Today’s aerospace, defense and automotive component manufacturing industries are challenged with machining a variety of exotic alloys and hard metals. This can take a toll on the carbide cutting tools used, and as a result, the tools must be changed out more frequently as they dull or break. Tool replacement, not to mention loss of production time due to frequent changeover, can escalate costs as well.
Photo courtesy of JM Performance Products
Founded in 1978, Preco Manufacturing established itself in aerospace manufacturing with its precision machined components for military, government and commercial customers around the world. A minority owned company, Preco is helmed by president Martin Munguia and consistently driven by its ability to provide customers with optimally engineered parts solutions. To fulfill this commitment and maintain a competitive edge, they recently replaced all of their machines with new equipment to take full advantage of today’s sophisticated manufacturing technologies.
The ISO9000:2008 and AS9100 registered company’s goal is to control costs and provide a shorter turn around by manufacturing all phases of a component from start to finish–regardless of its critical tolerances. To achieve the result of holding tight tolerances, the company invested in the MAM72-35V Matsuura Five Axis Machining Center from Matsuura Machinery Corporation.
The MAM72-35V provides the advanced integration of a multi-pallet stacker, tool carousel, and close tolerance machining center. It also features a 35 tower pallet system with an option for a 520 tool matrix magazine base. This robust configuration was able to meet the manufacturing challenges of Preco’s predominantly exotic material castings. Utilization of these materials creates a unique set of production machining hurdles when considering it typically requires high speeds in excess of 20,000 RPMs. The MAM72-35V features a 20,000 RPM Hi-Tech spindle, coupled with hand built precision, which makes for an accurate and robust unattended solution for complex work like Preco’s.
The MAM72-35V provides a multitude of helpful integrated components.
In this realm of optimizing machining to its limits via hard torque, Preco was frequently experiencing broken retention knobs, resulting in costly downtime, poor finishes and challenges to the bottom-line cost efficiencies. Additionally, they experienced excessive chatter at high RMPs because the tooling wasn’t balanced. Discovering a solution for manufacturing high speed aluminum parts with chrome finishes at 20,000 RPMs was key.
The immediate goal for Preco was to find a retention knob solution that wouldn’t fail. Doing so would allow them to avoid increased costs per part and remove negative impacts in their ability to move toward their goal of max-efficiency aerospace manufacturing.
JMPP / HIGH TORQUE FINISH / SYSTEM SOLUTION:
JMPP’s High Torque retention knobs were designed to address problems that cause CNC milling and boring issues.
It was imperative a retention knob solution was found to improve the contact, reduce the spindle loads and increase the speeds and feeds. It was also critical for the solution to improve the capacity to remove more cubic inches of metal per minute. While seeking out knobs, Preco contacted JM Performance Products Inc. (JMPP), a manufacturing innovator of CNC mill spindle optimization products since 2009. The company’s patented High Torque retention knobs were the only knobs on the market to fully address the collection of vital, costly CNC V-Flange tooling production issues negatively impacting tool life.
JMPP’s High Torque retention knobs are specifically designed to eliminate the toolholder expansion responsible for costly and ongoing CNC milling and boring issues. Toolholder expansion caused by standard retention knob installation can reduce the toolholder to spindle contact by 70% or more. Key to the design is a relief beneath the precision pilot that forces the threads of the knob deeper into the threaded bore of the toolholder. There, a thicker cross-section of material resists the expansion and deformation.
JMPP plant manager, Craig Fischer, emphasized that, “Fundamentally, JMPP’s knobs also work as an integrated system that starts at the connection of the spindle and the knob. The system includes precision-cut threads taking into account the mechanical functionality of each thread, magnetic particle testing revealing any faults and cracks in the material, installation torque specifications based on draw bar force and taper size and replacement recommendation specifications.”
PRECO RESULTS / FINISHES / CONCLUSION:
Preco was using more than 100 tools on their MAM72-35V machine, so they tested a High Torque knob for every tool including drills, facemills, taps and more. The same knobs were used across multiple types of tools.
According to Preco president, Martin Munguia, “The benefits were immediately deep and far-reaching as better taper connection resulted in spindle load reduction, increased speeds and feeds and the ability to remove more cubic inches of metal per minute. Most visibly, we were able to achieve a combination of higher quality chrome finishes on parts which is essential in aerospace and defense applications.”
The results from switching to JMPP’s High Torque knobs on a variety of different tools were immediate and beneficial.
Preco’s machinist-operator, Sam Flores, expanded on these advantages, stating, “Achieving better surface finishes also eliminates additional benching operations that add to the cycle times. We’ve had experiences with poor finishes in the past, but now, we can run deep 4” bores with six finish with no taper on the end mill.”
With these empirical results in hand, Preco moved swiftly to converting all of their 5-axis machines and milling centers to JMPP’s knobs. For over two years now, JMPP’s knobs have been in operation at Preco facilities. Munguia concluded that, “In the aerospace and defense industries, price is a factor, but the customer is more interested in top quality parts delivered on time. We wouldn’t dare change back to standard retention knobs.”
Flores concurred, “It started with the new Matsuura machine which proofed out the overall great finishes even when running heavy tools on some parts. In essence, we now exclusively use the High Torque knobs on every tool on our machines. They have better concentricity, fit exactly and the tools perform better across the board. Most importantly, with the heavier milling we do with titanium and stainless steel parts, there are no issues with the retention knobs.”
JMPP’s Fischer surmised, “In implementing our High Torque knobs over the long haul, Preco will continue to increase speeds and feeds that deliver better cycle times to actualize superior finishes and substantial savings for their demanding aerospace applications.”