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Developing a New Process for Hypotube Stripping

Mon, 12/09/2013 - 3:12pm
Paul Ogden, Director of Sales, Syneo

Combining Two Proven Technologies Provides  a New Alternative for Medical Applications

Syneo LLC designs Syneo chose to work with Comco’s PowerFlo 2400 which is one of their most sophisticated microblasters. (Credit: Comco Inc.)and manufactures automated tube cutting equipment and systems as well as automated feeding systems for catheter manufacturing. This includes total automation that typically involves picking up and feeding catheters and guidewires through all processes including cutting and drilling, laser ablation, printing and even various types of grinding processes that are typically used to make guidewires. Syneo machines are the standard for catheter manufacturing in the medical device industry.

Syneo also works with many OEM companies that make their own process machines, helping them to fully automate their processes. When OEMs need something new, they may come to Syneo with a developed process and ask for help with only the automation. Others give the whole problem to Syneo and ask for a machine that can handle the entire application from start to finish.

Application Background
In this case, the customer came to Syneo with a challenge in finishing PTFE coated hypotubes. A hypotube is a stainless steel tube commonly used in catheter manufacturing.

Hypotubes are often coated with PTFE to decrease surface friction and wetting. Yet, chemical bonding processes may be required to assemble the hypotube to other elements of the catheter assembly. To achieve satisfactory bonding, the PTFE must be completely removed in the bonding area. The PowerFlo 2400 is highly automated and programmable. (Credit: Comco Inc.)Any PTFE film contaminating the metal surface will compromise bonding.

Where a wire must be connected to receive or transmit an electrical impulse, such as attaching a pacing lead to the heart and the opposite end of the lead to a pacemaker, a sensor, battery or signal transmitter, the coating must be stripped off. These wires are so fine, the coating must be very precisely removed chemically, by laser or in this case using microblasting.

Other reasons to remove coating are for marking adhesion, or to reduce the diameter of the overall catheter or guidewire to allow another element to be added without increasing overall catheter diameter. Often, the coating needs to be partly removed, not all the way down to the bare wire. A marker band is a common add-on device on a catheter. The marker is installed and swaged onto the reduced diameter section so that the OD of the band is the same as the catheter so a balloon can slide over it smoothly without catching on the marker band.

An example of the ring nozzle assembly inside of a manual blaster. (Credit: Comco Inc.)This particular application was to remove the PTFE to stripe sections of the hypotube. Syneo provides laser systems that do this, and many companies use them. They work well, but they have challenges. Lasers can be slow, or sometimes they burn through the wrong things. They also tend to be expensive and there are many regulatory issues around them. There are some global locations such as Puerto Rico, where local regulations make importation of lasers particularly difficult.

Why Microblasting?
Syneo was already familiar with Comco Inc’s microblasting technology, but had never used it. A customer who had experimented with manual microblasting asked if a system could be developed that incorporated all the benefits of the Syneo’s programmable process automation with the finishing benefits of microblasting. That started the development of a whole new process system.

The Syneo Syneo automated hypotube stripping/marking system using microblasting technology. (Credit: Syneo)Microblasting utilizes a mixing process to feed aggressive, abrasive media into an air stream. These abrasive particles are fine (10-300 microns), much smaller than what is normally used for sandblasting applications. Comco’s Microblasting systems precisely focus and control the abrasive stream to treat only specific areas of any part.

Integrating machinery from different vendors to create unique automated systems is something that takes full understanding of each process and a close partnership between the companies involved. Syneo chose to work with Comco’s PowerFlo 2400 which is one of their most sophisticated microblasters. That system brought a lot to the table in programming, flow regulation and automation instead of being only a raw blasting system. The PowerFlo blaster is designed specifically for automated applications. It includes a number of sensors to monitor system performance and communicate with a host PLC. Communication with the host PLC allows for data tracking and control over the blast process which can be linked to a master control for the entire integrated machine. The PowerFlo is also capable of supplying abrasive to multiple nozzles; a feature common to many automated microblasting applications.

This specific application required the ability to blast in a very accurate way to ensure the proper material removal; not too much or too little. Comco’s Ring Nozzle assembly was used to hold the nozzles at a specific distance and angle. Testing was conducted at various blast pressures. When the proper settings were created for each product, a program was set that can be pulled up, as easy as programming a microwave oven. Unlike CNC where an engineer needs understand G-Code or require special software, the Syneo/Comco system is programmed just by filling in tables like a spreadsheet.

Close up of the automated ring nozzle assembly in the Syneo system. (Credit: Syneo)The Syneo automation picks up the wires from an input stack, locates the wire tip precisely, and then moves the part at controlled speed through the blast process while modulating the blaster to stripe the part exactly to specifications. Because of the Comco nozzle system, blasting is even around the diameter of the part so the part does not need to rotate to get consistent abrasion. The PowerFlo gives control of the blast of media coming out. The combined technologies created the perfect scenario for what this customer needed and for what turned out to be a highly flexible and cost effective system for multiple medical guidewire and hypotube applications.

The system is also designed to keep the surrounding workspace clean. It includes air knives that strip the media from the part so that parts come out clean. And the blast cabinet contains filters that trap any dust. Even the refill process is managed, with a spill area that can be easily cleaned, containing any media spills within the cabinet.

Example of a medical wire textured by microblasting. (Credit: Comco Inc.)Current and Future
The system provides the automation needed to manage production costs and maximizes throughput for future expansion. An operator loads in 200-300 parts – pushes a button and walks away. The machine will run for an hour without any operator interaction. It does the job and turns itself off. The finished products are waiting in the output bin.

The system can hold up to 100 processing programs in memory. The process can be pulled up using a program name or barcode reader. Changeover takes less than a minute. This is a technology that can replace a laser in many applications, and compliment a laser in other applications, such as cleaning up slag from laser drilling or cutting.

A wide range of extremely fine, regulated media is available for all types of microblasting applications. (Credit: Comco Inc.)

When microblasting can replace laser processing, the end user can see at least 30% less investment, lower ongoing costs, and other significant advantages. There are fewer things to learn, and fewer safety issues. There are virtually no regulatory hurdles to the microblasting process, compared to laser systems, which face regulatory scrutiny that includes recurrent training. The system is extremely easy to use and understand.  Ongoing maintenance is low and predictable. There are no expensive, life-limited components.

This partnership between Comco and Syneo gives Syneo’s customers another alternative to choose from. It provided an answer that integrated the overall equipment and automation and finishing process together so this particular customer could start manufacturing quality catheters in a way that would be efficient, fast and cost effective.

And, it opened up a new product line for Syneo.

Syneo will continue to provide laser ablation/material removal systems, but now can also offer automated media ablation too. It gives customers a choice that will fit their particular product and budget and if regulatory issues are a problem, this avoids that challenge also.

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