We supply custom Neodymium trapezoid (keystone) magnets with angled side walls. They are common for motor rotors and Halbach arrays. The tapered profile allows multiple segments to fit together forming a circular or arc pattern. Such a magnetic assembly maximizes field strength. And also minimizes air gaps in brushless motors and magnetic assemblies. The critical specification is the angle of the side walls. It determines how many segments are needed to complete a circle or arc. A 10-degree angle yields 36 segments per full ring; a 15-degree angle yields 24 segments. Incorrect angles cause gaps between segments or force-fitting that creates assembly stress. We grind to ±0.1° angular tolerance and can match segments as sets for balanced rotor assemblies. Available in custom dimensions from 5mm to 50mm on the large face. Provide your angle, base dimensions. And whether you need individual segments or matched sets. The Geometry: Defining Your Shape “Trapezoid” can mean many things. So please define the dimensions clearly to prevent production errors. To manufacture this shape accurately, we control the Cross-Sectional Geometry: W1 (Top Width): The narrower flat face. W2 (Bottom Width): The wider flat face. Angle (α): The incline angle of the side walls. Symmetry: – Standard supply is an Isosceles Trapezoid (both sides angled equally). – We can also produce “Right Angle Trapezoids” (one straight side, one angled side) upon request. The “Halbach Array” Specialist Engineered for Flux Focusing: Small trapezoid magnets are the building blocks of Linear and Circular Halbach Arrays. The Challenge: – Building a Halbach array requires magnets with varying magnetization directions to be glued next to each other. Our Solution: – We can supply these magnets with specific Magnetization Vectors (e.g., magnetized parallel to the angled face). – Ensure your array concentrates magnetic flux exactly where you need it. Tolerance: – We hold strict angle tolerances (±0.5°). – Ensure that when you assemble the wedges into a circle, so they close the loop perfectly without gaps. Manufacturing Advice: Sharp Edges Chamfers are Critical: A trapezoid shape naturally creates two Acute Angles (sharp points less than 90°) at the bottom corners. The Risk: – These sharp edges are extremely fragile. – They will chip instantly if handled roughly or snapped together. Our Standard: – Unless otherwise specified, we apply a micro-chamfer (0.1mm – 0.3mm) to these sharp edges. – This ensures the plating adheres correctly and the magnet survives shipping. Plating Quality: – Sharp edges cause “current crowding” during plating, leading to rough, brittle burrs. – Our chamfering process ensures the smooth, shiny finish you see in our product photos. Magnetization Directions Through Thickness: – Magnetized North/South on the Top (W1) and Bottom (W2) faces. – Standard for holding. Transverse / Lateral: – Magnetized through the side walls. – Common for motor segments. Multi-Angle: – Custom orientation for Halbach assemblies. Surface Coatings Ni-Cu-Ni (Nickel): – As shown in photo. – Provides a hard, wear-resistant surface. Black Epoxy: – Recommended if you are gluing the magnet into a carbon fiber or steel rotor assembly. – Epoxy bonds better than Nickel. Zinc: – Not recommended for tiny trapezoids. – The plating thickness is harder to control on angled surfaces. Applications Brushless DC Motors (BLDC): Reducing cogging torque and maximizing flux density. Magnetic Couplings: Dovetail-shaped magnets that lock mechanically into a hub. Holding Systems: “Wedge” anchors that tighten under load. Research: Particle accelerators and undulators (using Halbach arrays). Ordering Guide: What We Need To quote a trapezoid magnet, please provide a drawing. Or, simply write the following data to us: 1). Dimensions: Top Width (W1), Bottom Width (W2), Height (H), Length (L). 2). Magnetization: Which direction does the field run? (Drawing highly recommended). 3). Application: Is this for a Motor/Halbach Array? (If yes, we will check the High-Temp requirement). 4). Quantity: (Trapezoids require custom grinding fixtures, so MOQ is typically 50-100 pcs).