3+2 Orientation Vector on and off

[iamcdn79]

Can someone explain to me what is the difference between a 3+2 toolpath that is using the orientation vector set to fixed vs. a 3+2 toolpath that is set to free in the machine axis control?

I have been told when doing 3+2 machining to set the machine axis control to orientation vector and fixed but I just made a bunch of toolpaths without realizing that the orientation vector is not on and I don't want to go back and recalculate them if I don't have too.

I posted the toolpath as is and everything seems to look normal. Am I in any danger if I leave it as is?

[LasseFred]

Machine axis control - strategy

Orientation type controls the coordinate system used by the machine tool or the tool orientation.

• Free — The tool orientation is irrelevant. Any tool orientation is acceptable.
• Polar — The toolpath looks like a 3-axis toolpath (the tool axis is the Z axis), however, it uses rotations about the machine's singular axis rather than moving in X and Y.
• Orientation vector — Steers the tool by aligning the vector in a particular orientation. The contact track of the tool remains unchanged, but the contact position on the tool is affected as the tool orientation changes.

taken from help: https://help.autodesk.com/view/PWRM/2019/ENU/?guid=GUID-AEC04B18-B085-4ED8-A459-2D3E894FCB26

did it help?

[iamcdn79]

Ya I read that but don't really understand what can happen if you have a roughing toolpath with a bullnose tool using the orientation type set to fixed or set to free so that's why I created this topic on here

[LasseFred]

my cnc operator prefers running 3 + 2  free machine instead of Orientation vector / fixed

They found it easier to understand how the path will run at the start and end point.

but i can not see a problem in that just set your toolpath connections / links to  rotate then move instead of simultaneous.

[LasseFred]

As I understand, there are not the big differences between the one and the other. besides toolpath connections.

and the machine see the toolpath as a 5 axis toolpath.

[iamcdn79]

One difference I have seen is I cannot swap the configuration of the head if I wanted to when I do it produces a gouge. Which I can deal with in this scenario

[richard.pedley]

Hi Andre,

To answer your question I need to explain a little bit about how the orientation vectors work.

Instead of the tool being defined as a vector it is actually considered in PowerMill to be a coordinate system with it's origin at the tip of the tool, which I'll refer to as the tool workplane. (You can draw this in PowerMill with the command SIMULATE TOOLWP DRAW). See image:

This coordinate system has X, Y and Z axes.

When you're programming a path with Machine Axis control set to free you are defining a point and a vector for each position in the toolpath, with the point being the position the tool will move to and the vector defining the tool axis (the z-axis of the tool workplane).

The tool and the head of the machine are largely constrained however they are free to rotate about the axis of the tool.

When you program a path with Machine Axis control set to fixed direction you are defining a point and 2 vectors at 90 degrees to each other. The point and one of the vectors are the same as the first situation, the second vector is used to constrain the X axis of the tool workplane, locking rotation of tool and head about the tool axis.

Orientation vectors are used to control the orientation of the tool on machines with rotary tables to limit it to a single side of the table, Or, as you identified, to set the configuration of the head.

They are used a lot more for robot programming operations as they have more degrees of freedom.

To visualise this better I'd recommend you calculate toolpaths with and without orientation vectors and simulate on a machine tool, with the tool workplane drawn, to see the differences. 

You can also draw the Orientation Vectors on a toolpath from the Draw options on the Toolpath Ribbon tab.

Does that answer the question?

Richard

[iamcdn79]

Hi @richard.pedley

I never knew about the command SIMULATE TOOLWP DRAW, how do I turn it off? I tried SIMULATE TOOLWP UNDRAW but it didn't work

So I created 2 toolpaths with the machine axis control set to fixed vector and free and can see the difference between the workplane orientation at the tool point but what is that suppose to tell you? I also see the difference between the orientation of the head as well. https://autode.sk/2zNeU4E 

When I post the 2 toolpaths out I get the same values in the nc code. That is my main concern on the project I made my toolpaths on with the machine axis control set to free. I don't want them to be different between the 2 so it will cause me having to remake the toolpaths

[richard.pedley]

Hi Andre,

Apologies, the command to turn it off is, bizarrely:

SIMULATE TOOLWP NODRAW

They allow you to fix the orientation of the spindle relative to the workpiece.

Say for example, you have a rotary table and your machine tool can only reach half the table. From the point and tool axis only there are an infinite number of solutions where the tool can reach that position with different rotations of the table.

I have done a few simulations for this situation in the attached video:

In the first example there are no orientation vectors, the machine tool keeps the table static and moves the head of the machine until it reaches a machine limit, when it rotates the table until it reaches the end of the toolpath. The simulation therefore changes depending on the starting rotation of the table. It follows the simplest route in simulation. However the output will provide a fixed path and this may differ from the simulation.

In the second example the orientation vectors are all towards the centre of rotation, keeping the position of the head in a very small area of the table.

In the third example the tool remains at the edge closest to the machine, but has to under go significant movement at the corners to allow it to work.

It's all about the control and guaranteeing the actual output that goes to the machine tool.

Orientation vectors play a smaller role in head-head type machines as there is typically fewer possible solutions (normally 2 where you flip the configuration of the head). So you may not be able to use them fully depending on your machine limits and your post.

For 3+2 toolpaths using fixed direction will give you more control over what is actually output and if you do want to change the configuration of the head you will have to either recalculate the toolpath, or edit the orientation vectors to rotate them by 180 degrees.

Hope that helps.

Richard

[richard.pedley]

Now with screencast, hopefully.

[M_Hennig]

One thing to keep in mind. If you create a toolpath with the orientation vectors turned on and it's just a vertical toolpath, when you mirror or rotate a toolpath, the head, or table will flip around. This can and will be very annoying so if you do any mirroring or rotating, it's best to have them set to free.

[chuck]

We have Haas UMC-750-SS's and it must be set with Orientation Vector ON and FIXED.

It will work most of the time set at FREE but occasionally it will set the angle to the wrong angle ("C" axis rotated 180) causing gouge/crash even though the simulation looks correct in powermill.

[artur.boszczyk]

 PMILL-12872 is the reference - ambiguous orientation vectors are not output by PowerMill to the post-processor. Implementing OV - didn't solve this

[lxc]

Hi @richard.pedley
I have been looking for this video recording software for a long time. Can you tell me the name of this software? Thank you very much.

[richard.pedley]

Hi lxc,

Unfortunately Screencast has been retired so is no longer available.