Advanced Tubing Technology Trends

Rudi Gall on Advanced Technology Trends and Upcoming Challenges for the Tubing Industry

What are the latest trends in tubing that you are seeing in the industry, or from vendors and clients?

Recent developments in medical device requirements have led to the trend to unite, what was once seen as a fierce competition between metals, such as stainless steel, and plastics. Medical devices continue to be subject to more and more challenging designs and requirements to be able to deliver an ever-increasing level of performance. One reason for this is the unstoppable trend towards minimal invasive procedures, requiring smaller and smaller devices, made from micro-components, parts and tubing. Another reason is the growing trend of medical device connectivity, whereby data is transferred from the medical device / patient to an analytical or diagnostic system. This “real time data” allows for prognostic and strategic medical care of patients with the benefit for immediate treatment and / or prevention of critical health issues. New neurological and neurovascular devices, which just made their way into the market, or will most likely shape the future market in this particular field are a perfect example. Here is where thermoplastic polymers, metals and electronics morph into one product, whereby metal wires (e.g. copper) or cables are embedded inside of tubing walls, or are run inside the inner lumen of the tubing to allow for electronic data transfer and transmission from the medical device / patient. One such device is RAUMEDIC’s intracranial brain pressure catheter (ICP) which consists of a single lumen implant-grade polyurethane catheter protecting the wiring leading to a microchip embedded in a stainless steel tip at the distal end of the catheter. This microchip measures brain pressure, oxygen levels and temperature levels inside the brain of severely injured trauma patients. Here the wire helps to feed back all that valuable data from the patient to a bed side monitor.
All those products have in common that they require a high degree of customization and come with associated costs in engineering and development, as well as tooling costs. The big benefit however lies in the fact that such highly customized catheters or components cover all the necessary requirements and can therefore be directly installed into assemblies without the need for costly secondary operations and assembly work.

What are OEMs asking for the most when it comes to tubing?

One sentence describes it all: High, persistent quality of products delivered and ideally exceeding your customer’s expectation when it comes to that. The medical device market does not like changes and acts nervously when quality is at stake. This is not only due to the invasive nature of some medical products, but also due to the regulatory framework behind the medical device market. Add the more complex designs of a lot of new devices and you have the perfect storm brewing if quality is not at the core of your business. It is therefore necessary that suppliers have their homework done to reign in variability and to assure lot-to-lot consistency of their tubing supplied so the overall device assembly process remains robust. This calls for the availability of statistical process data and a closed-loop controlled extrusion process, which can be achieved through in-line measurement systems such as laser microscope measuring the outer diameter of a tubing and ultrasound to measure the wall thickness.
Having a stable quality system in place, understanding the market requirements of the medical device and technology market and by offering such value added capabilities as described above will guarantee that any single source provider for medical components and systems will be able to shape the future medical device market with their customers.

  • Different types of micro tubing
    Different types of micro tubing

Any new technologic advancements in the last year or two that I should elaborate on, and how they make things better or more efficient? How are the technological/production limits being pushed?

One specific technologic advancement I would like to single out is the market launch of medical-grade RAUMEDIC PTFE Moldflon™ tubing which is a symbiosis between PTFE properties and thermoplastic processing capabilities. PTFE Moldflon™ has very similar physical properties as compared to standard PTFE, such as high temperature and chemical resistance, very low coefficient of friction and tensile strength. The big difference however is that PTFE Moldflon™ is pelletized and can run continuously on a standard extrusion line, whereas traditional PTFE is a batch process and therefore non-continuous using RAM extrusion lines. PTFE Moldflon™ can therefore be run on micro extrusion lines for ultra-thin wall thicknesses down to 0.0005” to produce inner catheter liners, without the need to be drawn / necked down as necessary with standard PTFE. The biggest advantage of PTFE Moldflon™ however stems from its thermoplastic processing capabilities as this allows additional thermoforming operations on the tube such as tipping and flaring, without showing common manufacturing related issues such as shearing, cracking or flaking. It also can be easily co-extruded with Barium-Sulfate (BaSo4) stripes, which is widely used in IV catheter tubing. Also very fine Platinum / Iridium (Pt-Lt) lead wires of 0.001” can be continuously insulated / coated with PTFE Moldflon™, whereby the physical properties of those very fragile wires are protected. Such wires are e.g. used in cochlear implants to electrically stimulate the cochlea.

Moldflon™ is a registered trademark of ElringKlinger. For more details on Moldflon™, visit

Any challenges with new or advanced materials when it comes to tubing?

In recent months we have seen an interest to substitute Polyvinylchloride (PVC) tubing with alternative materials. This trend is fostered by the desire to come up with a material not related to the chlorine industry, as chlorine-derived materials can pose environmental and health issues if not incinerated properly with high enough temperatures. Also plasticizers need to be added to soften the PVC. But plasticizers tend to migrate out from the tubing and into the drug fluid path or even into the blood path of patients, raising questions on the biological impact of plasticizers. Independent studies using Nitroglycerin have also shown that PVC is prone to adsorb drugs and critical drug components and therefore raising questions on the dosing accuracy of drugs supplied to the patient. Alternative materials to PVC could be Thermoplastic Elastomers (TPE) or Polypropylene blends (PP). TPE’s however are not easy to bond to other substrates, such as Polycarbonate (PC) or ABS connectors, which are widely used in standard IV tubing sets. Good bonding characteristics can be achieved with PP tubing using Tetrahydrofuran (THF), however both TPE and PP have in common that they come with a high price and are not even close to the production costs of PVC. PVC will therefore stick around for the time being, until there is a political mandate to move away from PVC in the health care industry.

How about regulatory / FDA challenges – any relevant aspects to discuss for tubing?

Regulatory / FDA challenges with regards to tubing projects are more indirect, as some of our customers struggle to allocate engineering resources for new tubing developments. Recent years seem to have seen an increase of regulatory requirements being pushed on to Engineering departments with equal or maybe even less staffing. There is plenty of Engineering manpower and Engineering resources needed to qualify and validate new products or even materials. Some of this manpower seems no to be blocked by the regulatory work they need to comply to. New product developments and market launches seem to take longer than in the past, which is also a drawback to the US Medical Device industry specifically when compared to the European market. No wonder many companies now chose Europe first to launch their medical device, before they consider a product launch in the US.

  • Quality test during production processes

Please share some examples of innovative tubing solutions that you came up with to meet challenging OEM requests – can be new technology/modifications, best practices with existing approaches, etc.

One such challenge was to heat-bond a tight tolerance microbore PVC tubing into a tubing coil as a space saver (see picture “Coiled Microbore” attached). To heat bond PVC is not a challenge, but when it comes to keep tight tolerances on the tubing ID and OD, as well as on the tubing coil diameter it is, as PVC has a low melting point. PVC tubing therefore reacts and changes its characteristics in elevated temperatures resulting in out-of-spec dimensions. When heat-bonding PVC tubing in a secondary process the change of the material therefore needs to be carefully dialed-in to the production / extrusion of the tube so that an end product can be produced on basis of a statistically reliable process.

What might OEMs think is impossible (or that they misunderstand), but is actually possible, when it comes to tubing?

How about integrating a miniature camera into an bi-lumen micro tube (see picture attached)? RAUMEDIC’s intelligent catheter capabilities include a chip-on-tip integration of a tiny camera probe and polymeric optical fiber within the distal tip of a Nylon bi-lumen micro tube. RAUMEDIC’s NanEye camera probe provided by AWAIBA measures .07” x .04” x .04” in size and is applied in gastroscopy, respiratory and urological applications. The Nylon bi-lumen tube measures .089” on the OD, and .022” and .049” on the lumens.

Any breakthrough advances on the horizon that will make tubing a lot better? How fast is this field changing?

One topic which will somewhat change the current medical tubing landscape will be the introduction of bioabsorbable polymers such as PLLA / PLGA. Such materials are however expensive so it will be decisive for any tubing supplier to understand the extrusion process and the negative impact of a prolonged residence time on the physical properties of the tubing and the end device. Also concentricity (uniform wall thickness) of such tubes are very critical. RAUMEDIC’s micro extrusion lines are capable of running very low volumes of such expensive formulations with minimal residence time.

Any final thoughts / comments? Any other sources / websites / materials / vendors you’d recommend to contact?

I have talked much about the restrictions the current regulatory environment is putting on the MedDevice industry. However, it must be noted how much fun it is to work in this industry which is still full of new and bright ideas and minds, always thinking about how to improve patients life and comfort and working for the good of mankind. I am proud to be part of it.


This Q&A was done by Mark Crawford for Medical Product Outsourcing Magazine, Oct 2015.