Incompetance Causes Cnc

[richardandtracy]

I like making the odd pen or two, however I am very well aware of my inadequacies when it comes to turning pens.

 

I don't seem to have the hand-eye co-ordination required for hand turning of pens - in fact I never have had, I was dreadful at sports like cricket, squish and tennis too, even to the extent of being banned from squish at my first game because it was too dangerous for the other player. So, getting back to the point, I have to use a metal lathe. But curves are then difficult.

 

To overcome my incompetance in this field, I've taken drastic steps and gone all CNC:

http://i771.photobucket.com/albums/xx356/richardandtracy/penmaking/Sdc15675a_zps0f86baab.jpg

The machine is a 60x40cm engraver with fourth axis. It seems to be stiff enough to machine aluminium, so should be OK on plastics and possibly silver. NOT Nickel Silver though!

I have left a 6" vernier on the bed to give an idea of the scale of the thing. As you can see, there is currently no computer attached, because I'm in the process of setting that up before my first trial.

 

There is going to be a fairly long and steep learning curve, but with any luck I should be able to persuade it to machine curves as well as do some engraving on the surface of the pens eventually. My first effort this week is going to be a 2.5D routed timber headstone for a very dear kitten who died last week in a car accident. Once I am happy with three axes I'll progress onto 4.

 

Regards,

 

Richard

 

[basterma]

Good luck with that. Your summer will be filled with learning for sure. Could you things out on bars of soap to get the programming right before moving on to pen blanks? I know nothing about CNC lathes, but wouldn't using a softer material to get your geometry right save you some possible grief?

[richardandtracy]

Absolutely.

The first run of the program will be with air, then the second run with something harder. Soap is one option, I'm going to use candles though, as my wife gets a good supply of stubs from church which will be melted down to make the Advent candles. It doesn't matter two hoots whether the candle stub has been flaked by a machine tool before this happens.

 

Regards,

 

Richard.

[basterma]

The candles would be more like the blanks. I hadn't thought of wax.

[WayTooManyHobbies]

That is a good looking (and good sized) machine! I hope you have great fun with it.

[twissy]

Wow!

Please keep us updated Richard. I've been looking at getting the smaller version of this but have no CAD/CAM experience whatsoever. The spindle part on this looks a lot more robust than the (cheap) ones I've been looking at.

[richardandtracy]

I have no real CAM experience. In 1987 my degree project was to write a translator program between the DogsNC program and the Heidenhain controller for a Bridgeport mill. At no point was I allowed to test it on real machines. Furthermore, the language used bore no relationship to the current G & M codes used (despite the fact they were around at the time), so I have no experience there either.

 

I do have some CAD experience and many ideas, the problem may well be implementing them!

 

The machine uses an 800W watercooled spindle compared to the smaller machine's 300W aircooled spindle. The spindle is a lifed component - 600 hours, so I hope it'll last a project or two! The gantry is much stiffer than on the smaller machines too. I think the remainder of the extrusions used are identical though.

I seriously looked at one of the 3020 machines but came to the conclusion they were too small for anything other than doing the pen itself. The 4030 machines looked more practical, but inevitably what you want to do grows as you get more experienced with a machine, so I thought that it would be better to take a great gulp & fork out for a bigger machine. I have seriously investigated converting a metal lathe, but came to the conclusion that I'd have a fair bit of risk with backlash etc. and for the money, I'd end up with a 3 axis machine & no fourth axis capability.

 

Regards,

 

Richard

[tmenyc]

First, congratulations -- that's a big upgrade! Try and fit that into my Manhattan apartment...

 

about the candle wax -- isn't that stuff too imperfect to use without flaking and chunking off?

 

Tim

[richardandtracy]

The candle may flake off, but I'd still be able to get an idea of what the result looks like as it's cut.

 

The machine, from the Youtube videos I've seen, is just a bit noisy and ear defenders will be needed. I shall see this evening when I get the PC loaded with Mach 3 (the axis control software/G code interpreter) and give it a twirl. I suspect it would be somewhat problematical in an apartment where there are neighbours trying to sleep!

 

Regards,

 

Richard.

[twissy]

One thing I've wondered about the fourth axis. Is it a true fourth axis or does it just replace the X axis? I ask because I have thought it would be possible to put a seperate stepper motor and spindle in my laser engraver and just swap out the plugs of the Xstepper motor. As long as the gearing is correct I thought it would work.....but you know what thought did!

 

Really looking forward to seeing some results!

 

And by the way there were no inadequacies with your pens, but it's a great excuse to convince yourself you need more equipment!

[richardandtracy]

The fourth axis is a true fourth axis controlled independantly of the other three.

I have yet to imagine a shape where all four axes could be used at the same time. I'm sure it would look intriguing, but very hard to envisage. Even a fusee for a clock only needs 3 axes.

 

However, with the size of the bed I'll be able to set up the 4th axis accurately axial in one area, and still be able to machine engraved items elsewhere on the bed without it interfering.

 

One thing I plan on doing is thread milling of all threads with one tool. That will be fun, M7.4x0.55 to M13 x 3, triple start all with the one 1/4" dia tool. It will mean holding the circular part vertical for the thread, accurately centering it and then cutting the path. This appears to be a macro'd facility with the Mach3 add-on features so I shouldn't be able to bodge it unless I try hard. That will have to wait though, the thread mill is coming via a slow boat from the US.

 

Prior to using it in anger, I shall have to set the machine up. If the YouTube videos are correct, it's likely that the bed will not be quite perpendicular to the spindle. This can be altered by the use of shims under the bed extrusions at one end or other and under one side or other of the gantry.

 

Regards,

 

Richard

[Inspector]

I see from the picture that you are progressing from anvil to CNC. Your pens will improve by the same amount soon.

 

Cute little machine. Any provision for dust control on it?

 

I've seen machinable wax before and it is much harder than candle wax along with having a higher melting point. I'm curious to see if candle wax will work for your prototyping.

 

Pete

[richardandtracy]

The anvil and associated 14lb sledgehammer are stress relief tools for use on pens when things don't quite work as planned!

 

At the moment I have no control over dust. All my machines (thicknesser, router, electric plane, circular saw, mitre saw) produce huge amounts of dust in the workshop and that is going to be a problem. I have a long term plan to move this machine into another workshop, but I need to finish that building first. In the mean time, I'm going to use a vacuum cleaner & hose.

 

I got the engraver fired up last night, and it was wierd having a machine move about on its own. Due to a problem with getting the correct software on the machine and there being no internet connection to it, I was unable to load the CAM software on it. Apparently it needs the .Net 3.5 framework, which I had available, but the .Net framework won't load without a certain level of Windows installer, which naturally wasn't there. Why do confuters never make anything simple?

 

Regards,

 

Richard

[tmenyc]

I suspect it would be somewhat problematical in an apartment where there are neighbours trying to sleep!

 

Regards,

 

Richard.

Well, I do make a fair amount of noise when my air compressor and vent fan are both running...I have a paint booth for lacquer painting for my other hobby of scale auto building. I long ago decided that the neighbors can make their noise and we don't complain, so a mutual tolerance plan seems to work. I'm more concerned about the fumes from the lacquer...

 

Tim

[dougscott]

Oh, the places you'll go and the things you'll see!

 

Have fun with it -- I've had mine (a mill) for two years and am still learning.

 

Doug

[richardandtracy]

Having an interesting time with the manual. In places it's just plain wrong.

 

With the pin setup specified in the manual, the z axis goes down when it's meant to go up & vice versa.

Also the annotations used for the machine feel wrong to me. The X axis is across the gantry and the Y along the bed. It feels wrong to me, with the X being along the bed and the Y being across the gantry. I may have to fix that up too by re-allocating pins or swapping plugs.

 

Either I'm much more dense than I like to think I am, or actually the learning curve is even steeper than I thought. It is not entirely for the faint hearted.

 

Regards,

 

Richard

[richardandtracy]

Interesting problems keep cropping up.

The manual supplied didn't mention th setup for the A Axis at all, so it was rather trial & error to find the 177.777778 steps per degree necessary to put into Mach 3.

The Z axis in the manual is incorrectly set up, operating in the opposite sense to the manual definition. This had to be fixed.

 

I have now made sawdust having routed some planks and fixed a problem with one of the motor couplings (the gantry slipped with +x movements).

 

Oh joy. I shall learn eventually.

 

Regards,

 

Richard

[basterma]

Hang in there.

[dougscott]

It is a pastime, admittedly, that is not for the faint of heart. The Mach 3 manual is written with sensates in mind, leaving intuitives like me far behind (I get overwhelmed in a grocery store). Still, keep at it. The light began to dawn for me about month seven.

[richardandtracy]

There is a manual for Mach 3?

Where?!?

 

If it's online then.. I'm keeping that PC firmly off line to prevent anti-virus software from slowing it down.

 

Well. I did play last night, and am concentrating on simpler stuff to begin with. The first thing is a pen box, particularly one with a heptagonal insert in the top with a Chestnut Pens 'CP' logo in it. The insert will be substitute ivory inset in walnut. To test the program for each machining operation, a bit of pallet timber:

http://i771.photobucket.com/albums/xx356/richardandtracy/penmaking/Sdc15689a_zps7bb5ee30.jpg

 

For some reason Cambam cannot recognise the central 'CP' logo as a region so I have had to machine a perimiter around it and then cut away the residual on either side with another operation which I've not programmed yet. I did it last night with a 3mm cutter rather than a 1.5mm one (the 1.5mm cutter is on order) so part of the 'C' was cut away by the inner hepagon and the border was cut away by the top of the C. However, I'm pleased with the way it has worked so far.

 

Regards,

 

Richard