Mach 3

[sailfl]

Yesterday while running a file I needed to Feedhold the run to add a hold down bracket. The machine was in feedhold for a very short period of time. When I used Cycle Start, nothing happened. I could not get it to start cutting again. I had the start the file.

I am using version R2 so I am updating today.

Two questions

1) Has anyone had that experience?

2) How do you start from a different line?

Thanks

[mikefoged]

To start from a different line you have to high light the G-code line and then push the button RUN FROM HERE. Then you have to confirm and remember to click on Start spindle :) that is how I do it.

[Kobus_Joubert]

I have a question on Mach3. I don't know if it was ever addressed here or not, but let me try and explain my situation.
I bought a dial gauge the other day and last night I put it on old Big Blue to check the setup.

On the TAB called MDI I enter a value...say Y6.5 to move my Y axis 6.5 mm.
10302


The very next move say y6.66 show 6.6481 and on the dial gauge I can see the difference.

This happens on all the axis from time to time. WHY does mach3 not move the EXACT distance all the time ?
10303

[sailfl]

Kobus

You need to post this on the Mach forum and let the experts over there explain.

It is most likely the way the math works out.

[Kobus_Joubert]

Has nobody here ever noticed it. Is it maybe a setting I missed or is this a general issue in Mach3 ?
Thank's Nils will try it there as well...if I remember my login :o

[Greolt]

It is a product of the resolution. Steps per inch/mm in motor tuning.

Internally Mach knows the count is 6.6 units, but can only put out pulses to the nearest step.

Depending on the steps per unit setting, one step may be at 6.5582, and the next at 6.6481

What is your steps per unit on this axis? Sounds like it is fairly course.

Divide a unit by the steps/unit and this will give you the resolution.

Greg

[Kobus_Joubert]

Sorry for not responding sooner, but we were without power all day on Sunday and I could not go and check things on old Big Blue.

Previously I calculated the steps as per my pinion sizes etc and got to 54 I think. I then used the Calibration in Mach to FINETUNE it.
Firtsly I draw a block in CAD say 500 x 500 then cut it say 1mm thick. I then measured the block and got maybe 501.6mm. I then used the calibration and told Mach to move x=500. Now I know I measured 501.6mm on my block that was suppose to be 500. So when Mach asked how far did it move I entered 501.6mm. Mach then re-calculated the steps and got maybe 53.923456783......
I brought it back to a full number of 54 tonight and did not see the problem yet....will have to do some more testing.