INTRODUCTION

Flexible magnet covers a wide variety of magnet materials.  The different categories are defined partly by the actual input magnet chemical constituents and partly by the magnet material manufacturing process.  The most common constituents in flexible ferrite magnet material are Barium Ferrite and Strontium Ferrite and, more recently, in rare earth flexible material, Neodynium Iron Boron, all loaded into PVC binders.  Most flexible magnet material is produced in strip or sheet by extrusion process.  Higher magnetic characteristic/performance flexible material is obtained either by work rolling/hardening in the rolling process or by including special additives to the chemical constituents.

MAGNETIC PERFORMANCE

As with all magnetic materials, performance is difficult to quantify without going into complex formulae.  We strive in this section to give rules of thumb and an appreciation of different materials which will help in the selection of magnets.  Hands-on testing is definitely recommended (with papers/air gaps as necessary) to select the best magnet for the job.

1.   Material Types

Material                                                                                 Bhmax-Energy Product

a.   Isotropic/Semi Anisotropic Ferrite                                         0.7 to 0.8 MGOe

b.   Full Anisotropic Ferrite (High Energy Sheet)                            1.1 to 1.4 MGOe

c.   Neodynium Flexible Material                                                 2.0 to 2.5 MGOe

The more expensive material has superior magnetic energy performance.

2.   Material Thickness

Typical Pull Characteristics

The popular thickness range of flexible magnet material is 0.4 to 1.5 mm,
but thicker material is available in high energy. The thicker the material
the greater the pull. It is not in direct proportion, but the thicker the
material the greater the pull increases.
 

3.   Pull/Gap Curves

The graph is for 1.5 mm flexible ferrite magnet in widths of 12.5/20 and

25 mm and is typical for all flexible magnet.  The graph clearly shows

magnetic adhesion (pull) diminishes with an air gap.  By introducing a

0.25 mm air gap the adhesion is nearly halved! 

 25 mm  wide strip

 20 mm  wide strip

12.5 mm  wide strip

We review flexible magnet by:

STRIP PRODUCTS

SHEET PRODUCTS

OTHER FLEXIBLE MAGNETIC PRODUCTS

STRIP PRODUCTS

STANDARD STRIP (NON ADHESIVE BACKED)

Plain magnet strip is popular, economically priced material for general purpose applications.  It can be stapled, will accept small screws, or can be glued.  There are three popular types of magnetization.

The cross section of standard strips available are:       

EXTRUDED STRIP MAGNET SPECIAL SECTIONS

EXTRUDED STRIP MAGNET - FLAT PROFILE  (ADHESIVE BACKED)

Flat profile material, adhesive backed, is very popular both for display industry applications and for general craft projects.  The material is available in 1.5 mm thick, a number of widths, in up to three types of peel-off adhesive backing and in various types of magnetization.

Standard adhesive suitable to adhere to dry, clean, non-porous surfaces like plastic, metal, coated card etc.   Foam(mirror tape) adhesive, best applied to slightly porous surfaces such as ceramic, wood, etc.   Aggresive adhesive is specifically developed to adhere to flexible backings such as display laminates/posters. this adhesive requires a curinf time of 24 hours before rolling the laminate and extruded strip magnet.

Summary of Flat Profiles;  Adhesive Backed

* Random, will mate with itself if one piece is turned around ● Not yet stocked, but available with 6-8 week lead time

EXTRUDED STRIP MAGNET;  FLAT PROFILE (ADHESIVE BACKED) MAGNET TO MAGNET APPLICATIONS

The magnet to magnet applications are most useful for fixing of posters and graphics in display systems. In addition to Mag "A"/Mag "B", other types of self aligning systems can be manufactured on request.

EXTRUDED STRIP MAGNET;  FLAT PROFILE (ADHESIVE BACKED) MAGNET TO STEEL APPLICATION

Satin white steel strip comes in 30 metre rolls. It is extremely useful for work in magnet systems where there is no convenient steel/ferrous mating surface. As magnet to steel adhesion does not perfectly align/mate steel strip can be very useful to mount posters etc. on out-of-square frames.

Steel Strip mm

A popular application of steel strip/magnet application in Europe is holding double glazing frames to wooden window frames. This could equally apply in Africa to hold mosquito netting frames to wooden/aluminium window frames.

BOOKMARK MAGNETS (ADHESIVE BACKED) MAGNET TO MAGNET APPLICATION

Matched pairs of self adhesive magnet strip are suitable for making magnetic bookmarks. Bookmark magnets are sold per matched pair in packs of 100. The three stock sizes are:

12.7 mm x 61 mm
12.0 mm x 42 mm
10.0 mm x 30 mm

GUILLOTINED MAGNET STRIP;  HIGH ENERGY MATERIAL

High energy sheeting 1-1.4 MGOe material is manufactured in sheets 500 x 250 mm and 500 x 500 mm in a variety of thicknesses up to 12 mm. The sheet can be magnetized axially so one flat surface is one pole and the other flat surface the opposite pole. We guillotine locally such sheets into high energy strip, the most popular application being in the pneumatic control industry.

INTRODUCTION

Ferrite magnet sheet is produced by the same extrusion process as magnet strip using similar constituent magnet chemicals.  Most flexible magnet sheet used in the display/signage industry is magnetized multipole on one face as this gives excellent magnetic adhesion.  High energy and fully anisotropic flexible sheet are either magnetized axially with one pole on each flat surface or with a broad magnetic matrix/stripe through the thickness of the material.

APPLICATIONS OF FLEXIBLE MAGNET SHEET

The Display and Premium grades are primarily used for signage, planning boards, temporary signs etc., but they can be used for fridge magnets, calendar magnets, spray markers, educational aids and games.  The high energy grades are used in industrial applications like positional sensing, TV correctors, manufacturing prototype magnetic circuits, segment magnets, electronic applications and animal strain bandages.

REVIEW

We review flexible magnet sheeting as follows:

1.   SIGNAGE - DISPLAY AND PREMIUM GRADE FLEXIBLE SHEET

2.   HIGH ENERGY MAGNET SHEET

3.   OTHER MAGNET SHEET PRODUCTS

SIGNAGE - DISPLAY/PREMIUM + PREMIUM PLUS  GRADE MAGNET SHEET

This material is produced in rolls 30 metres long, the first table has a width being 610 mm plus a trim width.  The second table width is 1M X 10M long rolls.  There are four main thicknesses and surface finishes detailed in the following tables.  The signage material is all magnetized multipole on one face only so as to achieve maximum magnetic adhesion.

Magnet Sheet mm <Multipole one face>

Notes:

a) Vinyl facing normally adds 0.1 mm to material thickness.

b) The adhesive backed materials use standard adhesive with a pressure sensitive peel-off  back.

c) The main difference between Premium Grade and Display Grade is that Premium Grade has more flexibility than            

Display Grade and that characteristic, together with the slightly enhanced magnetic pull-off, makes Premium

Grade the preferred material for vehicle signage.

d) We stock the vinyl faced materials in colour white only.  Other colours are available, but only for orders of a complete

roll of 30 metres and a delivery of 6-8 weeks.

e)We can guillotine cut the adhesive backed material in pieces to custom size requirements.  The costing on large

order quantities works out more economical than magnet strip.

SELF ADHESIVE MAGNET  /  PRE-CUT SIZES ("kiss cut")

These pieces are suitable for placing on back of business cards, menus, photographs, calendars and many other applications.   The magnet is cut,  however the paper backing is not and therefore it is very easy to peel off and attach to your application.

i )   This fully anisotropic special high energy material is produced in small sheets of 500 x 250 mm and 500 x 500 mm. 

The material is magnetized either axially or with a broad striping through the thickness.  Thickness of material is available

up to 12 mm.  As the material has good magnetic characteristics it is often used to manufacture prototype segment

magnetics for electric motors using both the flexibility to form and magnetic characteristics without the special tooling

costs which would be incurred if a ferrite segment magnet was required.

ii )  The material with broad magnetic striping is useful where the magnetic adhesion of signage grade magnet is

inadequate.  The pull force of high energy magnet can be enhanced by using a steel backplate on the non-contact side.

iii ) We find high energy material useful to guillotine to magnet strip to give a high energy strip product used typically

around pneumatic equipment pistons where external position sensing is required.

OTHER FLEXIBLE MAGNET SHEETING PRODUCTS

FLEXIBLE FERRO MATERIAL

Ferro material is an iron oxide in a flexible format.  It is not a magnet, but acts as a flexible ferrous surface to which

magnet sheeting etc. will adhere.  The material has a thickness of 1.5 mm and is available in sheet width of 610 mm and in

30 metre rolls.  The material can be supplied either plain or with a pressure sensitive standard adhesive backing.  Ferro

material is particularly useful where the materials' flexibility can be used, i.e. putting a ferrous base on tight bends or

unusual geometry such as a magnetic licence disc holder adhering to a vehicle windscreen 

ii   Magnetic Paper

Magnetic Paper is only 0.2mm thick.  It has a white superior quality ink jet paper on one side and a flexible magnet on the other side.  The material is supplied in A4 sheets and is designed for use with a desktop inkjet printer.  This allows the production of magnetic pictures, fridge magnets, greeting cards, etc.   Magnetic Paper is unsuitable for laser printers.

MAGNABARS

This product can be used as a "gimme" which companies can use for promotion.   Advertising can be pad printed onto the top and they have a fairly strong magnet which can hold papers to a filing cabinet, fridge  etc.

The size  is   150mm long x  15mm wide and are currently available in RED, BLUE, GREEN, YELLOW,  BLACK and WHITE

TGD POWER  KNIFE RACKS

The knife rack is of pleasing design, white plastic finish, 36cm long x 5cm wide and comes complete with mounting screws and wall anchors.  The rack holds knives, scissors and other kitchen utensils.  We have also sold the unit to dental technicians to hold their tools and to wood carvers to hold chisels.

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