Polymagnet Catalog

Frequently Asked Questions

What products do you offer?

CMR designs standard products that are available in the Polymagnet Catalog. Design customization services are available to modify catalog designs for size, feel and function. Use the Contact page to inquire about pricing and services

How do the prices of Polymagnets differ from standard magnets?

The price of a Polymagnet Smart Magnet depends upon the complexity and behavioral function or combinations of functions.  Browse the Catalog from a list of ready-to-order magnetic behaviors.  Sample quantities are available at a range of reasonable prices.

How do Polymagnet Smart Magnets work?

There are two simple principles of magnetics to explain Polymagnets.  The first is that magnets always form a circuit between the north to south poles. Magnetic flux leaves one pole and seeks the opposite pole.  The second principle is that flux lines seeks the lowest energy path from  north to south. By creating patterns of north and south poles on the surface of magnet, CMR controls the shape of the circuit and the path of the magnetic flux. We’ve created a series of magnetic patterns that focus magnetic energy to produce greater holding forces and direct magnetic energy to create entirely new magnets with alignment, spring or latch features.

How does a Smart Magnet differ from a "typical" magnet?

Polymagnets are engineered magnets.  Unlike common magnets whose strength is determined solely by size and shape, for custom applications, CMR engineers design specific patterns and apply them to a traditional magnet that is tuned for strength and behavioral functionality.

Are Polymagnets RoHS and REACH compliant?

RoHS Compliance
Typical Neodymium magnets supplied by CMR through CMR’s authorized suppliers are “RoHS” and RoHS II compliant. Such magnets do not exceed the designated levels of Cadmium, Hexavalent Chromium, Mercury, Lead, Polybrominated Biphenyls or Polybrominated Diphenyl Ethers.
Additionally, typical neodymium magnets supplied via CMR do not contain Deca Brominated Diphenyl Ether (Deca BDE) legislated under the provisions of the European Commission Decision of 13 October 2005 (2005/717/EC), do not contain as intentional additives Perfluoroocantylsulfonates (PFOS) legislated under the provisions of the European Parliament and Council Directive 2006/122/EC (30th amendment to EU Directive 76/769/EEC), and do not require any exemptions per “RoHS2.”

REACH Compliance
Typical neodymium magnets supplied by CMR do not contain Substances of Very High Concern (SVHC) as listed by the European Chemicals Agency (ECHA) under the provisions of Regulation (EC) No. 1907/2006 of the European Parliament and of the council concerning the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) per the ECHA 15/06/2015 and previous updates.
To the extent a customer specifies a coating other than standard nickel-copper-nickel, CMR makes no statement as to RoHS and REACH compliance of such coating, but will work with our customers to evaluate RoHS and REACH on a case-by-case basis.

Where can I get technical data for sintered NIB magnetic material?

Below are details on performance characteristics for various grades of sintered NIB magnetic material.


Technical data of sintered NdFeB

Grade Br mT(kGs) Hcb kA/m(k0e) Hcj kA/m(kOe) ( BH ) max kJ/m³
Max working temperature
N27 1030-1080(10.3-10.8) ≥ 796(≥10.0) ≥955(≥ 12) 199-231(25-29) 80°C
N30 1080-1130(10.8-11.3) ≥ 796(≥ 10.0) ≥955(≥ 12) 223-247(28-31) 80°C
N33 1130-1170(11.3-11.7) ≥836(≥ 10.5) ≥955(≥ 12) 247-263(31-33) 80°C
N35 1170-122001.7-12.2) ≥868(≥ 10.9) ≥955(≥ 12) 263-287(33-36) 80°C
N38 1220-1250(12.2-12.5) ≥899(≥11.3) ≥955(≥ 12) 287-310(36-39) 80°C
N40 1250-1280(12.6-12.8) ≥907(≥11.4) ≥955(≥ 12) 302-326(38-41) 80°C
N42 1280-1320(12.8-13.2) ≥915(≥11.5) ≥955(≥ 12) 318-342(40-43) 80°C
N45 1320-1380(13,2-13-8) ≥923(≥ 11.6) ≥955(≥ 12) 342-366(43-46) 80°C
N48 1380-1420(1 3.8-14.2) ≥923(≥ 11 .6) ≥955(≥ 12) 366-390(46-49) 80°C
N50 1400-1450(14.0-14.5) ≥796(≥ 10.0) ≥876(≥ 11) 382-406(48-51) 80°C
N52 1430-1480(14.3-14.8) ≥796(≥ 10.0) ≥876(≥ 11) 398-422(50-53) 60°C
30M 1080-1130(10.8-11 3) ≥796(≥-10.0) ≥1114(≥ 14) 223-247(28-31) 100°C
33M 1130-1170(11.3-11.7) ≥836(≥10.5) ≥1114(≥ 14) 247-263(31-33) 100°C
35M 1170-1220(11.7-12.2) ≥868(≥ 10.9) ≥1114(≥ 14) 263-287(33-36) 100°C
38M 1220-1250(12.2-12.5) ≥899(≥ 11.3) ≥1114(≥ 14) 287-310(36-39) 100°C
40M 1250-1280(12.5-12.8) ≥923(≥ 11.6) ≥1114(≥ 14) 302-326(38-41) 100°C
42M 1280-1320(12.8-13.2) ≥955(≥ 12.0) ≥1114(≥ 14) 318-342(40-43) 100°C
45M 1320-1380(13.2-13.8) ≥995(≥12.5) ≥1114(≥ 14) 342-366(43-46) 100°C
48M 1360-1430(13.6-14.3) ≥1027(≥ 12.9) ≥1114(≥ 14) 366-390(46-49) 100°C
50M 1400-1450(14.0-14.5) ≥1033(≥13.0) ≥1114(≥ 14) 382-406(4.8-51) 100°C
30H 1080-1130(10.8-11.3) ≥796 (≥10.0) ≥1353(≥ 17) 223-247(28-31) 120°C
33H 1130-1170(11.3-11.7) ≥836(≥10.5) ≥1353(≥ 17) 247-271(31-34) 120°C
35H 1170-1220(11.7-12.2) ≥868(≥ 10.9) ≥1353(≥ 17) 263-287(33-36) 120°C
38H 1220-1250(12.2-12.5) ≥899(≥ 11.3) ≥1353(≥ 17) 287-310(36-39) 120°C
40H 1250-1280(12.5-12.8) ≥923(≥ 11.6 ≥1353(≥ 17) 302-326(38-41) 120°C
42H 1280-1320(12.8-13.2) ≥955(≥12.0) ≥1353(≥ 17) 318-342(40-43) 120°C
45H 1320-1380(13.2-13.8) ≥955(≥ 12.0) ≥1353(≥ 17) 342-366(43-46) 120°C
48H 1370-1430(13.7-14.3) ≥995(≥12.5) ≥1353(≥ 17) 366-390(46-49) 120°C
30SH 1080-1130 (10.8-11.3) ≥804(≥10.1) ≥1592(≥20) 223-247(28-31) 150°C
33SH 1130-1170(11.3-11.7) ≥844(≥10.6) ≥1592(≥20) 247-271(31-34) 150°C
35SH 1170-1220(11.7-122) ≥876(≥ 11.0) ≥1592(≥20) 263-287(33-36) 150°C
38SH 1220-1250(12.2-12.5) ≥907( ≥11 .4) ≥1592(≥20) 287-310(36-39) 150°C
40SH 1240-1280(12.5-12.8) ≥939(≥11.8) ≥1592(≥20) 302-326(38-41) 150°C
42SH 1280-1320(12.8-13.2) ≥987(≥12.4) ≥1592(≥20) 318-342(40-43) 150°C
45SH 1320-1380(13.2-13.8) ≥1003(≥12.6) ≥1592(≥20) 342-366(43-46) 150°C
28UH 1020-1080(10.2-10.8) ≥764(≥9.6) ≥1990(≥25) 207-231(26-29) 180°C
30UH 1080-1130(10.8-11.3) ≥812(≥10.2) ≥1990(≥25) 223-247(28-31) 180°C
33UH 1130-1170(11.3-11.7) ≥852(≥10.7) ≥1990(≥25) 247-271(31-34) 180°C
35UH 1180-1220(11.8-12.2) ≥860(≥10.8) ≥1990(≥25) 263-287(33-36) 180°C
38UH 1220-1250(12.2-12.5) ≥899(≥11.3) ≥1990(≥25) 287-310(36-39) 180°C
40UH 1240-1280(12.2-12.5) ≥899(≥11.3) ≥1990(≥25) 302-326(38-41) 180°C
28EH 1040-1090(10.4-10.9) ≥780(≥9.8) ≥2388(≥30) 207-231(26-29) 200°C
30EH 1080-1130(10.8-11.3) ≥812(≥10.2) ≥2388(≥30) 223-247(28-31) 200°C
33EH 1130-1170(11.3-11.7) ≥836(≥10.5) ≥2388(≥30) 247-271(31-34) 200°C
35EH 1170-1220(11.7-12.2) ≥876(≥11.0) ≥2388(≥30) 263-287(33-36) 200°C
38EH 1220-1250(12.2-12.5) ≥899(≥11.3) ≥2388(≥30) 287-310(36-39) 200°C

Can Polymagnets make magnetic bearings?

In a static magnetic system – such as two permanent NIB magnets facing north to north or south to south – it is impossible to create this configuration of magnets without some way to prevent the magnets from sliding past each other or flipping over. The controlling principle is called Earnshaw’s theorem. If you provide a lightweight mechanical connection to prevent the magnets from moving laterally, the magnets will appear to hover or pseudo-levitate – CMR calls this a spring function.

In a bearing system, magnet systems can be created to make a bearing system as long as part of the system is mechanically held apart.

Can you make Polymagnets hover?

In a static magnetic system – such as two permanent NIB magnets facing north to north or south to south – it is impossible to create a configuration of magnets without some way to prevent the magnets from sliding past each other or flipping over. The controlling principle is called Earnshaw’s theorem. If you provide a lightweight mechanical connection to prevent the magnets from moving laterally, the magnets will appear to hover – we call this a spring.

How does CMR's performance data compare to performance data for standard magnets?

All Polymnaget data is derived from in-house force testing in CMR’s magnet characterization lab. Where comparisons data is shown, results are of directly comparable magnets of the same size and grade under consistent conditions.

It is important to note that during testing, magnets are held parallel and aligned. Unconstrained application testing where magnets are not either parallel or aligned may give lower forces due to the magnet tilting away from target during engagement and disengagement.

By contrast, most magnet force and pull strength data on the internet does not represent real-world conditions. Rather, most of it is from idealized conditions that dramatically overstate the forces that can be achieved in product design by 2x or more. It is therefore not very helpful to product designers looking for accurate data.

It is common to see magnet data on the internet described as coming from Case 1 or Case 2 configurations, which are idealized scenarios.

Case 1 is the maximum pull force generated between a magnet and an “infinitely” thick piece of steel.

Case 2 is the maximum pull force generated from a magnet sandwiched between two “infinitely” thick pieces of steel against another “infinitely” thick piece of steel.

It’s obvious why these scenarios are idealized. It is critical to understand the source of the data used for prototyping and product design and rely only on real world test data.

How do I work with CMR to design products with Polymagnets?

There are two ways to work with CMR. First, CMR makes a library of standard Polymagnets available though our online catalog for prototyping. These magnets fill the requirements for many designs. For custom magnetic systems, please fill out our custom application form to have your requirements reviewed by an applications engineer.

Are Polymagnets stronger than standard magnets?

Polymagnets focus the energy already in a magnet to increase holding strength. Normal magnet to metal connections waste a tremendous amount of magnetic energy due to leakage of magnetic flux. By focusing the energy into the metal, Polymagnets hold with much more strength.

What is the smallest magnet you can make?

CMR has engineered magnets down to 4mm in diameter. But this answer can’t capture the complexity of designing magnet systems with very small magnets. Small magnets have much less energy that large magnets since the energy scales with the volume. Other physics of small magnets also reduces the available energy unless the magnet is practically in contact with what’s it’s attaching to.

What do CMR's patents cover?

CMR has more than 100 issued U.S. patents and many more pending.  CMR’s patents cover a range of technologies related to magnets and magnetization.   For example, CMR’s patents cover the processes and equipment used to make Polymagnets.  CMR also has patents that cover unique and innovative magnet behaviors, including those found in the catalog.  CMR’s patents typically cover behaviors regardless of whether those behaviors are achieved via Polymagnets, conventionally magnetized magnets, or assemblies of discrete magnets.  CMR also has issued or pending patents in most of the major consumer and producer markets around the world.

Do the magnetic properties of Polymagnets wear out?

The world’s strongest magnets are made from Neodymium-Iron-Boron (NIB or NdFeB) plus small amounts of other elements. These magnets are called permanent magnets because they retain a very strong magnetic field after being energized and are very hard to demagnetize. An NIB magnet naturally loses its magnetic properties (degausses) at about 1% every 100 years. There are 2 ways to fully de-magnetize NIB. The first is to put the magnet under high heat for an extended period of time – from 130F to 200F over about 45 minutes depending on the magnet grade. The second method is to put the magnet in a very high reverse magnetic field on the order of 5 times the strength of an NIB magnet. Polymagnets behave exactly the same way – retaining their strength unless exposed to heat or a very high reverse magnetic field.