In modern medical technology, a fraction of a millimeter often determines functionality, safety – and ultimately the lives of patients. Processes such as EDM in medicine have therefore become indispensable building blocks in the production of medical components.
Thanks to this technology, even the most complex geometries can be precisely implemented in high-strength materials such as titanium or nitinol – for implants, microsensors or surgical instruments, for example. At the same time, however, the requirements are also increasing: in terms of surface quality, biocompatibility and documentation in accordance with ISO 13485 or FDA guidelines.
This guide sheds light on how EDM can meet these challenges – practical, well-founded and with a clear view of the industry’s requirements. It shows what is important when selecting the process and the right partner, what pitfalls exist and how these can be avoided.
At the end, you will have a clear understanding of how EDM can be used specifically in medical technology to realize high-precision, safe and regulatory-compliant solutions.
- Eroding enables maximum precision with titanium, INOX & Nitinol
- Ideal for implants, microsystems and surgical instruments
- Tolerances up to ±0.001 mm and surfaces up to Ra 0.10
- Contactless processing without thermal stress
- Certified according to ISO 13485 - suitable for FDA & MDR
- Economical even for small batches and complex geometries
Table of contents
Why EDM is a key technology in medicine
The growing importance of micromachining
Modern medical devices are becoming increasingly smaller, more complex and functionally denser. Where there used to be room for generous tolerances, today micrometers often count. At the same time, the materials used must meet the highest requirements – both mechanically and biologically. This is precisely where micromachining comes into play. It enables the production of extremely fine structures that could no longer be realized with conventional processes, or only with considerable compromises.
Eroding – as a central component of micromachining – allows even difficult-to-machine materials such as titanium, stainless steel or Nitinol to be machined precisely. It therefore opens up new possibilities for components that require maximum dimensional accuracy and filigree geometries. From micro nozzles and sensor sleeves to guide elements in minimally invasive surgery: the smaller the part, the greater the importance of this technology.
Requirements in medical technology: biocompatibility, tolerances, miniaturization
Medical components are subject to particularly strict regulations. Biocompatibility is not negotiable – nor is absolute dimensional accuracy or complete documentation. Even the smallest residues or dimensional deviations can have an impact on the safety or function of a product.
Miniaturization also places high demands on production. Drill holes in the sub-millimeter range, cutting widths of less than 0.1 mm and radii of just a few hundredths of a millimeter have long been a reality. At the same time, surfaces must not have any sharp edges, burrs or discoloration in order to ensure tissue compatibility.
In addition, all process steps must be reproducible, validatable and traceable – requirements that can only be met with specialized production technology and experience in medical technology.
How eroding precisely fulfills these requirements
EDM is based on the principle of contactless material removal through electrical discharges. This method generates hardly any mechanical stresses and avoids thermal influences that could change the material structure – a decisive advantage over machining processes.
By using the finest wires or electrodes, structures in the micrometer range can be produced with high repeat accuracy. Shape and position tolerances of +/- 0.001 mm can be achieved, even with materials that are difficult to process. The surface quality can also be specifically influenced: Values below Ra 0.1 are easily achievable – a prerequisite for applications with direct physical contact.
Another advantage is that the geometries created are not limited by tool restrictions. This results in free-form surfaces, undercuts or microchannels that would be difficult to achieve using conventional methods. This makes EDM a key technology for the next generation of medical products – precise, reliable and easy to document for regulatory purposes.
Understanding the basics – What is EDM anyway?
From spark erosion to die sinking and wire erosion
EDM is not a single process, but an umbrella term for various technologies for precise material processing using electrical discharge. All processes are based on the same physical principle: electrical sparks remove tiny amounts of material at the machining point without direct contact between the tool and the workpiece.
EDM sinking uses a shaped electrode that corresponds negatively to the desired geometry. It is lowered into the workpiece, creating cavities, channels or 3D contours – often used for complex internal geometries.
Wire ED M, on the other hand, works with a thin, continuous wire that serves as a cutting tool. This method is ideal for contour cuts and high-precision outlines – especially for plate-shaped or rotationally symmetrical components.
Drill erosion and spark erosion grinding complement the range with specialized applications, such as for starting holes or the ultra-fine machining of round parts.
How does the erosion process work technically?
The machining process always takes place in an electrically non-conductive liquid – the so-called dielectric. This ensures controlled sparking and cools the workpiece at the same time. An electrical voltage is applied between the electrode and the workpiece. As soon as the distance is small enough, a spark is discharged, which generates local temperatures of several thousand degrees.
This extreme heat vaporizes or melts microscopically small areas of material. At the same time, the resulting particles are flushed out of the processing zone with the help of the dielectric. This process is repeated several thousand times per second – fully automated and controlled with high precision.
The coordination of numerous parameters is crucial: Discharge energy, cycle frequency, wire feed or electrode feed not only influence the shape, but also the surface quality and processing time. Modern CNC-controlled erosion machines enable very fine adjustment and therefore maximum reproducibility.
Differences to other manufacturing processes
In contrast to machining processes such as milling or turning, material is removed during erosion without the application of mechanical force. The workpiece is not deformed or subjected to vibrations. Thermal influences such as changes in hardness or microstructural changes are also minimal – a clear advantage for sensitive or critical materials.
Another difference: with eroding, even hard, conductive materials such as hardened steel, titanium, hard metals or certain ceramics can be machined with high precision. Conventional machining reaches its limits here – both economically and technically.
In addition, EDM enables the production of complex geometries that would be virtually inaccessible with rotary tools – such as deep undercuts, tight internal radii or fine webs. This makes it the ideal choice for functional micro-components, which are often required in medical technology.
Typical applications – where EDM is indispensable in medicine
Production of implants (dental implants, hip joints, prostheses)
Implants must be able to do more than just fit perfectly. They must be permanently integrated into the human body, must not trigger any reactions and must be extremely mechanically resilient. Materials such as titanium or special stainless steel alloys are used here in particular – materials that are difficult to process using conventional methods.
EDM offers the possibility of processing even these difficult materials with exceptional precision and without thermal influence. In the case of dental implants, for example, microscopically precise thread structures and clean surfaces are essential to ensure secure anchoring in the jawbone. The same applies to joint prostheses: Here, the machining quality determines the fit, mobility and service life.
In particular, the control of roughness values and dimensional tolerances makes eroding the ideal technology for the high-precision production of implants – whether one-off production or small series.
Surgical instruments with complex geometry
Modern surgical methods rely on specialized instruments that can be used in a minimally invasive manner, but must also be stable, sterile and ergonomic. Geometry plays a decisive role, especially for precision mechanical tools such as bone spreaders, biopsy forceps or microsurgical scissors.
Non-contact erosion enables the production of intricate contours with exceptional sharpness – even in hard-to-reach areas. This results in tools with fine tips, precise guide channels or functional surfaces that offer optimum grip.
Another advantage is that the materials used – such as hardened INOX steel or Nitinol – retain their microstructure, as there are no machining forces or heat that could change the material. The result is durable, reliable instruments with precisely reproducible properties.
Microsystems and components for minimally invasive procedures
Increasing miniaturization in medical technology brings with it new requirements: components must not only be smaller, but also more functional and resilient. Microsensors, actuators or fluidic systems must fit into complex devices with millimeter precision – often with tolerances in the range of a few micrometers.
With wire diameters from 0.02 mm and a machining accuracy of up to ±0.001 mm , EDM is ideal for these applications. Cavities, openings or microchannels can be created that would be impossible to achieve with machining processes. Even with the smallest components, the dimensional accuracy remains constant, which is crucial for the subsequent function of the overall system.
What’s more, the smooth, clean surfaces reduce friction, facilitate assembly and improve hygienic safety – all of which are essential for use in medical technology. EDM offers precise solutions for highly sensitive requirements, particularly for catheterization devices or in ophthalmology.
Challenges in practice – and how to overcome them
Removal of the rearrangement layer for optimum biocompatibility
The heat generated during erosion creates a so-called recast layer. This microscopically thin layer consists of newly solidified material that can potentially contain cracks, inclusions or impurities. It is particularly critical in medical technology as it can impair the biocompatibility and long-term stability of an implant.
Various methods are available for removing this layer. Glass bead blasting is often preferred as it is dimensionally stable and optimizes the surface structure at the same time. Alternatively, chemical milling or electropolishing are used – but with the risk of color changes or dimensional changes. It is crucial to choose a process that meets both the technical and regulatory requirements without damaging the base material.
Only if this post-processing is carried out consistently can safe integration in the body be guaranteed – whether for implants or sensitive microsystems.
Risk of contamination and how to avoid it
In medical production, even minor contamination is enough to jeopardize entire batches. Particle residues, traces of oil or chemical reactions on the surface can render the end product unusable or even lead to rejection during approval. Contamination control is therefore not an optional step, but an integral part of the process chain.
The right combination of mechanical cleaning, passivation and certified sterilization can minimize the risk. Depending on the material and application, processes such as acid pickling, autoclaving or UV irradiation are used. However, a controlled environment is even more important: cleanroom technology, suitable packaging solutions and closed-loop process documentation ensure that no step is left to chance.
These measures are not only important from a regulatory perspective – they also protect the investment in a precisely manufactured component from avoidable recalls or complaints.
Process validation and ISO 13485: More than just a mandatory program
For medical technology applications, it is not enough to simply manufacture a part “well”. Each individual production step must be validated, documented and traceable. The ISO 13485 standard forms the basis for quality management systems in medical technology. It requires not only precise processes, but also complete traceability.
Even the smallest changes – such as replacing a hose in the blast cabinet – can require a new validation. The effort is high, but it pays off: Only those who control their processes can deliver consistent quality in the long term. At the same time, this creates trust among customers, inspectors and certification bodies.
Professional manufacturing service providers have therefore established standardized processes that are re-evaluated and documented with every change. This creates a system that is not only efficient, but also audit-proof and future-proof – an enormous advantage, especially for recurring production series.
Materials & technology – What counts when eroding
Suitable materials: Titanium, INOX, Nitinol, hard metals
Not every material is suitable for every processing method. In the medical sector, materials that are corrosion-resistant, biocompatible and at the same time mechanically highly resilient are preferred. These include titanium, stainless steel (INOX), Nitinol and hard metals. These materials often pose major challenges for conventional machining processes – either due to their hardness or their reaction to heat.
In eroding, on the other hand, hardness plays no role. The only decisive factor is the electrical conductivity. This means that even materials with extreme material properties can be processed with the highest precision. Titanium, for example, is not only cut, but treated so gently that the original microstructure is retained – a clear advantage for the long-term stability of implants or functional components in the body.
Hard metals and alloyed special steels can also be structured by eroding without causing thermal damage or dimensional distortion – a point that is particularly important for complex micro-components.
Surface quality & tolerance accuracy in the µm range
In medical technology, consistent tolerances and perfect surfaces are not an option, but a must. An implant that cannot be inserted precisely or an instrument with excessive roughness can cause serious problems in clinical use. This is why controlled process parameters that minimize any deviation are essential for eroding.
Surface roughness below Ra 0.10 can be easily achieved with modern erosion processes. These mirror-smooth results not only reduce friction and deposits, but also facilitate cleaning and sterilization – key requirements in medical applications.
At the same time, eroding enables tolerances in the range of ±0.001 to 0.003 mm – even for very small structures. This achieves a high accuracy of fit between individual parts without the need for additional post-processing steps. This accuracy ensures reliable functionality and a long service life, especially for delicate components.
The role of state-of-the-art machines & microelectrodes
The performance of an EDM process stands and falls with the technology used. Modern machines not only offer automated axis movements and precise control, but also the ability to work with extremely fine electrodes. Wires with a diameter from 0.02 mm or carbide electrodes for holes of less than 0.10 mm open up new dimensions in micromachining.
In addition, specialized generators that work with needle pulses ensure an extremely low thermal load and therefore maximum mass stability. Intelligent machine monitoring systems also regulate the wire feed, the discharge energy and the flushing of the dielectric in real time – for consistent processing results even with long running times.
The combination of high technology and reliable process control enables reproducible series production of components where every detail is important – whether implants, sensor housings or the finest cutting contours.
Quality is no coincidence – this is how erosion machining is tested
Microscopic control and measurement protocols
In micromachining, it is not uncommon for a ten-thousandth of a millimeter to determine the functionality of a medical component. This is why the production process in EDM does not end with the last spark, but with precise quality control.
The standard equipment includes high-resolution microscopes, which can be used to assess the finest structures magnified up to 700 times. In this way, edge contours, radii and surface qualities are visually inspected and documented. Tactile or optical measuring methods are also used to precisely record dimensional accuracy and geometry.
Measurement reports are created either during the process or on a batch basis – depending on the requirements. They form the basis for approval and are particularly essential in the regulatory environment. This ensures that every manufactured part meets the specifications – regardless of whether it is a single piece or series production.
Traceability and documentation for FDA & MDR
Anyone who wants to bring medical products onto the market faces a complex web of regulations. The European MDR guidelines and the requirements of the US FDA demand complete traceability of every single production step – from the raw material batch to the final packaging.
In the eroding process, this means that every setting, every tool use and every material change must be documented. Modern systems enable digital process tracking, in which all production data can be archived and retrieved as required – even years later.
This transparency not only creates trust with authorities and customers, but also reduces the risk of recalls or complaints. At the same time, it allows a precise root cause analysis in the event of deviations – a key factor for continuous process optimization.
Certified processes at suppliers – what manufacturers need to look out for
Not every EDM workshop is automatically suitable for medical technology applications. Manufacturers should therefore pay particular attention to certifications such as ISO 13485 , which provide evidence of structured quality management and regulatory conformity. This standard is far more than just a seal of quality – it regulates the handling of processes, risks, validation and traceability down to the smallest detail.
In addition to pure certification, practical skills also play a role: Does a provider know the typical requirements of medical technology? Does he work with validated cleaning processes? Are sensitive batches processed under cleanroom conditions?
Only the combination of technical excellence and regulatory understanding makes an EDM service provider truly fit for medical use. For manufacturers, it is worth looking beyond the machinery – towards processes, mindset and experience.
Subtractive instead of additive manufacturing – why EDM is (still) ahead
When additive processes reach their limits
Additive manufacturing is synonymous with flexibility and design freedom. However, this technology repeatedly comes up against physical and process-related limits, particularly in medical technology. Although complex internal geometries can be built up layer by layer, they cannot be realized with the required dimensional accuracy and surface quality – at least not without extensive post-processing.
Another problem is that the selection of biocompatible materials that are approved for 3D printing and at the same time have a high mechanical load-bearing capacity is very limited. Metallic materials such as titanium or nitinol in particular show weaknesses in their microstructure or porosity – both of which are undesirable for implants or functional precision components.
In addition, there is often a lack of validated processes that fully cover the requirements of ISO 13485 or MDR. This poses a considerable risk for regulated markets.
Why EDM is superior for complex materials such as titanium & nitinol
Materials such as titanium or nitinol are used in medical technology – not least because of their high biocompatibility, corrosion resistance and mechanical properties. However, they are extremely difficult to machine. Many processes generate stresses, structural changes or thermal influences that can impair their functionality.
EDM completely avoids this problem. As a non-contact process, it does not generate any mechanical pressure and only uses punctual discharge to remove material. As a result, the microstructure remains stable, even with the finest structures.
This property is particularly important for shaped elements made of titanium that are used in minimally invasive systems. Nitinol, which is thermally sensitive to processing, can also be shaped precisely using EDM – without impairing the so-called memory function.
Precision, surface quality and process reliability in comparison
Subtractive processes such as erosion offer clear advantages in terms of dimensional accuracy and repeatability. Where additive processes have tolerances of ±0.05 mm or more, erosion easily achieves accuracies in the range of ±0.001 mm – even with complex micro-geometries.
The surface quality is also superior to EDM: While 3D-printed components often have to be reworked, EDM produces smooth, defined surfaces with roughness values below Ra 0.10 during the manufacturing process. This not only saves time, but also reduces risks during implantation or functional losses.
In terms of process reliability , EDM scores highly with its mature, certifiable processes. Reproducibility is high and integration into validated quality management systems is much easier than with many additive processes. As long as additive technologies do not meet these standards across the board, EDM will remain the superior approach in medical technology – especially for highly complex parts.
When precision counts – what matters when choosing the right partner
The quality of a medical product stands and falls with the precision of its individual components. However, even the best technology can only develop its full potential if it is used by a partner with experience, specialization and an understanding of regulatory requirements.
A service provider must offer more than just machine capacity. It is crucial that they feel at home in the world of ISO 13485, MDR compliance and zero-defect tolerance. Processes must be documentable, validatable and traceable at all times in the event of an audit – not as an exception, but as the standard.
Retero GmbH brings precisely this combination of technical expertise and industry-specific understanding of quality to the table. Specialization in micromachining, electrical discharge machining and small series production is combined with over three decades of experience and an uncompromising focus on medical requirements. This focus pays off, especially for prototypes or small series where maximum flexibility and attention to detail are required.
Added to this is a deep understanding of the processing of demanding materials such as titanium, Nitinol or conductive ceramics – materials that play a central role in medical technology and can only be reliably processed by a small number of suppliers. In combination with personal support at eye level, the result is a manufacturing partner that you can not only rely on – but that becomes a strategic advantage.
Let us realize your ideas together - contact Retero GmbH and benefit from our experience and our commitment to precision and quality.
Conclusion – Why EDM is a game changer in medical technology
Summary of the advantages
EDM is more than just a manufacturing process – it is a precise solution for highly sensitive applications where errors are not an option. Thanks to its contactless processing, it enables the production of the most intricate structures in extremely hard and demanding materials without subjecting the material to thermal or mechanical stress.
The achievable tolerances in the sub-micrometer range, the outstanding surface quality and the ability to produce complex geometries regardless of shape or depth make EDM the first choice for medical components. In combination with validatable processes and complete traceability, it also offers excellent regulatory integration – ideal for the development and series production of medical technology products.
Which companies benefit from working with specialists
Not every project requires standard solutions – and not every service provider is prepared for the special requirements of medical technology. For companies operating in a sensitive, highly regulated environment, the choice of manufacturing partner is crucial.
Manufacturers of implants, microsystems or surgical instruments in particular benefit from specialized providers who not only master the technology, but are also familiar with certifications, documentation requirements and cleanroom processes. Prototype development, small series with tight schedules or projects with difficult materials are typical fields of application in which collaboration with experienced EDM experts makes all the difference.
The next step for innovative medical devices
Innovation begins not only with an idea, but also with the ability to implement it precisely and reliably. Anyone who sets out to develop new medical solutions needs partners who think just as consistently in terms of quality, precision and reliability.
EDM provides the necessary technological basis for realizing miniaturized, functional and regulatory safe products in the future. In combination with the right manufacturing partner, this results not only in components – but also in reliable innovations that stand the test of time.
Whether start-up, OEM or supplier: those who use EDM strategically secure a real competitive advantage in an industry where precision can save lives.
Frequently asked questions about eroding in medical technology
How small can you erode components?
With modern erosion processes, structures from a wire diameter of 0.02 mm and drill holes from 0.05 mm can be realized. Tolerances of up to ±0.001 mm can be achieved – ideal for micro parts in medical technology.
Is EDM also economical for series production?
Yes, especially for complex geometries, expensive materials or small quantities. EDM is virtually tool-free, enables continuous production without reworking and reduces rejects thanks to high precision.
What certificates does an EDM service provider need?
ISO 13485 is crucial for medical applications. It certifies a comprehensive quality management system, especially for medical products. ISO 9001 is also commonly used as basic certification.