Spinning thinning rate and how to calculate the diameter of spinning material

①Spinning thinning rate
The thinning rate of Spinning products is usually about 10-40%, the shape of product is different, the thinning rate is difference, in addition to select different spinning path , adjusting the clearance of the spinning roller and  mold can affects the thinning rate of products.
1) bucket : the height increase or diameter reduce , the thinning rate  increases.
2) cone: taper is smaller, the thinning rate is bigger ,the thickness after spinning  = blank thickness T * sine α
3) complex shape : it is based one bucket shape or cone shape ,May be it is made by neck spinning or flaring spinning in the second step .

② How to estimate the diameter size
Sheets of blank quality in theory is equal to the spinning quality and the cutting in the process of machining.Both:
Material piece weight = spinning product weight + trimming + bottom cutting loss (cut the weight of the material at the bottom of the piece)
Trimming loss weight= spinning products* 1% 
Cutting bottom loss = （πr²t）*p
Diameter =2* blank quality /pπt
Note: t stand for material thickness , p stand for material density. r stand for radii .
you can known the spinning product weight by weighing , or using 3 d modeling to measure.