Author Topic: PCs for CNC (Read 3317 times)

Roger B · « **on:** August 28, 2018, 10:16:11 AM »

I don't want to further hijack Mike's thread so I will start a new one.

I would like to start experimenting with CNC. I can buy a kit to convert my Proxxon Micromill which gets me to a parallel interface. That's ok.

I have looked at my selection of old PCs but none have a parallel port. Reading up a bit it seems that for CNC you need a real port not an emulator as it has direct access to the interrupts. USB to parallel converters will work with printers but not in applications that require time sensitive bi directional communications.

What do others do?

kvom · « **Reply #1 on:** August 28, 2018, 12:26:38 PM »

After using Mach3 with parallel port for years. I made the switch to PathPilot from Tormach. Here the pulse generation is handled by a hardware card from Mesa. PP itself is a version of LinuxCNC; I had a computer built using the least expensive components possible, since the software uses relatively little CPU capacity. The computer cost about $350, Mesa card was $125, and the PP software was $100. I was able to reuse my existing BoB and driver card.

Biggest improvement was faster rapids since pulse rate is not dependent on CPU interrupts. The PP UI is also superior to Mach3 in my opinion.

Admiral_dk · « **Reply #2 on:** August 28, 2018, 12:40:14 PM »

Most never (and older) compact and full size PC's has one or more expansions slots that will accept a true Parallel Port plug-in board - just beware that you get the right expansion interface + size version for that particular PC or even better check that you still can get what fits the one you will like to buy, before you commit.

Dave Otto · « **Reply #3 on:** August 28, 2018, 01:27:39 PM »

I'm using a Smoothstepper USB motion control board on my system.
https://warp9td.com/index.php/products

Someday I would like to switch to better machine control software but I haven't had time to dive into it. I get by with Mach3 ok for the time being.

Dave

Vixen · « **Reply #4 on:** August 28, 2018, 01:45:46 PM »

Roger,

Most laptops do not have a paraport these days. If you have an old desktop box, you should be able to buy a PCI card with a paraport and slot that in. That would be adequate for your Proxxon micro mill. If you can get that to work, then you probably do not need the added expense and complication of an external motion control board, like a Smoothstepper or the Mesa card for a LinuxCNC installation.

Mike

jadge · « **Reply #5 on:** August 28, 2018, 02:48:46 PM »

I started by running a custom version of Mach3 on a clean install of XP on an old computer (with parallel port) with my Tormach CNC mill. I had some issues with the software and computer. As in sometimes it went AWOL during a "toolchange". I eventually discovered it was going into relative mode for some unknown reason. I "fixed" it by adding an absolute command in the post-processor code at a toolchange. Eventually I upgraded to a proper Tormach controller, still running Mach3. Personally I didn't particularly like Mach3. The screens were messy and inconsistent. And the 4th axis stuff, especially feedrates, plain didn't work. Ultimately I upgraded to PathPilot, and also had to upgrade the controller as well. Generally so far so good. PathPilot is much easier to use, with more logical screens. The only caveat is that it isn't quite as user friendly if you use metric rather than imperial. A jog step of 10mm could be quite exciting!

Andrew

Vixen · « **Reply #6 on:** August 28, 2018, 03:15:46 PM »

Roger,

Mach3 needs Windoze to run. LinuxCNC and Pathpilot are both fresh installations of Linux.

I am with Andrew in disliking Mach 3

Pathpilot needs a fast modern processor, whereas LinuxCNC will run a 3 axis mill happily on and older (XP vintage) PC.

Pathpilot was developed by Tormach (from LinuxCNC) specifically for Tormach machines but can be successfully adapted to others (expect no help from Tormach if you do this).

LinuxCNC is good for any machine and works well in both Inch and Metric units.

LinuxCNC does not need and external motion control card if you have a paraport

You may gather I like LinuxCNC, I have it driving three mills and a lathe via the paraport, no motion cards. Each machine has it's own mini PC, laptops can be problematic.

Mike

fumopuc · « **Reply #7 on:** August 28, 2018, 07:29:16 PM »

Hi Roger,
may be worth to look here.
https://www.itsco.de/pc-dell-optiplex-760-sff-intel-core-2-duo-e8500-2x-3-16ghz.html

Stuart · « **Reply #8 on:** August 28, 2018, 07:53:54 PM »

That’s the Same one as I use for mach4

Got mine as a refurb from micro dream in the UK

Works fine one year warranty for £300 not to bad deal but it what they have in stock

Roger B · « **Reply #9 on:** August 29, 2018, 09:04:43 AM »

Thank you all for your thoughts

I see two problems:

1) I am starting out in something new to me. Do I want to base it on an obsolete interface? I know from my day job that PC technology evolves much quicker than machine technology.

2) My workshop space is extremely limited. It will be difficult to find a place for a desktop PC that is out of range of high speed swarf.

I will have to buy something. It could be a parallel card for an existing PC, it could be a PC with a parallel port or it could be some sort of motion controller. I am tending towards Linux CNC on my netbook with a USB link to a motion controller. Is this feasible?

Vixen · « **Reply #10 on:** August 29, 2018, 10:31:19 AM »

Hello Roger,

I have never considered a Netbook with a USB link to a motion controller. I do not know if it is feasible. LinuxCNC do not recommend laptop type PC's

I would be inclined to run LinuxCNC on a small form PC, similar to the one identified by Achim. You could mount the PC out of the way on a remote shelf or under the workbench or protected by a perspex screen. You only need access to press the ON button. The cost of that PC is minimal and once set-up will last forever.

You may need to do some research into the interface for the mill. Mach3, Pathpilot, LinuxCNC with or without a motion controller, will all give three pairs of 'step and direction' signals for the three axes. You will need to check what the Proxxon interface needs or expects.

Mike

nj111 · « **Reply #11 on:** August 29, 2018, 11:27:57 AM »

I don't know if this is helpful but a friend of mine is getting great results converting large industrial heavy duty CNC routers to run UCCNC - a Mach 3 competitor. The nature of his work requires fast 3D profiling - at high feedrates (compared to what we need) and in his testing he found this totally outperforms Mach3 that was previously installed. he calls himself automateanything on you tube - Most Recently he's converted a Denford Mill to run this software whilst still using it's original Fanuc Servo motors - complete with rigid tapping cylces etc.
Search on youtube "Uccnc overview of screens- quick talk through" "Rigid tap - done!" and also "uccnc vcarving on old rye mg cnc rebuild" Nick

Roger B · « **Reply #12 on:** August 30, 2018, 03:07:06 PM »

The GoCNC kit for the Proxxon micro mill includes a version of Linux CNC,

https://gocnc.de/shop/en/cnc-acessories/cnc-software/273/linuxcnc-dvd

A parallel interface card for one of my old PCs will cost 20-30 so I can put it all together and see what happens

I think that one PC is Win 7 and the other is Win 10. If I put in the Linux CNC DVD will it install Linux (and deinstall/deactivate Windows)?

How do people protect their keyboards?

Will I also need some form of CAM software?

https://gocnc.de/shop/en/cnc-acessories/cnc-software/450/estlcam-software-vers.11

Vixen · « **Reply #13 on:** August 30, 2018, 03:18:34 PM »

Hello Roger,

The LinuxCNC disc will overwrite everything on the PC's hard drive. Make sure you have removed or backed up anything of importance first. It will overwrite whatever windoze already installed. You will get a stand alone LinuxCNC controller. Best to disable the internet.

CamBam is a very popular CAM you get a free trial period before you need to pay for it. Never heard of the one in your link so cannot comment.

You will also need a 2D CAD package capable of outputting your drawing as a DFX file. The CAM program converts the DXF file into the G-code file, which controls the CNC mill.

Mike

Roger B · « **Reply #14 on:** August 30, 2018, 03:44:13 PM »

Hello Mike,

I think I understand how this goes together now

I use DraftSight 2D CAD. The CAM package will go on the same PC as the CAD package and will allow me to create 'G code'. I then transfer this G code file to the Linux CNC PC (via a USB stick?) The Linux CNC PC then outputs step and direction signals (via the parallel port) to the stepper motor driver that is in this case installed in the milling machine.

Vixen · « **Reply #15 on:** August 30, 2018, 04:57:34 PM »

Hello Roger

By Jove he's got it!!!!

Yes the CAD and CAM can live on the 'office' Widoze PC. The USB stick is the most convenient way to transfer the g-code file to the machine shop LinuxCNC machine. The LInux desktop (file manager etc) is very widowesque in the way it operates. The LinuxCNC is a stand alone program. You can control it by the mouse or by the keyboard. I much prefer keyboard entry.

This is my latest mill installation. I have positioned my mouse underneath the keyboard shelf and outside of the vertical panel, this keeps the majority of the chips out of the works. The vertical panel, which can be MDF or perspex or whatever you have, provides most protection and also somewhere to mount the shelves. The flat screen monitor sits on top of the small form PC. You can even see my blue USB stick. The spindle VFD inverter also sits on the (invisible) perspex mouse shelf.

Mike

dieselpilot · « **Reply #16 on:** August 30, 2018, 05:06:39 PM »

Is that a VMC-100 missing the turret?

Vixen · « **Reply #17 on:** August 30, 2018, 05:16:18 PM »

Quote from: dieselpilot on August 30, 2018, 05:06:39 PM

Is that a VMC-100 missing the turret?

Yes it is, well spotted.

Hand-draulic tool changes are now ~~twice~~ ten times quicker than with the turret.

Mike

Stuart · « **Reply #18 on:** August 30, 2018, 05:18:37 PM »

Roger don’t forget fusion 360 cad/cam it’s free for hobbiests just need to sign up every year but you don’t loose your work if you do it in time cons it’s cloud based and needs a internet con to work . But you can go off line for a few days

As is the case there are many answers to questions

Stuart

Roger B · « **Reply #19 on:** August 30, 2018, 07:31:08 PM »

Thank you Mike

I am being very pedantic about this as once I install the CNC kit on the mill it is disabled until CNC works. Previous day job experience has involved the 'Oh you need one of these as well, it costs XXXX and is on 6 week delivery'

Vixen · « **Reply #20 on:** August 30, 2018, 07:48:20 PM »

Hello Roger

Very wise, it's better not to burn your bridges too soon.

Perhaps your best bet would be to buy a CAM program like CAMBAM or even Fusion 360 and learn how to use your CAD and CAM packages together, to create your tool paths and conversion into G-code. Wait until you have got the hang of that, before going onto the next step.

You could then instal LinuxCNC on the workshop PC and run simulated machining operations, before going onto the final step of disabling/ converting the mill.

Take it one step at a time. Master each one in turn.

Cheers

Mike

kvom · « **Reply #21 on:** August 31, 2018, 12:41:04 PM »

I second using CamBam. You get 40 executions in the free trial, and by not shutting down the program you can get a lot of mileage out of each execution. By using Camotics (a free CNC simulator) you can machine your parts to visually verify the results.

Roger B · « **Reply #22 on:** August 31, 2018, 01:47:38 PM »

'Perhaps your best bet would be to buy a CAM program like CAMBAM or even Fusion 360 and learn how to use your CAD and CAM packages together, to create your tool paths and conversion into G-code'
Another thing I didn't know

That looks to be a good way to start

kvom · « **Reply #23 on:** August 31, 2018, 07:37:42 PM »

One other piece of software I use is G-Wizard, a program for calculating tool feeds and speeds. This has saved me a lot of broken tools.

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Author Topic: PCs for CNC (Read 3317 times)