Slitting set-up equation

[Stephen Duquette]

Greetings,

I have been searching the internet for sometime now and have yet to find the answer so hopefully someone here knows this. When setting up coiled metal for slitting, there is a equation for setting the vertical clearance (penetration) and horizontal clearance (break) but I have yet to find this formula. a loose guide is usually setting both to 10% of the gauge of the metal being slit and then adjusting based on burr, crossbow, etc. However I know there is a true formula for a correct setup the first time. I know the variables are the tensile of the metal, hardness of the blades, diameter of the blades, angle the metal as it reaches the blades, and width of the blades but I am not sure how they all factor into the equation or what the actual equation looks like.

Any suggestions on where to look for this?

Thanks!

 

[EdStainless]

I have slit a lot of material and I have never seen such equations.
Our penetrations were higher and the gaps lower that 10%.
The strength of and gage of the material matter, but so does the nature of the alloy.
I have slit Si steels, and stainless steels (both ferritic and austenitic) and gages down to 0.004".
The edge break on the knives matters also.
We only used carbide knives, no steels at all.
We had an outside vendor that used a lot of steel knives, all of his were made from CPM (powder metal) tool steels.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[MagBen]

I have ever seen some simulation/modeling work, but no such a thing as equation. too many factors are in play.
the best bet is a combination of experience, and trial and error.

horizontal clearance perhaps is the most critical set-up. typical is 2-10% of thickness of the sheet. 10% is seldomly seen. the basic rule is to balance between shear and fracture. This can often be evaluate the cross section, shear zone is burnished and so shiny, fractured zone is dull because compressive forces exceed the ultimate strength of the sheet.

Too tight clearances result in deeper shear zones and smaller fracture zones, and the separating line between the two will be uneven and not as defined. On the other hand, if the clearance is too wide, the sheet will be torn apart rather than sheared. There will be a large rollover zone and a minimal shear zone.