Topics

61

General Mach Discussion / Educational Sources???

« on: February 13, 2016, 04:16:42 AM »

Hi all,

Having embarked on building a CNC router/mill of around 400x500mm size, and so far only having knowledge of 2d CNC in plasma cutting I realise I have a pretty large gap in my knowledge base  

With all you multi-talented types on here, can anyone point me to a resource that would help bridge the gap between CNC plasma cutting and CNC milling - I have no idea about cutter compensation, homing (plasma is always top of material), cutter length, tool height setting, tool numbers etc.

Some sort of CNC mill primer??

Youtube is loaded but mostly not relevant stuff or presumes knowledge already.


Thanks

62

General Mach Discussion / Mini-Mills - any good???

« on: February 06, 2016, 12:18:05 PM »

Been looking at various threads on here regarding the abundant min-mills like the 3020, 3040 and 6040.

Was thinking of taking the plunge but are they really any good or a pile of bits for an upgrade project??

Most likely the 3040 as the 3020 is too small and the 6040 is getting a bit beyond experimental fun spendy spendy

Obviously it would be fed by Mach but there seem to be two flavours - a cream unit and a black unit model, any one better than the other, any recommended UK suppliers?

I would like to run aluminium, obviously feeds would be low but can they do it?
Also engraving and sign making etc.

Just wondering.

63

General Mach Discussion / THC moves on the Z axis...

« on: January 30, 2016, 10:23:19 AM »

Been doing some tuning on the table and got to the Z axis, trying to decrease plunge time etc.

I had it set originally at 1200mm/min and 900mm/s/s acceleration, this seemed a tad low so I pushed it up until it screeched which was at 2000mm/min so i backed off to 1500mm/min. The acceleration went way up to 5000mm/s/s before a screech so backed that down to 4000mm/s/s which gives an estimated 0.3g and 744rpm measured with a tacho on the motor shaft. I think thats ok for a 3.1Nm Nema23 motor. Steps per mm is 1000, 3mm pitch screw direct drive.

This has given a much snappier Z action and normal repeated G0 Z50 / G0 Z0 moves showed no loss of position.

My question is, is there a way to simulate a THC move - these use no acceleration and is usually where the trouble starts??

64

General Mach Discussion / Msgbox function...

« on: January 28, 2016, 01:07:34 PM »

Can the msgbox function be invoked from g-code or something like a button script only?

I am tarting up my new probing system with a little g-code block that will likely get called from a screen button.

I have no idea how the msgbox works but i need to prompt myself with something a little more prominent than the M00 (please do whatever) message

Could someone point me to a snippet that would go in a screen button, prompt a response then run a block of code presumably from a macro?

I need to tell myself to remove the torch, then run the code block, then tell myself to replace the torch and then run another code block.

Thanks

65

General Mach Discussion / Z-Axis Dro - Odd behaviour?

« on: January 16, 2016, 10:30:48 AM »

Can someone have a look at the video clip I have linked below?

It shows my Mach3 plasma screen before a file load, during file load and then when pressing my "Set Origin" button.

As you will see, the Z is happily parked at 14.991mm which is where it really was after the end of the previous run. When i press set-origin it jumps to 0.437mm then to -0.9mm then to 0.437mm where it stays. The actual axis does not move - just  the DRO freaks out and leaves a meaningless reading on it which puts it in a bad position for a dry run on a new file.

The 14.991mm is wrong as well because my final Z move is always to 15mm dead, the difference  between 15mm and 14.991mm is the reading of the "THC Adjustments" DRO when the last cut finishes, if i run with THC off it always ends on 15mm dead.

Here is a link to a video showing what I believe to be odd behaviour of my Z-axis DRO.
https://youtu.be/WCmHRbIpm1o

Is there any logical reason for this, or a cure maybe???

The set-origin button does this...
DoOEMButton(1008)
Sleep(500)
DoOEMButton(1009)
Sleep(500)
DoOEMButton(242) 'Copy X Y Z to G54
Sleep(500)
DoOEMButton(160) 'Regen Path
   

66

General Mach Discussion / Display Mode Button - Not Working?

« on: January 15, 2016, 06:51:37 AM »

Could there be a reason why my display mode button does nothing?
It has this VB code in it ...

value = GetParam("Boundry")
if  value = 1 then
SetButtonText " Job "
SetParam "Boundry" , 0
 else
SetParam "Boundry" , 1
SetButtonText "Machine"
end if

So I am going out on a limb here and guessing the button text should change when pressed but mine always says "display mode" and seems tot do bugger all.

Just wondering

Also, is there a zoom-to-fit option anywhere??

67

Brains Development / Logic failure, help please

« on: January 12, 2016, 01:24:00 PM »

I have a #var being set to 1 or 0 via G-code.

I have a brain that switches an output IF two conditions are met -

The #var being = 1 AND the RUN(804) LED being on i.e. we are running code.

However the logic fails as the output is triggered when I load a g-code file OR when doing a path regeneration.


Any reason why this should fail and is there a way to make it work??

68

General Mach Discussion / Limit switches and G28.1

« on: January 11, 2016, 03:16:46 PM »

Am I correct in my assumption that limits are disabled when doing a G28.1 homing??

69

General Mach Discussion / Probably simple but...(G-Code help)

« on: January 09, 2016, 04:36:38 PM »

If I have my axes at say X100 and Y100 and in g-code I want to temporarily move to say curretntX+50 currentY+50 , do something then move back to where i was before, how would I code it??

Do i need to be looking at the DRO's etc as variables and adding/subtracting my move ?? or is there a sensible way??

Anyone care to throw an example my way??

70

General Mach Discussion / Mach3 and the THC...

« on: January 02, 2016, 07:10:09 AM »

Ok, possibly not in the right forum for this and it's not a Mach gripe for certain but...

On my plasma, I have the Z axis homed to the plate surface at every start, Z axis is controlled by the THC as normal (CandCNC MP3000-DTHC2) during the cut and the last line of the code is G0 Z15 which should park the torch at my safety height.

What it does though is park it at Z15 +/- and difference in the THC readout, so if the cut ended with the torch at 1mm lower than it started, it parks at Z14 not Z15.

Is there an easy to explain reason this could be??

Its like the THC is updating a work offset or something during the cut rather than just issuing up & down commands.