The international standard DIN EN ISO 13485 refers to both the supply of medical devices and the associated services. The primary aim of this international standard is to harmonise the legal requirements for quality management systems of medical devices.
Ensinger GmbH has introduced a quality management system in accordance with DIN EN ISO 13485:2016 in many areas for the development, production and distribution of thermoplastics at its Nufringen and Cham sites. With this certified quality management system for medical technology, Ensinger offers its customers additional security.
For medical grade products, the aim is, to keep the materials and the manufacturing process as unchanged as possible. In case of changes, high evaluation standards apply within the scope of the medical grade change management and the customers are informed of relevant changes as early as possible with a change notification. The aim is, to always provide equivalent products despite necessary adjustments.
Plastic materials within the Ensinger MED- / MT-standard-portfolio are tested according to ISO 10993 pursuant to their intended use, preferably on the product. They fulfil the requirements specified in the respective test. However, the evaluation of biocompatibility can also be completely adapted to the customer's individual needs.
The packaging for medical products is an important aspect to protect the product from corrosion, contamination and damage. The product needs to be protected from high air humidity, dust and dirt, temperature extremes and direct sunlight during transportation and storage at Ensinger or on the customer's premises. Depending on the customer's requirements, this is achieved by using film or sleeve packaging, which can be adapted flexibly to the product, to some extent even shrunk or used in multiple layers. Furthermore, the product can be cleaned or washed and sterilized as required.
The Ensinger product portfolio contains materials with a variety of different declarations, including the following areas:
Biocompatibility (in accordance with ISO 10993, USP Class VI, etc.)
Drinking water contact (including KTW, DVWG, WRAS, NSF61, etc.)
Flammability (including UL94, etc.)
as well as material qualification testing for the following industries:
Depending on the material involved and in close cooperation with raw material suppliers and test institutes, we issue the listed confirmations relating to the materials by the customer’s request. In the interests of ensuring full traceability, these confirmations are only issued by Ensinger in direct connection with an actual order and with the material supplied
Ensinger semi finished products for the food industry are manufactured in accordance with the requirements of the following legal European regulations on conformity for food contact:
In addition to (EU) No. 10/2011, which is applicable across Europe, Ensinger products also comply with specific directives such as FDA approval for raw materials and recommendations on the suitability of plastics for contact with food issued by the Federal Institute for Risk Assessment of Germany (BfR). A suitability statement is provided by Ensinger's technical office with confirmation of the material listing.
Ensinger products for the food industry are compliant to specific directives of FDA approval for raw material.
Certificates in accordance with FDA requirements are issued by Ensinger for stock shapes products intended for repeated contact with food. A suitability statement is provided by Ensinger's technical office with confirmation of the material listing.
Drinking water does not fall within the scope of food manufacturing guidelines, but is monitored in accordance with special regulations which are not internationally standardised at present.
Since drinking water is frequently used in the preparation of food, either as a manufacturing component or in cleaning processes, Ensinger semi finished products are available with raw material compliance to the following specific directives:
The country specific test specifications are not transferrable and must be individually tested in each case. However, their statements are similar in respect to the suitability of specific application conditions for drinking water. These are comparable according to KTW, WRAS and NSF 61, and are classified into three categories: cold water (e.g. up to 23 °C), warm water (e.g. up to 60 °C) and hot water (e.g. up to 85 °C).
Analogous to the issue of suitability for contact with food, raw materials intended for contact with drinking water have to pass suitable migration tests. As a rule, raw material manufacturers must carry out these migration tests for the qualification of suitable materials and decide for themselves according to which regional regulations they will carry out the tests.
Ensinger offers a variety of biocompatible materials with different sterilisation capabilities for products ranging from medical devices to short-term implants.
Find out more about biocompatibility and our solutions here.
The Ensinger product portfolio contains materials with specific fire behaviour, assessed by relevant testing.
Combustibility testing to UL94 is generally performed on raw material. Alongside testing in accordance with the specifications of UL or using a UL-accredited laboratory, listing and using so called yellow cards is also performed directly by UL itself. For this reason, a distinction must be made between materials with a UL listing and materials which only comply with the requirements of the respective UL classification (without listing). If listed materials are required for special applications, please consult our Sales Departments before ordering, as it is possible that specific raw materials may have to be used.
Alongside flame retardant classification in accordance with UL94, there are other industry specific tests, which classify the combustion behaviour of plastics.
Both standards require quality control tests such as specific gravity, hardness, tensile property and elongation tests, as well as chemical resistance test procedures for the qualification of thermoplastic materials exposed to fluids at elevated pressures and temperatures over an extended period of time.
There are no significant differences between EN ISO 23936-1 and NORSOK M-710 for the evaluation of thermoplastics regarding sour fluid resistance. The main practical difference is that the pressure, temperature and sour fluid concentration requirements for ISO are more stringent than for NORSOK M-710. So testing according to the conditions given in EN ISO 23936-1 is also relevant to compliance with NORSOK M-710.
There are no aviation-specific statutory regulations for the field of semi-finished plastic parts which are directly applicable to subcontractors of corporations with aviation approval. Manufacturing corporations can draw on a series of national and international standards, which they can apply in cooperation with suppliers. If the specifications in the standards do not comply with the manufacturer's requirements, they are frequently supplemented by additional individual specifications.
Ensinger, as a manufacturer of semi-finished products, is capable of complying with the required specifications and is familiar with the customary procedures and processes for product qualification and order processing in the aviation sector. An in-house sales team specialising in aviation and an efficient compliance management department ensures that in each individual case, according to customer requirements, Ensinger semi finished products can be supplied which are compliant with these main following European standards:
In its own laboratories, Ensinger has a range of sources for determining material characteristics. The table below offers an overview of possible tests, which can also be performed as part of a works test certificate 3.1 in accordance with DIN EN ISO 10204.
In addition, we work in close cooperation with various external test institutes, through which additional and more complex tests can be performed in a variety of areas.
All variations should be generally protected:
Variants not dyed black should be protected:
If correctly stored, plastics themselves do not pose a fire risk. However, they should not be stored together with other combustible substances.
Plastics are organic materials and are consequently combustible. Their combustion or decomposition products may have a toxic or corrosive effect.
Plastic
waste and chips can be processed and recycled by professional recycling
companies. In addition to this, it is possible to send the waste for
thermal processing by a professional company to generate energy in a
combustion plant with suitable emission control in place. This applies,
in particular, to applications where the plastic waste produced is
contaminated, e.g. in the case of machining chips contaminated with oil.
There is no definition of the maximum residual contamination which may be present on a component for the food and medical technology sectors. Since no level of cleanliness is defined, individual producers have to set out/define their own limits for admissible contamination.
The FDA and EU guidelines define directives and regulations on the migration of substances into products, but not on the degree of surface cleanliness.
The solution is:
Semi finished products from Ensinger:
Definition of limiting values for admissible cleanliness in mutual agreement with the customer
A variety of different welding processes are available, which work either on a no contact basis (heating element, ultrasound, laser, infrared, gas convection welding) or by contact (friction, vibration welding). Depending on the process used, certain design guidelines must be observed during the design phase in order to guarantee optimum connection. In the case of high temperature plastics, it should be noted that an extremely high input of energy is required for plastification of materials. The welding method to be used depends on these factors; shaped part geometry, size and material. Common welding techniques used for processing plastics are:
Decisive factors for a good bonded joint:
When bonding plastics, stress peaks should be avoided and a compressive, tensile or shear load should preferably be applied to the adhesive bond joint. Avoid flexural, peeling or plain tensile stresses. Where applicable, the design should be adjusted so that the bonded joint can be configured for suitable levels of stress.
For the machine processing of plastics/semi-finished goods, normal commercially available machines from the wood and metal working industries can be used, with tools made of high speed steel (HSS).
In principle, tools with cutting edge angles like those used for aluminium are suitable, however, we recommend the use of special tools for plastic with a sharper wedge angle.
Hardened steel tools should not be used to process reinforced plastics, due to the low holding times and long processing times. In this case, the use of tungsten carbide, ceramic or diamond tipped tools is advisable. Similarly, circular saws fitted with carbide tipped saw blades are ideal for cutting plastics.
Therefore, only flawlessly sharpened tools should be used. Due to the poor thermal conductivity of plastics, steps must be taken to ensure good heat dissipation. The best form of cooling is heat dissipation through the chips produced.
In the extrusion process, materials are melted and compressed in a cylinder via a screw conveyor and then homogenised. Using the pressure arising in the cylinder – and the appropriate tooling – semi-finished goods are delivered in the form of sheets, round rods and tubes and calibrated via a cooling system.
Ensinger offers a broad product portfolio of semi finished plastics, which may be processed optimally by machining.
The resulting pressure in the extrusion process produces a shear movement and flow of the molten plastic mass. The semi finished goods discharged by the tool slowly cool from the marginal layer to the centre. The poor thermal conductivity of plastics results in different cooling rates. Whereas the margins have already solidified, the centre still contains plastic in the liquid state or fused plastic. Plastics are subject to a typical shrinkage pattern for that material. During the cooling phase, the plastic centre is hindered from contracting by the rigid boundary layer.
Dimensional stability is to be considered as a characteristic in every system, in each process step, from the production of semi finished plastics to the final end use. There are various factors which can influence the dimensional stability of a component.
There is currently a trend towards using dry machining with engineering plastics. As there is now sufficient experience available in this area, it is frequently possible to machine plastics without the use of cooling lubricants. Exceptions for thermoplastic machining processes are:
However, it is possible to use a cooled cutting surface to improve both the surface quality and tolerances of the machined plastic parts. Furthermore, this allows faster feed rates and consequently reduced running times.
If cooling is required, it is recommended to cool
Dimensionally precise parts can only be made from stress annealed semi-finished products. Otherwise, the heat generated by machining will inevitably lead to the release of processing stress and component warping.
Ensinger semi-finished products are always, in principle, subjected to a special annealing process after production in order to reduce the internal stress created during the manufacturing process. Annealing is carried out in a special recirculating air oven, however, it can also be performed in an oven with circulating nitrogen or in an oil bath.
The annealing process involves thermal treatment of semi-finished goods, moulded or finished parts. The products are slowly and evenly warmed to a material-specific defined temperature. This is then followed by a holding period, the length of which depends on the material and its thickness, in order to thoroughly heat through the moulded part. Subsequently, the material has to be slowly and evenly cooled back down to room temperature.
Plastics can be cut using a band saw or a circular saw. The choice depends on the shape of the stock shape. Generally speaking, heat is generated by the tooling when processing plastics and, as a result, damage to the material is the greatest danger. For this reason, the right saw blade needs to be used for every shape and material.
Plastics can be processed on commercially available lathes. For optimal results, specific plastic cutters should be used.
Advantages:
Advantages:
When drilling, particular attention must be paid to the insulating characteristics of plastic. These can cause heat to build up quickly in plastics (especially semi crystalline plastics) during the drilling process, especially if the drilling depth is more than twice the diameter. This can lead to "smearing" of the drill and internal expansion arising in the component, which can lead to compressive stress in the part (especially when drilling into the centre of round rod sections). The stress levels can be high enough to cause a high level of warping, dimensional inaccuracy, fractures and bursting open of the finished component or blank. Appropriate processing for the material will prevent this.
Plastics can be milled using customary machining centres. This should be done using tools with adequate chip space in order to guarantee reliable discharge of chips and to prevent overheating.
Planing and plane milling are chip production methods with geometrically determined cutting, used to produce certain cuts, equal surfaces, grooves or profiles (using shaping milling).
Planing involves a straight line of material being removed across the surface using a planing machine cutting tool. Plane milling, on the other hand, involves the surface being processed using a milling head. Both processes are well-suited to produce even and/or equalised surfaces on semi-finished goods. The main difference is that the appearance of the surfaces is different (surface structure, gloss).
Threads are best introduced into engineering plastics using chasing tools for male threads or milling for female threads.
Optimally adjusted machinery and the right choice of parameters for the corresponding material ensure that very good surface quality with slight roughness, diameter tolerances up to h9, roundness and straightness can be achieved.
Our cutting service is able to provide ground round rods. Thanks to high surface quality and narrow tolerances, ground round rods are easy to process and are suitable for continuous production processes.
To ensure good surface quality, the following machining guidelines should be adhered to:
The typical de-burring methods for engineering plastics are:
Possible causes:
Possible causes:
Possible causes:
Possible causes:
Possible causes:
Possible causes:
Possible causes:
Possible causes:
Possible causes:
Possible causes:
When machining carbon-fibre and glass fibre reinforced plastics the following factors should be observed:
Semi-crystalline, unreinforced materials – TECAFORM AH / AD natural, TECAPET white and TECAPEEK natural – are very dimensionally stable materials with balanced mechanical properties. These materials are very easy to machine and tend to produce short chips. They can be machined with very high delivery and high feed rates.
However, it is important to ensure a low heat input as far as possible, as TECAFORM and TECAPET – in particular – have a high tendency to undergo post-shrinkage by up to approx. 2.5 %. Warping can occur due to local overheating. In the case of the materials mentioned above, very low surface roughness can be achieved with optimised machining parameters.
Polyamides such as TECAST T natural, TECAMID 6 natural and TECAMID 66 natural, tend to have have naturally very brittle characteristics – this may also be referred to in the context of a "freshly moulded" condition. Due to their chemical structure, the polyamides tend, however, to absorb moisture - this property gives the polyamides their very good balance between toughness and strength.
The moisture uptake via the surface, leads to a virtually constant distribution of water content over the entire cross section with small semi-finished dimensions and components. In the case of larger dimensioned semi finished goods, (in particular for round rods / sheets of 100 mm diameter / wall thickness upwards) the moisture content decreases from the outside inwards.
In the most unfavourable case, the centre is of a brittle and hard character. Added to the internal tension produced by extrusion technology, machining can carry a certain risk of producing tension cracking.
In addition, it should be remembered that as a consequence moisture uptake can change the dimensions of the material. This "swelling" has to be allowed for in the processing and design of components made of polyamide. The moisture uptake (conditioning) of semi-finished goods plays an important part in the case of machining. Especially thin walled components (up to ~10 mm) can absorb up to 3% moisture. As a rule of thumb:
A moisture uptake of 3% causes a dimensional change of about 0.5%!
Machining of TECAST T natural:
Machining of TECAMID 6 natural and TECAMID 66 natural:
Generally speaking, we recommend pre-heating to 80 – 120°C with larger dimensioned work pieces (e.g. round rods > 100 mm and sheets with a wall thickness > 80 mm) and machining close to the centre, in order to avoid tension cracking during processing.
TECANAT, TECASON, TECAPEI are amorphous materials, which are very prone to develop stress cracking due to contact with aggressive media, such as oils and fats. Also, cooling lubricants often contain media which can trigger tension in the material. The use of cooling lubricants should therefore be avoided when machining these materials as far as possible or a water based medium should be used, for example.
The materials can be used to manufacture very dimensionally stable prefabricated parts with very narrow tolerances, taking suitable machining parameters into account.
Materials containing a PTFE component (e.g. TECAFLON PTFE, TECAPEEK TF, TECAPEEK PVX, TECATRON PVX, TECAPET TF, TECAFORM AD AF) frequently exhibit slightly lower mechanical strength.
The TECASINT product groups 1000, 2000, 3000, 4000 and 5000 can be processed dry or wet with standard metal working machinery.
Due to the increased tendency of polyimides to absorb moisture, it is advisable to seal these parts with a vacuum barrier film to avoid dimensional changes to ensure very high quality and should be opened just before use.
TECATEC is a composite based on a polyaryletherketone filled with 50 and/or 60 % carbon fibre fabric. Machining TECATEC is considerably more complex than machining short fibre reinforced products. Due to the layer structure of the material, incorrect machining can have different effects:
For this reason, specific processing is required for such material. This has to be established on a case-by-case basis, depending on the component in question.
The suitability of TECATEC for a certain application and the quality of the finished part depend primarily on the position of the component in the semi finished part. In the development phase, it is important that the directionality of the fibre fabric is considered, especially with regard to the type of load (pulling, compression, bending) on the application and subsequent machine processing.
For higher standing times in comparison to HSS or carbide steel tools, we recommend the use of
In addition to higher standing times, these tools help to minimise the feed forces when the specific material is also considered in the design.
We recommend paying attention to the following parameters:
This information is intended to provide initial assistance in the machining of TECATEC. Detailed information varies, depending on the individual case.