Magnetic domains locked in, result in the ability of a permanent magnet to support an external magnetic field.  Once established these domain positions are held until acted upon by forces exceeding those of the locked domains.  The energy required to change the magnetic field produced by a magnet varies for each type of material.  The following factors affect the strength and stability of permanent magnets.

TIME

The effect of time on today’s permanent magnet materials is minimal.  Typically losses are less than 3% over the useful life of the magnet.

TEMPERATURE

Changes due to temperature effects fall into 3 categories

• Reversible losses
• Irreversible losses
• Metallurgical change

REVERSIBLE LOSSES are losses which are recovered when the magnet returns to its original temperature.  Reversible temperature coefficients, expressed as % per degree, have been established for each material.  They vary widely for various classes of material.

IRREVERSIBLE LOSSES are losses due to exposure to high or low temperatures.  These losses take place when the operating point of the magnet falls below the knee of the material demagnetization curve.  This type of loss can be recovered by re-magnetization.

METALLURGICAL CHANGES – occur as permanent magnets are exposed to high temperatures.  For all practical purposes, metallurgical changes render the magnet useless.   Manufacturers have established “Maximum Use Temperatures” for each grade of material.

RELUCTANCE CHANGES

These changes occur when the operating slope of the magnet changes.  Removal of a magnetized magnet from its circuit and replacement may cause the magnet’s operating slope to fall.  Altering dimensions of the magnet circuit during use may cause reluctance changes.  The magnitude of the loss is related to the material characteristics and the degree of the reluctance change.

ADVERSE FIELDS

Exposing magnetized magnets to opposing external fields produces a demagnetizing effect.  This effect is most apparent in permanent magnet materials having a non-linear demagnetization curve, such as Alnico.  These adverse fields may be produced by current carrying conductors or by allowing magnets to come into contact with other magnets or ferrous material.  The degree of the loss depends on the material characteristics.

Other factors such as SHOCK and VIBRATION have very little effect on today’s permanent magnet materials.  Unfortunately, most of today’s materials are brittle and crack prone, and must be handled carefully to avoid damaging the magnets.  RADIATION. Particularly at high levels, does result in flux changes which must be addressed in the design stage.

Adams’ standard flexible magnets are marked with a line running down the “weak side” so that you can be sure to apply the stronger side in your application. If adhesive is applied to the magnets, it is applied to the weak side, thus covering up the indicator line.

High energy flexible magnet is also available, and usually has almost equal strength on both sides in contrast to standard energy product. High energy flexible magnets can be magnetized through the thickness in several methods. Click here to read more details on methods of magnetization.

Adams’ flexible magnetic material can be bent, twisted and flexed without loss of magnetic energy. These materials can also be cut, scored slit, punched or machined.

The IMA develops, maintains and distributes industry standards, and is currently in the review process of updating and revising the soft ferrite standards. You can find these current standards in our cores section:

Soft Ferrite Cores User Guide
Standard Spec for Ferrite Pot Style Cores
Standard Spec for Ferrite Toroid Cores
Standard Spec for Ferrite U E I Cores
Standard Specification for Ferrite Threaded Cores

To learn more about the IMA working group and TTA, visit www.transformer-assn.org.

Please contact us for assistance or download a copy of a cross reference tool we’ve published in coordination with VAC. Our sales team is prepared to help identify a VAC product that may fit your needs, arrange samples and provide price quotes.

Micrometals Arnold Powder Cores

Micrometals-Arnold is also publishing a new catalog next month.  To request a copy, or for more information on Optilloy™ or other Micrometals-Arnold products, please contact Keith Hook at 800-747-7543.

If you’ve placed an order recently, you may have noticed that we are experiencing price increases and lead time extensions on some of our magnetic assemblies. As a valued customer you deserve to know why these things are happening.

Higher-Priced Materials and Higher Standards
The main driver behind the price hike is raw material costs, especially in iron ore. Annual fixed-price contracts for iron ore are being replaced by a quarterly pricing system that is subject to more cost fluctuation. Also, new higher standards within the magnet industry have resulted in different processing requirements that also contribute to higher costs. However, there is some compensation here in the creation of a higher-quality finished product.

Magnet assembly prices, as well as order fulfillment, have also been impacted by the labor situation in China, where most of Adams’ ceramic magnets are manufactured. The Chinese economy is undergoing dramatic growth and transition, which has resulted in greater competition for the nation’s workforce.

Other issues have also contributed to our current challenges, including an increase in electric power and coal costs in our factories, and the value of the American dollar against foreign currencies from the nations where our magnets are produced.

Eliminate Shortages by Planning Ahead
We are doing what we can to mitigate these circumstances so that our customers will be as minimally impacted as possible. However, you may also avoid running short on magnet assemblies by increasing the size of your inventory. Adams offers discounts on larger upfront orders that will offset some of the cost of doing so. Contact your account representative to work out a personalized plan for your business.

Thank you for your understanding that this price increase means we can retain our standards and our level of service for the years to come. If you have any additional questions about a current order or the price of our magnet assemblies, please do not hesitate to contact us.

For any successful signage project, communication with clients is critical, and magnets are no different. Though magnets are a low-maintenance signage option, there are still certain considerations to ensure your clients are receiving the best products available. From manufacturing to application, there are elements that can directly affect how the magnet performs in various environments, and they must be identified before you even begin production.

Prior to printing, don’t forget to find out exactly where the magnet will be placed, as its location can determine the thickness. For outdoor use, you’ll want a stronger magnet that can endure tougher elements, such as wind, hail or rain. Stronger magnets are typically thicker, but a large surface area provides extra adhesion power, as well. Generally, a .030 magnet is thick and strong enough for most applications, with an approximate lbs. pull of 85 lb. per square foot, while still being flexible enough to easily adhere to curved surfaces.

Before creating a magnet, also be sure to ask your client if his or her vehicle has ever been in an accident. Though this may seem irrelevant, it can determine whether the magnet adheres to the vehicle. Damaged vehicles are typically patched with Bondo, an automotive repair substance. If the damage was severe and there is too much Bondo on the vehicle, the magnet does not attract to the metal.

In fact, Gene Wise, partner of Wise Signs, Reading, Pa., experienced this exact dilemma. He once had a client who ordered a magnet, but it would only cling to one door. After trying several spots on the vehicle, Wise discovered the door was in a previous accident. The door was covered in so much Bondo that the magnet would not stick.

So that the customer is aware of the proper care, maintenance, and application of their magnetic sign the following link to Adams Magnetic Products web site is invaluable: http://www.adamsmagnetic.com/pdfs/magnet_sign_cleaning.pdf

With just a couple simple questions, you are well-prepared before you even begin creating your magnets. There is less room for error, and your clients are happier in the end.

Question:

Magnetic Sheets

Answer: Hello Justin. Thank you for the question.  There are a number of ways you can accomplish your goal.  We use special equipment which is designed specifically for use with magnetic sheet.  It is highly automated and developed to handle large volume production runs and may not be a feasible solution for you.  Instead, I think you would be better served by using one of two fairly simple methods.

You can get a very clean cut by using a table top paper cutter, believe it or not. You want to make sure it is designed to handle heavy duty cutting.  It should be in good condition and have a sharp blade.  You would be best served by using one that has a steel edge against which the blade cuts.  This steel will aide in holding the magnet sheet in position while you cut.

Another option would be to use a straight edge and utility knife.  You should always start with a new, sharp blade.  Simply place the straight edge where you want to make the cut and make sure it is secured properly.  Then score the magnetic sheet by pulling the utility knife safely along the straight edge, using extreme caution.  Remove the straight edge, fold the magnetic sheet at the score and then tear apart.

One thing to always keep in mind is that, when cutting magnetic sheet with an adhesive or vinyl laminate, you want to cut through the laminate first.  Doing so will result in a much cleaner cut.

I hope this advice is helpful.  Good luck!

Question:

Answer: Unfortunately, this issue is not as uncommon as you would think, mostly because there are a number of possible contributing factors.  However, let’s start by addressing your question specifically.

When making magnetic car signs we first have to be concerned with the thickness of the magnetic sheet.  Its thickness is directly related to its strength (pounds of pull).  It has been universally accepted throughout our industry that the minimum acceptable thickness for automobile signs is .030”, also commonly referred to as 30mil.  Anything less than .030” may not provide the pounds of pull required to withstand the external forces an automobile sign is subjected to.

With that being said, there are a number of other issues which may be causing your customer’s car signs to blow off, the most common of which involve cleaning and storage of the sign.  When not in use, the best way to store your magnetic sign is by laying it flat on a steel surface.  If this is not a possibility, you can roll it up, but be sure that the printed side of the sign faces outward.  If you roll it up the other way, you are introducing ‘memory’ in the magnet which could prevent the edges of the magnet from lying flat while on your car.  With the edges lifting up from the surface of your car, the possibility of wind getting underneath the magnet and basically ‘prying’ it up are much more realistic.  This occurrence will obviously result in the sign eventually blowing off.  The other most common contributing factor is the cleanliness of both the magnet and the automobile.  If not properly maintained, you can end up with debris being trapped between the magnet and car.  This issue is detrimental in two ways, the first of which is similar to the ‘memory’ issue discussed earlier.  Larger debris can create channels through which wind can penetrate underneath the magnet and ‘pry’ it off.  Debris can also introduce ‘air gaps.’  These are gaps between the magnet and the surface to which it is trying to attach.  This situation will essentially decrease the holding force of the magnet and possibly allow it to blow off.  The magnet and automobile surfaces should be properly prepared and maintained to avoid this issue.  For more information and specific instructions on cleaning please click on the following link: Car Magnet Cleaning.

Thank you for your question.  If there’s anything else we can answer please let us know.

Answer: There are several ways you could expand into refrigerator magnets.  A few ideas include:

1. Tipping or gluing printed magnets into your existing card designs.  The magnets could match the artwork of your current card designs.
2. Adding a magnet strip to the inside front cover of existing card designs.  This would work well if you offer cards that have photo frames incorporated into the cover.  Adams can provide magnetic strips with adhesive pre-cut or scored to the desired size.
3. You could expand into postcard greetings that have magnets glued or laminated to them.

Magnetic Strips

If you want an easy and inexpensive way to make prototypes of your refrigerator magnet ideas, you can use our PrintMAG magnet sheet in your ink jet printer to make mock-ups.

There are companies like Magnetic Attractions or Rainbow Magnetics who print magnets and can package them in bulk or individually for retail, or they can tip/glue and laminate them to card stock.  They can even print the card stock if you like.

Please let us know if you’d like to see samples of what we describe above, or if you have any additional questions.  If you’d like to discuss any of this in person, please give us a call at 800-222-6686.  Thanks Deborah!