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By David
Millson with Richard Filsinger
techdivr@bellsouth.net
techdirections November, 2002
Richard Filsinger teaches the core courses in three of six
"attractor magnet" curricula in the Interdisciplinary Program at
Suncoast Community High School: Drafting Technology, Engineering
Technology, and Communication Technology. Filsinger concentrates on
the end products of student design
and CAD/CAM projects as the leverage for increased acceptance in the
job market and/or college.
He satisfies that goal and keeps materials costs at a
minimum.
"We,
spend $ 200, maybe a little more, for a year’s stock," he says.
Therein lie some pointers for consideration.
There’s also a side trip into the more exotic realm of machining
from digital point measurement: finite element analysis, the
stuff reverse engineering is made of. It’s all part of the end
Filsinger seeks for students who matriculate through any of his
magnet areas: exposure to the full design-production-marketing
cycle.
"Then, he says, "they’re ready to target an employer or a college
with a portfolio and experience that identify them as serious
players in an expanding global market." Beyond that, he understands
his importance in helping his school fulfill its mission.
Now
in its 14th year, Suncoast Community High School was specifically
established to attract a diverse student population by offering an
alternative to the regular comprehensive high school. A "Magnet
School of Merit" and U.S. Department of Education "Blue Ribbon
School" in Riviera Beach, FL, Suncoast offers a college preparatory
curriculum with a mission to end minority isolation.
The
school provides a challenging, innovative program to a diverse
student population. Each individual is empowered to succeed in and
contribute to the global society by engaging in challenging academic
course work in several unique advanced-placement programs. Both the
Advanced Placement Program and the International Baccalaureate
Organization rank Suncoast, in the nation’s 14th largest school
district, as one of the top schools in the U.S.
Filsinger has designed his intermediate curriculum as a progression
of applied skills grouped by the stages required to use CAD/ CAM/CNC
to turn unique stock pieces into increasingly complex finished
products. The variables inherent in these projects are Filsinger’s
platform for teaching and/or reinforcing basic math
skills-"real-life math skills the kids will definitely need for
their SATs," he points out.
Relearning basic geometry factors.
"Some
students studied for their Geometry I tests and promptly forgot the
basic relationships of diameter vs.radius, how to read a ruler,
parallel vs. perpendicular and even what ‘perpendicular’ means.
"They
have forgotten because," according to Filsinger, "they weren’t shown
its relevance to real life. They studied Algebra II only so they
could pass the State test, and on and on. But when they must
remember the material in order to complete a practical project, it
sticks with them."
Setting up toolpaths.
Students must make tool choices based on the smallest radius they
will cut."Students must create a mental relationship between the
geometry they will cut and the tools they’ll use to do it. They must
understand the rules about the maximum depth of any single toolpath,
and they must examine their project and calculate how many toolpaths
they must make given those parameters of pocket depth."
Project precision = precision measurement = precision thinking.
"When
my students realize that, unless they’ve accurately carried out
10-based measurements, they’re, going to crash a tool into the
stock, the fixturing, or the table. All of a sudden the theoretical
becomes a practical concern. Many of them have never used a
micrometer or calipers. To do the class work, they must add,
subtract, divide, multiply; they must exercise some, rusty basics."
Physics principles met or remembered.
"Some
kids haven’t had physics, or maybe they’ve forgotten the basics. For
instance, when a student has machined a brass piece and picks it up,
it’s likely to be warm. "The same action with an aluminum piece
would result in burned fingers-that’s practical thermodynamics. Link
that to the need for different coolant flow for different metals.
"It’s the same with the properties of hardness and how they affect
cutting speeds. The kids learn the different cutting parameters for
machining aluminum, brass, and acrylic. Their need to retain
information they thought was useless is brought home in an emphatic,
hands-on way."
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Rick
Filsinger’s students have carried off six Firsts and four Seconds in
the Chrysler’s Miami-regional "Build Your Dream Car" competition. In
2000, they bagged Third, Second, and First Place in the regionals
plus the May 25"’ national championship. That award reflects the
quality of Suncoast’s education and the caliber of students
attracted to this very special secondary program.
But
what technology teacher doesn’t have budget worries? Filsinger
insists that mining scrap industrial piles can dramatically lower
materials costs and provide an additional curricular
challenge. Rather than receiving a precut piece of stock or using
general shop tools to cut stock to a precut size, Filsinger’s
students receive his recycled, random-sized stock: very economical
acrylic industrial scra
Since the pieces are cut in random sizes, students can’t share,
machining programs. They also must learn or refresh their skills on
using precision measurement devices because they begin each project
by measuring the stock. "Some of my colleagues use machinable,
reusable wax to cut costs," says Filsinger, "but my students need
examples of their work to augment their portfolios. This way, I keep
my material costs to a minimum, and each student can take home each
of her or his projects."
The
frugal Filsinger also focuses on keeping tooling replace-ment costs
low. He requires students to start a dry run of every project 1"
above the 0,0,0. Though each student uses toolpath verification, I
want the dry run," he says, "because, for example, if a student
fails to enter a spindle speed while setting machining parameters,
the spindle doesn’t turn on when the program executes, the tool is
forced into the work piece, and then it usually snaps when the
machine starts its run. "A crashed dry run causes a little
embarrassment, but not a broken tool. Also, if there’s a holddown,
clamp, or screw head sticking up from their piece and they haven’t
allowed for the proper tool limits, it’s `Goodbye, tool; goodbye,
budget"’
As
you’d expect, beginning students in the Engineering Technology
curriculum begin designing and machining in two dimensions. When
they reach the intermediate stage, they begin 3D design and
toolpathing, with one significant variable: Though they have
predefined general project parameters, material sizes vary and other
unknowns remain that they must solve for. The projects follow
sequentially, in order of increased complexity. Here are three:
The power of the pen:
One
advanced project, a penholder with base, challenges pragmatic
engineering and precision toolpathing. The turned brass penholder
must be freestanding putting normal pressure on the brass part won’t
force it out of its acrylic base yet be
able to slip in and out for ease of "shipping and customer assembly"
in the real world.
"I provide details on the shape of the brass penholder, the diameter
of the bore, and the shape of the ball end which must fit inside the
base," says Filsinger. "The brass pen holder is machined on a Light
Machine PL3000, with an eight-tool turret head. I assign my students
to compile at least three toolpaths and make at least one tool
change in the process of machining.
"Clearance, between the brass holder and the hole, machined with a
pocket toolpath into the base, is 0.010". If done correctly, the pen
holder will hold securely, can be adjusted in a variety of
positions, and can be inserted and removed easily."
Students must design and toolpath the acrylic base, selected from
random sized stock, to conform to standard finish characteristics.
They must use concave and convex arcs to create a swept surface
around the upper edges of the base and machine it using a flowline
toolpath. Then they must generate a contour toolpath to project
their personalized engraving onto the surface plaque.
Another project-cost: 25¢ to 50¢ per student transforms random
blocks of acrylic scrap into stylish business card holders. This
project teaches students how to work using levels, how to make
different geometry visible and invisible, and to generate a wide
assortment of surfaces and toolpaths.
Students must create a
pocket toolpath in order to rough in the slot where the cards go.
Using a long 3/8" flat end mill to machine the project, they can cut
deeply without flaring out the top of the project. Then they create
either a ruled or loft surface, with a slant from behind the pocket
and around the bottom of the slot. This allows the business cards to
lie back in the holder. For this cut, they use a long 5/16" ball end
mill. With the long cutting surface, the bit won’t scrape the slot
edges.
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The art of the design takes its form from a Coons surface based on
four concave-convex lines created on the front, left, and right
surfaces, and one right before the pocket. The Coons surface is
machined using a multi-surf rough toolpath with a flat 3/8" cutter.
They complete the surface with a multi-surf finish toolpath.
To complete the card holder, the kids engrave their names onto the
Coons surface. To do this, they generate a flat contour toolpath of
their name, save it as an *.nci file with a depth of 0.10". The *.nci
is then projected onto the Coons surface. Depending on the, size and
number of the letters to be created, students choose either a 1/8"
or 1/16" flat end mill to perform the engraving.
"The results are pretty dramatic," Filsinger asserts. "Students use
random stock sizes to create the project, and they learn the value
of creating text files to remind them which cutters are used to cut
each toolpath. In effect, they are prototyping a product using fixed
parameters on non-standardized stock sizes.
"They’re proud when they see the beauty of the piece they’ve learned
to create, and they have moved up a notch on their ‘personal
marketability’ scale."
I always wanted to do this ever since I trained on Rhineros", a 3D
modeling program that accepts input from the MicroScribe. Rhino can
create, edit, analyze, and translate NURBS curves, surfaces and
solids in Windows."
Filsinger saw in the MicroScribe /Rhino combination a perfect
compliment to his graphics, animation, design, and advanced CAD/CAM
courses. He uses them at Suncoast to digitize the image of an old
mouse for toolpathing and machining copies with Mastercam.
Touching grid points on the mouse; with the Micro-Scribe stylus,
students loft an exact 3D model in Rhino, which converts the data to
IGES. Easily imported into Mastercam, students now use the file to
generate rough and finish multi-surface; toolpaths. Using pocket,
multi-surface, and flowhne toolpaths, students create the grooves
that separate the mouse buttons, then project the resultant toolpath
onto the irregular surface of the mouse. Again, another complex
project requiring the application of many drawing and toolpathing
tech-niques, at a material cost of about 50¢.
Throughout much of what Rick Filsinger has achieved over the past
seven years with Suncoast’s highly select student body-- three of 10
applicants are admitted--flows the decades of experience of one
community volunteer, Israel Levine, a retired engineer. He brings
industrial standards to bear on students’ thought processes and
working techniques. Since Filsinger isn’t an engineer, he and Levine
engage in a lot of side conferencing. Levine received the "Community
Volunteer" award from the state of Florida four years ago for his
dedication to Suncoast’s mission.
His one-on-one coaching--his gift of patient wisdom--has changed
young lives beyond measure. His collaboration on three-dimensional
analysis, a sophisticated digitizing/machining project, with
Filsinger and a group of advanced students exemplifies the creative
freedom and personal contact that raises Suncoast students’
achievements far beyond the norm.
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