The Right ChoiceBurr OAK Tool Slashes
Production Time with ESPRITThe Michigan-based tool and die shop reduced
time to machine die from 11.3 to 4 hours
J a n u a r y 29, 2020
Burr OAK Tool Inc. is the leading producer of dies used to produce two types of fins for window airconditioners. Evaporator fins on the side of the air conditioner inside the window transfer heat fromthe inside air to the cold refrigerant flowing through the evaporator coil. Compressor fins locatedon the side of the air conditioner outside the window move heat from the now hot refrigerant to theoutside air. Burr OAK Tool dies progressively stretch and reform the fins through a series of metal
forming operations that extrude and reduce the thickness of the fins. The very complex geometry ofthe dies must be controlled within +5/-0 ten thousandths of an inch in order to meet fin tolerances.

Inadequate Solutions
Until recently, the company finished and semi-finished fins on a Makino Form Grinder because its
machining centers could not hold the required tolerances. It took 9.2 hours to produce fins witha waffle form and 11.3 hours for sine wave fins. Burr OAK Tool recently purchased a Mazak VTC800 4-axis vertical machining center with the goal of reducing machining time for these dies. The
new machine is much more difficult to program than any of the machines used previously by thecompany. Adding to the challenge is the fact that parts are designed in 2D because they have somany holes and other features that it would take prohibitively long to design them as solid models.
Burr OAK Tool previously used a CAM software package that did not accurately simulate machining
operations. The company mounted many of the parts it machined on workholding devices called
tombstones and it was not unusual for a spindle driven by a new program to crash into a tombstone,
which often required expensive repairs. “We switched to ESPRIT CAM software from DP Technology
because it accurately simulates the machine, turrets, spindles, tools and workpiece in real-time operation,” said David Schwartz, CNC Programming Manager for Burr OAK Tool. After switching to thenew CAM software, Burr OAK Tool programmers attended ESPRIT training for the Mazak VTC-8000
and the company purchased a Solid Mill Free-Form 3-Axis add-on for one of its ESPRIT licenses.

Reducing Overhead

A Promising FutureWith ESPRIT, Burr OAK tool programmers
detect crashes and gouges during theprogramming process before downloading the program to the machine. ESPRIT’s
simulation capabilities have eliminatedcrashes while substantially improving theproductivity of the company’s programming
team. Over the time it has used ESPRIT,
the company has reduced its program-

Most machining operations are performed
with the spindle tilted at 30 degrees withrespect to the workpiece because ball noseend mills perform better when cutting ontheir sides than on their points. The milling
operation is typically run at a 250 inches per
minute feed rate and produces an 8 ra finish,even better than the 16 ra finish produced
by grinding. The roughing operations are
performed on the same vertical machining
centers as in the past and leave about 0.010
inch of stock. The semi-finishing operation is
performed on the Mazak machine to remove
all but the last 0.002 inch. A small ball noseend mill removes the last 0.002 inch. ESPRIT simulation automatically identifies any
moves where the spindle or tool passes too
close to the part or machine. Programmers
closely compare the part after machining to
make sure it matches the design spec. Asa final step, programmers use the ESPRIT
post-processor for the Mazak VTC-800 to
produce code that runs perfectly every time.

Completed Fin Die & Fins Produced on Burr OAK Dies

ming team from 12 to 6 people throughattrition while substantially increasing its
programming volume and its revenues.
The first step in programming the fin diesis importing the 2D models that contain thepart definition. Only a few clicks are neededto extrude the 2D models to create the 3D
surface geometry. The next step is to definefeatures such as holes and bosses which
map into machining operations. Burr OAK
Tool programmers currently perform this step
manually although in the future they plan toinvestigate the automatic feature recognition
capability of ESPRIT. Burr OAK Tool programmers use ESPRIT’s mill between curves
feature to define the surface to be milled.

DP Technology Corp.
1150 Avenida Acaso
Camarillo, CA 93012 USA

T +1 805 388 6000
F +1 805 388 3085

“We switched to ESPRITbecause it accurately
simulates the machine, turrets,spindles, tools, and workpiecein real-time operation.”David Schwartz,
Burr OAK Tool Inc.

esprit@dptechnology.com
espritcam.com
The Right Choice