Machining Aluminum #122 - Sydney, Australia

[pblackburn]

That is interesting Gerald.

There is an interesting section in the mach install manual at the section of native units. For a test you could create another profile with native units as inch. I am certain you are outputting your toolpath in metric so it would take care of that part. It would be interesting to see if it is a native units issue.

Mach does have some quirks. I found that with G02/03 if you had cv stop with angles turned on and you had tabs in your tool path it would cause hesitations only seen when the feed rate was higher than 150 at the locations of the tabs. Took me forever to find the cause of the problem because it only did it when the motion was in a clockwise rotation but not counter clockwise. Turning off cv with angles got rid of the problem. Not everyone experiences these problems so it is sort of like gremlins in the machine. The thing is one you get a good running profile make sure you copy your xml file.

[Regnar]

I am not a Mach user but in Linuxcnc you can switch between commanded and actual. Seeing the difference would drive me nuts. Prime example of driving me nuts would be this guys Dro. Cool project but is a great example of the machine not being able to always achieve the commanded position. http://youtu.be/dHXoMG2s5yE

[racedirector]

Russell, from what I have learnt about linuxcnc to date yoy can see all sorts of things you can't see in mach. How long have you been with linux? Care to share any settings you may have that are beyond standard?

[Regnar]

Bruce I have been using LinuxCNC for 5 or 6 years now. No special settings at all just run it like it installs. I did try to install a auto z zero but gave up. Probably the most out of normal thing I did was set the file location to load to my DropBox folder and use a old IPhone as a Pendant. I also changed the way the machine Homes itself.(first Z the X and Y at the same time)

[lonestaral]

I knew someone who had a twin set up.
He had a start up screen which asked what he wanted to run before the main start up.(was it boot up as)

[racedirector]

Originally Posted by Regnar

Bruce I have been using LinuxCNC for 5 or 6 years now...

Excellent, never would have picked it from your videos Must look at your build thread again.

One last question... did you hook up your start & pause buttons or are you running without them? Probably should look your thread to answer that

[Regnar]

I hooked up the Estop but start and pause are not. Most of the time I zero with the phone and hit start from it. In a production environment where you cut the same sheet all day long and paying someone to run it I can see their worth but in this one man shop I just haven't seen the value in hooking them up yet. But everything is run just have to figure it out in the software.

[racedirector]

Ah OK. I am going to give them a go, will share what I find out

[sailfl]

I have EStop, Pause and Start on my machine and I have found them to be very useful. As Russell mentioned, it more useful when you are running the same file over and over. I also find that there are times when I need to pause a cut when I am not near the computer such as when I need to move a clamp or I have to answer my phone.

[Fox]

For the minor extra cost I have found them very useful already. I use them often to check for clamps, or when I forget to switch on the dust cleaner again (need to automate that bloody thing) or answering a call, also I stop the machine sometimes temporary to check after first part is cut to check the quality etc. It's a convenience not a necessity.. but damn useful.

[smreish]

...completely worth the time and $ to add.

[racedirector]

Dunno if you guys are referring to me or Russell... I have them on my machine, its just working out how to get them to work under LinuxCNC

[racedirector]

Russell

If you are reading this would there be any chance of you attaching your stepconf, ini and hal files from LinuxCNC? I have Y and Z performing way better than I ever had them under Mach3 but the dual X motors are driving me nuts. I just cannot get them to play together and seeing as you have been running for 5 years, yours must be doing something mine isn't

Will understand if you can't/don't want to

This also applies to anyone else who is running LinuxCNC successfully, any and all help would be more than extremely helpful and grateful

Cheers
Bruce

[sailfl]

Bruce

What kind of performance changes are you seeing?

Thanks

[Regnar]

I would but I am in a middle of a move back to Florida. When I used the setup wizard I did 2 outputs as the X axis and just reverted the one side so it would run the opposite direction.

[racedirector]

Thanks Russell, understand. I did what you did but minea not playing ball. I have to go back to Mach (boohoo) as I have stuff to cut and will try again later.

Nils, no accurate measurements just observations. I had the Y axis jogging at 1500ipm no probs at all, smooth as silk. Under mach the best I could manage was a tad over 750ipm. It just seems so much smoother under linuxcnc.

Cheers

[racedirector]

Well, after giving up but trying one more time I managed to get the X working under LinuxCNC. Had to do it differently than Russell but it works... or seems to. Will tweak a little more, air cut a couple of file and then look into Z touch off and Modbus for my spindle.....

[pblackburn]

Keep us updated on your progress. It will be interesting to see what you find as far as performance. I do not have the problems that you had on the DRO but my problems were in other areas. Would be nice to see pics of the computer config when complete also. It may help others down the road.

[racedirector]

I will Pete, LinuxCNC has been a bit of a marathon effort to setup but I am finally getting there.

Got homing working, does this brilliantly too. I decided to check distances and set everything up to check the DRO vs actual travel. Told Y to go 50mm, DRO showed 50mm and the actual travel was spot on 50mm - totally rapt!

Air cutting a file at the moment, the commanded distances from G code are exactly what appears in the DRO's. If you remember I had trouble with Mach not doing that, well LinuxCNC does every time. Never going back now!

[pblackburn]

I am glad you are making headway. The Mach issue you were having seemed to be odd to say the least. I have often thought of trying a setup with LinuxCNC on another hard drive and giving it a test drive.

I do have to say for others that may read this thread that Mach does display the closest obtainable DRO that can be set based on your setup criteria. For instance and this is generalized, if your setup is calculated out to distance per step as 0.00762mm(0.000348") then to travel 50mm(1.9685") the steps would be either 6561 or 6562. So your DRO in Mach would read 49.9948mm (1.9683) or 50.0024mm (1.9686). This has to be because you step distance is a constant that is bound mechanically and electrically by the driver. Now how Mach determines which is closer I do not know, I would assume based on the direction traveling and commanding a stop not to overshoot but I do not know. I did not design it.

I posted this to help others understand what is happening. Now both LinuxCNC and Mach are excellent software controllers. I have read good and bad with both. I can also say there are a lot of very satisfied users of both. So the choice is left to the end user and in the end, the one that works the best for you is the one you use. You should pick the one that is more suited to the direction that you wish your build to develop and grow.

[spyderxxx]

Bruce

How about a linuxCnc tutorial. I would have no idea where to start.

Ed

[pblackburn]

Ed, start with the LiveCD at linuxcnc to test your computer first and check out the software.

[racedirector]

Ed, Pete has good idea's Yup, start with the live CD and see how your computer performs.The latency test is a good start.

I would gladly tell what I know so far once I get to grips with the software. I have been cutting a few things with it this weekend including a new vcarved business logo in some exotic timber from an old set of drawers. I'll post some pics soon of the work. That has been a good test for LinuxCNC and so far I am loving it.

I currently run with a PMDX-126 but later this month I will be changing to Mesa boards, namely the 5i25 and the 7i76. LinuxCNC works great with these boards by all accounts and they offer a stack of inputs and outputs that even dual parallel ports don't offer. At around $350.00 AUD for the 2 it is cheaper than a 126 along with an ethernet smoothstepper. My smoothstepper is currently redundant and I am deciding what do with it.

[spyderxxx]

Thanks

I'll have a look. Will Linux work with a Gecko 540?

Ed

[pblackburn]

Linux is a software controller just like Mach. It will send pulses that your driver will interpret.

[racedirector]

Ed, there are quite a few installs using the G540, a search of the LinuxCNC forum reveals all sorts of things.

You can get a feel for LCNC by using one of the simulation installs, with that you can play around with all sorts of things without a machine connected.

[racedirector]

More success with LCNC.... I have my poor mans toolchanger working. Just like the multi change process in the 2010 screenset for Mach, mine will ask for a tool by moving to the toolchange position and after that moves to the fixed plate and measures the tool in the spindle. From there it goes back to the origin and starts cutting! Absolutely rapt!

[racedirector]

I have been working with LinuxCNC for a little while now when I found out that Tormach uses it for their mills & lathes, its called PathPilot. I very much liked the interface, made me fell more at home leaving Mach 3 behind.

Today I managed to get PathPilot running my Mechmate via the parallel port. Alot of help from the guys at the LinuxCNC forum. I have yet to modify the tool change routines from standard PathPilot to my custom versions but so far so good.

https://youtu.be/ZgU57Zdec9I

[pblackburn]

That is great to hear.

[Alan_c]

Did you buy the PathPilot from Tormach or did it come directly from the LinuxCNC source?