Problem with 2 sided setup confusion

[george]

Is it just me or is the process to pick your WCS frustrating? Unless I'm doing something else wrong the only difference when moving to the bottom side should be the direction of the Z Axis and in my case the Origin is on the bottom corner of the stock.

Whenever I flip an axis the origin gets moved to a different point on the stock and end up going in a visious circle of picking and flipping until I somehow magically do the right order that allows me to place it properly. 

For me it seems like you should just be able to pick the origin point and then say what direction each axis goes without the origin moving on you.

[jeff.walters]

I understand what you’re saying but Fusion works just the opposite. You set the orientation then the location relative to the orientation.

[george]

Uh, huh? I'm working on a model that I started way back when I first started with F360. For some reason that model has an origin orientation that I wouldn't deam corrct. It has Y going up, Z coming at you, and X going to the right. Not sure if that's part of my issues or not but I thought I would mention it.

When standing in front of the CNC at the shop I use X goes away from you, Y goes to the left, and I would call Z going up. If I'm doing an operation on the top side I want my WCS to match that and I can do this with the origin located at the top of the stock. My CNC origin isn't going to change so for my bottom side operation all I want to do is move the origin to the bottom of the stock and change the Z axis direction. 

I have tried every combination and order of operations that I can think and I can't get this to happen. I didn't catch that the Y axis was to the right last night and when I tried to run a job the CNC crashed because it tried to move to the right.

I'm not an expert but at least for me it seems extremely odd to have your stock move when you are trying to define WCS.

[Anonymous]

The standard cartesian coordinate system follows the right hand rule.  If you imagine grabbing the Z axis with your right hand and your thumb pointing in the positive Z direction, your fingers will curl around through the X axis first and then the Y axis.  You can't just flip the Z axis sign without affecting the direction of at least one of the other axis.

If you have a part that you mill one side and then you flip it over along one axis, the part is now going to be mirrored along that axis from how it was originally.

I would think the most common machine coordinate system has positive X pointing to the right, positive Y pointing away from you, and positive Z going upward away from the table.  So it's like looking at the table from the left side of the machine you use.  That would take some time getting used to...

[Anonymous]

I just played with this for a few minutes, I normally use the click on the leg of the WCS then click on a plane that I want it to be normal to.  Usually works the first time by selecting the Z axis and the top of the part, but Fusion seems to default to the more common case of then putting the X axis pointing to the right.

The easiest way I could find to do what you need is to select each option in the Work Coordinate System section of the Setup tab under Setup.  So change the Orientation from Model orientation to "Select X && Y axes" then select an edge for the x axis, and select and edge for the y axis, and probably click both of the Flip X axis and Flip Y axis boxes.  After that you can select the origin point. -- I do see what you're saying about the stock moving and that has to be a bug.  I can't get it to do it right now since I'm trying to make it happen, but earlier it would rotate the stock box around or flip it over to one side or the other when I made changes... weird!

Here's a simple part with milling on two sides.  Hopefully it will help somewhat...

[HughesTooling]

I think a new install of Fusion has Y set as up, when I fist installed it a year ago that was the default. Once you start a design you can't change that setting so you may have changed the default setting but that doesn't change an existing design.

It doesn't matter how you designed the part anyway you can set the orientation is the CAM setup. Here's an example the setup origin is in the red box. The model Z is at right angles to the setup Z.

Your machine layout sounds quite unique, every machine I've used X is left to right Y is back to front and Z in up down. As long as the + direction match the CAM I don't think that will make any difference though.

Mark.

[george]

Well at least it doesn't sound like I'm totally crazy or just doing something dumb. The computer that operates the ShopBot is at the end long end of the table if that makes sense, I wish I had a picture. But sitting looking down the table the positive X goes away from you down the long end and Y is the short side with positive going to the left. Here's a picture of my top side setup with matches the machine setup:

It makes sense that the model orientation doesn't matter when doing a CAM setup but I thought I'd mention that in case it was an issue.

So in the picture I've inserted for the top setup I'm trying to make the bottom setup move straight down to the bottom point of the stock and flip the Z direction. I need to look at the example setup attached to the earlier post but isn't that the proper way to setup the bottom side? I know the top side orientation is correct because I have run 2 top side jobs with this orientation.

[george]

I'm looking at your example and am beginning to think this is perhaps a problem of perspective when viewing the model? If I set F360 to view straight down from the top and then look at the 2 setups the origin location moves as well as the X direction. If I think of physically rotating the stock on the table to perform the bottom side operations the location change of the origin seems to make sense but I still wonder if the X/Y directions will be correct when I generate the machine file.

When I compare a top view to a bottom view the origin doesn't move and the X/Y directions stay the same so I guess I need to use your model, generate some machine code and look at the files and check the +/- of the moves and see if they're the same.

[HughesTooling]

An advantage to having X from left to right and Y from back to front on your machine is it's the same as laying your computer screen on the table of the machine, it makes visualising the setup a lot easier. I don't know if you could swap the cables on your machine to end up with a more standard setup. If not you just have to imagine your computer screen on the table rotated 90°.

There's a nice free back plot program here, if it runs your g code ok it might help set your mind at ease before trying to run the code on your machine. Of course you can always run the code above the job first until you have a bit more experience of what's happening between Fusion and your CNC.

If the code comes out rotated 90° to what you expected it's quite easy to go back to the setup and rotate the origin 90° and have another go.

Mark.