Anyone had a crack at DIY CNC machines?
I'm currently planning out a CNC mill for doing circuit boards, and aluimium pieces. The majority of the costs so far have been in bearings and ball screws($350 a pop!) and you need one of them for each axis.
Once I start building, I'll probably document my particular project if anyone is interested.

you have far too much spare time

x2

but id be interested, definately!

Get it to work alloy billets and come talk to me..

The days of sniffing Ammonium Persulfate will be gone!!!

In true Bob fashion, 5 months later I've finally gotten around to doing some work on it.

The Z axis is almost finished, just needs a bit of timber attached to the small piece at the front to mount the spindle to, and some bits on the side to make it a bit more rigid.

Tomorrow's job is to finish the Y axis which holds the one below, and then start working on the bed. I'm waiting on bearings though which were ment to be in on Friday!!

Making this is harder than it first looks. Jigs need to be made to make sure things are perfect, as even half a mm out, and the thing will be horrible for manufactiring things with.

If this all works to plan, I'll use it to mill parts for a new one, out of 10mm aluminium.

Nice
I run and program DMG 5 axis cnc lathe and a 5 axis cnc mill at work.
What program are you going to use to generate iso code or are you going to write the programs ya self ?

Mine runs off G-code.
I havn't explored it heaps, but I have something that converts my Eagle (pcb cad software) to g-code which is the main thing I am building it for.

Yeah Iso is G-Code should be good would like to se a little vid of it in action when its done.

When being the key word haha. I'm off to Europe in 3 weeks for a month, so hopefully when I get back I can finish it.

Hey Bob...




...Any news?

I have to finish off one more axis and the mechanical work is done. I finished off the table yesterday so it's just the gantry that has to be built.
It's actually starting to look like something finally!
The project got held up a bit with regards to bearing holders but I have since made them up and have slowly been progressing with it

I just went and took these snaps. It's a little bit dirty from greasy hands so it will get a good sanding once it's finished and then a clear applied over the top.




And the u-beaut bearing holders for the ball screw. These had to be machined to tight tolerances else the bearing will get crushed when being pressed in, or they will be a loose fit if the sizing isn't right
Ignore the surface rust.

Looks good Bob, I just thought about it today when i was googling DIY Panel Saws (yep i want a panel saw) and I came up with a few DIY CNC sites

I was only just looking at some DIY CNC's on Youtube yesteday and remembered seeing someone building one here. Good to see you haven't given up!

Have you chosen your stepper motors yet?

http://www.oceancontrols.com.au/motors/ste...pper_motors.htm
MO-102 Stepper Motor - 23HD601
With almost 1N.m of torque (0.98N.m or 138oz-in) this motor is a great performer with a rated current of only 0.6A. Suitable for small CNC machinery.

Features
• Rated Current: 0.6A
• Step angle: 1.8deg
• Ambient Temp -10 to 40degC
• Temp Rise 85degC
• Dimensions: 56mm x 56mm square face, 56mm long, 47mm between mounting holes
• Weight: 0.62Kg

They are the ones I am planning on using for the X and Y axis. I only purchased one for now to see if it is suitable and if so I will buy another, or upgrade if needed.
The z axis is using a cheap one I found on eBay. That assembly has enough torque to hurt my hand a fair bit when I get it caught in the slide lol. But I will see how it holds up.

As for giving up... I have come close. I have found a mill I like for $1500 and was thinking of bolting up the stepper motors to it, but I have gone this far I might as well finish it!

*subscribed*

very interesting - looking forward to a finished result

what are you going to use to control it?

is there a control unit you can buy that plugs into the PC or do you need to make one

Great thread! Cant wait to see more progress, keep up the good work Bob.

You can buy ready to go boxes Dogo. Dont know what Bobs doing though from memory I think I remember him having bought a controller.

Machinery design isnt easy Im finding out just doing something simple like a panel saw so I cant imagine how much work goes into something like a CNC machine!

I started building my own stepper controllers but then found a kit from Oatley which would do the job, and was less hassle. My original design was going to do half step and all that crap, but I didn't need it.
Oatley have everything - the parallel port interface (I made my own though), the constant current power supply modules, and the stepper driver boards.

Have you got a total cost so far

One ball screw I got given to me (score! - worth approx $300)
The other 2 ball screws I got for $150, and $50(for the tiny one) off eBay. Small stepper motor was $12 off eBay, larger one was $80ish?.
Linear bearings were $150 inc pillow blocks
Angular contact bearings $48 for 4
Radial bearings $40 for 4
MDF under $40
Stainless steel rods free
Control gear will be another $150 or so I think

Bob's back for 5 mins

I know some of you were keen to see how the CNC was turning out, so I thought I'd keep updating this thread as the project continues.

It's starting to look like something even more now. All that is left is to bolt the rails up to the y axis, add some more reinforcements, and then the mechanical side of it is complete.

Was very keen to see how this turned out, something i'd like to give ago myself one day

And there you were saying you'd never return to us

Looks good so far.

Awesome. I want to see this make something!

this looks awsome. dont wat to think how much time must have gone into that.

what sort of things will you be able to turn out on a mill this size?

"subscribed"

Wow Bob, the CNC is the sex! interested to see how it turns out and what it can do!

"subscribed"

Going by the start date of this thread you could be waiting a while for up[dates to that subscription

Seeings as how Bob hasnt been on CAA for the best part of 3 months with no intention of returning, good luck seeing any updates.

He was on yesterday (when he last updated), and my impression is that he will return to update this thread as the project progresses.

Who knows

Hooray for actually reading threads

It may be taking a while, but it's getting there lol. Today we finally mount the Z-axis (which is the assembly shown at the very start of the thread), and the bracing will be put on the uprights. From there I can get around to mounting my stepper motors and making up the controllers for it all.
I had a slight accident with the Z axis - it fell off a 2meter high shelf after I didn't sit it there right. It looks like one corner only got slightly damaged, and everything is moving, but once I finally get the machine up and running, I'll use it to make up a new Z axis.

If this works, and it all works well, I'm looking at making one from 10mm thick steel or aluminium, but reducing the X axis (the long one) travel by half.
Enough talk, here's a couple of more pics from Friday's work.

looks great bob, can't wait to see some of the stuff you'll be making with this

The Z-axis can twist towards the front and rear on its rails, so just have to make some supports with bearings to eliminate that. Other than that, just waiting for the couplings to turn up, then I can bolt the steppers on and start making it move.

it looks the sex Bob. what are you gonna get it to do first once finished?

Mill the table flat to fix up any of my stuff ups... lol

LMAO no plans to set it up go go into small production runs making more of these to sell to others?

BTW good to see ya round Bob

It's taken me two years to make one for myself, let alone for other people haha.

Cheers mate, still won't be around here much, just every now and then I'll have a flick through some posts and any updates to this thread. Wouldn't mind turning up to a meet some time soon to catch up with a few people though.

Wow just discovered this project. What software/ hardware are you using to control it? I'm most curious on how to achieve it on a small scale. (I'm training as a cnc tech)

Well, here it is as promised.




The power supply without it's top, I still need to put a big fan onto the case so I'm just waiting for that.


The stepper motor controller


My first project . You couldn't wipe the smile off my face as it was going. I tried out the same code but with a pen instead of a cutter, but today was the first time the cutter got bolted up.
For now, I'm just using that flexible shaft adapter thing that came with the Dremel, just to see how it all worked. I will be mounting the Dremel direct onto the axis though.
I still have to machine the table flat, as there is about 1.5mm variation across the whole lot. That can be seen to the right of the logo I machined into the timber, that it isn't as deep on that side.
A back board still has to be put on the uprights as well, for some extra support.

that is awsome, now you have to show us some of the stuff you have made

you must be a very happy person

To say I'm impressed would simply be an understatement!

Well done bob!

Well, the machine sucked. The idea behind it was alright, but the flexing in the rails was too much. It was simple to overlook, as we thought using a 20mm ball screw would keep it stiff, but we forgot to take into account the twisting the axis could do around the ball screw.

So anyway I ripped half of it apart and rebuilt it.



Under the ball screw you can see the timber mounted, with some stainless steel rods attached. For the bearing material I used HDPE (chopping board material). This is along side with the existing rails with linear ball bearings.

There is still a bit of movement in the axis which results in a .1mm variation in the middle, compared to the ends.
This is unacceptable so I have bit the bullet, and purchased precision THK linear guideways. Ebay is the best source for this kind of stuff as you get it from surplus retailers at a considerable saving.

I am also replacing the ball screws. They are both the rolled variety and their accuracy varies by .05mm over 300mm. They also suffer from backlash (slop in the ball nut that requires the screw to rotate x amount before the nut moves). This can be dealt with in software, but I'm going for precision.

Again, ebay is the source as ground ball screws with .07mm variation over 300mm with minimal backlash (under .01mm) are incredibly expensive brand new.

Another problem with using MDF is it absorbes moisture from the air and expands and contracts. The varnished stuff won't, but the rest will.
I'll be using extruded aluminium like this
Anyone have a source for that by any chance? Best I have found is $76 a meter for 40mm X 80mm.

My goal with the new machine is to have accuracy within .01mm so I will be going a bit smaller (200x200mm working area)

There is also .15mm of runout (how far from centre it spins) in the dremel shaft, so a home made spindle is on the cards also.

I'm confident all this can be done for under $1000. The first machine though is great as far as learning things. I have learnt a heap with regards to automation, accuracies, mounting methods, etc.

Also made my first circuit board with it on the weekend. Watching it drill all the holes was the best, no more squinting in front of a drill press, trying not to break a .8mm drill bit!

Here is what I am aiming for

This blokes website has inspired me not to settle for 2nd best and to just do it all properly. http://www.5bears.com/cnc.htm

Stay tuned!

Awesome work as usual Bob! glad to see you keep coming back with updates for the happy viewers. it looks awesome. good luck with version 2.0

wow, what more can i say, what a project. Looks good, good luck with the next one.

Man I cant for the life of me remember what the extruded aluminium section is called.
Great for making AV racks though - one of the guys I used to work with loved the stuff.

http://www.linearbearings.com.au/Products/...92/Default.aspx

Linear bearings sell it - but I dont know a cost on it

its called ITEM

Edit : just been told by a mate I used to work with the ITEM (pronounced IT-EM) is a brand the product is normally refered to as "engineering mechano"

ITEM is (or at least was) the brand sold by linear bearings and is supposed to be one of the better brands

You're the person I had in mind when I made that post haha. Cheers mate.

I've sent them an email to see what sort of price they can do. This is the place I originally found it from http://www.robotunits.com/start_frameset_au.htm.

Bob send me a PM if you want. The above mentioned mate has said if he can help in any way he will. He has a LOT of experience in design of machinery and use of CNC mills and said that your project sounds like an interesting one

... WOAH! Im astonished. Best to you & this project. I have nothing to possibly contribute.