Magfine Corporation

Strict quality control to continue providing the highest quality magnets.

Magfine Corporation is the best magnet company with 25 years in business

Quality Control

Various institutions in Japan and abroad advocate quality management and inspections. Regulations include ISO, an international standard for management and inspections, set forth by International Organization for Standardization and JIS, a Japanese standard set forth by Japanese Industrial Standards Committee. Other regulations include REACH, RoHS and PFOS which are European standards for quality, materials and products. Although our plant in Japan is not ISO certified, we are committed to the standardization of production procedures and inspection standards, in accordance to various relevant standards.


Quality control procedure

Here we would like to explain the quality management procedure of neodymium magnets, which are well-known typical rare earth magnets. On our website, we have introduced the production sites, with the cooperation of our OEM manufacturer in China. (The procedures for quality management also differ slightly due to the different production procedures depending on the material such as ferrite magnet, samarium cobalt magnet etc.) In order to prevent defected products from being shipped out, design, production and finishing procedures are managed and inspected strictly by our company’s employees that have been assigned in China. We are committed to improvements and identifying the source of any issues by traceability, in the event of any failures.

No. Procedure Facility Characteristics Method Processing for failed products Images
No. Product Procedure Specification tolerance for production procedure, Control method Sample Management adjustment method
Worker Check
Allowance Frequency/time Allowance Frequency/time Worker Check
1 Acceptance of raw material
1 Structure
Work standard ICP analysis device
4 units Each batch Inspection statistical handbook ICP analysis report Return product IMG_0487
IMG_0493
IMG_4266
2 Appearance Visual check 4 barrel (cartons) Technical instructions
Inspection for alloyed Pr Nd 3 Contents ICP analysis device 4 units IMG_0809
2 Preparation of material Polishing cutter 1 Appearance
Inspection for changes, rust, oxidization, impurities Visual check All inspected Each batch
Re-treat IMG_0811
3 Melting
1 Mixing of materials
Weight inspection

Instruction book for ratios of mixing materials Adjustment device for electrical scoreboard Once Each batch
Mixed procedure book
Re-treat Re-adjust
4 Melting Vaccuum melting furnace 1
Recovery rate 97%-99.5% Adjustment device for electrical scoreboard
1pc Each input Daily record of melting Trend diagram
020
2 Vaccuum pressure Instruction diagram for melting procedure Vaccuum gauge Once Each input
Daily record of melting inspection Separation limit
3 Argon pressure
Barometer
Each time
4 Cooling Time
5 Appearance after molding
Instructions for molding procedure Visual check
1pc Each batch

Record of appearance inspection after making molding template
Separation limit
6 Thickness after molding Instructions for molding procedure Micrometer 4pcs Each input Record of thickness inspection after making molding template
5 Roasting under nitrogen environment (heat treatment) Nitrogen incinerator 1
Vaccuum pressure <=1Pa Vaccuum gauge Once Each input 1pc At each time of replacement HP original record HP record Separation limit 030
2 Nitrogen pressure 0.1-0.2Mpa Barometer
3 Conformity 2-2.5h Time
4 Dehydrogenation temperature 550°C-590°C Temperature control device
5 Dehydrogenation time 6-8h TImer
6 Cooling 3.5-4h
6 Pulverizing Puliverizing jetmill 1 Particle size
3.5-4.0 micron Measurement device for average sizes
Once Each barrel Daily report of size inspection (Average value)X-R chart Separation limit IMG_0501
IMG_4269
IMG_4274
IMG_4275
2 Contains oxygen
Oxygen analyzer 100%
All inspected
Each batch
Record of pulverizing
3
Separation rotation speed 3000-4500r/min Speedometer 100%
All inspected
Each batch 1pc Every day Record of pulverizing
7 Weighing powder Scale 1 Scale Measurement of weight of powder Production plan adjustment Scale 1 type Each time Each size 3 timesEach time 1 type Each time Record of molding Record of molding Re-make 032
IMG_4285
8 Molding Magnetic forming machine 1
Magnetization current >40(A) Ammeter 100%
All inspected
Each time Each size 1pc Each time Record of molding Record of molding Reprocessing
Adjustment
040
IMG_4291
041
2 Magnetization trend >=1500mT
>=1200mT
Gauss meter Once Each time Each size
3 Molding size Production adjustment Caliper 1pc Each time Each size 3 timesEach time Re-make
4 Appearance No chips, impurities Visual check 100%
All inspected
Each size
5
Packaging
No air leaks after suction
No air leaks after suction
No air leaks after suction

Parallel magnetization 6 No air leaks Separation identification IMG_0512
9 Separation agent Nitrogen cartridge 1 Appearance
Parallet magnetization and oil removal, no oil leaks
100%
All inspected
Each time Once Each time Record of sintering Record of molding Separation identification
2 Amount of oxygen contained
<1ppm Oxygen content meter Each time
10 Sintering Vaccuum incinerator 1
Weight inside the incinerator Instructions for sintering Calculation (single weight x total) Once Each input Once Each time Record of sintering Record of sintering Separation limit IMG_0538
053
050
IMG_0534
IMG_4302
IMG_0530
IMG_0536
2 Sintering temperature Instructions for production Electrical scoreboard, temperature adjustment device 100%
All inspected
3 Sintering time
4 Tempering temperature
5 Tempering temperature
6 Vaccuum pressure Instructions for sintering Vaccuum gauge Once
11 Magnetic properties inspection
1 Calibration device
Coil for calibration Testing device for magnetic properties
Once Every day

2 20+/-3°C
Br
Specification record Check regulations for sampling for material inspection Record of properties NdFeB Record of properties Separation or lowering of grade 060-3
IMG_4307
3 20+/-3°C
Hcb
4 20+/-3°C
Hcj
5 20+/-3°C
(BH)max
6 Density Precision measurements >=2 PCS Each batch

Record of density testing Separation
12 Centerless grinding Centerless 1 Dimension
Production adjustment Micrometer
AQL=1.00 Each batch
Record of grinding procedure Re-treat
2 Appearance inspection, cracks, pinholes, chips, rust, finish
Appearance inspection, cracks, pinholes, chips, rust, finish
Finish, work standard
Finish, work standard
Visual check 100%
All inspected
Record of grinding procedure Separation IMG_4323
IMG_4320
3 Chamfering Micrometer >=4 PCS Re-treat
4 Magnetization Measurement using micrometer of demagnetized magnet
13 Bonding of material Bonding base 1 Perpendicular
Production adjustment Visual check 100%
All inspected
Each size
Record of cutting procedure Limit IMG_0656
Attaching material
2 Perpendicular Place the work piece perpendicular to the blade Anglemeter for blade IMG_0652
IMG_0653
Cutting Cutter 3 Cutting speed Heavy hammer
3kg-6kHeavy hammer
3kg-6k
Scale
4 Cutting size Production adjustment Micrometer Each batch Re-treat
Removal of adhesive agent, cleaning
Removal of adhesive agent, cleaning

5 Boiling time 1.5h-2h TImer Limit
14 Pre-surface treatment inspection
1 Dimension
Work standards for pre-surface treatment Micrometer
AQL=1.00 Each batch
Sample record 100%
All inspected
IMG_1944
IMG_1945
2 Appearance inspection, cracks, pinholes, chips, cutting marks or scratches, sealing oil, flatness, holes, number of defects Visual check 100%
All inspected
Re-treat IMG_1947
3 Circulatory Micrometer 4% Separation
Re-treat

4 Magnetism Measurement using micrometer of demagnetized magnet Re-treat
5 Number of pieces Instructions Instructions/measurement device 100%
All inspected

100%
All inspected
Sample record Supplement
17 Finish inspection Magnetization device 1 Dimension
Instructions Micrometer
AQL=1.00 Each batch
Record of sample of finished product Re-treat 080
2 Appearance inspection, cracks, pinholes, chips, cutting marks or scratches, rust, holes or surface treatment Work standards for measurements Visual check 100%
All inspected
IMG_6272
3 Coating thickness Instructions Coating thickness gauge 2-6 PCS Record of coating thickness inspection
4 Coating
Corrosion
Instructions for salt spray Salt spraying test 1-6 PCS Record of salt spraying IMG_6275
IMG_4313
5 Coating
Corrosion
Surface magnetic flux density, work standard Gauss meter 10-80 PCS Sample record Select only defected products after inspection of all products METER0004
6 Total magnetic flux value Total magnetic flux value, work standard Fluxmeter 10-80 PCS METER0002
7 Number of pieces Production adjustment Instructions/measurement device 100%
All inspected

100%
All inspected
Supplement
18 Packaging
1
Packaging method Packaging specification Visual check

Twice At each time of replacement
Packaging record Re-treat 101

磁石コンテンツの区切り線
Sampling inspection

The below standard for sampling inspection is one of the standards set by Japanese Industrial Standards Committee. The inspection standard and number of samples (N) can be determined as necessary. The variability, tolerance and standard deviation is dependent on, and determined by the number of samples. Inspection standard: JIS Z9015/Inspection standard S4/AQL 1%

Lot size Strict inspection Average inspection Lenient inspection
(Number in 1 lot) Number of samples Number required for pass Number of samples Number required for pass Number of samples Number required for pass
Below 0 Below 0 Below 0
15  Below 0 Below 0 Below 0
16  Below 0 Below 0 Below 0
26  50  Below 0 Below 0 Below 0
51  90  Below 0 Below 0 Below 0
91  150  Below 0 Below 0 Below 0
151  280  13  Below 0 13  Below 0 Below 0
281  500  13  Below 0 13  Below 0 Below 0
501  1,200  20  Below 0 20  Below 0 Below 0
1,201  3,200  32  Below 1 32  Below 1 13  Below 1
3,201  10,000  32  Below 1 32  Below 1 13  Below 1
10,001  35,000  50  Below 1 50  Below 1 20  Below 1
35,001  150,000  80  Below 1 80  Below 2 32  Below 1
150,001  500,000  80  Below 1 80  Below 2 32  Below 1
500,001  125  Below 2 125  Below 3 50  Below 2
磁石コンテンツの区切り線
Appearance inspection

Appearance inspections are all conducted visually. Since the inspections are visual inspections, unfortunately it is not possible to prevent all defects in appearance and other failures. The permissible range for appearance defects varies according to the size. In principle, the permissible ranges are determined as below. Permissible ranges are determined beforehand and set forth in the product specification for products for which appearance is considered important and require mechanical strength. It is not possible to completely prevent chips and scratches on magnets as they have similar physical characteristics to china and glass and thus break easily. Therefore, unless there is a large chip that may weaken the magnetic characteristics or surface treatment that is stripping off which may lead to corrosion, the product will be accepted under concession.

Boundary sample for appearance

Item Diagram Dimension A B C Accepted number of defects Remarks Pass Fail
Chipped pole face 磁石外観限度基準01 φ5 ≦1.0mm ≦1.0mm ≦0.5mm ≦1pc There must be surface treatment on the chipped area 磁石検査合否判断01 磁石検査合否判断02 磁石検査合否判断03
φ10 ≦2.0mm ≦2.0mm ≦1.0mm ≦1pc
φ20 ≦2.0mm ≦2.0mm ≦1.0mm ≦1pc
φ30 ≦2.5mm ≦2.5mm ≦2.0mm ≦1pc
φ40 ≦2.5mm ≦2.5mm ≦2.0mm ≦1pc
φ50 ≦3.0mm ≦3.0mm ≦2.5mm ≦1pc
Chipped pole face 磁石外観限度基準02 φ5 ≦1.0mm ≦1.0mm ≦0.5mm ≦2pc
There must be surface treatment on the chipped area
磁石検査合否判断04 磁石検査合否判断05 磁石検査合否判断06 磁石検査合否判断13
φ10 ≦2.0mm ≦2.0mm ≦1.0mm ≦2pc
φ20 ≦2.0mm ≦2.0mm ≦1.0mm ≦2pc
φ30 ≦2.5mm ≦2.5mm ≦2.0mm ≦2pc
φ40 ≦2.5mm ≦2.5mm ≦2.0mm ≦2pc
φ50 ≦3.0mm ≦3.0mm ≦2.5mm ≦2pc
Pinhole 磁石外観限度基準03 All ≦0.5mm - - ≦2pc
There must be surface treatment on the pinhole area




Scratches 磁石外観限度基準04 Scratches, ex. by nails are not acceptable
There must be surface treatment on the scratched area
磁石検査合否判断08


Crack 磁石外観限度基準05 All not acceptable Determine whether it is a crack or streak
磁石検査合否判断07

Discoloration due to rust 磁石外観限度基準06 There must be no discoloration due to rust and no areas may be have any bulging or paint stripping off
磁石検査合否判断09 磁石検査合否判断10 磁石検査合否判断12


※1 All items will be determined by visual inspection.※2 In cases which the inspection standards are set according to the boundary samples, the boundary samples shall take precedence.


Magnetic measuring device

There are various types of magnetic measuring devices that measure magnetic forces, depending on the inspection purposes. Below are typical measuring devices that are used mainly in the magnet industry.


Manufacturer Type Hall effect element
probe
Image of probe Neodymium magnet
φ10mm×10mm
Remarks
Denshijiki Industry Co. GM-4002 T-401 METER0009 506.5mT Floor standing type
T-402 METER0008 535.1mT Floor standing type
KANETEC Co. TM-601 TM-601PRB METER0007 488.0mT Mobile type
Simple accuracy device
Magfine Corporation Magnetic calculator
494.1mT Predicted values based on magnetic calculations


Difference in measurement results due to difference in measurement device and probe. Testing material neodymium magnet φ10mm×10mm

Testing device for magnetic characteristics Standard Magnets

A magnet that corrects or calibrates errors of tesla/gauss meters and fluxmeters are called standard magnets. Since tesla/gauss meters are precision devices, errors may occur due to age and environment. Even if such errors occur, these testing devices are designed so that they cannot be manually corrected. Therefore, standard magnets are used to conduct regular tests of the meters in order to calibrate any errors. The standard magnets are also regularly tested at a testing institution to check they meet magnet industry standards.


Fluxmeter

A fluxmeter measures the total flux and can accurately and quickly inspect a large volume of magnets to check which ones have a large or small variation in the characteristics. It is suitable when all the products need to be inspected or a large volume inspection is required. The unit used is Wb or Mx. It is necessary to build a search coil that suits the magnet to be tested so that it is possible to measure the variation of the total flux when the magnet is removed from the search coil.


BH analyzer

The BH analyzer measures the magnetic characteristics of magnetic material which then makes it possible to find out the demagnetization characteristics and energy product that is necessary for designing magnetic circuits. It can also check whether the values of the magnetic characteristics which are set forth for each magnetic material are within the specification range. In order to measure the characteristics, a powerful electromagnetic field and a power-supply device with a high voltage is required. It is mostly used at magnet manufacturing plants and magnet research and development institutions.

Tesla meter, gauss meter

The tesla meter or gauss meter measures magnetic flux density. A hall effect device is set up on the magnet surface or other surface and the density of the magnetic flux that passes through an area of 1cm2 . According to the definition of magnetic flux density, when 1 Mx of magnetic flux perpendicularly intercrosses, the magnetic flux density is 1 gauss. The unit commonly used for measuring devices is tesla or gauss. It is most widely used out of all the magnetic testing devices since it can easily check magnetic characteristics. The measurement values may largely vary because they are easily affected by the testing environment and testing method. Therefore even if the same magnet is tested by the same person in the same environment, in some cases, the measurement values may differ largely depending on the manufacturer, type, accuracy of the probe(hall effect device) , points measured on the surface and room temperature. Since the measurement enviroment criteria depend on the usage environment, absolute values like dimension tolerances cannot be indicated. For that reason, there may be a large difference in the measurements values indicated on our products and customer's measurement values. Measurement methods and environments differ according to the manufacturer and the testing standards within the industry are also not the same. The testing environment and magnetic flux density that shall serve as the standard shall be determined based on the testing environment used by the user.

磁石のコンテンツ終点

To buy any products or ask any questions, please visit our online store or contact the corresponding department.
111-10 Moniwa-aza-hitokita-nishi, Taihaku-ku, Sendai-shi, Miyagi 982-0251 TEL +81 22-281-3956 FAX +81 22-281-3967

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