@Peter_Fouche1
LinuxCNC has a latency testing utility so your trust is irrelevant.
@Peter_Fouche1 I’ve lived without the hassles of Windows for 19 years myself. Linuxcnc has a lot more features, flexibility, versatility, support, and longevity than Mach3 ever will too. Linuxcnc is also free.
The free thing was the hook for me. But mach3 is nice looking. Haven’t even tried it yet though. But personally I’m thinking the hard part is going to be the CAM part of things (as in the Gcode generation). Paths, spiral hole cuts and what not… Would luv to hear details on what everyone’s doing there.
But as far as not trusting a PC, I look forward to details on how that works out. So keep the details coming please. But the thing to consider on the linuxcnc stuff is that I assume it’s been stripped of most anything that would affect the CNC part. And it’s true that aside from the lack of hardisk drive letters (when looking for your g code file), there’s no linux voodoo needed. Plus you can install it from inside windows ( it will do a dual boot thing at startup, as in give you a choice but default to windows) and change nothing. It’s worth a look I think…
As you know, I already have a all in one 4 axis parallel port type board as well as a USB arduino setup going here. Just to keep my options open. So one more option is always a plus I think.
So like I said, please do keep the details coming…
@Mat_Helm
Linuxcnc has some gcode generater scripts it ships with. But they’ve not exactly world class CAM software. Here is a page describing some of them
http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Simple_EMC_G-Code_Generators
Here’s another
http://www.linuxcnc.org/docs/2.4/html/gui_image-to-gcode.html
@Mat_Helm from a cad point of view I’m seriously considering buying cambam having had good use of trial. Seems pretty capable and not unreasonably priced
@Daniel_Would What is the price? I thought I looked at that and didn’t consider it reasonable at all…
@Peter_Fouche1
What have you learned about speeds, and feeds so far? I know with SolidWorks anything that is call for a quote is out of my budget.
Surface speed formula:
(π * DIA * RPM) / 12 = SFPM
@Peter_Fouche1
I’ve heard Mach3 doesn’t work with lathes. About half Linuxcnc users are former Mach3 users with lathes.
@Mat_Helm £93 according to their web site. I’d consider that a pretty fair price considering how much better and faster it is than something like pycam. Though if there are good free/cheap alternatives if love to try them
@Peter_Fouche1
I bet you can’t do this manually
@Peter_Fouche1 Chock N Charge?.. lol n that was the nicest one that came to mind… ;p
@Daniel_Would I guess I’m a cheap ole B, cause yea that seems like a lot for what seems like a middle step in the process. But I’m a newb, what do I know. I think I’ve subconsciously avoided the pay stuff in order not to spoil myself. But I’ve been using “dxf2gcode”
( https://code.google.com/p/dxf2gcode/
Installing:
https://code.google.com/p/dxf2gcode/wiki/Installation )
for the linuxcnc stuff, as it produces the “.nfc” file that linux seems to like. Posted the process (from sketchup 8 to linuxcnc) on the other diy cnc back on Apr 12th. I can adjust the paths and such, and a lot more I think if I spent more time with it.
Plus @Paul_Frederick just posted those links above " http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Simple_EMC_G-Code_Generators
Here’s another
http://www.linuxcnc.org/docs/2.4/html/gui_image-to-gcode.html "
I’ve done straight-cut gears manually on a lathe and a mill, and helical-ish manually on a universal mill, but ugh it was not pleasant.
@Peter_Fouche1 Can’t?.. or won’t… ;p
@Mat_Helm I guess as I work in the software industry I don’t begrudge a fair price on what is a complex piece of software. I found pycam to be good enough for simple 2d stuff. But cambam has a lot of nice options, generates paths faster, handles 3d etc etc. Most of the commercial stuff is way more expensive.
Doing some searching today this looks like an interesting option http://m.ebay.co.uk/itm/351047862659?nav=SEARCH
Or possibly this, since UK supplier I’ve used before http://www.cnc4you.co.uk/index.php?route=product/product&path=87_117&product_id=378
@Daniel_Would I couldn’t disagree more. I find most software wildly over priced and monopolistic… is that even a word?.. For instance, could I sell prime rib steak for 100 a pound when hamburger can be bought next door for a dollar. I think that what one is paying for with software now days is based on a price structure left over from the days when stealing it was much easier.
That first listing is exactly the same components I have, except for bigger motors (too big for a 15a PS?) and a nicer case for the driver board.
The second is better I think, if for no other reason than the separate drivers.
Wondering what you’re thinking machine wise, cause those are large motors.
@Mat_Helm I read some less than flattering things about that tb6560 how are you finding it?
I realise the motors are way large which is slightly odd since I got this far on really small motors. And I may go for smaller versions. But part of me thinks if I’m spending money to get decent electronics etc then maybe big motors future proofs for what ever I wind up doing. If I have the space I’d love to go up to a 8’x4’
@Daniel_Would I think 4x8 (as we call it in the US) is the goal of every DIY CNC’er.
I’ve run the board for hours at it’s highest current settings (had to quick tie a heat sinks to the X n Y axis motors) and on the bench it seems fine. But I’ve read the stories as well. But keep in mind that it can be had on ebay for $60 US ($48 in my case). But I guess if one driver burns out, the whole board is dead, so individual drivers would be the way to go. If you do end up with it, I have a link here somewhere on upgrading the opto’s (27) and 4 of the tiny capacitors on the bottom, which increases the frequency and reliability of the board.
@Peter_Fouche1 Large stepper motors generally develop more torque at slower speeds. Well all stepper motors do, but large motors especially. The way to maintain torque with stepper motors at higher speeds is to run them at higher voltages. As any stepper motor goes faster the time to get current into its coils diminishes. Less current equals less power. More voltage on the other hand equals more current, and consequently more power too. Even with a PWM drive current drops off at speed. But the higher voltage you run the higher the speed before the drop off occurs.
@Mat_Helm I don’t know how critical the oscillator timing capacitors are with TB6560s. You can definitely run too high a speed there. The most important components you didn’t even mention. Those are the current sensing resistors. Low current definitely means low power output. A lot of those imported boards are hard wired to limit current to 1 amp per phase I’ve heard. Absolute maximum ratings are funny things though. There is no one saying that all ratings can be maxed out at the same time without bad things happening. The maximum voltage of TB6560s is another value that is suspect. I wouldn’t want to be around one when someone tried to put 40VDC into it that’s for sure!
Although crappy optos are crappy. All optos are crappy really, but some are much crappier than others. My homemade TB6560 drives are very sensitive to step timing with Linuxcnc. I couldn’t get my drives to run right below 5,000ns. That is a limiting factor when it comes to top speeds. There is a ratio between system latency and step timing that determines a maximum step rate. On my one PC with really lousy latency it was a limit I ran into.
I think the setup time of a TB6560 is 5,000ns though. It was a while ago when I made my drives but I kind of remember that.