Preferred scale direction conventions?

[leebro61]

Hi All -

I have been up and running with a 3 axis setup on my Series 1 Bridgeport for a year or so now and I couldn't imagine going back to my life without it. I'm very impressed with the app, with this forum, and with the support that Yuriy provides!

Most of the time I'm just using the tablet to read position as I work, but on several occasions I have made good use of the linear and angular hole pattern features. I have also been testing the newer feature where you can bring in a drawing and then orient it to the part as a reference ... very cool stuff.

The problem seems to be that every time I attempt to use one of these advanced features things never end up where I am hoping they would go. In other words, if I'm wanting a pattern of holes to move up and to the right they might move down and to the right, or vice-versa. I can usually figure this out with some planning, but I literally never get it right on the first try, which means creating a new workspace to clear the erroneous pattern. The app also doesn't allow the concept of a "negative step", so if you picked the wrong hole to start your pattern from you will be moving the table again to change your start location. I've experimented a bit with swapping individual axes directions and trying some of the features again but if I'm honest, most of my garage time is spent in the late evenings after a long work week and I'm not always firing on all cylinders mentally.

I currently have my scales set up such that moving the table toward the column is the +y direction and moving the table to the right (when facing the column) is the +x direction. I'm guessing that my convention around the y direction is reversed compared to what most are observing? Is there a default that the app is "expecting" that I would do well to follow?

Thanks!
Lee

 

[ycroosh]

Hi All -

I have been up and running with a 3 axis setup on my Series 1 Bridgeport for a year or so now and I couldn't imagine going back to my life without it. I'm very impressed with the app, with this forum, and with the support that Yuriy provides!

Most of the time I'm just using the tablet to read position as I work, but on several occasions I have made good use of the linear and angular hole pattern features. I have also been testing the newer feature where you can bring in a drawing and then orient it to the part as a reference ... very cool stuff.

The problem seems to be that every time I attempt to use one of these advanced features things never end up where I am hoping they would go. In other words, if I'm wanting a pattern of holes to move up and to the right they might move down and to the right, or vice-versa. I can usually figure this out with some planning, but I literally never get it right on the first try, which means creating a new workspace to clear the erroneous pattern. The app also doesn't allow the concept of a "negative step", so if you picked the wrong hole to start your pattern from you will be moving the table again to change your start location. I've experimented a bit with swapping individual axes directions and trying some of the features again but if I'm honest, most of my garage time is spent in the late evenings after a long work week and I'm not always firing on all cylinders mentally.

I currently have my scales set up such that moving the table toward the column is the +y direction and moving the table to the right (when facing the column) is the +x direction. I'm guessing that my convention around the y direction is reversed compared to what most are observing? Is there a default that the app is "expecting" that I would do well to follow?

Thanks!
Lee

Lee,
TouchDRO follows the [standard] convention, which is exactly opposite from how your scales are set up.
Imagine that (0,0,0) point is the lower-left corner of the table. As you move the spindle to the right (table to the left), the X dimension should grow. As you move the spindle towards the back of the table, the Y dimension will grow, and as you lift the spindle the Z dimension will grow.
In your setup the (0,0,0) point appears to be in the upper-right corner.
You can find more info here: https://www.touchdro.com/resources/dro-manual/dro-coordinate-system-and-datums.html or here: https://www.yuriystoys.com/2014/01/touchdro-coordinate-system.html

Regards
Yuriy

 

[ChazzC]

Lee,
TouchDRO follows the [standard] convention, which is exactly opposite from how your scales are set up.
Imagine that (0,0,0) point is the lower-left corner of the table. As you move the spindle to the right (table to the left), the X dimension should grow. As you move the spindle towards the back of the table, the Y dimension will grow, and as you lift the spindle the Z dimension will grow.
In your setup the (0,0,0) point appears to be in the upper-right corner.
You can find more info here: https://www.touchdro.com/resources/dro-manual/dro-coordinate-system-and-datums.html or here: https://www.yuriystoys.com/2014/01/touchdro-coordinate-system.html

Regards
Yuriy

Hi, Yuriy,

Unfortunately, in Mini-Land, the axes don't follow convention. As noted in some of the conversations in your second link, the Y-Axis is reversed on the Mini-Mill, so that clockwise rotation increases the readings on the dial, but the spindle moves away from the back of the table. I've inverted the display to correct this on the display, but it's always hard to remember clockwise is (-). Similarly, on the Lathe, the cross slide dial readings increase with clockwise rotation, rather than decrease (for some reason this doesn't bother me as much as the Y-Axis on the Mini-Mill; maybe I think better in 2-D?). I now have yet another project: make new dials for the Lathe X-Axis and Mill Y-Axis so at least if I look at them, the numbers will change in sync with the displays.

Z-Axis on the Lathe makes sense since the hand wheel turns CCW to move the saddle towards the headstock, and on the mill pulling down on the had wheel makes the spindle go down (I customized the Z-Axis fine feed long ago, so no numbers to worry about).


Regards,


Charlie

 

[extropic]

 

[leebro61]

Lee,
TouchDRO follows the [standard] convention, which is exactly opposite from how your scales are set up.
Imagine that (0,0,0) point is the lower-left corner of the table. As you move the spindle to the right (table to the left), the X dimension should grow. As you move the spindle towards the back of the table, the Y dimension will grow, and as you lift the spindle the Z dimension will grow.
In your setup the (0,0,0) point appears to be in the upper-right corner.
You can find more info here: https://www.touchdro.com/resources/dro-manual/dro-coordinate-system-and-datums.html or here: https://www.yuriystoys.com/2014/01/touchdro-coordinate-system.html

Regards
Yuriy

Hey Yuriy, I'm confused again.

From your site:

"Vertical milling machine is probably the most intuitive when it comes to it’s coordinate system. As I mentioned earlier, the axis parallel to the spindle is Z. On a vertical mill this axis is, well, vertical, therefore table’s longitudinal travel will be “X” and cross travel will be “Y”, with the numbers increasing as it moves to the right and away from you."

From my post:

"I currently have my scales set up such that moving the table toward the column is the +y direction and moving the table to the right (when facing the column) is the +x direction."

Aren't we saying the same thing?

If I'm missing something obvious then I apologize ...

Thanks!
Lee

 

[ChazzC]

I realized that since the only reason to replace the dials on the Y-Axis (Mini-Mill) and X-Axis (Mini-Lathe) is for my brain struggling with positive vs. negative numbering, and that I didn't need the accurately position the dials (that's what the DRO display is doing), all I had to do was flip the dials on the axes.

Mini-Lathe

Mini-Mill

Now the numbers get smaller when the diameter gets smaller on the lathe and when the spindle moves in the negative direction on the mill.

 

[ycroosh]

Hey Yuriy, I'm confused again.

From your site:

"Vertical milling machine is probably the most intuitive when it comes to it’s coordinate system. As I mentioned earlier, the axis parallel to the spindle is Z. On a vertical mill this axis is, well, vertical, therefore table’s longitudinal travel will be “X” and cross travel will be “Y”, with the numbers increasing as it moves to the right and away from you."

From my post:

"I currently have my scales set up such that moving the table toward the column is the +y direction and moving the table to the right (when facing the column) is the +x direction."

Aren't we saying the same thing?

If I'm missing something obvious then I apologize ...

Thanks!
Lee

Lee,
That paragraph is confusing. "It" refers to the spindle. You are measuring the movement of the cutter in relation to the workpiece. On a traditional "American" mill, the table moves in two or three directions (X, Y and sometimes Z). On many European mills the table moves in X and Z direction, and the head moves in Y direction. Quill is second "Z" axis component.
The graphic extropic posted above is correct. Note that the arrows are attached to the spindle.
Regards
Yuriy

 

[leebro61]

"It" refers to the spindle. You are measuring the movement of the cutter in relation to the workpiece.

Hey Yuriy,

I have never doubted that your recommendation is 100% correct and I will happily implement the changes and move on with my life ... but, please allow me to gripe for 2 minutes and then I will get over it.

It feels sloppy to me to refer to "it" moving and hope that people will assume that "it" refers to the spindle when the spindle doesn't actually move (in any conventional sense). If your vehicle's owners manual said 'press the accelerator pedal and "it" will move backwards' you probably would assume that "it" was referring to the car and not the trees on the side of the road. All is forgiven in either example if you add explicit verbiage like "in the part's (or driver's) reference frame" or similar. I'm actually surprised that terms like "part reference frame" vs. "operator reference frame" aren't more commonly used.

The brings me to my second gripe. My day job is designing jet engine components where the blades rotate and the vanes don't. We have the concept of an "absolute" reference frame for stationary parts and a "relative" reference frame. Pressures and Temperatures get an "A" or "R" suffix to denote which one they are in. Velocities in the absolute frame are labelled "V" and velocities in the relative frame are "W". Angles are alpha and beta, respectively. In other words, we go through quite a bit of effort to ensure that this is as clear as possible, especially for folks that aren't subject matter experts (read, me - in this particular case!). Sticking the coordinate system on top of the spindle is way too subtle. I just assumed that the origin was located there in the picture because that's where all 3 axes nominally intersect. In all honesty, I looked at the picture and noticed that the table was displaced to the right. That was more suggestive to me of the positive X direction than aligning the coordinate system to the spindle. (Yes, I realize you didn't create that picture).

Third gripe (... and then I swear I'm done) - my coordinate system still follows the right hand rule, it's just rotated by 180 degrees about the Z axis AND it's consistent with the dials on my Bridgeport which are apparently in the "operator reference frame." More clarity required

I'll go swap my settings and see where I end up ... thanks all!
Lee

 

[leebro61]

I'll go swap my settings and see where I end up ... thanks all!

To the surprise of nobody (myself included), reversing the x and y-axes seems to work better.

Now to just retrain my smooth brain to set the top right corner of the piece as 0, 0...

 

[kokoroko]

Hi Lee,

It sounds like your issue with the advanced features is likely due to a mismatch in coordinate directions between your setup and the app's default settings. Adjust your machine's configuration so that +y moves the table in the direction you intend. This should align the app's features with your expectations.