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Switching from conventional power tools
to a CNC router helped a manufacturer of gun safes increase
productivity by 400%. When Champion Safes used power tools to
produce racks for its gun cases, each person could only produce
enough parts for 20 to 30 safes per day. To increase productivity,
the company invested in a computerized numerical control (CNC)
router that works unattended to produce parts of any shape, simple
or complex, based on a computer program. Now a single person can
produce all the parts needed for 120 safes in one day. Quality has
been substantially improved because the CNC router doesn’t make
mistakes and cuts to an accuracy of 0.002 inch compared to typical
1/16 accuracy for manual cutting. “We have substantially reduced our
manufacturing costs while increasing our quality,” said Terry
Zierenberg, Director of Engineering for Champion Safes, Provo, Utah.
“What’s really amazing is that the CNC router that does all this
costs only $18,000.”
Champion Safes has been building heavy
and tough safes since 1998. The company’s safes sell for between
$800 and $2,500. Champion Safe bodies are
pressure-formed from thick A-36 carbon steel plate with fully welded top
and bottom caps. Doors are built out of heavy
A-36 carbon steel plate with sandwiched fire insulation, offering more
security and better fire protection than a plate steel door alone.
Champion uses heavy- duty, ball bearing internal hinges and multiplere lockers that collectively protect a safe against drilling
and forced entry. Champion Safe is the only home security safe
company to use a glass, bank-vault type relocker. To protect the
lock from attack, it bonds industrial diamonds to tungsten steel
hardplate. The company includes fire protection, standard on all
models, ranging from 30 minutes at 1200oF to 105 minutes at 1550oF
for different models.
Previous manual machining methods
The notched racks that hold the guns
inside the safe are cut out of three- quarter inch particle board.
The geometry of the racks is complex because each rack typically
holds 20 to 30 guns. In the past, skilled woodworkers cut these
racks using hand routers with bearing bits by following templates,
and with table saws. The accuracy of the racks depended on the
accuracy of the templates, and making good templates required
patience and long experience. Frequently, templates were ruined and
new ones had to be made before the job could continue. A skilled
craftsman was needed to accurately follow the lines of the template.
Even though the operator would follow the template carefully, he or
she might bump corners or otherwise damage the template so that it
got worn out and had to be replaced. For all these reasons, one
person was only able to produce enough components for about 20 to 30
gun safes per day and five people would have been needed to handle
today’s production volume.
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Zierenberg had long thought about
purchasing a CNC machine to perform this operation but, when he
originally checked, the cost of these machines put them out of
reach. “When I worked for a competitive safe company, we bought a
CNC router for $65,000,”he said. “prices have dropped since then but
until a couple of years ago, the cheapest machine that I could find
that would do this job cost about $45,000, which was more than we
could justify,” he said. “These were machines with servo- motors and
ball screws that provide high levels of accuracy, and large tables
that make it possible to produce big parts. We didn’t want to spend
that much because we only have one group of wood products, so we can
only use the machine in a few areas. When I heard about Techno’s LC
router, which offers essentially the same features and capabilities
for under $18,000, my first question was: can it hold up? I saw a
demonstration at a local dealer and it looked good so I decided that
for that money it was worth the gamble.”
New router offers mix of performance
and economy
Techno’s LC series CNC routing system
provides a number of critical features that allow it to deliver
accuracy and long-term reliability of a level that has previously
only been available from machines at a much higher cost. Ball screws
are provided on all three axes, offering smooth motion, a high level
of accuracy and repeatability, and minimal maintenance. Ball screws
have a number of advantages over racks. They don’t have the play or
the requirement for adjustments that racks do; they also do not wear
as easily as racks do and they are far less likely to get debris in
the mechanism than racks to cause skipping and errant motion. A
closed- loop servo control system provides constant position
feedback, higher power, and smooth continuous motion that eliminates
the possibility of losing position in the middle of a part.
Servomotors, unlike stepper motors, do not “lose position” and
cannot skip steps. Servos are also far better for 3D applications
because they can change speed “on the fly” without losing power as
steppers do.
Zierenberg generated programs for the
gun racks and a number of other wood parts, such as center dividers,
used in the company’s different models of safes. He designed jigs
that hold the particle board blanks in place. An operator simply
loads the jig with a precut blank, calls up the appropriate program,
and hits the start button. He then walks away while the router
finishes the part. It typically takes the Techno router about one
minute for each rack that is machined. Some of the racks are more
complex and take as long as four minutes. While the router is busy,
the operator can work on other jobs, such as cutting out blanks on a
table saw.
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Automating the process of machining
racks
“When we got the new process for
machining racks up-and-running, I felt like I had died and gone to
heaven,” Zierenberg said. “The LC Series machine does everything we
need it to do at a remarkably low price. As far as durability goes,
I have been amazed and satisfied. We have been running the machine
all day, every day for two years and have no problems.
By the way, besides being less
expensive than other CNC routers, the LC also takes up quite a bit
less space, which provides additional savings.” The LC series
machine includes a heavy steel ground stress- relieved base and an
aluminum T-Slot table that can be easily converted to a vacuum table
by installing the Techno vacuum table accessory kit. Because the
frame is a single welded piece, there is no chance for it to get
“out of square” or require alignment.
“Techno’s sales team were very helpful,
not only giving me all the information I requested about the
machine, but also helping me find the right software package and
providing me with the necessary training to get my production
up-and-running quickly,” Zierenberg added. The machine comes fully
assembled and includes Techno’s Windows-based CNC G-Code interface
with free lifetime software upgrades.
The machine is available in three sizes,
with work envelopes of 30 by 24 inches, 50 by 48 inches and 50 by 96
inches. Each of these models provides a repeatability of 0.001
inches, a resolution of 0.0002 inches and a maximum speed of 250
inches per minute. A wide range of optional equipment is offered
including a laser scanning module, CNC lathe attachment, Porter
Cable router, vacuum blower, and fourth axis rotary table.
Higher productivity means increased
profits
The increase in productivity that has
been achieved with the new machine has significantly reduced
Champion’s manufacturing costs. “Clearly, the availability of
high-quality, low-cost routers has the potential to dramatically
improve the profitability of every manufacturer that uses wood in
their product, ”Zierenberg said. “Our savings extend through the
assembly process as well because the more accurate parts that we
produce with the new CNC router avoid the need for manual fitting.
Having lower manufacturing costs than our competitors gives us the
opportunity to offer greater value to customers and increases our
sales volume. Higher productivity means that we are able to handle
this volume without adding workers, which increases profit margins.
Techno’s LC series CNC is clearly the wave of the future for
woodworking manufacturing.”
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