Parting off blade shape.

[Susquatch]

What kind of nonsense is this? The parting tool cuts on the top, not the front or the sides.

Ding ding ding!!! I think we have a winner! The top is what does the cutting. The top cuts from the front edge of the top back to the depth of cut determined by the feed rate. All that the front and sides do is support the top.

 

[jaek]

The top cuts from the front edge of the top back to the depth of cut

Clear language makes it so much easier to be understood, eh?

 

[Parlo]

Ding ding ding!!! I think we have a winner! The top is what does the cutting. The top cuts from the front edge of the top back to the depth of cut determined by the feed rate. All that the front and sides do is support the top.

Thanks for the simpler explanation confirming the cutting perimeter.

Because the cutting edges have two faces, horizontal and vertical, the cutting perimeter seemed easier to describe using the vertical faces i.e. the front face and the side faces.

In hindsight, I should have just posted the drawing earlier as it clearly shows the cutting perimeter without needing a written description.

 

[jaek]

This ASME document names the various parts of a lathe cutting tool. You might want to read it.

 

[Parlo]

This ASME document names the various parts of a lathe cutting tool. You might want to read it.

Thankyou for the link, it really helps to show how more than one cutting edge is required.
The document has an excellent description to explain cutting principles using the nomenclature of major and minor cutting edges.
Using the nomenclature from the document, the major edge of the trapezoidal tool in this discussion is the front and the minor edges are the sides.
Figure 4 on page 11 demonstrates the effect of the minor cutting edge(s) on the surface finish, which in this case are the sides of the groove.

 

[Susquatch]

This ASME document names the various parts of a lathe cutting tool. You might want to read it.

Sometimes it's good to review such things.

After doing so, I think it might have been more productive to have discussed cutting edges instead of faces. That might have more quickly narrowed the discussion. But even then, the feed rate determines the size of the bite and that still involves more of the top face than just the top front edge.

 

[Susquatch]

Using the nomenclature from the document, the major edge of the trapezoidal tool in this discussion is the front and the minor edges are the sides.

Yes. I contemplated this major minor comparison too. But I think the feed rate gets lost in the discussion and that is what decides the size of the minor edge.

What gets lost in doing that is the rectangularity of the cut itself. It really isn't just an edge. Edges are lines. But the cut has length and depth which is an area or surface not a line. In fact, it is this surface that dictates both a major and minor cutting edge.

Moreover, a detailed stress analysis of a cut would show a distribution of forces both in the material and in the cutting tool that go beyond the cut surface itself.

 

[Parlo]

Yes. I contemplated this major minor comparison too. But I think the feed rate gets lost in the discussion and that is what decides the size of the minor edge.

What gets lost in doing that is the rectangularity of the cut itself. It really isn't just an edge. Edges are lines. But the cut has length and depth which is an area or surface not a line. In fact, it is this surface that dictates both a major and minor cutting edge.

Moreover, a detailed stress analysis of a cut would show a distribution of forces both in the material and in the cutting tool that go beyond the cut surface itself.

I hoped that the diagram I posted would show the area on the top of the tool which is the same as the chip section.

Here is the link - https://drive.google.com/file/d/1QyfOBTufVaYmN_7zdSYRsrYRQBbSRcW5/view?usp=sharing

 

[Susquatch]

I hoped that the diagram I posted would show the area on the top of the tool which is the same as the chip section.

Here is the link - https://drive.google.com/file/d/1QyfOBTufVaYmN_7zdSYRsrYRQBbSRcW5/view?usp=sharing

Your drawing shows the dark rectangular cutting surface on the top of the tool perfectly.

Too bad there is no way on here to show a live 3D video of the cutting stresses in the tool and in the part as the tool cuts the part. That is what is missing in this whole discussion.

Does anyone on here have access to an engineering workstation powerful enough to run CAE software that can simulate parting off and create a short video?

Ideally, the video would show several cross sections of the part and the tool at various places and demonstrate the stress gradients of the parting process.

 

[WobblyHand]

Your drawing shows the dark rectangular cutting surface on the top of the tool perfectly.

Too bad there is no way on here to show a live 3D video of the cutting stresses in the tool and in the part as the tool cuts the part. That is what is missing in this whole discussion.

Does anyone on here have access to an engineering workstation powerful enough to run CAE software that can simulate parting off and create a short video?

Ideally, the video would show several cross sections of the part and the tool at various places and demonstrate the stress gradients of the parting process.

Would an IR camera would show the heating of the cutting edges? Might be useful to confirm the simulation?