Picaxe cnc

[Michael Gilligan]

Greetings,

As a new member of the forum, I do hope this is not "old news"

I have found an excellent project, by a Czech AeroModeller: He has converted a small Proxxon Milling Machine to CNC.
There is nothing particularly unusual in that; BUT he is driving the whole machine from a PICAXE and a VDRIVE2 ... Strictly speaking, [because it is essentially a dumb sequencer] the "local" system is probably more "NC" than "CNC"; but that does not stop me considering it a work of genius.

The system that he has devised would be easily adapted to other machines, such as; PCB Drilling/Routing, Microscope Stage movement, Panoramic Photography, etc.

The original page is in Czech, but Google Translate makes a reasonable job of converting the text to English.


I commend this project to anyone with an interest in using Servos or Stepper Motors [he has used both] ... But, as a novice, I would be grateful for comment from the forum's experts.

MichaelG.

 

[Roman505]

That looks more like a Proxxon hand-held tool on an MB140 stand than a milling machine, like using a Dremel on a drill press. I can see that what looks like the KT-70 X-Y table has been added to give mill-like functions. I admire the work on automating the product but a mill, this ain't.

 

[Michael Gilligan]

That looks more like a Proxxon hand-held tool on an MB140 stand than a milling machine, like using a Dremel on a drill press. I can see that what looks like the KT-70 X-Y table has been added to give mill-like functions. I admire the work on automating the product but a mill, this ain't.

.
Quite probably ... although it wasn't really the Proxxon hardware that interested me.

MichaelG.

 

[Roman505]

As I said, I admire the automation work. I just did not want people to go away with the impression this was a Proxxon mill, given they also sell real mills and lathes as well as hand-held tools. Adding steppers to create an NC machine or associated with DRO is recognised. I was interested in the fact that this modeller used as his first stage a push-botton actuation of the steppers, so milling was effectively by push-button by tenth of a millimetre (or so I interpreted the translation). It is a good way to start on automating the processes. The further stuff with Picaxe looks like devising a language by which to mill parts. I can imagine that using a Picaxe or similar to manage milling steps under the control of a higher level language which calls process steps may be an efficient way to roll your own.

This is not without interest to me, you might say. I own a Proxxon lathe with a mill in transit, and am under some pressure from my son to have gone CNC given he wants to cut gears for his heli and other gizmos.

 

[Michael Gilligan]

Roman505

Regarding "... devising a language by which to mill parts ..."

If I have understood the translation correctly: He is using Corel Draw on the PC to create a .PLT file [a.k.a. HPGL ?]; saving this to USB stick, then transferring that to the VDRIVE2. Effectively, it appears that the Proxxon machine has become an "XY Plotter" or "Engraving Machine".

I like this idea ... although it would help to see a better Czech to English translation, as I'm not sure if he is using the Z Axis for anything more than "Pen Lift" [unlikely, given that .PLT is a 2D concept]

MichaelG.

 

[SAborn]

Have you ever looked at G-code to cut a simple circle, and counted how many lines of code is generated by a cad program, its not uncommon to have over 500 lines of code for a circle.

Try fitting all that in to a picaxe.

And why would you bother when using a retired PC and cheap driver boards, you can have unlimited program space along with many free CNC / Cad packages to suit.

Untill you use a CNC all these idears might look great ,but also next to useless without a good software package like Mach3.

 

[marzan]

Have you ever looked at G-code to cut a simple circle, and counted how many lines of code is generated by a cad program, its not uncommon to have over 500 lines of code for a circle.

Try fitting all that in to a picaxe.

And why would you bother when using a retired PC and cheap driver boards, you can have unlimited program space along with many free CNC / Cad packages to suit.

Untill you use a CNC all these idears might look great ,but also next to useless without a good software package like Mach3.

Totally agree with Pete. Many easier ways to do it. Mach3 and its ability to use Gcode is the easiest way for a hobbyist to get going with CNC. Vast amounts of information is out there to do anything you want using Gcode. Milling machines can be converted to 3D printers without much fuss if you are already using Gcode, Mach3 also supports mills, lathes and plasma cutters with the same software. As Pete says, you can get an old clunker PC to run Mach3 as it dosen`t need the speed of modern day CPU`s to operate efficiently There is also a cheap add-on program called D2NC that runs inside Mach3 that lets you import Diptrace DXF files and convert them to Gcode to make your own PCB`s
Marz.

 

[Michael Gilligan]

Sorry folks ... I evidently misunderstood.
I thought that [this being the PICAXE forum] people might be interested in what can be done with the device.

I am well-aware that there are very capable, PC-driven, CNC systems available; but that wasn't really the point. ... The system that I referenced is really more of an engraving machine, and stands alone "plotting" whatever is stored on the USB stick.

MichaelG.

 

[lewisg]

I thought that [this being the PICAXE forum] people might be interested in what can be done with the device.

EXACTLY!

A better link to the project is here: Adjusting for CNC milling machine Proxxon for a few bucks. No the Proxxon isn't a Bridgeport or Haas but is is useful. Several things in this project could be used for all sorts of things, inter Picaxe communication, directly driving steppers, reading a flash drive. There are links on the page to the code which is well written and can be followed even with the language difference.

A link to his page should likely be in the User Projects - Miscellaneous forum since many seem to want to go down that path. Yes a PC is easier for CNC but this guy (Daniel?) is producing good accuracy with minimal hardware which I applaud.

Thanks for posting this!

 

[marzan]

Sorry folks ... I evidently misunderstood.
I thought that [this being the PICAXE forum] people might be interested in what can be done with the device.

I am well-aware that there are very capable, PC-driven, CNC systems available; but that wasn't really the point. ... The system that I referenced is really more of an engraving machine, and stands alone "plotting" whatever is stored on the USB stick.

MichaelG.

Well then maybe your post should have been titled "Engraving machine"

Marz.

 

[JamesWhite]

Awesome link, I can't believe the comments though. You would think that people here of all places people would see the genius of this. And judging by the pics, this is no mere engraver. Whatever though, your loss if you can't see this for what it is... another awesome example of what picaxe is capable of!

 

[Michael Gilligan]

lewisg and JamesWhite,

Thank you for the positive comments.
... perhaps these will encourage others to explore what has been done.

MichaelG.

 

[Roman505]

Mr Gilligan, among the various replies the work was acknowledged, difficulties mentioned and strategic alternatives discussed. However, you appear to have your knickers in a knot over all but the most fawning responses. This forum is in general exceptionally polite and I am very happy about that. Had I written as you now have then I would reflect further on my own tone, but you are free to choose.

 

[Michael Gilligan]

Mr Gilligan, among the various replies the work was acknowledged, difficulties mentioned and strategic alternatives discussed. However, you appear to have your knickers in a knot over all but the most fawning responses. This forum is in general exceptionally polite and I am very happy about that. Had I written as you now have then I would reflect further on my own tone, but you are free to choose.

Frankly, I am astonished by this comment
You and I had a brief exchange concerning hardware; which I thought to be perfectly reasonable.
This was followed by very negative comments from two Senior Members.
I have since thanked two other members for their positive comments about someone else's work.

MichaelG.

 

[Jeremy Harris]

FWIW I think this is quite an ingenious use for a Picaxe. I've been toying with the idea of something similar for a while now, as often the full blown hassle of using CNC (and I have some CNC kit) isn't needed, but direct hand control of the steppers in a machine is useful. You can do this in Mach 3 but I have two CNC machines and one old PC that I switch between the two. I've often thought of making a simple hand controller using a Picaxe and display that would allow simple jobs, like cutting out a rectangular display cutout in a hobby box, just a matter of setting a tool speed and manually telling the x or Y axis to go so many mm in a particular direction.

There are lots of little jobs like this that you find yourself doing with a milling machine or CNC router that don't need CNC control, because the time taken to do a drawing, load into Mach 3 etc takes longer than it would to do the job by hand. Another example is squaring off the end of a bit of stock neatly. I often use my small CNC Taig Milling machine for this, as the stock can be quickly stuck in the vice and the end milled off square. A hand controller would make this easier than either using the CNC capability or manually winding the steppers with the handles (which is awkward in my case, because of perspex box the machine sits in).

 

[SAborn]

For mamual control i simply uses the keyboard arrows for X & Y and page up and page down for Z, or write a few basic lines of code in notepad to cut a square out or whatever, can it get any easier than that.

And those with twisted knickers, perhaps need to look at the cost of building a CNC setup, then to be limited to a few basic tasks because of a controller used, dont make a lot of sense to me.

Could you engrave or drill a PCB with a picaxe controller..... i doubt it, cnc is a powerful tool, with the hard part and also costly is building it, the cheap and simple part is controlling it.

 

[marzan]

Frankly, I am astonished by this comment
You and I had a brief exchange concerning hardware; which I thought to be perfectly reasonable.
This was followed by very negative comments from two Senior Members.
I have since thanked two other members for their positive comments about someone else's work.

MichaelG.

How is what was posted "very negative comments" ? You ask for peoples opinions and get bent out of shape when they don`t agree totally with yours.
I like the idea of the picaxe in this project. It is the way it is being used that I think could be improved. The circuitry is extremely basic and does not come anywhere close to utilising the motors to a decent level. The reason you use stepper DRIVERS is that they use voltages well over the motor rating to compensate for the loss of torque at any decent speed, especially transitioning between cuts (rapids). Added to that most of them provide some microstepping from, say, half stepping to 1/32nd. To run these stepper drives only needs 2 pins. One for step, and the other for direction. boards can be as cheap as $10 for very basic ones, up to whatever you are willing to pay.
Suggesting that this would be a good use for a PCB drilling setup would be like driving across Australia in first gear. You can do it, but why would you. Without the drivers compensating for the rapid movements between drilling, it would become very tedious very quickly.
It is my *OPINION* that you could use a picaxe to do all the complicated vectoring, speed ramping up/down, inerpolating between axis` and leave the sequencing of the stepper motor as well as torque compensation to the driver boards that are in abundance in the CNC world
A lot of people read these forums, I would hate for them to read your post and think that the machine you mentioned could be easily converted to do other things, e.g pcb drilling, then go ahead and build one, only to be very dissapointed with the outcome. I would suggest that nearly all of us who built our own machines did not get it right first time because of all the incorrect information that is on the internet on this topic.
I have only commented on the Picaxe/electronic element of this machine, as that is what is relevant to this forum.
Marz.

 

[Jeremy Harris]

For mamual control i simply uses the keyboard arrows for X & Y and page up and page down for Z, or write a few basic lines of code in notepad to cut a square out or whatever, can it get any easier than that.

And those with twisted knickers, perhaps need to look at the cost of building a CNC setup, then to be limited to a few basic tasks because of a controller used, dont make a lot of sense to me.

Could you engrave or drill a PCB with a picaxe controller..... i doubt it, cnc is a powerful tool, with the hard part and also costly is building it, the cheap and simple part is controlling it.

OK IF you have the particular CNC machne hooked up to the PC at the time. In my case I have two CNC machines, a small table router and a converted Taig milling machine, but only one PC driving both (it a small netbook running the machines via the USB port and a dedicated driver).

In any case, the project that is the subject of this thread is very much a beginners project using a Proxxon drill stand and XY table. I found that the learning curve with DIY CNC was steep and this project seems to give a very simple and basic introduction to the fundamentals. As a learning tool I think it's great. Sure it's limited and won't do a great deal, but that's not the point as I see it, if it, like the Picaxe, is aimed at real beginners, where the fact that they can build something like this, and understand how it works, will be an achievement. They may well move on to more capable and expensive CNC machines, but this basic little Proxxon drill stand at table is an affordable way to start learning.

 

[Michael Gilligan]

Marz,

What I interpreted as very negative comments were raised by SAborn, and supported fully by you.
... 'though perhaps I should have said "dismissive" rather than "negative".

The system described does not need to do any heavy processing, because all it is doing is "plotting" from a .PLT file.
... Just like in the old "NC" machines that ran paper tapes! ... except that this uses a USB stick to store the file; which I presume, therefore, could easily hold many thousands of instructions [making it very easy indeed to drill and rout a circuit board, for example].

Personally; I think it's a brilliant idea, and I simply wanted to share my enthusiasm.
This thread has gone very wrong; but I don't want a fight, so let's just agree to differ.

MichaelG.
.

P.S. I do agree that the Stepper Motors would be better driven by a dedicated board [my own favourite being from JAF Motion in the UK] ... not least because these handle BiPolar motors, and also manage current limiting. But I still think the concept of using the VDRIVE2 in the way that he did is a stroke of genius.

 

[marzan]

Marz,

What I interpreted as very negative comments were raised by SAborn, and supported fully by you.
... 'though perhaps I should have said "dismissive" rather than "negative".

The system described does not need to do any heavy processing, because all it is doing is "plotting" from a .PLT file.
... Just like in the old "NC" machines that ran paper tapes! ... except that this uses a USB stick to store the file; which I presume, therefore, could easily hold many thousands of instructions [making it very easy indeed to drill and rout a circuit board, for example].

Personally; I think it's a brilliant idea, and I simply wanted to share my enthusiasm.
This thread has gone very wrong; but I don't want a fight, so let's just agree to differ.

MichaelG.
.

P.S. I do agree that the Stepper Motors would be better driven by a dedicated board [my own favourite being from JAF Motion in the UK] ... not least because these handle BiPolar motors, and also manage current limiting. But I still think the concept of using the VDRIVE2 in the way that he did is a stroke of genius.

As you will soon find out, this forum is a great place for the exchange of ideas. personally I don`t mind a lively debate on the pros and cons of an idea. If this sort of thing was around when I was building my first mill it would have saved me a lot of money and aggravation. I don`t think mine or SAborn`s replies were that negative. We have both built CNC machines, and can see the parts of that particular machine that are lacking. We simply want to make sure that everyone understands that there is a lot involved in CNC milling. The fundamental issue when using steppers for milling is that it is not a closed loop system, meaning you rely on the steppers not missing steps because there is no error checking as there is with servos. So many times the missing step issue is down people not knowing about the torque curve of the stepper motor, and how driver boards can drastically improve a stepper motors performance.
Personally I use geckodrives g540 for all my projects these days. 10x microstepping but changing to full steps on rapids. PWM not chopper so less heat. Mid band resonance compensation. etc. As always, you get what you pay for.
Marz.