Plastic-bonded, injection-molded magnets are typical composite materials that are created by embedding hard ferrite or rare earth magnetic powder in thermoplastic plastics (matrix material PA6, PA12, PPS). The proportion of the magnetic powder dictates the magnetic and mechanical properties.
The filling degrees of plastic-bonded, injection-molded magnets vary between a magnet powder content of between 84% and 94% (percent by weight). The magnetic values are therefore below those of plastic-bonded, injection-molded magnets. Plastic-bonded, injection-moulded magnets can be produced in complex shapes and in combination with insert parts - all in a single process.
Plastic-bonded, injection-molded
HF magnets
Plastic-bonded HF magnets consist of hard ferrite powder embedded in a plastic matrix. depending on the operating temperatures and ambient conditions, the matrix materials PA6, PA12 or PPS are used.
Plastic-bonded HF magnets are characterized by very high media resistance and an excellent price/performance ratio. Remanences up to typ 305mT or max. energy product BHmax of up to 17kJ/m³ are achieved.
Magnetic and mechanical characteristics
A typical data sheet for a permanent magnetic material contains its key magnetic and mechanical characteristics. The magnetic characteristics are usually measured in accordance with DIN EN 60404-5. In addition to magnetic values, the data sheet also contains mechanical characteristics such as density, hardness and strength properties.
You can find all data at a glance here:
Polyamide 6 (PA 6), polyamide 12 (PA 12) and polyphenylene sulphide (PPS) are used as the plastic matrix in injection-molded magnets. The maximum application temperatures depend on the magnet and matrix material.They are 160°C for grades bonded with PA 6, 140°C for grades bonded with PA 12 and 220°C for grades bonded with PPS. The maximum operating temperature depends on the duration, the magnet dimensions and the specific application.
Production process
The first stage of the production process of plastic-bonded, injection-moulded magnets is the production of the magnetic compound. This is done by mixing the plastic granulate and the magnetic powder in a hot melt kneading machine or a twin screw extruder before they are extruded and granulated. The next step is processing the compound with modified injection moulding machines. When injection moulding anisotropic magnets, a magnetic field in an axial, radial, diametric or multi-polar direction is also created during the injection process. It generates the preferred direction of the magnetic material parallel to the given orientation. In the case of plastic-bonded, injection-moulded magnets, a mechanical machining of the finished injection-moulded part is generally not required.
Plastic-bonded, injection-molded HF-magnets are more elastic compared to sintered magnets. However, they do not achieve the mechanical properties of technical plastics due to the high filling levels. Press-fitting onto shafts, for example, is possible under certain circumstances. Furthermore, gearing can even be molded directly from plastic-bonded magnet material.
However, such pressed connections or gearing can only be used for low loads.
The magnetic characteristics of plastic-bonded, injection-moulded magnets vary depending on the filling degrees and the magnetic powder being used. The possible maximum operation temperatures vary, depending on the magnetic and matrix material, between +120°C and +220°C. In case of unfavourable shapes, in particular those with thin wall thicknesses or narrow pole pitches, there can be deviations in the material data due to solidification processes that are too quick or orienting field strengths that are too low.
The chemical resistance of plastic-bonded, injection-moulded HF-magnets, as is generally the case with composite materials, is determined by the plastic matrix as well as the magnetic filling material. Magnets with polyphenylene sulphide (PPS) as carrier material have a significantly better chemical resistance than PA-bonded magnets (oils, greases, fuels, etc.). However, the chemical resistance has to be tested in individual cases
Plastic-bonded, injection-molded
NdFeB magnets
Plastic-bonded NdFeB magnets consist of NdFeB powder embedded in a plastic matrix. Depending on the operating temperatures and ambient conditions, the matrix materials PA6, PA12 or PPS are used.
Isotropic NdFeB powder is predominantly used for plastic-bonded NdFeB magnets. This results in many degrees of freedom in magnetization, which can be carried out by us or directly by the customer.
Plastic-bonded NdFeB magnets are characterized by a high power density. Remanences of up to typically 570mT or max. energy product BHmax of up to 55kJ/m³ are achieved.
Magnetic and mechanical characteristics
A typical data sheet for a permanent magnetic material contains its key magnetic and mechanical characteristics. The magnetic characteristics are usually measured in accordance with DIN EN 60404-5. In addition to magnetic values, the data sheet also contains mechanical characteristics such as density, hardness and strength properties.
You can find all data at a glance here:
Polyamide 6 (PA 6), polyamide 12 (PA 12) and polyphenylene sulphide (PPS) are used as the plastic matrix in injection-molded magnets. The maximum application temperatures depend on the magnet and matrix material. They are 160°C for grades bonded with PA 6, 140°C for grades bonded with PA 12 and 180°C for grades bonded with PPS. The maximum operating temperature depends on the duration, the magnet dimensions and the specific application.
Production process
The first stage of the production process of plastic-bonded, injection-moulded magnets is the production of the magnetic compound. This is done by mixing the plastic granulate and the magnetic powder in a hot melt kneading machine or a twin screw extruder before they are extruded and granulated. The next step is processing the compound with modified injection moulding machines. When injection moulding anisotropic magnets, a magnetic field in an axial, radial, diametric or multi-polar direction is also created during the injection process. It generates the preferred direction of the magnetic material parallel to the given orientation. In the case of plastic-bonded, injection-moulded magnets, a mechanical machining of the finished injection-moulded part is generally not required.
Plastic-bonded, injection-molded NdFeB magnets are more elastic compared to sintered and plastic-bonded pressed magnets. However, they do not achieve the mechanical properties of technical plastics due to the high filling levels. Pressing onto shafts, for example, is possible under certain circumstances. Furthermore, gearing can even be molded directly from plastic-bonded magnet material. However, such pressed connections or gearing can only be used for low loads..
The magnetic characteristics of plastic-bonded, injection-moulded magnets vary depending on the filling degrees and the magnetic powder being used. The possible maximum operation temperatures vary, depending on the magnetic and matrix material, between +120°C and +180°C. In case of unfavourable shapes, in particular those with thin wall thicknesses or narrow pole pitches, there can be deviations in the material data due to solidification processes that are too quick or orienting field strengths that are too low.
The chemical resistance of plastic-bonded, injection-molded NdFebB magnets is determined by both the plastic matrix and the magnetic filler, as is generally the case with composite materials.Magnets with polyphenylene sulphide (PPS) as a carrier material have significantly better chemical resistance (oils, greases, fuels, etc.) than PA-bonded magnets.However, the chemical resistance must be tested in each individual case.
Plastic-bonded, injection-molded
SmFeN magnets
Plastic-bonded SmFeN magnets consist of SmFeN powder embedded in a plastic matrix. Depending on the operating temperatures and ambient conditions, the matrix materials PP or PA12 are used.
In contrast to the plastic-bonded isotropic NdFeB magnets, anisotropic SmFeN powder is predominantly used. As a result, significantly higher remanences of up to typically 710mT or max. energy product BHmax of up to 89kJ/m³ are achieved.
Compared to NdFeB magnets, SmFeN magnets are only exposed to minor fluctuations in raw material prices, so that price stability over a defined project duration is conceivable.
Magnetic and mechanical characteristics
A typical data sheet for a permanent magnetic material contains its key magnetic and mechanical characteristics. The magnetic characteristics are usually measured in accordance with DIN EN 60404-5. In addition to magnetic values, the data sheet also contains mechanical characteristics such as density, hardness and strength properties.
You can find all data at a glance here:
Polyamide 12 (PA 12) and polypropylene (PP) are used as the plastic matrix in injection-molded magnets.The maximum application temperatures depend on the magnet and matrix material.They are around 140°C). The maximum operating temperature depends on the duration, the magnet dimensions and the specific application.
Production process
The first stage of the production process of plastic-bonded, injection-moulded magnets is the production of the magnetic compound. This is done by mixing the plastic granulate and the magnetic powder in a hot melt kneading machine or a twin screw extruder before they are extruded and granulated. The next step is processing the compound with modified injection moulding machines. When injection moulding anisotropic magnets, a magnetic field in an axial, radial, diametric or multi-polar direction is also created during the injection process. It generates the preferred direction of the magnetic material parallel to the given orientation. In the case of plastic-bonded, injection-moulded magnets, a mechanical machining of the finished injection-moulded part is generally not required.
Plastic-bonded, injection-moulded SmFeN magnets have greater elasticity compared to injection-bonded, pressed magnets. However, due to the high filling degrees, they do not achieve the mechanical properties of technical plastics. That means it is possible, for example, to inject gearings straight from plastic-bonded magnetic material. However, these gearings can only be subjected to low stresses since the sliding properties are less favourable than those of unfilled plastics.
The magnetic characteristics of plastic-bonded, injection-moulded magnets vary depending on the filling degrees and the magnetic powder being used. The possible maximum operation temperatures vary, depending on the magnetic and matrix material, between +120°C and +140°C. In case of unfavourable shapes, in particular those with thin wall thicknesses or narrow pole pitches, there can be deviations in the material data due to solidification processes that are too quick or orienting field strengths that are too low.
As with composite materials in general, the chemical resistance of plastic-bonded, injection-molded SmFeN magnets is determined by both the plastic matrix and the magnetic filler. Magnets with polypropylene (PP) as a carrier material have significantly better water resistance than PA-bonded magnets.However, use in water must be tested on a case-by-case basis.
- Goods receipt purchased parts (shafts, bushes, soindles, etc.), epoxy resins/additives, magnet powder
- Inspection of incoming raw material/components
- Compounding
- Pressing without magnetic field (anisotropic)
- Pressing with magnetic field (isotropic)
- Curing
- Magnetising, marking, coating according to customer specifications
- Outgoing goods inspection
Automated manufacturing processes, e.g.: Feeding of components, Magnetisation, magentic and/or visual/mechanical inspection, packaging
Additional product areas
The requirements of our customers are very diverse, as is our product portfolio. More than 5,000 custom-developed products stand for quality and reliability.
Sintered magnets
Sintered magnets offer tremendous holding power and durability and are custom produced as hard ferrite magnets or rare earth magnets.
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Plastic bonded magnets - pressed
Plastic-bonded, pressed magnets offer a filling level of up to 97% NdFeB powder and thus higher magnetic values than injection-molded magnets.
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Sintered or plastic-bonded magnets with plastic
Since the 1980s, we have been overmolding sintered and plastic-bonded magnets with plastic and manufacturing functional elements for integration into assemblies.
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System solutions
For magnet assemblies, we process sintered and plastic-bonded permanent magnets into a customer-specific magnet system.
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Holding magnets
Our standard holding solenoids with holding forces from 5N to 900N such as pot magnet and bar magnet systems offer the right solution for every need.
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