Whether in transformers, electric generators or electric drives - magnetic cores made of electrical sheet are essential components of these and play a decisive role in efficient energy generation and conversion as well as its transport. Thanks to our know-how in the field of miniaturisation and micromotors, we have specialised in cutting processes such as laser fine machining of sophisticated electrical sheets in the thin sheet range from 0.1 to 0.5 mm. In the process, we manufacture individual laminations by laser fine cutting and also produce rotor and stator packages by means of laser fine welding or adhesive technology (baking varnish).
Electrical steel or electrical steel strip is usually a soft magnetic or semi-hard alloy with transition metals such as nickel, iron and cobalt. These materials are used in the production of rotor and stator laminations for magnetic cores that are used in electrical machines, for example for energy conversion and distribution.
Depending on the intended use, the laminations are referred to as transformer laminations, core laminations or motor laminations. These magnetic cores are often referred to as iron cores, although nowadays they are no longer made of iron due to high eddy current losses, but of electrical steel. Due to their special material properties, laminations made of electrical steel ensure better energy efficiency when they are used as motor or transformer components.
The cold-rolled electrical sheets are differentiated on the one hand by their annealing condition: they are either in the final annealed condition - standard grades according to DIN EN10106 or DIN EN10303 - or in the non-final annealed condition - standard grades according to DIN EN10341. In the latter case, the annealing treatment typically only takes place after the layout has been produced.
Cold-rolled electrical steel sheets are classified according to their yield strength under DIN EN10265, i.e. the limit above which the material deforms under load. This standard also includes the magnetic properties of electrical steel sheets.
Depending on the properties of the materials used, they are also divided into grain-oriented (anisotropic) according to DIN EN10107 and non-grain-oriented (isotropic) according to DIN EN10106 - the material is accordingly magnetized in two directions or one direction. The decisive factor is the magnetic homogeneity when used in rotating machines - smaller deviations are compensated for by the use of certain technologies.
The magnetic cores made from electrical steel are a crucial part of electric motors, dynamos and other electrical machines. This makes transformer or dynamo sheets a crucial component of electromobility. An iron core is used as an armature in the motors, which is wrapped with several copper wires that then form the copper coil. This is the rotor. There is also a stator, which in most cases is also made of electrical steel.
Rotors and stators are used as generator components, for example. Both components work together: The rotor rotates in the stator and generates an electromagnetic field - this drives current through the windings of the stator, which induces a voltage and thus a permanent change in the magnetic field is generated.
Various materials are used in the production of electrical steel sheets. One example of this is silicon sheets, which are made from a silicon-iron alloy (SiFe alloys) and are characterized by their excellent soft magnetic properties. On the other hand, cobalt-iron alloys (CoFe alloys), enable particularly high power densities. Nickel-iron alloys (NiFe alloys) also offer a suitable option for the production of electrical sheets.
Silicon-iron alloy (SiFe)
- grain-oriented or non-grain-oriented, baked enamel coated or simple insulating layer
- Production of rotor and stator laminations as well as core and transformer laminations for motors, generators, transformers, transformers, chokes and relays
Dimensions (Selection): available materials and NO grades
- 0.10 mm electric sheet NO10 with baking varnish coating only
- 0.20 mm electrical sheet NO20-12 with baked varnish coating only
- 0.35 mm electrical sheet M235-35A with both C5 and baked enamel coating
- 0.35 mm electrical sheet M270-35A with both C5 and baked enamel coating
- 0.50 mm electric sheet M270-50A with both C5 and baked enamel coating
- 0.50 mm electric sheet M400-50A with both C5 and baked enamel coating
Cobalt-iron alloy (CoFe)
- for applications with high requirements on saturation induction
- high flux densities with low weight
- low coercivity
(concrete properties of a special material can be requested from the manufacturer).
Nickel-iron alloy (NiFe)
- relatively high permeabilities
- low remagnetization losses
- their overall high saturation inductance enables high performance energy storage and transfer at low to medium frequencies
- use in devices such as transformer cores, toroids, sensors, motor laminations, clock springs, flap valves and actuator springs, as well as in various shielding applications
- DC motors as microdrives for pumps and dosing equipment
- micromotors and servomotors for industrial automation and robotics
- microdrives for aerospace and terrestrial mobile applications
- motors for transport systems, conveyor belts and palletising systems
- fan and blower motors
- DC micromotors for medical operating, laboratory and analysis technology and prosthetics
- spindle drives for industrial tools, e.g. milling and drilling machines
- servo motors for weighing systems
During punching, high-precision tools ensure the desired shape of the electrical sheets. On the further step follows punch stacking. Here, the soft magnetic stamped parts are stamped, formed and joined in a continuous production process. Maximum precision is crucial here, as deviations of just a few hundredths of a millimeter mean that the electrical steel can no longer be used.
Laser cutting of single sheets guarantees sharp corners, clean contour runs and high positioning accuracy with a cutting contour accuracy of +/- 0.02 millimetres. It is also possible to cut almost at right angles when laser cutting electrical steel. Optimized laser cutting technology minimizes insulation damage and enables virtually burr-free and distortion-free production of the laminations. The latest laser technologies are used here, each of which has its own advantages.
We also offer our customers the production of rotor and stator packages. This is achieved by laser fine welding or baking individual rotor or stator laminations. In the latter case, a coating with baking varnish is used to bake the electrical laminations. The baking varnish is applied as a coating and melts as soon as the laminations are heated to a defined pressure, baking the laminations together. The process has proven particularly effective for electromobility.
In general, the electrical steel strip is coated with insulating varnish, which electrically insulates the different electrical steel strip laminations from each other. Which insulating varnish is used depends on the intended use and properties such as chemical resistance, degree of insulation and resistance to heat.
We would be happy to advise you!
The specific data sheets of the individual materials are available on request. The list of materials is merely a current selection without any claim to completeness. Do you have special requirements? We would be happy to advise you personally on your questions regarding our available materials and services. Discover, for example, our laser fine processing with ultrashort pulse lasers (USP) for particularly thin and delicate structures.