Inverted axis on machine simulation (5axis)

[maxime.eichenlaub]

Hi

I'm facing a problem with machine simulation. I built my machine on Solidworks with all the axis in the same orientation than the real machine.

Z axis is carrying the spindle

X axis is carrying the Z axis + spindle

Y axis is carrying A and C axis + the table

The Mechanical Zero is set correctly and the axis have the same orientation than my solidworks machine assembly.

My problem is the following : when i move the X and Z cursor to the right (positive) the axis moves in the positive direction of the axis, which is great. But when i do the same with the Y axis cursor ( cursor to the right), the axis moves in the negative direction of the axis.

You can see in the screenshot here : Y cursor is on +110 but the table moves up when it should move down (Y is oriented to the bottom)

I spent more than 6 hours trying to solve this problem playing around with the mechanical zero axis orientations and whatever i do, there is always one axis that doesn't follow the good direction.

Also i tried to post process a gcode with the machine in the screenshot above and the behavior of the machine is exactly the same behavior as the simulation, Y is inverted.

I don't know what i can do to fix this, i feel like i've tried everything and i feel stucked. Please let me know if you have an idea how to fix this.

Thanks 

Maxime

[kacper.suchomski]

I'm pretty sure you're misinterpreting the axes in a real machine.
The top always has a positive axis direction.

[maxime.eichenlaub]

Hi, thanks for your answer.

No, all the axis are right i doubled checked just now.

I really want to understand why the Y axis of the machine simulation goes in the opposite direction when i'm playing with the cursor, makes no sense to me

[kacper.suchomski]

Show a picture of the axis on the machine.

[maxime.eichenlaub]

Okay so this is the machine in the same configuration as my screenshot : 

This is what i read on my control software : 

And this is my machine in another position : 

And the screen for this position : 

As you can see my X and Y direction in Solidworks are pointing the good direction. Only the Z is inverted from reality but i set the spindle orientation to -1 in the machine configuration : 

[kacper.suchomski]

What axis is along the spindle? Y or Z?

[maxime.eichenlaub]

Z is the spindle axis

Y is the axis moving the table

[kacper.suchomski]

Exactly. So why m model have z axis set with opposite sense?

[maxime.eichenlaub]

Because solidworks don't allow me to orientate Z in this direction. If i click on flip Z axis it automatically flip the Y axis too. See :

[kacper.suchomski]

And it's very good that it flip around. So it has to be. We are at home.

[kacper.suchomski]

It worked?

[maxime.eichenlaub]

I just finished trying. I flipped Z and did a test gcode on the machine and it seems to work properly now. I'm pretty sure i tried this before and it didn't work but i must have made a mistake somewhere else. 

Now everything looks fine 😁 thank you very much for your help, i would have probably take forever to figure this out myself 😅

[kacper.suchomski · Accepted solution]

So we go back to what I wrote in the first comment - you misread (interpreted) the axis directions from the infographic compared to the real machine.

I saw this before I finished reading your post as it's a common problem for newbies. Especially if you haven't dealt with machining before.

Remember - CAM interface support is the last thing. Beforehand, you need to know the construction, we have the principles of designing technological processes, the principles of selecting a cutting strategy and many other issues. 

As for the direction of the axis - you fell victim to "ease making it harder".

CNC programming is the process of defining the path of the tool relative to the part.
When you write a program, you decide how the tool will behave.

For many years, manufacturers of equipment and products have been guided by the maxim "Don't make them think". Products and devices are to be idiot-proof in use.
For CNC machines, there are 2 types of positions - programmers and operators. And all the facilities that don't make them think are aimed at the operators. Not to programmers.

For this machine, the Y-axis is described for the operator (in fact, the direction is reversed); the operator does not think how to position the tool, but how to move the table.

But I remind you - CNC programming is a process of defining a toolpath - TOOLS, NOT TABLE.

The Y axis moves the table, but you want programing the tool. Only the postprocessor translates the tool path into local movements resulting from the machine design.

Therefore, as a programmer, you must use the nominal (logical) coordinate system, not the operator's convenience.

Therefore, learning programming should proceed in the following way:
mathematics -> geometry -> machine building -> machining technology -> CAM programming.
The interface of the program is the last episode, which only serves to speed up the implementation of your choices, not to make them for you - and for this you need to know the mentioned issues.

Learn the principles of (conventional) machining and machine building in your free time. It will be useful to you and will make it much easier to navigate in the CNC environment.

[maxime.eichenlaub]

Thank you very much for taking your time to explain all of this, it makes much more sense now.

I was using a 3 axis router before to upgrade to this 5axis desktop machine, it's definitely more complicated than expected 😅 But thanks to you i'm ready to continue learning 😁