CwazyWabbit Posted November 1, 2014 Share Posted November 1, 2014 Life would be boring if everything worked perfectly first time wouldn't it? Have you thought of using the steel V groove bearings? or do they work out more expensive? eg http://www.aliexpress.com/item/Factory-direct-sale-V-type-groove-bearing-6000zz-size-10-30-8mm-10pcs-lot/1470696098.html?s=p Quote Link to comment Share on other sites More sharing options...
robertspark Posted November 1, 2014 Author Share Posted November 1, 2014 What about 624VV bearings? Or something similar (Not sure if that's what crazywabbit proposed off aliexpress) Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted November 1, 2014 Share Posted November 1, 2014 The ones I posted were a bit larger but I only chose a random V groove bearing just to show a steel one. 624VV bearings can be had for as little as $0.90 however I have no idea of the quality. http://www.aliexpress.com/item/Free-shipping-5pcs-624VV-V-Groove-Sealed-Ball-Bearings-Vgroove-4-X-13-X-6mm-2/1386127059.html Quote Link to comment Share on other sites More sharing options...
simonr Posted November 1, 2014 Share Posted November 1, 2014 Good plan - I've ordered 10x 630VV bearings at about £20. I should have done this in the first place. I think I ordered the plastic ones because they were available from the UK. Thanks Robert & Barry! Si Quote Link to comment Share on other sites More sharing options...
simonr Posted November 2, 2014 Share Posted November 2, 2014 Some more photos. Si Quote Link to comment Share on other sites More sharing options...
bishbosh Posted November 2, 2014 Share Posted November 2, 2014 Good news on the tolerances Si! No idea what influences them though, might be the thin wall, might just be the numbers I quoted were upper limits so the actual tubes produced are typically well within them? Would make sense as I can't see Tata scrapping 100's of metres of tube because it was out of spec! Quote Link to comment Share on other sites More sharing options...
zim Posted November 2, 2014 Share Posted November 2, 2014 Just curious, for those of us that have never used a cnc machine before. How hard is it to learn something like this Mach 3 ? Is the freebie version ok for basic cutting ? G Quote Link to comment Share on other sites More sharing options...
Blanco Posted November 3, 2014 Share Posted November 3, 2014 Excellent question, if it is quite straight forward there could be a few of us with the wall space Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted November 3, 2014 Share Posted November 3, 2014 I looked at mach 3 for a project that never came off. The biggest problem I can see with it from a home users perspective is it drives the machine from the g-code you give it. This means you need to be able to write the g-code manually or have a cad cam package to generate it. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted November 3, 2014 Share Posted November 3, 2014 The way I plan to use my CNC plasma when it is built will be as follows :-CAD program: No getting away from this, you have to draw the part, this needs to be saved in DXF file format, you have a choice of programs to use.SheetCam: This will take your DXF file and convert it to G-Code, it will offset the cut path to allow for kerf thickness and also add other things like lead in and lead out for cuts etc. This looks easy to use once you have got it set up (set up will require experimentation to get parameters to match your machines and is the difficult bit)MACH3: This is doing the actual moving the motors, it uses the g-code produced from sheetcam. Once setup this seems quite simple ..... again that has the 'once setup' caveat as it needs to be tuned to your machine, however if you are building the same machine as SimonR I'm sure he can provide you with some suitable settings for most of the parameters (such as acceleration)So the answer is, quite easy to use once you have everything set up, but set up might be difficult (although only needs doing once). Quote Link to comment Share on other sites More sharing options...
simonr Posted November 3, 2014 Share Posted November 3, 2014 If you're using Mach3 to control a Mill or Lathe, it has lots of 'Wizards' built in for most common operations - things like turning a taper, screwcutting, drilling patterns of holes or cutting circles. The simplest way to use it is just to string these together to make the part you want. Generally to make the first part, I use the wizards to generate the code for each operation, one by one and save them to files. When I'm happy with the result, just add all the bits of G Code to a single file and run it to make subsequent bits. You can also run the machine 'manually' moving the axis with the cursor keys which is fine for simple stuff. For Plasma, you don't have the wizards so you need to use something like SheetCam to convert a drawing. There are other programs (Scan2Cad) that you can use to make a DXF from a scanned drawing / photo / something you've drawn in another app. People use this kind of thing when they want to cut things like company logos. The whole computer side of things is fairly easy to learn and there's loads of info on line. I think if you can build the machine, the computery bits will not be too much of a challenge for you. Si Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted November 3, 2014 Share Posted November 3, 2014 Draftsight is a free version of 2d autocad by dassult systems (solidworks) You just have to reregister every year which is simply a case of typing in your name, email address etc and clicking a button. 1 Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted November 3, 2014 Share Posted November 3, 2014 Here's a nice video which shows a bit more of the process than most on youtube He has a few other videos on his CNC plasma to. Quote Link to comment Share on other sites More sharing options...
robertspark Posted November 5, 2014 Author Share Posted November 5, 2014 damn, this wiring is taking an age!!!! too many solder connectors and too much of a perfectionist with the wiring arrangement + futureproofing for mill & lathe interface. Quote Link to comment Share on other sites More sharing options...
discomikey Posted November 5, 2014 Share Posted November 5, 2014 this thread is rather interesting, something i would absolutely love to make and would use all the time, i can do CAD all day long, but when it comes to setting computery things up, i havent got the first clue. the building of it i would have no problems with. the designing a control circuit, not a clue. its one of my modules this year and i also will have to program an arduino for my IP to control some stuff. once again, the programming at the moment is proving tricky, however i think i can get the hang of it over time. mostly its the cost of a decent plasma cutter that sets me back! Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted November 5, 2014 Share Posted November 5, 2014 Build the table but until you can afford the plasma just run it with a felt pen in it. Then you can do the fancy and more importantly dimensionally accurate designs and cut to the line with the tools you have. That way you can learn and develop your skills and machine without the outlay for the machine. I love the idea of having one but the outlay in cash and space for a machine and a stock of material makes me think I'd be better just sticking to out sourcing to laser and water jet cutters.not as much fun though ; ) Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted November 5, 2014 Share Posted November 5, 2014 this thread is rather interesting, something i would absolutely love to make and would use all the time, i can do CAD all day long, but when it comes to setting computery things up, i havent got the first clue. the building of it i would have no problems with. the designing a control circuit, not a clue. its one of my modules this year and i also will have to program an arduino for my IP to control some stuff. once again, the programming at the moment is proving tricky, however i think i can get the hang of it over time. mostly its the cost of a decent plasma cutter that sets me back! The electronics side of this is no more difficult than wiring a car. It really is just running wires and adding a few switches, buy a kit with motors, power supply and drivers and you don't have much to worry about. Cost of a decent plasma? I'm sure you probably still have a few series land rovers to put together and sell Cynic-al's idea of using it as a big plotter till you can afford the cutter is actually a really good idea Nice bit of plotting in this plasma cutter video and a cheaper one drawing with a finer pen (but no z axis yet as it is during the build) Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted November 5, 2014 Share Posted November 5, 2014 What do you mean actually?!?!?!?! Wasn't mine sadly, I sold an old A0 Roland 8 pen plotter which we replaced with a 42" wide format printer to a sculptor once who bought it for that very reason I loved it, it held the paper in place with a static bed, you had a button that charged and released it and it sucked the paper down instantly. It was also fun to hatch big areas and watch it colour it in. Well ok.. maybe fun is a strong word but you get what I mean! 1 Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted November 5, 2014 Share Posted November 5, 2014 Lol, 'actually' was just a turn of phrase, no offence meant by it. I honestly thing it's a great idea. Quote Link to comment Share on other sites More sharing options...
robertspark Posted November 5, 2014 Author Share Posted November 5, 2014 The wiring is actually not a problem, its just the way I've chosen to do it with a load of connectors, it is no more complex that wiring between point a and point b with screw terminals at either end if that's the way you want to do it. All the electronics is pre-made with screw terminals (or there are options for push in connectors pre-wired too). Space is a concern, hence mine and Simons route, both could be disassembled easily and hung on the wall or from the rafters if desired. It all depends on economics, how much do you farm out, in what thickness, and what do you think the payback on a £600 table + whatever you want to spend on a plasma will be (thickness dependant + maybe edge finish too). For me, I use CAD in the day job, and electronics + software is not a problem, I find it difficult to delegate / subcontract out, knowing it will arrive as I need it (and more importantly that I got my design right before farming it out!!!! [wasted cost / my error]) Hence the cnc plasma allows me to design and cut and if I get it wrong, other than a bit of steel, electric and plasma tip life I've wasted little in my design error + there is no better feeling than holding in your hand something you've made from an idea or to get you out of a jamb no matter how small! I was tightening up some M3 nylock nuts, problem is they are 5.5mm AF, no correct spanner, could not get long nose pliers into the space / adjustable etc and limited space, solution, bit of scrap 1.2mm plate, and careful work with a thin cutting disk on the angle grinder and I had a spanner in seconds, really minor thing, but it gave me a smile at what is a hobby for me. Similar thing when I was rebuilding diffs and all the fab'd tools that were made from scrap steel and old bearing races. Same thing I will do when I rebuild the TR6060 to change the mainshaft myself. Quote Link to comment Share on other sites More sharing options...
simonr Posted November 5, 2014 Share Posted November 5, 2014 this thread is rather interesting, something i would absolutely love to make and would use all the time, i can do CAD all day long, but when it comes to setting computery things up, i havent got the first clue. the building of it i would have no problems with. the designing a control circuit, not a clue. its one of my modules this year and i also will have to program an arduino for my IP to control some stuff. once again, the programming at the moment is proving tricky, however i think i can get the hang of it over time. mostly its the cost of a decent plasma cutter that sets me back! The computery bit is straightforward - just off the shelf software. Export your CAD drawing to DXF, load into SheetCam which turns it in to G-Code (this is doing the same job as a printer driver, as if you were sending a document to your printer) then load the G-Code into Mach3 which actually drives the CNC machine (analogous to your printer). There is no actual programming involved, though it's useful to be able to understand a bit of the G Code - just as a reality check to make sure it's generated something sensible and it starts in the right place. There is no control circuit to design - you buy a 'breakout board' which allows your PC to talk to the stepper drivers. You buy stepper motors and a driver for each. The driver takes signals (how much to move and in what direction) from the Breakout board and generates the signals to the motors which actually move the thing. As someone said, the connections between the boards is no more complicated than wiring say some lights in to your car. Most of the board manufacturers give you a simple wiring diagram to follow, and often the settings for Mach3 (which output on the PC controls which motor etc). I only have a cheap Plasma Cutter - which is very chinese and cost about £450 on eBay. However it cuts quite nicely up to about 6mm. Time will tell how nicely it actually works on this - but I have high hopes. More expensive plasma cutters seem to be more forgiving over the torch height and speed you move it - making it easier to cut neatly by hand. But I figure the computer will control both and once it's set up, it should cut every bit as nicely! My aim was to have a complete cutter including the Plasma itself for under £1000. I'm pretty close to that so long as the mechanics of the table works OK and I don't have to make a Mk2. The build process has shown me a few things I've forgotten (such as fixings for the cable-chain) & changes I'll make to make it easier to assemble. Some of the bolts were hard to reach requiring you to build it in the right order. I'll make the changes before I get any more cut - I don't think it will make any difference to the cost though. Si Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted November 6, 2014 Share Posted November 6, 2014 My cheap plasma cutter (cobel cut 40) had to have the tip struck against the steel to create the arc then lifted away to the normal working gap for making the cut, will the table be programmed to do this on start up or will it only work on air start (if thats the correct term?) cutters? Quote Link to comment Share on other sites More sharing options...
simonr Posted November 6, 2014 Share Posted November 6, 2014 You can program it to do either. Mine is HF start - no no need for me but I don't think it would present a problem. Si Quote Link to comment Share on other sites More sharing options...
bishbosh Posted November 6, 2014 Share Posted November 6, 2014 This any good for torch holding? https://www.youtube.com/watch?v=l9hBQafpr9M&list=UUDmxnPem-pPfJQATIkfgY2Q Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted November 6, 2014 Share Posted November 6, 2014 I watched that earlier in the week .... he is selling them for $699 iirc Quote Link to comment Share on other sites More sharing options...
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