Homebrew PCB CNC machine 4 less then £100 is this possible??

[jomac]

Yes its very possible..

I posted a couple of comments on another topic about easy PCB making. I had gone through all of the other options, toner transfer and a couple of dozen different types of glossy papers, wax transfer sheets and others without much success.

About a year ago, a friend showed me a CNC machine he had built around a hobby milling machine, to say i was impressed, was an understatement, hooked was nearer the mark, here was a system that turned out cheap PCB's without chemicals, etching the kitchen work tops, tee dyeing your best shirt or burning your fingers, i had to know more, and set about my own.

There are 1000's of sites on the web for home made CNC's, all done a different way, using different parts, software, electronics etc. For a while it was a bit of a learning curve, but i soon got the hang of it, and finished up with a machine that not only does PCB's, but mills metals, engraves, cuts holes in panels and is invaluable in the workshop.

Since then, ive built a second CNC milling machine, ive CNC'd a small model lathe, ive built a vinyl cutter/plotter and toying with the idea of making a 3D printer.

So whats the common factor between all of these different machines? Simply pretty much everything, same electronics, same motors, same software, just the actual mechanics that you make is different.

The opening line was can it be done for less then £100, and the simple answer is yes! On another website (alas now defunct) I started a similar topic, and over 60 machines were built in assorted shapes and sizes. None of the parts are special, the 'engineering' bits came from cheap hobby shops, and the electronic controller from Amazon. Depending on your junk box, the average price was around £79. Quite a few CNC used nothing more then cheap MDF for the frames.

Recently, i discovered a source of small geared stepper motors, with the driver board from China, via Amazon for just £1.52 each, bringing the possibility of a cheap small CNC down to about the £30 mark.


IF....there is enough interest, i could start a similar topic here for making a homebrew CNC. WHere to get the bits, sources of free software, and general help to get going.

Im not saying im an expert in this field, but once i had made the first one, and things fell into place in my mind, i found out how simple and easy it really was with just basic tools and a bit of time..

[smokescreen]

Go for it!

I started builing one about three months ago, I've made the stepper control board its based around three SLA7062M chips and have three nema23 motors.

I'm now looking into the mechanics and would be interested in what you have done. I was going to build something similar to the ZEN microsystems 12x12 one, but have been stuck with how to connect the table and gantry to the lead screws as the pictures don't seem very clear.

At the moment as I say all the mechanics are still just in the thought process, so I'm still open to other methods / idea's.

[kr0ne]

Yeah I'd be interested to hear more as well.

What kind of tolerances do you achieve?

BTW - I noticed in a comic that CPC stuck through my door recently, there is a 3D printer kit for around the 500 quid mark...

[jomac]

I did Google and looked for the ZEN microsystems 12x12 and simply couldnt believe the price of the basic mechanical kit...$680, let alone the fact that someone would want to part with this kind of money to get something that could be made for just a few £££'s..(http://www.amazon.com/Zen-Toolworks-Car ... uctDetails)

The frame on my first home build, and in over 60 other home builds used nothing more then ordinary 12mm MDF board for the frame. A sheet of which will cost less then £10.00 All of the joints were drilled before screwing, glued, and 90 degree angle blocks were used to add strength to the construction. Plywood can also be used, especially marine ply which is stronger then MDF, but tends to be prone to warping if it becomes damp, so many coats of varnish are advised to prevent this.

It makes no difference if the main support pillars to hold the vertical 'Z' axis is in the centre of the frame, or at the end of the frame like in the ZEN system. Its down to personal choice and looks. All that matters is that there is enough room from end to end of the frame, to allow full travel of the Y axis.

Most of the CNC's built were for a cutting size of A3 which is quite large, but the forum it was originally posted on, most of these machines were used for cutting the long frames for multi rotor or multi copter frames and arms.

Accurate drilling is a must, and access to a pillar drill helps in this.

Bearings and slide are pretty easy and cheap to come by, either from ebay of from hobbyist stores online for a £ or two each. Some stores even sell cheap kits with CNC builders in mind.

Apart from accuracy, aiming for very little slack or 'looseness' in all of the axis is pretty important too, although i must say, that in most decent software packages, slackness or backlash can be programmed out and be allowed for.

As long as you get your dimensions right, for the size of cutting area or table you want, how you do it, what style you make it in, is purely down to personal choice and build.

[jomac]

Yeah I'd be interested to hear more as well.

What kind of tolerances do you achieve?

BTW - I noticed in a comic that CPC stuck through my door recently, there is a 3D printer kit for around the 500 quid mark...

If its the same as the machine that Craplins sell (Maplins) and also Rapid Electronics in Colchester which it is (just Googled) Its the very expensive kit made by Velleman.

A friend of mine who helped me a lot with my first CNC build, and still gives advice is an expert in the CNC field, having worked in this industry for over 30 years. He took the Velleman build instructions and the comprehensive parts list and with the exception of the electronic controller, (which is a custom velleman board), sourced and priced each part of the velleman 3D printer. He then added a generous £50 for a controller from Amazon, and the shopping list came to a little over £200. A heck of a difference from the Velleman price.

Lots of manufacturers rely of the fact that you dont know what you are doing and that you know nothing about the subject and therefore charge high prices for your ignorance!!! In reality, there is nothing complex to these machines, and the only skills required is a sound DIY experience and a good eye for detail.

Many of the people i spoke to, who made their own CNC's said afterwards...'Is that it, is that all there is to it, i didnt realise what all the fuss was about!'

They are simple machines to make, and to set up if you follow the basics, and shopping wisely will bring the price down to under the £100 mark.

As for tolerances, ive worked very easily down to 0.2mm and did an engraving of road runner that was 2.5mm high which looked the same as a larger one done 50mm high. The software and steppers support measurement down to 0.0001mm but i seriously doubt that the machine would achieve this.

[kr0ne]

That's pretty impressive!

I saw the Velleman kit in a Chrimbo mail shot yesterday but didn't really look at it. Just a co-incidence...

This is something I've always told myself that I will have a go at one day but have never really looked into it seriously. I'd love to see some pictures of your build.

I have some fairly high powered IR laser diodes that I've always wanted to CNC in order to etch front panels etc. I always figured I would end up using bits of old inkjet printers, so started chucking these in the junk box whenever I replaced any. Needless to say, I've never got any further than that though.

[jomac]

Just to Reply Kr0ne with a little cut and pasting...

..."I have some fairly high powered IR laser diodes that I've always wanted to CNC in order to etch front panels etc."

Ive looked at some of the 20 to 40 watt lasers from China with a view again to do PCB's but various factors in the end put me off, I did some experimenting along the engraving route with some pretty impressive results, but for front panels i was most impressed with 'reverse engraving'. This is where you take a piece of suitable plastic, give it a very thin coat of spray paint you want the main body of the panel to look like, then engrave your design or lettering in reverse onto the paint. Clean up the engraving with a toothbrush or similar, and then using enamel paint, paint in the lettering in any colour or even multicolours. When dry, fix some double sided tape to the painted side for fixing onto the equipment. Looking at the other side, you see a high gloss plastic finish, with the lettering almost 3D like against the main colour. When i priced up commercially 3 sample panels of 300mm X 100mm, the cost came to more then the cost of making the machine. The bits i use are standard 0.5 to 1.0mm drill bits for PCB drilling.

I constantly monitor our local freecycle website where people give away printers, often there are no takers as the ink costs more then the printer. I salvaged an HP1200 series all in one machine, which is a square box like printer scanner. This ive saved for a rainy day to convert into a PCB drilling and milling machine. The scanner part will be the 'X' axis, the printer bits used to make the 'Y' axis and other scrap bits for the 'Z' axis holding a quick release mount that takes a 'Dremel' style drill.

[Techquest]

Count me in
I have had this on the back burner for some time now.
plan to use a old flatbed scanner as the bed the base is folded steel plate 3 to 4mm . and recycled guide rails from printers.

[jomac]

Well its deciding now which way to go and how to shape this, what do people want, do they want plans for a complete build from the ground up, or guidelines for modding something they already have?

[kr0ne]

How about some photos for a start?

Got any good links? Had a quick look at http://buildyourcnc.com/ but they seem to primarily trying to sell pretty expensive kits although there is some info as well.

[jomac]

Pics, no problems, although most are on my dead desk PC, so i will have to pull the HDD, ive plenty of the modded model milling machine i converted, and thats undergoing a major rebuild into a custom frame/stand with dedicated PC and inbuilt monitor. Ive some of a wooden framed CNC i did, made from MDF...let me have a dig around.

[Techquest]

Its probably safe to assume no one has done this before so from the ground up would be the way to go.
choice of materials ??? recycled printers/scanners for guides steppers etc which i think quite a few of use probably already have hoarded away (for that OH that might be useful some day )that never seems to arrive.


lets go make some mistakes and learn

[jomac]

When i first set out to make a CNC from scratch, i viewed the whole scene as some sort of magical art. I knew the basics of how they worked, and that was it. Like many, i thought a CNC was a little too technical, and a bit beyond me. This is the view many people have, first of all, its not a magical art, its basic mechanics, and most of that is woodwork. The electronics side is off the shelf and plug & play, it can be as simple or as complex as you wish, prices for the stepper motors, range from about £1.50 per motor to under £30 for a fully featured 3 axis controller.

Software to drive a CNC can be found all over the place, a lot free and in versions to suit all tastes. The two main contenders, one is windows based and is called MACH 3, a demo version can be found here...

http://www.machsupport.com/software/

The other is Linux based, and is called LinuxCNC, that can be found here...

http://www.linuxcnc.org/

Ive tried both versions, and both versions have extensive video tutorials which can be found on youtube. At the end of the day, i settled for MACH 3 as it seemed easier (for me) to use and appeared more flexible then the Linux version.

What started me on the trail of making my own, after seeing my friends CNC in action, was a CNC project called the Mantis 9. When i looked at it, i couldnt believe that a lump of wood, with basic electronics could turn out precision parts like it did. The Mantis 9 project was part of the MIT university sponsored scene in the states, where all sorts of CNC's were made using pretty much the same basic technology. The Mantis 9 project was made out of wood and can be found here...

http://makeyourbot.wikidot.com/mantis9-1

And further reading at the MIT's website can be found here...

http://mtm.cba.mit.edu/

I found a video on youtube of a home made Mantis 9 in action, this was a first build for a guy and was the first testing as well...

http://youtu.be/M8F4tn_b76o

Another 'wooden' build for under $100 is posted here...

http://hackaday.com/2010/06/21/100-cnc-mill/

My first CNC was made from MDF, steel tubes, aluminium blocks and threaded rod. It didnt quite go the way i planned, i'd made a few mistakes, but it worked, and had an accuracy of about 0.2mm which wasnt quite enough for the small PCB tracks i wanted to mill. This was ebayed (and fetched a silly price.. ) and the funds put towards the second one.

[jomac]

My first CNC as i said was made from MDF, and this is what it looked like.

I had made a measurement error and the Z axis motor jammed on the top of the frame, so i had to mod it..

[jomac]

The next machine i started, i cheated a little, and bought a second hand mini milling machine, the Proxxon MF70. I did a couple of mods to increase the milling area size, but the basic conversion amounted to just adding 3 stepper motors in place of the 3 small hand wheels.

http://www.conrad-electronic.co.uk/ce/e ... archDetail

The controller board was bought from Amazon as i was in a bit of a hurry, otherwise its under £30 via the slowboat from China, this board is extremely versatile, and i would highly recommend using this in a CNC. Its featured in many websites, and there is a lot of support for it...

http://www.amazon.co.uk/TB6560-Stepper- ... Controller

Note...This listing is for the full kit and not just the controller board, the seller i bought from has the wrong picture on their listing, but this is the controller and some of the options you can add to it.

This is my modded CNC which has an accuracy of 0.05mm (measured)