There are several things you can do to enhance the bending performance
of your Magnabend Machine.
Minimize
the time that you spend doing a bend. This will help to prevent the
machine becoming hot. When the coil gets hot its resistance increases
and therefore it draws less current and thus has fewer ampere-turns and
thus less magnetising force.
Keep
the surface of the magnet clean and free of significant burrs.
Burrs can be safely removed with a mill file. Also keep the
surface of the magnet free of any lubrication such as oil.
This
may cause the workpiece to slip backwards before the bend is completed.
Thickness
Capacity:
The magnet looses a lot of clamping force if there are air gaps (or
non-magnetic gaps) over one or more of the poles.
You
can often overcome this problem by inserting a scrap piece of steel to
fill up the gap. This is particularly important when bending
thicker material. The filler piece should be the same
thickness
as the workpiece and it should always be steel no matter what sort of
metal the workpiece is. The diagram below illustrates this:
Another
way of getting the machine to bend a thicker workpiece is to fit a
wider extension piece to the bending beam. This will give
more
leverage on the workpiece, but obviously this will be no help unless
the workpiece has a sufficiently wide lip to
engage
the extension. (This is also illustrated in the diagram
above). Special
Tooling:
The ease with which special tooling can be incorporated with the
Magnabend is one of its very strong features.
For
example here is a clampbar that has been machined with a special thin
nose to accommodate the forming of a box edge on a workpiece.
(The thin nose will result in some loss of clamping force and
some loss of mechanical strength and thus may only be suitable for
lighter gauges of metal). (A Magnabend owner has used tooling
like this for production items with good results).
This
box edge shape could also be formed without the need for a specially
machined
clampbar by combining basic steel sections to make the tooling as shown
on the left.
(It is easier to make this style of tooling but it is less convenient
to use compared with the specially machined clampbar).
Another
example of
special tooling is the Slotted
Clampbar. The use of this is explained in the
manual and
it is depicted here:
This
piece of 6.3 mm (1/4") thick busbar was bent on a Magnabend using a
special clampbar with a rebate milled thru it to take the busbar:
Rebated
Clampbar for bending copper busbar.
There are a myriad of possibilities for special tooling. Here
are
some sketches to give you the sort of idea:
When
using a non-attached pipe to form a curve please note the details in
the drawing below. It is most important that the parts are arranged in
such a way that the magnetic flux, represented by the dashed lines, can
pass into the pipe section without having to cross a significant
air-gap.