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Polymer Coating on SMD-Thermistors and SMD-Varisto

The market demands of an increasing amount of electronic…

The market demands of an increasing amount of electronic systems and subsystems, combined in decreasing frames and housings, forces the development- and design –engineers to minimize the PCB’s and components. Smaller components, like Thermistors in SMD size, are replacing the old fashioned Wire Typed Thermistors and Wire Typed Varistors.
While the Wire Typed Thermistors and Varistors only experience smaller processes of optimization, the SMD Thermistors/-Varistors have more need to become optimized, as their importance is increasing.
The Thermistor is the core of the temperature control unit, it has to be of outstanding quality and reliability. The sensitive ceramic product, which a SMD Thermistor is, has to be treated carefully and to be protected as optimal as possible against environmental and mechanical influences, to safeguard its functionality over a long working life period.
Several kinds of coatings have been developed to protect SMD Thermistors like described above. Glass coatings are used as well as polymer coatings.

Joinset Co., Ltd. has developed a new kind of polymer coating which obtains best protection grades against environmental and mechanical damages of the JoinTherm™ SMD Thermistor.
In contrast to the glass coating, which requires a high temperature process to be applied onto the Thermistor body, what causes the risk of damaging the element, the Polymer Coating is applied by a smooth evaporation process, neither stressing the material, nor using high energy levels. The further advantage of the Polymer Coating against the Glass Coating is the hermetically closed surface, which guarantees a 100% sealing of the SMD Thermistor. The Melting process, used to apply Glass onto the SMD Thermistor, causes the risk of keeping holes and enclosures (bubbles) in the surface, which will possibly break and result in a leaking seal of the SMD Body. So the needed protection is not given and the SMD Thermistor will possibly deteriorate and loose it s functionality. Joinset’s Polymer Coating is flexible and can withstand also mechanical shocks. A Glass Coating is fragile and will take damage if hit by a mechanical shock. Exposed to environments of high humidity, the JoinTherm™ SMD Thermistor will show a longer working life time than Glass coated SMD Thermistors, which will deteriorate, due to the not hermetically closed surface.
The JoinTherm™ working temperature range from -40°C ~ 125°C covers all temperature environments, a PCB can take and has sufficient reserves to withstand also high temperature peaks without any damage.
Therefore, for any application of SMD Thermistors, the JoinTherm™ SMD Thermistor will be a better fit to your needs than a glass coated one. The high reliability and quality, shown in the 1%-Tolerance of our JoinTherm™ Thermistors and our reasonable pricing, makes them the best choice.

For more information contact the Overseas Marketing Department and ask for our product broschure. Sample requests are to be addressed to santo@joinset.com directly


Thermistor Bare Chip Plated with Gold & Silver Lay

Thermistor Bare Chips are very sensitive components…


Thermistor Bare Chips are very sensitive components of the total Thermistor system. If the quality of the Bare Chip is not fulfilling highest demands in quality, the whole system will suffer from it and only become an averaged one in quality and reliability.
The Bare Chip implemented in the Thermistor system, is the main source of quality and reliability for the final result. So the quality process, to produce a Bare Chip, begins with the sourcing of the pure basic materials and is ongoing through the whole manufacturing procedure. In every step the pureness and concentration of ingredients in the material is controlled and guaranteed, to achieve a product, fulfilling high quality requirements.

Further the connector assembly, soldering and coating of the Thermistor are important processes, which may have important influence onto the Thermistor systems quality and reliability.

But there is no need to spend most attention on the manufacturing process, if the key point , the Bare Chip, is not hermetically sealed against environmental and mechanical influences, due to it’s special characteristics and requirements to safeguard it’s pureness and quality.

Taking this into consideration, Joinset developed a Gold – Plating, over a Silver Electrode (patent pending), for the Thermistor Bare Chips.
This Gold – Plating is protecting the pureness of the Bare Chip against environmental influences, by isolating the silver electrode in the Bare Chips against oxidation and humidity. So the Bare Chip, before it’s final assembly and also assembled into the Thermistor system is of guaranteed pureness and quality. No Oxidation or deterioration, taking place in the storage time, between delivery and final assembly, will decrease the Bare Chip quality to a lower level and help to achieve sufficient Yield- Level rates.
Achieving a better Yield-Level also means to reduce cost and wasted time for the whole process.
Productivity and work efficiency will also increase and help to keep pricey competitiveness, in times of rising cost, against competitors, who use unsealed Bare Chips for Thermistor production.

Further advantages of the Gold-Plated Bare Chip are to be seen in functionality. The Gold surface provides optimal electrical parameters and if the coating of the Thermistor unit is leaking or broken, the Gold – Sealing will protect the implemented Bare Chip against environmental influences and keep the Thermistor systems functionality ongoing.
This provides highest reliability of the Thermistor system and makes it usable for the hardest application situations. High temperature and aggressive chemical environments will no longer influence the Bare Chip. As long as the assembled system is on function, the Gold-Plated Bare Chip will work without loosing reliability or increasing it’s tolerances.

Joinset’s Gold – Plated– Thermistor – Bare – Chip is a nearly perfect tool, to meet the highest quality requirements of the biomedical, automotive, wire less communications and building automation industries.
Where ever highest reliability, duration and ongoing functionality even in worst case situations is requested, the Gold – Plated – Bare – Chip from Joinset will meet the demands without any compromise.

Information About the Electrical Conductive Hotmel

New Developed Multifunctional Conductive Hotmelt Film…


New Developed Multifunctional Conductive Hotmelt Film

Following the markets and manufacturers needs of minimizing housings and PCB’s by also integrating more electrical and electronic components in downsized space, materials are needed, which combine functions to prevent from multiple and complicated manufacturing steps, which cause the risk of damaging the fragile component or system.

On the other hand, under the pressure of decreasing cost in developments of new systems and components, there is no room left for expensive and multiple devices and tools. Complete solutions, decreasing the amount of parts and tools to be handled, with a good cost – need relation are searched for.

The above mentioned arguments taking into consideration, Joinset developed a combined tool for bonding, water and oil proof sealing, ESD prevention and EMC shielding, based on an electrical conductive hotmelt film, applied onto an electrical conductive woven mesh fabric.

The implemented woven mesh fabric gives an excellent mechanical stability and electrical conductivity to the film. Therefore the ECHF can be used for cable harness for sealing and shielding applications in the automotive and building automation industry as well as in the electronics and medical industry.

Used as a contact strip, which is possible caused by the stability, given to the ECHF by the fabric, it prevents the contacted items from ESD overcharge. It may be used in high velocity paper copying systems, fax and printer units.

The high quality Thermoplastic and fabric materials used in the production of the ECHF, guarantee for a long work life time circle and an over average reliability of the ECHF. The film has a thickness of only 100 μm. 80 μm is the thickness of the PET - fabric, which is covered by 10 μm of Thermoplastic material on both sides.

The ECHF is easy to handle and needs no new tools, or special trained personnel, to be applied. So cost saving by its multifunctional characteristics and advantages in front of standard hotmelt films, cable bonders, or ESD strips, is easy to be seen. Also the multifunctional of the ECHF allows to decrease the amount of used items and makes production processes easier to oversee and to plan.

More detailed information about the pending patent and the ECHF are available at Joinset Co., Ltd. directly.

Contact the Overseas Unit by phone +82 31 495 2601