Custom Micro-Precision Neodymium Blocks with Bore

We supply small Neodymium block magnets with a central through-hole made to your specifications.
They are a square or rectangular magnet with a cylindrical bore along one axis.

Typical dimensions range from approximately 2mm to 10mm per side.
And the hole diameters range from 0.5mm to 3mm.
They depend on the block size and wall thickness required for structural integrity.

These magnets can be:
– Threaded onto wires
– Pinned onto a shaft
– Or, integrated into micro-assemblies, wearable devices, sensors, or textile systems.
For such applications, a magnet needs to be positioned on a linear element.

The through-hole is produced by laser drilling or micro-machining after sintering and before coating.
Hole centering tolerance is typically ±0.1mm to ±0.2mm, depending on block size.

Coating the inner bore can be challenging.
Uncoated bores or epoxy fill may be necessary depending on dimensions.

Magnetization is typically through-thickness (perpendicular to the hole axis).
Or axial (parallel to the hole).
Standard nickel plating is typical for the outer surfaces.

Minimum wall thickness around the hole is typically 0.5mm to 1mm.
The purpose is to prevent cracking during handling or installation.
Minimum order quantities are typically higher due to the added machining step.

The Engineering Logic: Why a Hole in a Micro-Block?

1. Mechanical Pinning (No Glue Required):

The Problem:
– Gluing a 3mm magnet is difficult.
– The glue creates a mess and adds thickness.

The Solution:
– The central bore allows you to insert a non-magnetic pin (brass/plastic).
– Or screw to mechanically hold the magnet in place.

The Benefit:
– Secure retention in vibration-prone environments (like haptic motors) without the variability of adhesives.

2. “Bead” Functionality:

The Application:
– The hole allows the magnet to be “strung” onto a wire or filament.

The Benefit:
– Ideal for magnetic jewelry clasps, floating sensor arrays.
Or “smart clothing” connections where the magnet needs to slide along a guide wire.

Dimensional Definitions (Critical)

To manufacture this accurately, we map the dimensions to the geometry:

– Length (L): The dimension parallel to the hole?
– Width (W) & Thickness (T): The dimensions of the face with the hole.
– Hole Diameter (ID): The bore size (e.g., ∅1.0mm).

Note:
The wall thickness (distance from hole to edge) must be calculated.
Ensure the magnet doesn’t crack during production.

Magnetization Orientation (The Tricky Part)

Through Length (Axial):
– The magnetic poles are on the two ends with the holes.
– Like a beads on a string.

Through Thickness (Transverse):
– The magnetic poles are on the solid sides.
– Used for side-clamping.

Surface Coatings & Hole Protection

Plating the inside of a 1mm hole is chemically difficult.

Barrel Plating (Nickel):
– We use specialized small-media barrel plating.
– The purpose is to ensure the Nickel solution flows inside the bore.
– This prevents “Inside-Out Corrosion.”

Parylene:
– Highly recommended for medical applications (catheters/implants).

Gold (Au):
– For electrical conductivity if the magnet is acting as a connector contact.

Applications

Micro-Robotics: Joint actuators pinned to a shaft.
Wearables: Magnetic clasps for necklaces or smart-watch bands (threaded onto the pin).
Medical: Endoscope tip guidance.
Electronics: Miniature Hall-Effect triggers mounted on a PCB post.

Ordering Guide: What We Need

To quote this micro-part, please clarify the “XYZ” axis:

1). Dimensions: Please provide a sketch labeled L, W, H.
2). Hole Size: Diameter.
3). Orientation: Does the magnetic field run parallel to the hole (like a tube) or perpendicular to the hole (like a tire)?
4). Coating: Nickel, Gold, or Parylene?