Overall, stamped parts can be very
challenging to “quickly” unfold with proper material
compensation for an accurate blank layout. The difficulty is
not the “initial rough” blank since crash-forming FEA software
has been on the market for decades. The dilemma is staging
(doing it in steps) the formation of the part since most parts
are done in some sort of progression. Either a progressive
die, transfer die, or stage tools are created to accomplish
this process or series of operations.
Laying out this process in 2D systems is
the common approach with simple notes and basic 2D cutting
operations. The rest is left for the designer to “hopefully”
compensate for during the design process with his or her
mind’s-eye! This leaves the door open for many costly errors
and days, weeks or months of frustration. Nonetheless, this
has been the way it has always been done and therefore many
are complacent with the 2D limitations. However, since 3D has
become main stream in the product development world tool and
die makers are facing a new challenge—leveraging the 3D model
throughout their design process!
The 3D evolution is happening right before
our eyes. The majority of work tool designers are quoting
comes in as 3D data in some form. In 2005, over 60% of tool
designers were receiving 3D data to quote and design the
tools. This factor grew from 45% to 60% the prior year so;
this is no flash in the pan. Majority of 3D data should be a
good thing however; most tool designers are only converting
the data from 3D to 2D, and then doing the rest of the design
in 2D. Then the CAM programmers work from the 2D drawings to
recreate the 3D to program the CNC equipment. This is a major
productivity lost to say the least!
2D design has no future—Major innovations
are strictly coming from the 3D R&D centers throughout the
world. For those who stay with 2D, as their main design tool
will also have a limited future since, these individuals must
take on the learning curve of this new technology. Since
learning a tool proficiently doesn’t happen overnight they
will have to learn at the worst time; when they have to! Also,
product designs are much more complex and delivery dates
shorter then ever adding even more pressure to the learning
curve. If you are making blocks and cylinders type parts, 3D
won’t be much of a challenge, however we know the majority are
making parts with complex formed sculptured surfaces out of
unpredictable new materials with incredible tolerances. Don’t
wait until too long to start learning 3D—it is just the
beginning of the road!
The design and manufacturing process of
any sheet metal component must take into consideration
unfolding the part—blank prediction. For parts that are
designed native to the CAD system with only straight bends,
this can be achieved by most CAD systems today very easily.
However, reality sets in as soon as you import a part with
deformed features (stretched or drawn material), complex
bending and cutting. Besides being more complex, there are
typically design errors, material variation, and flanging that
can also cause many headaches even if unfolding in the native
CAD system.
For these and many other scenarios, 3D
QuickTools designed their own unfolding and strip layout
engine to quickly delivery an accurate blank and process
layout in record time all within SolidWorks; 3DQuickStrip and
3DQuickForm.
To start the process the system doesn’t
require the part to be native to SolidWorks therefore, you can
import the part via IGES, STEP, SAT, X_T, etc. The part can be
either surfaces or solid. The part could have been designed
with any method and technique—not requiring it to be a “sheet
metal” type part. The part can also have any type of features
including simple and complex multi-stage formed areas.
After the part is imported, 3D QuickTools
examines the part and does automatic feature-recognition. The
user only needs to establish the unfolding plane and bend
compensation. The unfolding plane can be a flat face, an edge,
or a reference plane entirely off the part. Very quickly the
system returns with the automatic recognition results and the
“Unfold Manager”. The Unfold Manager lists all the features
and allows the user to adjust any parameter. For instance, if
it is a round extrude, you can Zoom to, Unfold/Fold, and
adjust the initial piercing diameter. This also is allowed for
bends and embossments, lances, dimples, and compound forms
just to name a few. If there are features that the system
doesn’t automatically recognize, they user can assist the
system using User-Assisted Recognition (UAR mode).
UAR mode allows the user flexibility to
not only recognize complex areas but, also select what
geometry on the 3D model should be used and not used. This
mode will allow for material variations such as chamfering and
cold forging. There are also many other feature types to
support gussets, complex round extrudes, and complex bending
conditions—including designer errors! The most powerful and
flexible feature is called a User Defined Feature (UDF). This
feature can assist in designing multi-stage forming operations
that incorporate the initial blank, final form, and all other
stages in between. These are called “states”. Each state can
also have “steps”. States and steps are unlimited to support
any stages a tool must perform.
To define the states of a User Define
Feature users have three options. Manually create the internal
state by using traditional modeling techniques, use the
free-form geometric unfolder command built into 3DQuickPress
or use 3DQuickForm. 3DQuickForm is optional software that can
be used with or without 3DQuickStrip. In general, 3DQuickForm
works within the SolidWorks environment and calculates complex
formed regions for blank development. It will take into
consideration holding constraints, multiple projects,
lubricants, material types and properties such as hardness.
Thinning and thickening plot can also be displayed for
formability concerns. We will cover the use and benefits of
3DQForm and 3DQForm Advanced in future articles.
One of our early 3DQuickPress users,
Precision Tool & Stamping, Inc. (PTS) is located in the rural
area of Clinton, North Carolina. Tart Lee is the owner of PTS.
Having committed himself in the die making industries over 33
years, Tart was the pioneer in applying
computer-aided-drafting tools to the industries back to 1987.
“Initially, I tried to do the die design in 2D CAD. There were
problems and issues in the new tools. I had to go back to the
drawing board to finish the job. It took several years for me
to try out new software tools. I moved back and for between
the computer and drawing board before I finally made the
migration from manual drafting to 2D CAD. In 1991, I settled
down in choosing AutoCAD as the design tool. I did make a
number of macros in the system to automate the repetitive
works which our die design needs, this cannot be found in a
generic 2D CAD system. The world is changing and the
industries demand more in terms of speed and price. I kept on
monitoring the innovation in CAD software. My first purchase
of 3D software was back to 1997. I read the various CAD
magazines, and I realized SolidWorks was getting very popular
in the mechanical design industries. It was easy to learn and
easy to use. We invested the first seat that year and I
started to test the feasibility of applying only SolidWorks to
do the die design job in a timely fashion. The learning curve
for me was almost three months to get myself competence to use
SolidWorks to do the die design. I understood that there are
no generic 3D CAD may handle our specific need in tool design.
I have to adapt myself to use the 3D CAD to finish my job.
SolidWorks did help me to complete my job all in 3D, although
it might require more time than my 2D approach. It was
justified to use 3D SolidWorks because I may reduce a lot of
errors in the concept phase of the die design. Today, we
cannot afford to get errors which result in loss of time and
profit cut.”
Tart kept searching for better tools to
speed up his SolidWorks to do die design, he decided to buy
3DQuickPress, a in March 2004. “After I got the training in
3DQuickPress training centre, I knew that I made the right
decision to buy this new product. Of course, I may manage to
finish all my work in SolidWorks in a quality fashion. With
3DQuickPress, I can now finish the job much faster. The
overall gain in productivity was almost 30% after I
implemented 3DQuickPress to my SolidWorks environment.
3DQuickPress makes everything a lot faster. Strip layout
design today is much easier. Hole series is much quicker.
User-defined features in 3DQuickPress added much value to
SolidWorks for our industries.
Tart Lee grows with the US metal
manufacturing and devoted his over 33-years career to apply
new methods to make the US metal industries remain the most
competitive entities in the world market. When the world metal
manufacturers are still debating on the benefits of using 3D
for die design, Tart has shown to the world by finishing his
design in 3D in quality manner.
Today there are over 300 stamping
designers are doing their 3D stamping design using
3DQuickPress and SolidWorks. This trend will keep on because
this is the most probable way to improve the delivery time of
the metal parts in the stamping industries, after all the
advanced high speed tooling manufacturing hardware have been
employed and exploited.
Photos Courtesy of Precision Tool &
Stamping, Inc.
