Arburg Plastic Freeforming is predestined for the additive manufacturing of medtech components. The associated Freeformer-type additive manufacturing systems process the same plastic pellets that are used in injection molding. That makes the open systems very economical to use.

In the AKF process, resorbable original materials such a plate-implants similar to bone, can be manufactured. They are gradually replaced by endogenous tissue

Medical Product Manufacturers Are Processing Original Materials Using the Freeformer

Anlagen Additive Fertigung / 3D-Druck, andere

Anlagen für die Additive Fertigung

Biokunststoffe

Kunststoff Werkstoffe

Additive Fertigung

Medizintechnik

Medizinprodukte

Werkstoffe für additive Verfahren

Andere Werkstoffe

Arburg Kunststoff Freiformen

Verfahren für die additive Fertigung

Freiraumverfahren

New Possibilities for Use  in the Human Body

Additive manufacturing has the potential to manufacture tablets individualized for the particular patient, and thereby further digitalize the pharmaceutical industry. In medication development, the properties of a tablet, such as its shape, dosage or release of the active substance, can be individually tailored – by making just a few changes to the digital 3D print file. Merck scientists have used a Freeformer for their lab tests.

Merck researcher Dr. Thomas Kipping (right) and Nabil Lamrabet value the advantages that the Freeformer offers as an open system.

16:9

The Freeformer Allows a Tailor-Made Combination of Several Active Ingredients

Anlagen Additive Fertigung / 3D-Druck, Kunststoff

Patient-Specific Tablets

Up to now, the integration of electronic components and consequently, the production of customized 3D-printed sensors has presented a challenge. Now, together with the companies Arburg and Balluff, Fraunhofer IPA has achieved a breakthrough.

Demonstration model of customized sensor at different production stages: CAD concept (top left), after integrationof the electronic components (top right) and as a finished demonstration model (bottom)

Technik Trend

kunststoffe-international.com

Sensoren

Logistik

Lagertechnik

Sensors from the Printer

tesa develops e. g. adhesives for smartphone components and investigate the added value that additive manufacturing with plastics freeforming can bring.

“Printed” pressure-sensitive adhesives can be used, for example, to bond smartphone components together, without producing any waste

tesa Uses Freeformer for Novel Bonding Applications

Klebstoffe

Verbindungstechnik Verfahren

Chemisches Fügeverfahren

What Holds the World together

Arburg presents a total of four Allrounder exhibits and two Freeformers on show. All machines will be connected live to the Arburg host computer system ALS for demonstration purposes and to the arburgXworld customer portal, another focus of the trade fair display. Detailed information on the arburgGreenworld environmental and recycling program will round off Arburg‘s involvement in Chinaplas.

Arburg will be demonstrating the potential of freeformers for additive manufacturing on two exhibits at Chinaplas 2022.

Spritzgießen

Kunststoffverarbeitung: Verfahren

Spritzgießmaschinen

Kunststoffverarbeitung: Maschinen und Komponenten

High-End Wherever You Look

Molds for orthoses are usually machined. That is not optimal – neither for the patient nor for the manufacturer. Within the scope of a study, Lehmann & Voss therefore investigated whether 3D printing is an alternative – both ecologically and economically.

3D-printed laminating standard for the production of CFRP orthoses.

Molds for Orthoses

Polyethylenterephthalat

Thermoplaste

Technische Kunststoffe

3D-Printed, Not Machined

Due to its high-performing properties polyetheretherketone thermoplastic polymer is being used more and more frequently in many products.

PEEK can replace fluoropolymers in cryogenic applications. Advanced Engineering Valves uses PEEK from Victrex for sealings in ball valves

Polyetheretherketone (PEEK)

Elektronik-Fertigung

Elektronik

Polyetherketon

Mikroelektronik

Kunststoff

Bauwesen

Baustoffe

Hochleistungskunststoffe

Delivering Efficiency Even in  Harsh Environments

Styrenics can be polymerized using different technologies and it can be modified with a range of copolymers. The resulting plastics offer a wide range of properties allowing to customize them for different applications. Because of this range of properties they are suitable for many industries. Strong demand is for example driven by the automotive industry, healthcare and the packaging industry.

Styrene copolymers are frequently used in the exterior of vehicles. The Chinese manufacturer Lixiang, for example, uses an ASA for the radiator grill of its electric vehicles

Styrenic Polymers

Verpackungsmaterial

Automotive

Polystyrol

Styrol-Copolymerisate

Diverse Shapes and Applications

Lightweight construction, functionality and design are characteristic of material development in all areas of application for PC compounds, composites and films. The range of materials has enormous opportunities when it comes to the mobility of the future, lightweight structural construction with continuous fiber-reinforced composites, 5G technology and medical technology.

In electric vehicles, the original function of the radiator grille, namely to supply air to the engine, is no longer needed. It can therefore be used entirely as a design element, for example by integrating luminous logos and fade-out effects

Polycarbonate (PC)

Recycling

Umweltmanagement

Kunststoff-Recycling

Kunststoff-Aufbereitung

Polycarbonat

Present in a Multitude of Trends

In the production of plastic parts for the medical and pharmaceutical industry, the requirements for cleanroom environments are becoming increasingly stringent. In this area, not only the demand for all-electric injection molding machines is increasing. There is also an increasing use of electric drives for the implementation of mold movements, which meet the high requirements for cleanliness and reliability.

Fig. 1. Solutions for electrical mold movements, for example a 72+72 cavity stack mold for the closing cone production

Electrical Drives in Injection Molds

Elektrische Antriebe

Antriebe

Spritzgießwerkzeuge

Werkzeuge für die Kunststoffverarbeitung

Mess- / Regel- und Prozessleittechnik

Prozessautomation

Mess-, Steuer- und Regelgeräte

Qualitätssicherung

Qualitätssicherung Kunststoff

Reinraumsysteme / -technik

Mold Technology

Housings not only protect the inner workings of medical equipment, but also protect patients from electric shocks, for example. This function is very important for the increasingly widespread medical wearables, which are often in constant contact with the patient. When designing such devices, it is therefore important to select the appropriate housing material.

Housings play an important role in medical wearables. They protect their inner workings, but at the same time protect the users of the devices

Materials for Medical Wearable Housings

Gehäuse aus Kunststoff

Elektromechanik

Kühlkörper

Protection and Attractive Design

A Polish pharmaceutical company is developing inhalation therapy for the treatment of lung disease and the appropriate drug delivery drug. The inhaler has a complex interior and consists of 14 components. In order to be able to produce these with the required precision, Celon Pharma has formed a partnership with the mold making company Glittenberg and its hot runner sister Witosa.

For its complex functional mechanism, the inhaler requires 14 components

Glittenberg Supplies Tools for Vital Medical Devices to Celon Pharma

Heißkanalsysteme

Komponenten für die Kunststoffverarbeitung

Plastic in the Service of Medicine

Italy‘s RadiciGroup is investing EUR 15 million in a new plant for the production of meltblown nonwovens. The Group‘s strategic decision is intended to make the Italian supply chain for the base material for protective masks more autonomous.

Kunststoffverarbeitung allgemein

Kunststoffverarbeitung

Gewebe, technisch

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

Unternehmen

kunststoffe.de

Invest in a New Production Line for Meltblown Nonwoven

Thermoplastic compounds with integrated electrical conductivity offer a potential solution to resolve EMI, EMS and electrostatic discharge challenges. These thermoplastic materials can deliver the appropriate level of electromagnetic shielding for electronics, while providing freedom to design complex geometries and opportunities to streamline processing by avoiding secondary operations.

SEM analysis illustrates inferior dispersal (above) and good dispersion (bottom) of conductive fibers in molded polycarbonate parts. The distribution can be optimized by appropriate processing parameters and injection molding machines (PC resin)

Ensure the Electromagnetic Compatibility of Wireless Devices with Special Plastics

Compound

Kunststoff-Erzeugung

Well Protected against  Electromagnetic Interference

Pipette tips feature a challenging wall thickness/length ratio, an inner geometry that is key for analysis results, and a tip opening just a few tenths of a millimeter wide. They have been in extremely high demand during the coronavirus pandemic, which is why the mold construction and hot runner specialist Männer has developed a mold with an innovative cluster concept.

At the Männer test center in Bahlingen, Germany: an injection mold for manufacturing pipette tips, shown here in operation. Automation of the system is currently being set up

Pipette Tips: Männer Presents a Mold with Replaceable Clusters

Maintenance During (Nearly)  Uninterrupted Production

Bone Implants Straight from  the Hospital’s Printer

As part of the CAMed project being conducted by the Medical University of Graz, researchers are working on manufacturing custom implants in the hospital itself. This will benefit patients, but also has implications for the hospital because it will thereby become a medical device manufacturer. A key role in the first pilot study is being played by the Arburg Plastic Freeforming (APF) process.

Researchers on the CAMed project being conducted by the Medical University of Graz are working on producing custom implants in the hospital using 3D printers.

Artificial implants for humans are generally deemed to be safe, given that they undergo thorough compliance testing under the strict regulations governing the approval of medical products. Nevertheless, problems can arise, whether it is because even the latest products still show deficiencies in service or whether it is because, say, degradation mechanisms only start manifesting themselves after decades, when an implant has to be replaced. Otherwise, the functional supports often remain in in the body until the patient dies.

The greatest shortcoming, however, is that implants are often not customized for to individual patients. One solution to this that has already been tested and has proved useful in numerous studies is the additive manufacturing of exogenous replacement parts. The digital process chain, in particular, affords a way of taking the quality of therapy here to a new level, because the diagnostic imaging procedures employed at the outset can be used to derive the data needed for the patient’s custom implant. If this approach is taken to its logical conclusion, the question arises: Would it not make sense to manufacture these implants in the hospital itself?

This is what the Medical University of Graz, Austria, has set out to achieve in a project it calls Clinical Additive Manufacturing for Medical Applications or CAMed, for short. Aimed at getting 3D printing of custom implants for patients up and running in hospitals, the project, which is a collaboration between five scientific institutions and 15 companies, is being funded to a total value of EUR 6 million by the Austrian Research Promotion Agency (FFG) and the Austrian state of Styria and is set to end this year after a four-year term. Prof. Ute Schäfer (Fig. 1), the lead scientist on the project, puts it in a nutshell: “We want to take additive manufacturing techniques and materials, adapt them to human medicine and then print the implants ourselves, because so far the solutions provided by medical device suppliers have been less than optimal.”

Speaking to Kunststoffe, Schäfer cites rib implants as their most important strategic project. The reason is that up to now, if ribs have to be removed from a patient due to, say, a tumor growing into them, the affected bones have to be replaced by flexible metal bands. During the operation, these bands are molded to fit the patient’s rib cage and are attached to the remaining costal processes. However, because the parts are flexible, patients often return years later with their implants completely bent out of shape (Fig. 2). “Sometimes all it takes is for the patient to lay awkwardly, cough hard or be hit by a ball and the metal becomes deformed in the body,” Schäfer says. “So, we conducted a basic modelling project for the rib cage to define properties for printing ribs of the necessary stiffness and exact fit that could be used by the surgeon in the operating theater without the need for further adjustments and without any further risk of deformation.”

In order that a holistic R&D model of ribs and thorax could be developed, it was necessary to obtain some body donations, i.e. cadavers cleared for medical research. The cadavers were used, for example, for measuring the stiffness of the rib cage or the pressure exerted by the lungs during breathing and coughing. The resulting data were then transformed into a simulation, e.g. of a resuscitation, which mapped the stresses in the ribs and rib cartilage (Fig. 3). For the production of the first models, the researchers specified materials that were suitable both from anatomical and 3D printing aspects: thus, the plastic ribs (Title figure), like real bone, have hard and soft areas, which were printed together in a single process.

The two materials, each a medical-grade polycarbonate urethane (PCU; type: Bionate; manufacturer: DSM) but with different mechanical properties, were processed on an Arburg Freeformer 200–3X. This machine applies the polymer drop by drop at a high rate onto a movable build platform – following the contours of the individual layers from the STL dataset, which is generated from a CT model of the body part in question. “The Freeformer is the perfect machine for hybrid applications like this because the hard and soft areas which it produces cannot be separated from each other – the seam holding them together is more likely to tear first,” says Schäfer, summarizing the first interim result. Furthermore, the ribs possess the necessary overall stability. Only one thing remains to be resolved: how to integrate the metal fastener into the printing process.

Cranial Implants Made of PEI about to Enter Clinical Use

The project partners have made huge progress in the development of cranial implants. Having passed the necessary preclinical phases in respect of both cell culture and animal testing, this sub-project is set to enter the clinical phase.

A pilot study involving initially twelve patients will reveal how the implants behave in the body, whether they are biocompatible with human bones and whether they retain their mechanical properties in a biological environment. As patient safety is paramount, a whole battery of tests will have to be conducted first. The reason is, as Schäfer explains, the need to rule out cytotoxicity (tissue damage) and inflammatory response (occurrence of inflammation). The material must withstand sterilization processes and the detergents used in them without sustaining damage. And the mechanical properties of the implant have to be a very close match for those of the original.

Very good results have already been obtained in mechanical tests on the cranial implants, especially those made of PEI and PEEK, which were produced with the Freeformer (Arburg) and a filament printer (Apium M220), respectively. One striking aspect worth noting in this context is the following added bonus: A commercial, milled PEEK implant can withstand the piston pressure for a relatively long time in the test, when it breaks, it splinters. “That’s really not a great outcome for a cranial implant,” says Schäfer, a molecular biologist, before continuing, “The printed PEI implant can withstand the same amount of pressure, but breaks into just three large pieces, which is a big advantage.” One caveat, though, is that the implants used so far in the trials have been small. The implants used in reality are normally larger, such as when a stroke patient has a large section of skull removed to relieve pressure on the brain.

Quality Management as a  Matter of Urgency

The precise starting date for the study has not yet been set – and for good reason. Even though the researchers have already performed an elaborate risk analysis, permission has been granted by the ethics committee and the patients are comprehensively insured, the hospital managers have stipulated that a quality management system be put in place first. On one hand, this makes sense, because although the act of 3D printing renders the hospital a medical device manufacturer, it does not need to have the implants certified – unlike the case for medical device companies – for the simple reason that it does not market them. “This is uncharted territory for the hospital – when we work with medicines, we don’t need a QM system,” declares Schäfer.

One fact makes complying with the stipulation easier: “In my opinion, the APF process is ideal for manufacturing medical products, especially in the context of QM – the process chain stretching from transfer of patient data to simulation and data preparation through to printing is wholly digital, and all steps are verifiable,” says Schäfer. Morever, she adds, the Freeformer processes the materials in a way that is highly beneficial to the mechanical properties.

Nevertheless, as this is a sensitive application area, it is a requirement of human medicine that extensive basic research be conducted. Thus, the University of Leoben, Austria, which received the Freeformer on loan because it is one of the project partners, has qualified various materials – including PCU, PMMA, PPSU, PP and PET-G – for clinical use and has optimized the printing process at the same time. Among other things, the researchers have been able to demonstrate the influence exerted by the size of the plastic droplets on the mechanical stability of the implants.

Basic research will also be the focus of phase two of the project, CAMed II, which the research partners will soon be seeking funding for. The goal here is to integrate sensors into the implants. These electronic devices can either be incorporated during printing or be printed onto the implant afterwards – the technology is flexible in this respect. As Ute Schäfer explains, “We want to evaluate what happens to the implant in the body and what happens to the body as a result of the implant. Our goal is to detect deformation, material fatigue and cracks at an early stage. If possible, we also want to measure biological parameters, for example, whether adjacent bone tissue is degrading. That way, we can see whether it might be better to remove an implant after a certain period of time and to further improve the materials.”

But before all that takes place, the medical 3D printing center at University Hospital Graz has to come on stream.

ARBURG GmbH + Co KG  

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Medizinische Universität Graz  

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Ausgabenartikel

The 3D-printed rib made of PCU possesses the necessary stiffness and fit for insertion directly into the chest cavity.

Fig. 1. Molecular biologist Prof. Ute Schäfer is the lead scientist on the CAMed project. 

Fig. 2. The metal bands that formerly served as rib replacements must be adapted first during the surgical intervention and will deform after some time in the body.

Fig. 3. A simulated resuscitation. The sternum is pushed 40 mm toward the spine.

Hauptartikel

Additive Manufacturing of Implants on Site Benefits Hospital Patients

A total of 20 institutions and companies are collaborating on the CAMed project.

Additive manufacturing: Apium, Arburg, Hage3D (all polymers), Lithoz (ceramics), LSS, Trumpf (both metal), Faro (3D-laser scanning)

Materials: Böhler Edelstahl, DSM, Evonik, Heraeus, Ionbond, Mitsubishi Chemical, Solvay

Medical products manufacturer: Hofer Medical Solutions

Scientific partners: CAE Simulation & Solutions, Joanneum Research, Max-Planck-Gesellschaft, Medical University of Graz, Montan University of Leoben

<a href="http://www.medunigraz.at/camed/" target="_blank">www.medunigraz.at/camed/</a>

Read the German version of the article in our magazine Kunststoffe or at <a href="https://www.kunststoffe.de/a/fachartikel/knochenimplantate-in-der-klinik-drucken-4696366" target="_blank">www.kunststoffe.de</a>