Heimatec Speeders Key to Improving Production of Tiny Cardiac Monitoring Component
Medical device manufacturer, Boston Scientific, was recently searching for a better way to produce a cardiac monitoring battery component. They found it with 17 Citizen Swiss machines and speed increasers from Heimatec. Read further for the details -- and to pick up some high-quality machining knowledge in the process.
With over 15,000 products, Boston Scientific is a market leader in pacemakers, defibrillators, monitoring equipment, spinal & brain stimulation, stents, catheters and ablation devices.
Size Comparison of Insertable Cardiac Monitoring Component
On one recent cardiac monitoring battery component, a manufacturing engineering specialist at the company's Minnesota Arden Hills facility, Larry Hennig, reports, "We had an application running year-round on multiple mills, rectangular in shape, consisting of multiple milling operations per part, requiring an operator per mill at all times. Both mill operations consisted of multi-part fixtures as the process involved running Mill OP-1, light hand deburring and prepping the parts for Mill OP-2 -- fixture & process. The overall process was running around seven minutes per part."
Larry and his team members determined a Swiss process could be more beneficial.
Speeders shown on the Citizen L12 Type X machines at Boston Scientific for production of battery components.
They could eliminate manual deburring and get process time down to around three minutes. One operator could run multiple Swiss machines while auto-segregating particular parts for in-process dimensional inspections. The process proved to be more stable, and it eliminated manual deburring which produced a better surface with nearly triple the tool life.
This new process had a combined six-person headcount reduction.
The Swiss manufacturing process was capable of running 12+ hours unattended holding the targeted .0002" profile tolerance. Additionally, there was a significant improvement in material savings, according to Hennig. "We were using .300" of stock per part for the milling process, while the new process only requires .100" of stock material per part."
The machines were provided by Andy Walser at the local Minneapolis Citizen distributor, Productivity Inc., and their tooling representative, Terri Farrell.
Preben Hansen of Platinum Tooling, Terri Farrell of Productivity Inc. and Larry Hennig of Boston Scientific, all collaborated to achieve the results described in this story.
The story might end here, except for a key component in the radical improvement of production on the part. Terri brought Preben Hansen, president of Platinum Tooling Technologies into the situation and Preben introduced a Heimatec speed increaser (1:4 ratio) specially designed for the Citizen machines.
As Larry explains, "While this component is not a round part, it is small in size and requires small tooling. We were not getting enough rpm to match the tool diameter and necessary SFM, causing long process times and reduced tool life due to the tool not meeting the necessary rpm requirements. I have worked with many types of electric spindles and many brands of speeders. With the electric spindles, we had some success on light drilling and small-diameter high-speed milling, but the obstacles we faced involved load on the tool that would cause the electric spindle rpm to fluctuate and therefore leaving tool marks across the material or even alarming-out the electric spindle when load was applied."
As a result, the company needed to rebuild all the bearings and seals on their high-speed electric spindles annually, additionally rebuilding the previous manufactures gear-driven speeder heads multiple times during the year while running high-production volumes of parts.
Heimatec 1:4 speed multiplier, provided for the Citizen Swiss machines at Boston Scientific by Platinum Tooling Technologies, provides the optimum output in productivity on the ICM battery feed-thru parts.
Preben Hansen brought Larry a new idea. Several 1:4 speeder heads and tooling attachments were introduced to provide additional live tool positions and rpm's. According to Larry, "we achieved a superior surface finish when drilling, reaming, and profile & face milling, which improved our tool life and produced a major reduction in cycle time by using these speeders, compared to the 1:3, 1:2 and especially the 1:1 standard tool provided by the OEM or brand X."
Larry reports the Heimatec speeders provided by Preben have been in operation for over two years and have not required a rebuild. He says, "They still feel like the day I brought them into the process."
Preben notes, "We helped Larry convert the process for production of these components by enabling a single operator, a more stable machining operation, improved cycle times with the higher rpm and proper feed, plus the big advantage, an optimum surface finish, so critical on these parts. The deburring issue is simply no longer an issue," he concludes.
Milling inside Citizen L12-X Swiss Machine [Photo Credit -- Jess Vealetzek]
Hennig expanded on his experience. "We were able to develop some amazing new macro features with this latest project such as rotation macro-offsets for alignment from main to sub, developing safety crash macros to help prevent accidents into tool holders due to limited clearance between sub collet and face of part, as we are only chucking on .006" of the part during part pickoff/transfer and have limited clearance on the sub side. This prevents crashes into the cutoff or sub-spindle tooling, if setup or offset incorrectly. Together with our team's tribal knowledge, we designed custom tools that spot, drill, ream and chamfer all with a single tool, keeping the chamfers concentric, as well as the custom deburring tools providing a burr-free product. These were all conditions that we struggled with on most of the mills with their need for manual deburring and several tools intersecting the same feature."
He continued, "We have learned over the years that tooling specs rarely work in Swiss applications due to the lack of work holding compared to mills or even conventional lathes. For example, when programming a high-volume product, I usually start at 50% of the tooling manufacturer's recommendations and then run 15-25 test cuts at various speeds and feeds to find the optimal conditions."
He further noted that, when milling on Swiss applications, "I have learned by performing climb milling for rough cuts and utilizing a conventional mill spring or finish pass has helped tremendously with knocking off any burrs, providing an amazing finish on all surfaces, with extended tool life."
The speeder is shown here with other Citizen tooling provided by Platinum Tooling, the master importer of Heimatec products for North America.
Larry concludes that, with any medical or implantable device, Boston Scientific is tasked with much higher standards compared to most manufacturing facilities, when holding surface finish, dimensional requirements and creating no burrs.
"Here at Boston Scientific we hold every single part to the highest standards cosmetically, dimensionally and functionally. Our number one priority is quality and providing the best patient impacting components, regardless of expense. That's one thing I really value about this company."
Terri Farrell from Productivity added, "What I would like to add to this wonderful success story would be that it was a no-brainer to get Platinum Tooling involved in this project. Preben, his team and the products they offer to the manufacturing world are all top-notch. Having the opportunity to work with Boston Scientific and the caliber of machinists and engineers such as Larry has been one of the most rewarding experiences in my career. This team is not afraid to approach a project from a completely different angle and try new things. That's how you stay on the leading edge."
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