TSC Ferrite International (Soft Ferrite Cores)

 

        TSC Pyroferric (Iron Powder Cores)

 

        TSC–bourgeois (Magnetic Laminations)

 

 

TSC International is a manufacturer of magnetic materials for all frequencies.  Our many end markets include:  automotive, computer, lighting, telecommunications, instrumentation, industrial and consumer product industries across the United States and around the world.

 

Our objective is to provide the highest value magnetic products to our customers through a combination of exceptional quality, delivery, service and price.  We offer speed to market with one stop shopping for materials for all frequencies along with engineering support.

 

TSC FERRITE International was established in 1985 as a division of Tempel Steel Company and was purchased by Tempel Smith in 1990. TSC Ferrite International purchased the assets of AVX/TPC Thomson, Beaune France in 2004. TSC Ferrite International produces MnZn and NiZn soft ferrites, which are electromagnetic material used as cores for high frequency (10KHz-10MHz) transformers and inductors. 

 

TSC Pyroferric, founded in 1935, is the oldest manufacturer of iron powder cores in the United States.  TSC acquired them in 1995, and they continue to manufacture iron powder cores for power conversion, line filter and RF applications.

 

In 1992 TSC Ferrite International purchased the assets of TSC Arnold Technologies, which was formerly known as The Lamination Division of the Arnold Engineering Company.  TSC Arnold Technologies fabricates magnetic laminations by stamping.  The laminations are used to make low frequency (dc-10KHz) inductors and transformers.

 

A Joint Venture between TSC International and r.bourgeois known as TSC-bourgeois was formed in 1998 to provide Laminations to the North American Motor and Automotive Industries.

 

In 1999 TSC International acquired Accucore from Magnetics International. TSC Particle Core is a new revolutionary magnetic material that offers an alternative to Laminations.

 

Combined, TSC International has >125,000 square feet of manufacturing space and >70 presses dedicated to meeting our market’s demands.

 

 

POLICY STATEMENT

 

MISSION STATEMENT & QUALITY POLICY

 

It is the policy of TSC International to provide the highest value magnetic materials to its customers through a combination of exceptional quality, price, delivery and service.

 

OBJECTIVES

 

1.       QUALITY:  Achieve and maintain a quality system consistent with ISO-9000:2004 International Standards.  Produce magnetic materials within that quality system which satisfy our customers for quality and consistency and which meet or exceed the industry standards such as those of the Magnetic Materials Producers Association. 

 

2.       PRICE:  Maintain cost control by encouraging innovation, having a flat organizational structure with individual empowerment at all levels and by expanding market share.

3.       DELIVERY:  Achieve speed-to-market by maintaining efficient administrative and productive systems, good internal communications and fast factory throughput.

4.       SERVICE:  Maintain excellent service by creating working partnerships with open lines of communication at all levels.

 

5.      
Resources will be dedicated to continuous improvement while ensuring a sustainable manufacturing process.

 

 

 

 

INDEX

 

 

INDEX (cont.)

 

 

 

 

Ferrite Manufacturing Overview

Test raw material (MnO, ZnO. Fe2O3) Inspect for purity ¯ Weigh & mix raw materials Control Composition ¯ Spray dry Obtain a powder form Control bulk density ¯ Calcine Powder (Pre-firing) Control magnetic saturation ¯ Wet mill Control particle size ¯ Spray dry to obtain a pressable powder Control bulk density ¯ Form (Compact powder into “green cores”) Control pressed density ¯ Sinter (fire “green cores” to obtain a ceramic with a spinel crystal lattice structure) Control grain growth ¯ Finish (grind, tumble, coat) Control gap and surface finish ¯ Audit to insure that all parts meet all the customers requirements ¯ Pack & Ship

The process of manufacturing Soft Ferrites is made up of four basic steps: powder preparation, forming, sintering and finishing. At Ferrite International raw materials (manganese oxide, zinc oxide and iron oxide) are tested for purity levels. After the raw materials are approved they are weighed and wet mixed, and spray dried to a powder form then calcined. Calcining is pre-firing the material at a selected temperature between 800 degrees and 1100 degrees C thus creating a partial spinel structure and partially densifying the powder so that the pressed part will shrink less during the final sintering process. The calcined material is then wet milled to a specific particle size range. This particle size reduction enables better control of grain growth that occurs during the final sintering process. An organic binding agent is added to the slurry for the purpose of holding the pressed part intact. The slurry is then spray dried to provide a dry moldable powder composed of discreet spherical agglomerates with uniform characteristics.   The forming operation transforms the powder into a soft "clay like" material in the desired configuration. In this form they are called "green cores". The forming is done using presses and powder compaction tools. Because tool steels do not last under the wear of the abrasive Ferrite powder, carbide tools are used for large quantity items. The size, weight and thus the density of the green compact are all controlled within very tight tolerances.   To create the desired physical and magnetic characteristics the "green cores" are sintered in large kilns at temperatures between 1300 and 1450 degrees Centigrade. Close temperature and atmospheric control during sintering is critical. The sintering is divided into three stages. In the first stage the binders are driven off. The second stage is when the actual sintering takes place. The spinal crystal latus structure forms, the product shrinks and the magnetic characteristics are realized. The final stage is devoted to reoxidation and cool-down. Volume shrinkage is affected by the size, shape and the chemical composition. Each part must be molded oversize. A typical material may shrink 15% in any one linear dimension (approximately 50% of total volume).   Cores that will be assembled require machining. This process is critical to removing the final surface layer of reactive Ferrite (called skin) that result from sintering and to minimize any air gaps by insuring smooth flat and parallel surfaces. Some cores sets require gaps with tight tolerances in their flux path. This can be accomplished by grinding a pot core's center post or an E core's center leg. Because of the extremely hard, brittle and abrasive nature of the ceramic material diamond wheels and large amounts of liquid coolant are required for all machining operations.   Sintered toroidal cores are tumbled and sometimes coated with epoxy to eliminate any sharp corners or burrs that could damage wire insulation during the ensuing operation.   Finally the cores are tested electrically, inspected for dimensional and visual conformance and packed to be shipped to our customer.

Definition of a soft ferrite core

 

Soft Ferrites are ceramic electromagnetic material dark gray or black in appearance and very hard and brittle. The terms "SOFT" has nothing to do with their physical properties but refers to their magnetic characteristics. Soft magnetic materials also called electromagnetic exhibit magnetic properties only when they are subject to a magnetizing force such as the magnetic field created when current is passed through wire surrounding a soft magnetic core. This differs from hard magnetic (Permanent Magnets) in that once a hard magnetic material is magnetized by exposure to a magnetizing force it exhibits magnetic properties permanently.

A Soft Ferrite's magnetic properties arise from interactions between metallic ions occupying particular positions relative to the oxygen ions in its spinel crystalline structure. The magnetic domain theory suggests these interactions create magnetic domains, which are microscopic magnetized regions within the material. When no magnetizing force is present the magnetic domains are random and the net flux contribution is zero even though local domains are fully magnetized. When a magnetizing force is present the magnetic domains align in the direction of the magnetizing force resulting in a large net flux contribution.

Soft Ferrites are also semi-conductors meaning they are somewhere between conductors and insulators in their ability to conduct electron flow through the material.

Advantages Soft Ferrites have over other electro magnetic materials include their inherent high resistivity, which results in low eddy current losses over wide frequency ranges, high permeability and stability over wide temperature ranges. For inductor cores, transformer cores and other applications where electro magnetic materials are required to operate at high frequencies these advantages make Soft Ferrites paramount over all other magnetic materials.

 

 

 

 

Test Instrumentation & Methods

 

Core Loss

Published values of core loss have been measured on E21 size (41-16-12) double E cores. The cores are driven with an ENI Model 2100L RF Amplifier and measured using Clarke-Hess Model 2335 VAW meters under sine wave conditions. Flux densities were calculated using rms voltage values and effective core set parameters calculated per MMPA standard No. EUI310. Core loss density was calculated per the same standard. These curves are applicable to all sizes and configurations as long as the correct effective core set parameters are assumed. Data and graphical curves of core loss vs. temperature measured on ungapped core sets are included for each kiln firing and lot with each shipment of our products.

 

 

Initial Permeability

Published values of initial permeability have been calculated from measured inductance values at 5 gauss on toroids (OD=.870, ID=.540, HT=.250) using Wayne-Kerr model 6425 or model 3245 LCR meters. Flux density and permeability were both calculated using effective core set parameters (Le, Ae and Ve) calculated per MMPA Toroid Standard No. FTC410.

 

Power Permeability

(Permeability vs. Flux Density)

Published values of Power Permeability have been calculated from measured values of rms currents and voltages on 25-10-06 size double E cores using Clarke-Hess model 2335 VAW meters.

 

m = (L / Lair) = ((0.45*Erms)/(f*Irms*2.829))/((0.004*P*Ae*10^-6)/Le)

 

Saturation Flux Density

Published values of saturation flux density have been calculated from integrated voltage measurements on 25-10-06 size double E cores induced by a specific magnetizing force (15 oersteds).

 

Inductance Index (AL Value)

Published Al Values were measured on Wayne-Kerr model 6425 or model 3245 LCR meters using 100 turn coils. Mated cores have a clamp pressure of approximately 5 pounds per square inch of mating surface. Statistical data including a histogram and capability indexes of the AL value on gapped and ungapped core sets are included with each shipment of our products.

 

Total Harmonic Distortion

We measure harmonic distortion on an Audio Precision System Two (SYS-2022) in accordance to our customer’s part specific specification. The test circuit primary series resistance, output load resistance, frequency and drive level in Db, Vrms or Vpp are specified by our customers.

Ordering Gapped Cores

 

Gapped Cores can be ordered 3 ways:

 

1. To a mechanical dimension.

2. Two gapped cores mated together to yield a specific AL value.

3. One gapped core mated with one ungapped core to yield a specific AL value.

 

When ordering cores to an AL value, it is important to specify whether 2 gapped cores are mated together or if 1 gapped core is mated with 1 ungapped core. It is also helpful if each customer supplies us with their coil to avoid differences in fringing flux that would result in a difference in AL measurements between the customer and the manufacturer. On our throughput grinder, we are capable of holding mechanical gap tolerances of +/- .0007". Because the relationship between AL and gap depth is a decaying exponential, the AL tolerance we are capable of is dependent upon the depth of the gap (larger gaps yield smaller AL values with tighter tolerances then do smaller gaps).

 

 

Tolerances

 

Problems periodically arise concerning magnetic and mechanical tolerances of ferrites. The nominal and spread of a sample lot is not always indicative of production lots. As an example, toroids are supplied to a nominal AL value based on material grade, and a tolerance of +-25%. The nominal AL value for a large number of production lots is considered to be at 0.0%, then the total spread of a large number of shipments will be +-25% around this nominal.

 

Sample parts with given characteristics positioned at some desired point within the normal spread cannot be easily produced because chemical processes cannot be controlled this closely. For this reason, it is difficult to fill requests for “maximum” and “minimum” samples. Every TSC Ferrite International sample is supplied with data showing our measured values on each sample compared to the specification upper and lower limits.

 

 

 

 

 

 

 

 

 



 
FERRITE PART NUMBERING SYSTEM

Our material grade names have been chosen to make them meaningful to our customers.

These meaningful grade names, like the meaningful dimensional portion of our part numbering system,

are meant to help our customers identify important characteristics of our parts by the part number alone.

 

TSF-50ALL

                                                                Temperature of low core loss (<room to >100°C)

                                                                Core loss at 100KHz, 1000 gauss (50 mw/cm³)

TSF-5099

                                                                Temperature of minimum core loss (100°C)