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joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 9:10 am
by joey81
No, I'm not making a puzzle using a CNC.

The CNC machine IS THE puzzle!

Driver board and stepper motors are from HobbyCNC. Got the 4-axis kit and 305 oz-in motors. 4-5 more weeks before it gets here.
https://hobbycnc.com/product/hobbycnc-pro-combo-kits/

The rails I got from China, complete set (rails, ball screws, ball-nuts, bearings, etc). X is 1300mm, Y 1000mm and Z 300mm.
Dual ball-nuts for minimum backlash. ETA middle of next week.

On the software side I will be using LinuxCNC (http://www.linuxcnc.org). I already have it installed on old PC (dual-core 2.6GHz with 2GB RAM)
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LinuxCNC needs a printer port (not really, but alternatives are costly) to interface with the motor drivers. The PC's motherboard doesn't have one so I ordered this online:
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I checked it with this tool: http://wiki.linuxcnc.org/cgi-bin/wiki.p ... ort_Tester
And its working!

Re: joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 9:25 am
by joey81
Last night I was playing with the stepper configuration wizard and discovered that my PC can do a maximum of around 31,000 steps per second.
http://linuxcnc.org/docs/html/config/stepconf.html

The ball screw's pitch is 5mm. Meaning an axis travel of 5mm per 360-degree revolution of the screw. The stepper motor takes 200 steps per revolution. My initial calculation showed my setup can only do 750mm per minute! My PC is too slow.

I've read that using a video card instead of the on-board video adapter will free-up the CPU. The cheapest video card that will fit my board is 1,700 at PC Express. But if I add 1k more I can get a new motherboard!

It turns out the 750mm travel is per second, not per minute. Whew!

But in my panic I also discovered a brand new motherboard with buit-in printer port (yes, the interface is still alive!) for P2,850 at PC Express
https://www.asus.com/ph/Motherboards/H81MC/

Re: joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 9:32 am
by joey81
USB gamepads can be used with LinuxCNC for pendant control
http://www.ijohnsen.com/blog/linuxcnc-j ... t-control/

Gamepads are available at CD-R King for 180 to 350 pesos.

Re: joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 10:00 am
by bigfoot
English please. Lol! These IT guys is levelling things up, at least on the IT side.

Re: joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 10:51 am
by JojoD818
Hi Joey,

I've also been using LinuxCNC (formerly known as EMC2) for a little over 6 years now. It's a bit daunting at first but I guess my learning rate is somewhat clogged already. The best thing about it is it's FREE. :lolno:

You may want to check the list of motherboards with good Latency Tests scores here... http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Latency-Test

When my old Athlon desktop broke down I got myself an Intel D525MW mini-ITX, it's a small motherboard with the Intel Atom proc built-in (non-removable). Iirc, my reading about LinuxCNC suggests that proc power is not that important, the I/O "bus" that connects everything is what's more important and is what matters most for Latency. Anyway, I'm sure you are on top of these things already, Linux wasn't an alien for me but like I said, my brain got clogged up. :lolno:

Cheers and good luck!

Re: joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 11:34 am
by joey81
bigfoot wrote:English please. Lol! These IT guys is levelling things up, at least on the IT side.



Hindi ako IT. Hehehe. No offence meant to IT they guys :wave:

I'm an embedded software developer. So between Joel and Jojo, mas magkakaintindihan kami ni Jojo. Hindi lang ako nagdididikit sa kanya because my wallet likes my 8-bit ears as it is. :lolno:

JojoD818 wrote:Hi Joey,

I've also been using LinuxCNC (formerly known as EMC2) for a little over 6 years now. It's a bit daunting at first but I guess my learning rate is somewhat clogged already. The best thing about it is it's FREE. :lolno:

You may want to check the list of motherboards with good Latency Tests scores here... http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Latency-Test

When my old Athlon desktop broke down I got myself an Intel D525MW mini-ITX, it's a small motherboard with the Intel Atom proc built-in (non-removable). Iirc, my reading about LinuxCNC suggests that proc power is not that important, the I/O "bus" that connects everything is what's more important and is what matters most for Latency. Anyway, I'm sure you are on top of these things already, Linux wasn't an alien for me but like I said, my brain got clogged up. :lolno:

Cheers and good luck!


Great! May mapapagtanungan na ako.

Working with Linux on and off for almost 20 years now. I figured the my learning curve will be the same whether with LinuxCNC or a commercial solution. Dun na sa libre.

Thanks for the link. Made me realize I used servo thread (1ms) jitter value instead of the base thread. The correct max step rate for my machine is now 45.99KHz. Yay!

Re: joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 12:39 pm
by avmanansala
bow for @joey81 he is the #root !:-)

Re: joey81's CNC puzzle

Unread postPosted: Sat Jan 21, 2017 1:14 pm
by JojoD818
joey81 wrote:
Hindi ako IT. Hehehe. No offence meant to IT they guys :wave:

I'm an embedded software developer. So between Joel and Jojo, mas magkakaintindihan kami ni Jojo. Hindi lang ako nagdididikit sa kanya because my wallet likes my 8-bit ears as it is. :lolno:



I'll take 8-bit music anytime, it's a lot better than sheer silence hahaha!


Great! May mapapagtanungan na ako.

Working with Linux on and off for almost 20 years now. I figured the my learning curve will be the same whether with LinuxCNC or a commercial solution. Dun na sa libre.

Thanks for the link. Made me realize I used servo thread (1ms) jitter value instead of the base thread. The correct max step rate for my machine is now 45.99KHz. Yay!


Nakupo, gapang ako diyan nun nag setup ako. I might even be the one asking questions rather than you. :lolno:

You're welcome! Don't forget to run the tests while taxing your computer. Try running videos, music, and transferring large files while running the Latency Test for worst case scenario settings. Yan lang yata natatandaan ko hahaha!

Re: joey81's CNC puzzle

Unread postPosted: Mon Jan 23, 2017 4:33 pm
by joey81
Someone knocked at our door and left behind 2 boxes
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Re: joey81's CNC puzzle

Unread postPosted: Mon Jan 23, 2017 9:41 pm
by gattaca
It's a grown man's complicated (and expensive?) lego! It feels daunting to me, so more power to those diving into the world of CNC. :thumbup: