Analysis of the processing method of ferrite magnetic shielding material for NFC

- Feb 28, 2019-


Analysis of the processing method of ferrite magnetic shielding material for NFC


What is the relationship between NFC and die cutting, in fact, NFC itself has near field communication function, belongs to the RFID industry, and we are not associated. But ferrite, an indispensable absorber shielding material used in NFC near field communication, has a lot to do with us. With the wide application of near field communication function in mobile terminal, the demand for NFC absorbing ferrite material is increasing. And for the processing of ferrite materials is our die-cutting industry to do!


What is ferrite?


First of all, let's take a look at what ferrite is.


Ferrite is a compound oxide composed of iron and one or more other metals.


For example, the chemical formula of spinel type ferrite is MeFe2O4 or MeO·Fe2O3, in which Me is a group of various metal ions with bivalent average chemical valence (such as Mn2+, Zn2+, Cu2+, Ni2+, Mg2+, Co2+, etc.) whose ionic radius is similar to that of ferric ion (Fe2+).


Ferrite belongs to the category of semiconductor in electricity, so it is also called magnetic semiconductor. Magnetite (mainly Fe3O4) is the simplest form of ferrite. As early as the beginning of the 20th century, ferrite has been synthesized internationally. In the 1930s, France, Japan, Germany and the Netherlands have carried out systematic research. The Netherlands has been producing ferrite soft magnetic materials since 1946. Industrial production of ferrite began in China around 1956. Ferrite has been widely used in communication and broadcasting, computing technology, automatic control, radar navigation, space navigation, satellite communication, instrument measurement, printing and display, pollution treatment, biomedicine, high-speed transportation and other aspects.


Ferrite material is mainly magnetic iron oxide powder through high temperature sintering to form a fixed size shape of the magnetic sheet material, the way of incoming material for the sheet form, the general specifications ranging from 180x180mm to 40x40mm specifications. The terminal use of this material requires the magnetic sheet to be double-sided or single-sided adhesive tape wrapping, crushing, slicing, or die cutting before use.



Its application in the terminal is generally the upper and lower two layers wrapped single-sided plastic, protective film use. Its main function is to shield the interference signal of near-field communication equipment by absorbing wave material, which is widely used in RFID electronic tag industry.


Material characteristics and processing difficulties


Its material characteristic basically shows for: this kind of material appears with the form of piece material basically, ply is thin, quality is heavy, height is fragile, in the process that raises with the finger slightly exert oneself to do STH. Can produce rupture. Under normal stress, the crack does not crack along with the direction of force.


According to the above material characteristics, it is not difficult to find that the processing difficulties of this kind of material for double-layer coating like graphite sheet mainly include the following aspects:


1. Raw materials are difficult to extract and feed;

2. How to realize batch automatic patch operation;

3. How to realize the re-crushing process after edge wrapping;

4, how to effectively slice or die cutting;


Based on the above problems, we found that the common strategy of sheet metal to coil material is no more than to use a manipulator or a robot to grasp the operation through the vacuum chuck can be completed. But for the bizarre material we encountered today, our robotic vacuum chuck just touched the disk, a little force on the disk can be broken. Even if there is no fracture, there will be different degree of fracture due to the action of force in the process of magnetic disc transportation, which will seriously affect the composite processing of magnetic disc materials.


Current operating methods



At present, the processing methods of ferrite magnetic sheets in China are mainly manual, and distributed processing technology is completed with multi-type and station equipment. The main workflow is as follows:


1. Take the material by hand and place the magnetic strip on the peeled double-sided adhesive tape with equal spacing;

2, laminated upper single-side adhesive, basic use of simplex small compound machine;

3, and then through the different material bar, the use of different pull to achieve crushing;

4. Then enter the slicer for slicing;


In view of the above steps, we found that this process is extremely inefficient and the placement of materials is uneven. And the debris in the composite process is easy to produce. Finally, it is difficult to control the compound effect in the compound process. The crushing specifications are not uniform, unable to achieve the crushing effect of XY two directions. Around the above problems, hongwen technology took nearly three years of research and development results on the automatic molding of ferrite sheet. It is in the market in the near future constantly put ferrite automation machine. Through the on-site demonstration, we learned that this equipment not only has a complete set of automatic production process from automatic material taking, feeding, equidistance patch, material composition, XY two directions of fixed specifications to final section forming.


Firstly, in terms of material taking, the machine has realized the material box with batch setting. The function of the material box is to realize automatic material top by photoelectric induction after the upper material is taken out. Then the manipulator through the sponge sucker to complete the magnetic material adsorption grasp. It is worth noting that this kind of sponge sucker-disk can effectively absorb and grasp the magnetic material, so that the whole plane of the magnetic disc can be uniformly stressed, so as to avoid the rupture of the magnetic disc due to a single point of force, and at the same time to ensure that the magnetic disc in the process of transportation is not subject to the action of external force of transportation and rupture.


Secondly, in terms of feeding and positioning, the mechanical arm use visual positioning system can effectively identify the disk of the specifications of the direction of the position, through effective visual alignment positioning way to grab the patch in the disk specified position, and the limit mode includes the XY two directions (fodder direction and vertical direction) and then through the servo larry system precision is expected to top double-sided adhesive compound in the disk to complete the disk material on the coil spacing materials such as composite sheet.


Third, in the crushing aspect, this model carries on the pressure crushing through the XY two directions different roller, but the control crushing specification skill has obtained the effective solution above the roller grain tooth width.


Fourth, and in the magnetic film composite section die - cutting, the device does not in accordance with the traditional simple fixed length of the way to pull the slice. According to the magnetic characteristics of the ferrite sheet and the placement characteristics of the sheet, the high-precision electromagnetic induction sensor is used to control the tracking and positioning method for slicing. This method can effectively solve the problem of constant length accumulated tolerance and avoid the loss of magnetic materials caused by the dislocation of constant length.


As the market continues to mature, NFC, RFID, the two key words have been on the die-cutting industry's influence gradually emerged, I believe, dare to innovate, for development.