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Messages - PeteG

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General Mach Discussion / Constant velocity vs Exact stop
« on: May 21, 2020, 01:55:37 PM »
So, I am once again confused. I have been running my machine in constant velocity mode, which seems to be the default. I had a little issue with corners rounding off and corrected this by altering the acceleration and deceleration settings.

Then I saw a YouTube vid which introduced me to the wonders of ‘exact stop’. This works well and creates really sharp corners but is a bit weird when cutting circles. So I tried the option to turn off CV on an angle greater than 89 degrees. I assumed that this would make the machine run in CV mode until it encountered a 90-degree corner and would switch to exact stop mode. But it doesn’t. No matter what angle is set, it stays in CV mode.

What am I doing wrong?

General Mach Discussion / Re: Set for mm but moving in inches.
« on: May 16, 2020, 01:43:29 PM »
Around 200 plus a load of numbers after the decimal point. I had to massively increase the feed rate and accel/decel and it's all working very smoothly and acceptably.

I used a dial gauge to set the steps, but X wasn't coming out right as I was only able to check travel over 20mm. Y was spot on, maybe because there are two motors driving it - maybe, maybe not. So I rigged up a jig to hold a vernier gauge and was able to set X over a distance of 100mm and it is now super accurate.

General Mach Discussion / Re: Set for mm but moving in inches.
« on: May 16, 2020, 11:49:25 AM »
Your advice was spot on, thanks. I've just used the axis calibration tool, and run a test of X at 150mm & Y at 100mm, Y is exactly 100mm, but X is coming out 150.03mm so I think there maybe some errors creeping in somewhere.

General Mach Discussion / Re: Set for mm but moving in inches.
« on: May 16, 2020, 08:55:50 AM »
Thanks everyone, machine is working properly now.

General Mach Discussion / Re: Set for mm but moving in inches.
« on: May 16, 2020, 07:32:00 AM »
Hi Tweakie

Thanks for the reply. I tried you suggestion and X1 did indeed move by 1 mm, it took fifteen seconds though. So I reverted back to the original settings, set everything in inches and ran a file that was also in inches and it worked perfectly. But, Mach 3 then displayed an error message - Art 904. I could not find what 904 is, so I clicked the option to correct this. I then got another error message 9991. Clicking to correct this did nothing.

I closed Mach 3 then reopened, made sure everything was still set to inches and ran the same file again. This time, instead of rising 0.5 inch before moving to the start position, it just kept on rising.

Do you know what error code Art 904 is? I can't find any documentation about Mach 3 error codes.

I am confused, and what is most confusing is why the Z axis is not working correctly. I have been using my machine since January without any problems.


General Mach Discussion / Re: Set for mm but moving in inches.
« on: May 16, 2020, 04:25:34 AM »
Hi Graham

Thanks for your reply.

Pitch is 2mm, 4 starts, and you are correct when you say motors are driving the lead screws directly. I'm not sure what you mean by stepping though.

Mach 3 units are set to mm in the 'set native units' drop down and set to mm in the settings tab, this is confirmed by Mach 3 displaying G21 in the top right of the screen. Files are created in Vcarve and are set to mm, and saved to the mm option in the post processor save dialogue, and have G21 at the start of the G code .txt file.

This issue I have is not steps per unit; I set that empirically for the X and Y (the drives that I have changed) and Z has always been on a 2mm pitch, 4 start lead screw with 5120 steps per unit. I set X and Y to this and have made adjustments using the 'axis calibration' option in the settings tab. The issue I have is that now it only moves in inches, even the Z-axis which I haven't changed, only fine tuned with the 'axis calibration' option.

The only thing I am doing differently is that I have been using the MDI page when testing X Y movement. I have found that MDI only seems to work in inches, regardless of settings. i.e. with everything set to mm, an input of X1 in MDI caused a movement of 25.4mm, not 1mm as expected.

On the advice of newfangled solutions, I uninstalled/reinstalled Mach 3, but the issue remains.

Any suggestions?



General Mach Discussion / Re: Set for mm but moving in inches.
« on: May 15, 2020, 11:44:49 AM »
I could really do with some help on this as I can't see why this is happening.

General Mach Discussion / Set for mm but moving in inches.
« on: May 14, 2020, 10:58:47 AM »

I have been using mach 3 for several months now and had good results. I have a home made machine that moved on the X&Y axis using a timing belt and toothed pulley system. This worked well, but the belt tension was difficult to maintain and sometimes led to poor results, so I have upgraded to a leadscrew system for both axis. This required retuning of the motors. I used the axis calibration in the settings tab and got readings of around 5200, which seems about right and was close to the steps needed on the Z axis which was already on a lead screw system.

I created a test file using Vectric Vcarve to simply make a straight cut 300mm along the X axis, but despite the mach 3 being set to mm in the settings page, G21 being indicated on the program run screen and the Vcarve project being set to mm, the machine moved in inches.

When I first ran the machine after the upgrade I used the automatic axis calculation tool, but this seems to only work in inches. i.e. despite being set to mm, when using MDI a value of X1 this resulted in a movement of 25.4mm i.e. 1 inch, not 1mm. I got the same result whether the units were set to mm or inches.

What is puzzling is that the Z axis also now moves in inches and I had only fine-tuned this axis using the automatic calculation tool.
What have I done wrong?



General Mach Discussion / Saved axis settings
« on: May 01, 2020, 03:44:58 PM »
I will put my hand up and say that I am embarrassed to be asking this, but....

With my machine, the Y axis is driven by two motors which are 180 degrees from each other. I have slaved the A axis off the Y axis, with the A direction reversed. Everything works well but I am making a change to the machine that requires the slaved axis to not be reversed. But when I looked at motor configuration, I noticed that the settings for A are significantly different to Y settings. I have not noticed this before and had not to as all was well.

So my question is: if an axis is slaved, does it automatically use the settings from the axis that it is slaved from?

General Mach Discussion / Re: Not cutting circles neatly
« on: April 08, 2020, 10:27:32 AM »
Thanks for the reply, I was thinking that I might be that, good to get another opinion though.



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