A foreign client named Kim recently contacted Tengye about manufacturing a Halbach array to produce a uniform magnetic field. Kim also specified a series of requirements for the dimensions and performance of the Halbach array.
Kim:
Based on usage requirements, Kim put forward a rough requirement for the performance of the Halbach Array.
| Halbach Array Dimensions: OD≤76.2 mm, ID>20mm (adjustable), H≤100 mm
| Center Magnetic Flux Density: approximately 2000 Gs
| Magnetic Field Uniformity: The Halbach magnets are located on the XY plane, requiring magnetic field uniformity within 50 mm along the axial (Z-axis) direction. Specifically, the magnetic field uniformity error within 50 mm should not exceed 5%.
Tengye:
After receiving the client’s requirements, our R&D department first designed the Halbach array, then conducted simulation tests on the magnetic circuit design, obtaining the following test data:
| In the Halbach array with a height of 90 mm, a uniform magnetic field can be achieved in the 50 mm area in the middle of the axial direction.
| As for the radial magnetic field B on the XY plane, if the inner diameter is 20 mm, the magnetic field variation in the middle 15mm area can be < 6%.
Background Knowledge:
| The Halbach array is a magnetic assembly representing a near-ideal magnet arrangement in engineering. Through its special arrangement of magnets, it generates the maximum magnetic field using the minimum amount of magnetic material.
| One of the key advantages of the Halbach array is its excellent magnetic field distribution uniformity. Within specific regions of an annular Halbach array, the magnetic field strength distribution is relatively uniform, with minimal variations in magnetic field strength. This characteristic is particularly important for applications that require high magnetic field uniformity.
Kim:
After receiving our feedback, Kim discussed it within his company for several days and informed us of the latest adjustment plan, mainly involving dimensional adjustments:
| Reduce height from 90 mm to 50 mm.
| Increase the inner diameter to > 40 mm.
| To meet the center magnetic flux density requirement of 1T, the outer diameter can be larger, up to 90mm but not exceeding 95mm.
Tengye:
After receiving the client’s requirements for adjustment, our R&D department discussed and calculated, responding to Kim on the same day:
| If the height is reduced to 50 mm, the axial length for a 5% magnetic field variation will be much less than 50 mm.
| If the inner diameter is increased to 40 mm unless the outer diameter exceeds 95 mm, the center magnetic flux density may not reach 1T.
Background Knowledge
| Whether axial or radial, the uniform magnetic field formed by an annular Halbach array refers to the uniform field formed in specific regions of the array; it’s difficult to form a uniform magnetic field in areas close to the magnets.
| For annular Halbach arrays, increasing the number of magnets can improve field uniformity. However, as the number of magnets increases, the Halbach array dimensions also increase, leading to a decrease in center magnetic flux density if magnet properties remain unchanged.
Kim:
Based on our provided data and considering the actual usage of the Halbach assembly, Kim informed us that the inner diameter would remain 40 mm, but the magnetic field strength could be reduced, requiring only greater than or equal to 5000 Gs.
Tengye:
After understanding the client’s latest requirements, to provide more options and smoothly advance the project, our R&D department quickly conducted multiple magnetic circuit designs and simulation experiments, submitting the test data to Kim for reference:
Experiment A: OD95×ID40×H50 mm
Experiment B: OD90×ID40×H20 mm
Experiment C: OD90×ID40×H30 mm
Experiment D: OD90×ID40×H40 mm
Kim:
Kim was pleased that we could provide multiple sets of experimental data for selection. After effect verification, he ultimately chose the OD90×ID40×H30 mm solution and reached a purchase intention.
| Overall Dimensions: OD90×ID40×H30 mm
| Magnets: Composed of 16 magnets forming an annular Halbach array, creating a 2-pole magnetic field at the inner diameter.
| Nickel-plated magnets, outer diameter surface covered with 316 stainless steel.
Inner diameter center magnetic flux density: above 5200 Gs.
Just like our interactions with other foreign clients, our communication with Kim once again confirmed our credo:
| Customer-centric, continuously adjusting magnetic circuit design solutions according to customer requirements, helping customers find ideal solutions that meet their usage requirements.
| Relying on professional knowledge, providing professional solutions based on customers’ magnet usage requirements, and assisting customers in continuously advancing their projects.
Magnets Provider
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Stanfordmagnets
