deformation during heat treatment 1

[wiggum]

Hi.
After roughing, I have an IPW, where I can see the rest material. During heat treatment deformation occurs, So my IPW will not show the real state. How could I add some kind of blank stock to my IPW?
When the deformation of the part is similar to the cut depth of the rest roughing/prefinishing toolpath (cavity mill), then the tool will surely break.
Any thoughts?

 

[ewh]

How does this relate to NX?

"Know the rules well, so you can break them effectively."
-Dalai Lama XIV

 

[wiggum]

If I compare the original IPW (black contour), and the real hardened workpiece (the red one), it can be seen that (at least) on the top of the boss in the middle, there is more rest material than the IPW shows. If the roughing stock was 1 mm, the deformation ie. 0.5mm, there will be at least 1.5mm.

Once the bottom surface is clean enough, we flip the part and start the second setup. and if we did not take the full 1mm theoretical material here, it may increase the material thickness at the top of the boss further.
The first cutting level will be lower then it should be.

The cut depth is 0.5mm, and cannot be greater then 1mm. So the first cut level should be at the green line, not at the orange one.
I think there is some workaround in NX to deal with it.

In powermill we came up with a method, but it was not so easy, it took a lot of computing time, but it worked.

 

[Tingsryd]

In NX cam...
Cavity Milling operations and Rest Milling operations have a setting for Blank Stock in the Cutting Parameters-Stock tab. There you can specify additional stock to the IPW which I think will be helpful to you. After heat treating we specify extra stock and program with a large, inserted cutter first to remove most of the stock then follow up with finishing inserted cutters and solid carbide cutters. Using Blank Stock will add additional IPW stock on all surfaces so it is possible the initial operation could have some air-cutting time but this is unavoidable unless you scan the block and use that data for an IPW.


We experience the same issues when our H-13 workpieces are heat treated. The block sizes typically range between 300mm x 300mm to 1200mm x 1200mm. We always experience deformation and the more stock that is removed the worse it becomes. It typically is .5-1.5mm although we used to have a customer that specified a radical NADCA heat treating process that involved extremely fast cooling which deformed the steel quite badly. 3-4mm deformation was common but thankfully that customer no longer requires that process.

NX 12.0.2
Testing 1899
EVP's

 

[wiggum]

Thanks, great, i think this is what I need. The trick was that I had to raise the top level... We do very similar part sizes, the larger was 1600x800x400..but without hardening..