“Te quality of our finish is critical,” said Lester Jones, CMD
vice president. “We want to machine the workpiece complete, eliminating potential errors and inconsistencies resulting from handwork. In our LSR and MIM applications, the injection pro- cess is highly sensitive to flash, which can occur within shutoffs of only 0.0002" [0.005 mm]. As such, the fit between the A and B sides of the mold has to be very tight. Tis is some of the most challenging work that we do, using 0.004–0.006" [0.10–0.15- mm] diameter end mills. To produce these tolerances, we require the highest level of rigidity and stability.” Te V33i’s spindle features a unique core-cooling and un-
der-race lubrication system that minimizes thermal distortion at high spindle speeds for sustained dynamic accuracy. Tese features have been crucial to CMD’s precision hard-milling applications, many of which feature highly contoured surfaces in 60 HRC materials. “Any inaccuracies on either side of the mold are unaccept-
able,” said Jones. “Te cores must be interchangeable—even on a 16-cavity tool, each part must be identical. While we care about speed and efficiency, maintaining that accuracy to ±0.0001" [0.00254 mm] or less is critical. Te rigidity and repeatability of the V33i allow us to maintain a Cpk
[process capability index] of 1.33 or better on all critical dimensions.”
Graphite Machining for Complex-Feature EDM CMD acknowledges that hard milling oſten reduces the
need for EDM, and realizes that many shops may be moving away from EDM processes. However, the company has never been busier in its EDM work. “While we routinely search for opportunities to substitute
EDMing with milling processes, there are simply some specific features that demand EDM,” said Tomas Caron, vice presi- dent of sales at CMD. “Te sharp corners and thin ribs that we receive necessitate the unique benefits of EDM technology and inherently require a precision machining solution for elec- trode production.” Te company describes its EDM performance as a stacked
process that relies first on the capabilities of its graphite machining centers. Te precision achieved during EDMing is only as good as the accuracy of the electrode. “We performed a test-cut regimen with several leading
manufacturers of graphite machining centers and found the Makino V22 with graphite package to be more accurate and 20–30% faster than our current equipment,” said Jones. “Today, we push as much graphite work as we can through the V22 and have established plans to add a robot to keep the machine fed over weekends to further lower costs.”
Hogging Out Time in Mold Prep In 2013, CMD rounded out its enhancements to the
mold-building process with two 14,000-rpm PS95 vertical machining centers. Based on the machines’ flexible combina-
Relationships Matter As the plaque in the company lobby maintains, the preci-
sion and quality that CMD strives for in its work remains a driving force, and its investments in high-performance machining technologies are integral to that mission. Te com- pany already has nearly a half-century of moldmaking experi- ence, and it intends to remain a leader in quality products into the next 50 years. “We’ve come to find that some of our best relationships are
formed when overcoming a challenge that no one else can,” said Newkirk. “If this work were easy, everyone would do it. Tat is why we make a strategic effort to invest in game- changing technologies. We see these investments as a long- term decision, because the machine, like our people, has to be compatible with the work we do.” Caron adds that investing in equipment from Makino and
building a partnership with local distributor Productivity Inc. enable them to successfully anticipate the ever-changing needs of their customers, keeping CMD abreast of new technology and helping them push the boundaries in precision moldmaking. “We are always looking for ways to solve unique problems,
and that usually means providing tooling with closer toler- ances, shorter lead times and the highest quality,” said Caron. “To get involved with our customers early on in order to assist them with their designs and to bring all of that to fruition is what we really are focused on, now and into the future.”
Feature edited by Yearbook Editor Michael Anderson from information provided by Makino.
Medical Manufacturing 2014 59
tion of speed, power and torque, the company found the PS95 machines to be an ideal solution for improving the productiv- ity and quality of its preheat-treated mold preparation. “Prior to our PS95 investments we were performing all
mold preparation on a horizontal machining center,” said Jones. “While many might find our decision to move toward a VMC platform strange, the truth is that the PS95 spindle is more capable of handling our diverse product mix. For all intents and purposes, we’re getting the benefits of a high-per- formance HMC spindle at the value of a standard vertical.” Te majority of the work performed on the PS95 machines
includes roughing of various steels, including P20. As a result, the machine’s standard power (33.5 hp; 25 kW), torque (140 ſt-lb; 190 Nm), through-spindle coolant (435 psi; 3 MPa) and scraper-style liſt-up chip conveyor facilitate high metal-removal rates and efficient chip removal for improved lead times. “With the PS95, you get your money’s worth in standard
features that normally factor in as added costs on most other vertical machines,” said Caron. “It’s a value package that has improved our mold-prep efficiency and overall workflow. We never thought we would experience this level of performance from a standard VMC.”
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