Micro Magnets | Precision Manufacturing
High Precision Neodymium Micro Magnets
Micro Magnets, also called miniature magnets, nanomagnets, or tiny magnets, are a set of small exact magnetic components. They are generally well-liked in high-precision applications. Magnets of the micro-size can be bonded magnets, sintered neodymium magnets, samarium-cobalt magnets, ferrite, or alnico magnets.
Geometry of Microscale Magnets
Micro magnets are made with utmost precision. Their diameter tolerances are so acceptable that they can be contained within ±0.005 mm, and thickness tolerances can be a maximum of ±0.01 mm, creating highly accurate components for future applications.
They are available in different combinations, reflecting the incredible ability of the manufacturer to make these products. Spherical micromagnets as small as 0.8 mm and 1 mm are a perfect example of the company’s ability to produce tiny precision components. Cylindrical micromagnets are proof of the production of ultra-thin, elongated figures. Square thin-sheet magnets, with a 0.3–0.35 mm thickness, are the extreme case of current technology.
The minuscule size of the magnets leads to intricate manufacturing issues. The 1 mm spherical magnets were not easily recoverable in standard plating cages. Using specialized equipment and custom-made processes is inevitable for smooth sailing through these hurdles.
Applications: Precision Microscale Solutions
Unlike larger magnets used for attraction or holding, micro magnets are primarily employed for their sensing and actuation capabilities. Their compact size, high precision, and tailored magnetic properties make them indispensable in advanced technologies, excelling in the following areas:
Micro Motors
Actuators
Rotation Detection Sensors
Magnetic Encoders
Haptic Feedback Systems
Microfluidic Pumps
Optical Positioning Systems
Challenges in Precision Quality Control
As micro magnets decrease in size, the demand for consistency intensifies. Minor variations in material properties, processing tolerances, or electroplating techniques can significantly impact performance. The following are key factors affecting consistency:
Tolerance Control
Manufacturing micromagnets demands exceptional precision. Even a 0.01–0.02 mm deviation in magnetization direction can significantly affect magnetic flux and surface magnetic field. For magnets only 0.3 mm thick, such deviations represent a large proportion of the total size, amplifying their impact.
Material Consistency
Micro magnet blanks are typically produced in batches of 300–500 kg. Within the same furnace, factors like temperature gradients can cause performance variations in blanks at the top, middle, bottom, and corners. Such variations lead to inconsistency when these blanks are cut into tiny magnets. Minor fluctuations in material properties are amplified for micro magnets, necessitating stringent controls during material production to ensure consistency within and across batches.
Electroplate Control
Electroplating saves micromagnets from corrosion and increases their longevity; the process also brings difficulties.
A nickel-copper-nickel layer makes the magnet 3% less efficient in magnetization. the damage will be much more significant with smaller magnets. Salt solution erosion of the micromagnet during electroplating barely affects the size of the magnet.
The nickel layer prevents the magnetic field from running in many cases. For the micro magnets, more care is needed, and the thickness and composition of the coating should be precisely controlled. The zinc covers are very thin, and the magnetic field is less bothered, but not every situation can be solved.