Re: [CAD_CAM_EDM_DRO] Re: Press brake auto back stops - DRO / Accuracy

Hi Jerry And All:
Quick Question. What materials bend on the center line of the
stock thickness? Most sheet metal forms closer to the inside bend
side on the one-third of stock thickness line from my experience. i
just looked in my Engineers Black Book (2nd ed by Pat Rapp) and it
shows a "Q" correction factor for bends but does not show the bent
center line. It shows that a softer material can have a smaller
inside radius then harder material but not the bend centerline. I am
going by past experience and my diemaker design books. Another
fact not mentioned yet is to use two drive motors on two parrall
threaded rods (a known distance between centerlines) and then you can
set the backstop at an angle. This would be like is those used on
foot shears. I have one and the scales work great when you have good
light but it does take a bit of cranking to go from a short piece to
a long piece.
Also, I just though, do you you a third party software for
Solidworks to do your s/m layout and folding or can you do it
directly in Solid works. Awaiting your reply which will be very much
appreciated.
GOD'S BLESSINGS
Bill

Actually calculating setback's and bend radi is not an issue. It's
been done manaully for years and w/ a simple CAD system or some
simple math it can be done very quickly. I recommend doing a sample
break on a pc of scrap mat'l [ if your going for 0.01" accuracy] but
otherwise these formula's will get you VERY close.
Check out http://www.thefabricator.com/Bending/Bending_Article.cfm?
ID=356 or search on google about how to set out bend radi. The
basic's of it is knowing what thickness your mat'l is. Most metals
and alum will form around the centerline of the mat'l. You also need
to know the form radius [ the inside rad of the corner after formed]
then calculate your part length of your part [after its formed]
using your lip sizes and your radius. The total part length will be
the length of the centerline of the mat'l of the formed part.
Simple. The break location is the center of the formed corner rad.
Which can also be easily calculated. Or if you want to spend money
on programing, buy SolidWorks, its what I use and its dead accurate
and fast, and programable for mat'ls which don't form on the
centerline of the mat'l.

Jarrett Johnson