Similar in result to the Unfold tool, the Flatten
icon (see Figure 6b) toggles the model between
flat layout or the default, which is the formed configuration. This toggle icon is a convenient way to
switch between folded and flat.
The CAD jockey can take advantage of the way the
Flatten icon works to create step-by-step folding instructions. As each bend is processed in CAD, that
bend is flattened. If the bend processing for that
bend is suppressed, then the bend is not flattened.
Figure 6c illustrates the trick. The first step is to
unsuppress all bend processing to get a flat layout.
A quick way to do that is to click on the Flatten icon.
Next, suppress the bend processing for a desired
bend. To do that, select the bend, right-mouse-click, and select Suppress. The bend appears. In
Figure 6 almost all of the bends are processing, or
in the flat state.
By adding configurations to the model, we can
create quick transitions between flat and folded
in a specific sequence. This bend processing trick
might come in handy for designing illustrations for
CAD Forming Tool
Versus Hard Tooling
In the fab shop, punching machines use dedicated
tooling for applications such as stamping extruded
holes, forming louvers, lifting bridge lances, and
embossing countersinks. In the CAD world, these
stamped and formed features can be tedious to
model. To keep the tedium to a one-time occurrence, a CAD jockey can use a Forming Tool, a CAD
analog for the actual tooling die set.
The Forming Tool model is separate from the
workpiece model being designed. An example for a
bridge lance tool is shown in Figure 7a. The Forming Tool model represents the interior of the feature
being embossed—very much like the male punch in
the actual die set. While creating the Forming Tool
model, the CAD jockey defines a stopping face. Additionally, cut (instead of stretch) can be specified
to create openings; the sides of the bridge lance are
open, for example.
As represented in Figure 7b, the Forming Tool
model is drag-dropped from its folder onto a face of
the sheet metal part. The Forming Tool model may
be located and rotated for precise positioning. The
result of applying this bridge lance forming tool is
shown in Figure 7c.
The design shown in Figure 8 has evolved into
something that requires several setups. It was easy
to model and will be easy to edit, though.
Gerald Davis uses CAD software to design and develop
products for his clients at www.glddesigns.com. From
1984 to 2004 he owned and operated a job shop.
Gerald would love for you to send him your comments
and questions. You are not alone, and the problems you
face often are shared by others. Please send your questions and comments to firstname.lastname@example.org.
The Unfold feature is used in this demonstration to
flatten the part before adding the cut. This technique
allows the cut to wrap around the folded bend in a realistic manner.
Unlike Unfold/Fold, the Flatten icon relies on the suppressing and unsuppressing of bend processing. This
icon toggles the part from the folded to flattened state.
It automatically does the suppressing and unsuppressing of all bends.
Suppressing and unsuppressing of individual bends
can be used to create step-by-step illustrations for
how-to-bend documents such as an owner’s manual.
The demonstrated trick is to start with the part in the
flat state, shown in Figure 6b, and then unflatten the
bends in sequence. Here’s a quick CAD tip: Use configurations to capture the sequence steps.
An example of a bridge lance Forming Tool is shown.
The Forming Tool is the model of the interior of the
dent into the sheet metal. Optionally, the tool can remove sheet metal as well as extrude it.
The forming tool is applied to the sheet metal part in a
drag-and-drop work flow. Here, the bridge lance is being positioned. Figure 7c shows the result.
The application of the Forming Tool is complete. Additional bridge lance features are easy to drag and drop
onto the model.
This demo part has been easy to model, but it would
require several setups to fabricate. Hems, jogs, bridge
lances, and internal tabs all contribute unique expense
as well as benefit to the design.
In the CAD world, these
stamped and formed
features can be tedious
to model. To keep the
tedium to a one-time
occurrence, a CAD jockey
can use a Forming Tool,
a CAD analog for the
actual tooling die set.