Re: Bender question

Hello,

IME with this machine, now going on 12 years; it is not repeatable
enough (with thicker stock) to warrant the attempt to control final
ram position.

If you're doing thin stuff then you could perhaps gain a benefit
from the limit switch idea. (I might rig one up to see how it
translates for the thicker aluminum. BUT... I originally set up a
dial travel indicator, and found that my degree of bend didn't
correlate directly to the end ram position...

YMMV,

Ballendo

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "BobWarfield" <bob@...>
wrote:

>
> John, I have seen a similar project on Home Shop Machinist board:
>
> http://www.homeshopmachinist.net
>
> I want to say it was a tubing bender done by David Coffer (sp?).
> It's worth your doing a bit of searching over there. I seem to
> recall it worked more as a tab stop arrangement with an encoder,

but

> that could be completely off base. An encoder would certainly

help

> with the repeatability on different sizes of stock, or at least I
> think it would. Not sure ELS is set up to deal with one though.
>
> I've also seen a setup that didn't use a fancy controller at all.
> It just had a moveable limit switch. You'd make one by hand, set
> the limit switch when you got it right, and then pushing a button
> made it repeat over and over again.
>
> Best,
>
> BW
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, John Dammeyer <johnd@>
> wrote:
> >
> > Hi everyone,
> >
> > On Thursday one of those 3 in 1 30" sheet metal tools followed

me

> home. I
> > didn't have the heart to shoo it away so it now resides in my
> shop. The
> > original plan was to put a stepper motor on the back gauge and
> dial in the
> > lengths to cut or bend.
> >
> > Turns out that the back gauge is moved to either the bender or

the

> sheer
> > when used. On the sheer, it sits attached to the bottom knife
> assembly
> > which doesn't move. On the bender the die part moves up against
> the fixed
> > anvil to bend the metal so the back gauge has to move with it.
> >
> > This means the stepper controlled back gauge will have to be

easily

> > transported between the two mounting positions and some sort of
> repeatable
> > calibration approach used.
> >
> > My plan was to use the ELS (Electronic Leadscrew) electronics to
> drive the
> > stepper motor since it's not a really heavy or co-ordinated
> operation.
> > Taking into account metal thickness and whether it should be an
> inside or
> > outside bend should allow the back gauge to be positioned

without

> problems
> > and prepunched or drilled holes in the sheet metal should end up
> in the
> > correct spot relative to the bent edge. Just key in the bend
> length, press
> > start and when it's finished moving the back gauge, it would

beep

> and tell
> > you to insert metal and bend or cut.
> >
> > OK. So that's the plan. But like most far east products, this
> tool is also
> > slightly wanting. Adjusting it for 90 degree bends on small 1"
> wide 22g
> > coupons at the ends results in an under bend of a 30" wide piece
> of 22g.
> >
> > So here's the question. How do the large commercial CNC based
> benders set
> > up the depth for metal thickness? Do they have a leadscrew with
> an encoder?
> > Do they use a chain or belt drive between the two ends much like
> my surface
> > planer has leadscrews on all four corners connected by a chain?
> >
> > Or do they have a setup for thickness at all. Instead do they

just

> have a
> > zero reference when the anvil touches the die and then back off
> from that
> > for metal thickness?
> >
> > Thanks.
> >
> > John Dammeyer
> >
>