Magnetic Balls 216 Balls/Set

The magnetic balls 216 balls/set offer a convenient quantity of precision‑ground neodymium spheres, each measuring 5 mm in diameter, with a surface magnetic flux density of approximately 3,800‑4,000 Gauss. These sintered NdFeB balls are widely used for magnetic construction sets, educational physics demonstrations, magnetic separators, and even as stirring elements in laboratory vessels. Each sphere is manufactured from 100% virgin neodymium‑iron‑boron (purity ≥95%) using our vertically integrated process – from alloy melting to final Ni‑Cu‑Ni triple plating. The triple layer (5‑7 μm nickel + 3‑5 μm copper + 5‑7 μm nickel) ensures excellent corrosion resistance, maintaining magnetic performance even in humid environments. The 216‑ball quantity is a standard packaging size (approximately 0.5‑0.6 kg total weight) that allows end users to build moderate‑sized structures or replenish existing sets. Our quality control includes random sampling for diameter tolerance (held to ±0.05 mm) and pull force consistency. For B2B buyers, we offer custom diameters (3 mm, 4 mm, 6 mm, 8 mm, 10 mm), different set sizes (100, 216, 500, 1000 balls), and alternative coatings (epoxy, gold) for specialized applications. All magnetic balls 216 balls/set are shipped in anti‑static, foam‑lined boxes with clear labelling to prevent accidental ingestion (warning labels included for resale).

Consistent Sphericity & Size

Our grinding and tumbling process ensures diameter variation below ±0.05 mm, critical for applications where balls must roll smoothly or fit into tight cavities. Each batch is sampled with a micrometer and optical comparator.

Strong & Uniform Magnetization

Every magnetic ball is magnetized in a pulsed field to saturation, achieving a typical surface gauss of 4,200 GS. The magnetic poles are distributed uniformly, providing strong attraction between balls regardless of orientation.

Durable Triple Plating

The Ni‑Cu‑Ni coating not only resists corrosion (72h salt spray tested) but also gives a smooth, scratch‑resistant surface that maintains its shiny appearance under normal handling.

Available standard colors include orange, red, nickel, blue, sky blue, white, purple, black, silver, and gold. Custom color options are also available upon request. Please share your specific requirements for tailored solutions.

Our magnetic spheres come in versatile multicolor configurations, featuring curated sets of 5 to 10 harmonized shades. The popular 216-piece rainbow collection with six vibrant tones remains our top-selling ready-stock item. Prospective clients may request complimentary sample units-only requiring freight payment-to evaluate product quality and performance before committing to larger orders.

The 216 balls are packed in a sealed, anti‑static plastic jar or a foam‑lined cardboard box with a child‑warning label (for consumer safety). The inner packaging is then placed in a sturdy export carton. Custom packaging (blister packs, custom boxes) is available for private label orders. Lead times: 5‑7 days for stock sets, 15‑20 days for custom diameters or coatings.

Our integrated factory produces the magnetic cores using 100% virgin rare earths (no recycled powder). After vacuum melting and jet milling, the powder is pressed into cylindrical blanks, sintered, and then ground into spheres using multi‑stage tumbling and centerless grinding. The Ni‑Cu‑Ni plating is applied in automated barrels, followed by magnetization in a pulsed field. Each batch of magnetic balls is sampled for diameter (digital caliper), magnetic flux (Gauss meter), and coating adhesion (cross‑cut test). Salt‑spray testing is performed on samples to verify ≥72 hours without red rust. We supply a certificate of analysis for every set. Our IATF 16949 and ISO 9001 systems ensure traceability for quality‑sensitive buyers.

Q1: What is a typical use for a 216‑ball magnetic ball set?
A1: The 216 balls (usually 5 mm diameter each) are used for stress relief, geometric modeling, and magnetic sculpture building. Users connect them into cubes, spheres, or complex polyhedra. The high count (216) allows a 6x6x6 cube or a 55‑mm hollow sphere. They also serve as desk toys or STEM learning tools.

Q2: Are all 216‑ball magnetic sets made of neodymium?
A2: Genuine high‑power sets use sintered NdFeB (grade N35–N52). Cheaper sets use ferrite or weak NdFeB, but cannot hold complex shapes. A true 216‑ball NdFeB set has a pulling force of >800 g per ball (5 mm). Always check coating: NiCuNi (silver) or epoxy (black). Neodymium balls are brittle and can chip.

Q3: What is the main safety risk with a 216‑ball magnetic set?
A3: Swallowing two or more balls is a life‑threatening emergency. In the digestive tract, magnets attract through tissue walls, causing perforations or blockages. Never give 216‑ball sets to children under 14. After use, count all 216 balls immediately – lost balls are a hazard. Many countries have banned small high‑flux magnet sets for this reason.

Q4: How can I verify that my 216‑ball set contains exactly 216 balls?
A4: Do not trust the package label – factory errors happen. Count by grouping: make 9 stacks of 24 balls (9 x 24 = 216) or 6 stacks of 36. Use a non‑magnetic tray. Some sets include 217 or 215 due to automated packing errors. A missing ball means potential safety risk if swallowed by a pet or child.

Q5: Why does a 216‑ball set cost twice as much as a 125‑ball set of the same ball size?
A5: More balls require more raw material, longer coating time, and more manual sorting. For 5‑mm balls, 216 pieces weigh about 14 grams of neodymium, while 125 pieces weigh 8 grams. Additionally, high‑precision plating (NiCuNi) cost scales with part count. Molding, grinding, and magnetizing 216 balls also increases labor and reject rate.