High Speed Machining Precision Tooling - Indobiz.biz

Automation
This simple loader is designed for casually tended
operation. The track is manually loaded, and load/unload
time is 4.5 seconds
5,000 parts per day, the solution is
a little more complicated. And if, in
addition, there is a family of parts
where the lengths vary from 2 to 24
inches, the complexity jumps another
level. Now consider the automation
if the diameters vary from 0.25 to
1 inch, or if fl ats are milled on each
end that need orientation to one
another. Each variable added to the
product makes your automation
choices more important. There are
trade-offs between price, speed and
convertibility.
As the volume grows and the need for
speed becomes a major factor, the
complexity of the loader grows. An
example is a three-axis, pneumatically
driven, pick-and-place loader, which
is very fast. With the gripper for part
pickup, it is easy to change-over for
different part geometries. However,
the cost of this system is almost
double the simple shuttle type.
The simpler automation devices
are virtually part specifi c. That,
of course, makes them limited in
their fl exibility. Change-over of such
“hard automation” to accommodate
different types of parts will be diffi cult,
if not impossible.
The next step up the automation ladder
is either SCARA or fi ve-axis robots.
The advantage of these loaders is
their speed and fl exibility. They can
pick up parts from pallets, re-orient
them for workholding, remove fi nished
parts and replace them to a pallet or
conveyor.
The initial investment is substantially
higher, almost double the cost of
the three-axis pneumatic pick-andplace
style. However, for the most
possibilities and quickest changeovers
for very disparate parts, they
have their place. The benefi ts of the
multi-axis programmable robots,
when integrated with stacking pallet
systems, can be vast.
Automation systems can be confi gured
so machines can run untended for
hours on end. An example of this is a
robot integrated into a pallet system
that will hold 20 pallets with 30 parts
per pallet. That’s a run of 600 parts
throughout 10 hours at 1 minute per
part. At that point, integration of part
inspection can easily be done. Since
the robot has the part, why not perform
basic inspection? There is very little
lost time and much more confi dence
in your fi nished product.
Analyze Your Automation Needs
In most cases, confi guring an
automation solution is unique to the
application or applications being
looked at. Therefore, when thinking
about automation, there will be
different solutions for each shop.
Here is a checklist to follow:
Flexibility of change-over:
• Lot sizes
• Family variations
Part handling concerns:
• Blank variations
• Workholding issues
• Part cosmetics and fragility
concerns
Throughput requirements:
• Simple manually loaded magazines
• Conveyors
• Pallet systems
• Vibratory bowls
Environment:
• Coolant
• Abrasive chips
Shop capability and skill level:
• Electrical and electronic skills
• PLC and motion control axes
• Tool and die custom machining
After fi guring out which automation
direction to go in, its cost is not always
simple to calculate. The following chart
illustrates how the cost of automation
goes up with its complexity. The
chart below is based on typical costs
associated with automating a small
CNC lathe. Mills, grinders, drills and
any other shop process may be
automated; however, their costs will
be different.
The actual cost of the system will be
affected by its speed (time per part),
cost per change-over, frequency of
change-overs and maintenance and
support.
A Sea Change In
Automation Tools
The biggest change in automation
implementation has been the evolution
of 3D modeling software. A common
misconception by shops of all sizes
is that designing in 3D takes a major
investment in capital and time. It used
to be that delving into the world of
CAD took a fair amount of training and
an extended period of practice before
applying the investment.
Even then, the diffi culty of use
and limited tools hampered its
implementation by operators on the
front line. During the evolution phase
of an automated system, the ability
of the designer to experiment, try
out and research solutions requires
This CAD drawing shows a pallet station fed by a SCARA
robot. The pick and place until loads/unloads the
machine, gages fi nished parts and palletizes them
indometalworking news Vol. 2 / 2008 39