa type printer
The same Y axis base, broken!

And with that,...until next time!

Update 16 Feb 2020

What is the saying: time flies? Obviously that is the case on how often I update the website. All the usual excuses stand: Life got in the way, this is a hobby not a job, etc, you get the idea.

SInce my last update I did tried to improve the CTC 3d printer and to a certain extend I did managed that. But what became apparent was that the cappabilities for creating tiny little parts usefull for train models were very limited. So I ended up on investing on a resin 3d printer and I bought my self an Anycubic Photon. It is almost unbeliebevable what level of detail you can achieve in very small parts although there are certain considarations you have to deal with. Among them obviously the hazardous materials (resin) and the laborious cleaning you have to do every time while not forgeting the uv radiation for curing the parts you printed.

Playground toys printed in resin printer.