Feeback on cnc design

[wizard]

Nice progress! Very busy of late and haven't had a chance to look in on this thread! Very nice machine.

[metiz]

Thanks guys. Does anyone use this inverter or a similar one that (can) use(s) digital controls?

[ger21]

If you are using a relay to control the FWD terminal on the Huanyang. just run that wire through the normally closed terminal of your Estop button. When you press the button, the spindle will stop.

[metiz]

If you are using a relay to control the FWD terminal on the Huanyang. just run that wire through the normally closed terminal of your Estop button. When you press the button, the spindle will stop.

I'm not sure I understand. I'm just going to use a power switch to power everything off when the machine is not running. I will not be using a relay.

[metiz]

I build a control box for my machine. It houses the inverter, stepper drivers, power supply, 2nd 12v power supply and the arduino. All the drivers and motors are connected with plugs so I can easily take the unit inside so it doesn't have to sit out in my damp, cold garage all the time. It is mounted to the machine with 2 easily accessible nuts (surprisingly sturdy). The button on top will kill power to all but the inverter. (anyone?)

I really should have put more though into the external wiring, it's a mess now. When I get hold of some 4 strand cable I'll replace them. Still works fine though.
The black plug is for the water pump.

[metiz]

Can anyone advise on bed material? A thick slab of aluminium would be ideal I think, but that's realy expensive. Could a slab of hardwood work as well?

[Mogal]

I'm going to use a 1" sheets of MDF for the bed, with a 3/4" (maybe 1/2") sheet for a waste board.

Any issues with heat or EMF in that control box? I'm currently putting my cabinet together with similar dimensions and setup.

[metiz]

Heat shouldn't be a problem with the additional fan. I don't know about emf, but I think those devices are made to not be influenced by them. One thing I have noticed though, and I'm not sure if this is an emf problem or just intrinsic to the device: when the frequency drive is turned on and unloaded, the frequency bounces around by a couple of Hz from the set point.

MDF might work as a bed but I'm worried moisture and temperature might warp the plate over time. I suppose you could run the router over the bed to zero it out every now and then.

[ericks]

I am using a 20 mm aluminium extrusion for my base. Will possibly add an acrylic sheet as a spoil board

[LeeWay]

I think acrylic would be a bad choice for a spoil board. It cracks easily and generally melts when cut. Unless cutting with specific bits and recipes. That would leave melted plastic that would no longer be flat. You can't really surface or fly cut that stuff as needed.
Most use MDF. I do too on my new router, but I use white pine glue up on my old router. It's a little more stable for us, but does cost more too. It doesn't require surfacing as often.

[ericks]

I have been using mdf but it absorbs moisture and then swell up??

[LeeWay]

Yes it does. This is why we use the pine glue up on one. If you are not doing a lot of 3D work, precision dados and pockets, then you may not need the surface perfectly flat all the time.
If you do though, you would have to surface before use. You can also seal it after surfacing, but that costs time and money too. Even that is not permanent, but will slow moisture absorption.

[ericks]

There has to be something one can use that is water and heat resistant...

[LeeWay]

I do use starboard or polypropylene sheet for some jigs and fixtures. It is pretty nice stuff and doesn't melt easily. With that comes a cost though. It is reasonable, but not what I would call cheap.

[ericks]

I do use starboard or polypropylene sheet for some jigs and fixtures. It is pretty nice stuff and doesn't melt easily. With that comes a cost though. It is reasonable, but not what I would call cheap.

Thanks

[Todd-B]

Hi Metiz, did you finish this machine? How does it work? Anything changed or you would like different

[metiz]

Hi Metiz, did you finish this machine? How does it work? Anything changed or you would like different

It's finished, more or less. I found a pine table and used that as a spoils board. I need to zero it out with the mill. I made a test cut in aluminium with a mill I had lying around for 20 years for some reason and it works pretty good. I'm really putting off figuring out the software though. I've made some reinforcements to the frame to make it stiffer and added a water tank for the cooling. It could use some longer water hoses. I'm thinking about my first project, an axe handle, that should be relatively easy to do.

[metiz]

Can anyone suggest a good guide on what program to use to create a 2d toolpath? I want to cut out an axe handle but there's a bewildering amount of options out there and I don't know where to start. For the time being I want to convert a simple autocad (DXF) drawing to a 2d toolpath. I can set the depth myself between passes.

[fretman_2]

Here's what I use and it's as simple as it gets. Use Inkscape to convert the dxf to an svg. SVG is the native output of Inkscape. Then use http://www.makercam.com to convert the svg drawing to gcode. If you download the latest version of Inkscape, then make sure that you set the svg import default resution to 96 in Makercam. You'll find that under Edit, Edit Preferences.

Now a couple of gotchas...the zero of Inkscape (and subsequent zero of Makercam once the svg is imported) is the lower left corner. If you want to start cutting at the center of your piece, then you'll have to get the center of your piece to the lower left corner of the Inkscape page. Once you import your drawing into Makercam, you'll see where it has your zero positioned.

Makercam does basic very well, but has none of the advanced cutting regimes. If you have any question, feel free to PM me.

Can anyone suggest a good guide on what program to use to create a 2d toolpath? I want to cut out an axe handle but there's a bewildering amount of options out there and I don't know where to start. For the time being I want to convert a simple autocad (DXF) drawing to a 2d toolpath. I can set the depth myself between passes.

[ger21]

If you have AutoCAD, I have a macro that can create the g-code form within AutoCAD.
AutoCAD 2 G-Code