Koki Company LTD

Suppliers of solder pastes, wave soldering liquid fluxes and SMT adhesives and cored solder wires for all soldering requirements.


Established in 1964, KOKI have developed and introduced numbers of cutting edge soldering materials ever since.

Today, amid rapidly evolving electronics industry, we, as a manufacturer of soldering materials, are requested of technological advancement, environmental friendliness, and compliance.

With that in mind, we are actively advancing soldering technologies of next generation, such as halogen-free flux, anti-cracking, and low melting point solder alloy, in addition to existing high quality soldering materials. We KOKI, as a group of professionals specialized in soldering technologies, are eager to contribute to the development and advancement of the global soldering industry with latest technologies, quality excellence, and valuable services to provide.

Koki Company LTD Postings

1 product »

“Hybrid” High Reliability Low Ag Solder Paste

Tokyo, Japan – Koki Company Limited, global manufacturer and supplier of soldering materials, announces the release of new low Ag containing halogen free solder pastes that secures the equivalent joint reliability and heat profile to SAC3...

Solder Materials

3 technical articles »

An Investigation into Lead-Free Low Silver Cored Solder Wire for Electronics Manufacturing Applications

Jan 09, 2019 | Shantanu Joshi, Jasbir Bath, Kimiaki Mori, Kazuhiro Yukikata, Roberto Garcia, Takeshi Shirai

The electronics industry has widely adopted Sn-3.0Ag-0.5Cu solder alloys for lead-free reflow soldering applications and tin-copper based alloys for wave soldering applications. In automated soldering or rework operations, users may work with Sn-Ag-Cu or Sn-Cu based alloys. One of the challenges with these types of lead-free alloys for automated / hand soldering operations, is that the life of the soldering iron tips will shorten drastically using lead-free solders with an increased cost of soldering iron tool maintenance/ tip replacement. Development was done on a new lead-free low silver solder rework alloy (Sn-0.3Ag-0.7Cu-0.04Co) in comparison with a number of alternative lead-free alloys including Sn-0.3Ag-0.7Cu, Sn-0.7Cu and Sn-3.0Ag-0.5Cu and tin-lead Sn40Pb solder in soldering evaluations....

Improved Flux Reliability of Lead-Free Solder Alloy Solder Paste Formulated with Rosin and Anti-Crack Resin for Automotive and Other High Reliability Applications

Sep 05, 2018 | Shantanu Joshi, Jasbir Bath, Mitsuyasu Furusawa, Junichi Aoki, Roberto Garcia, Manabu Itoh

In recent years, a growing number of electronic devices are being incorporated into automotive and other high reliability end products where the challenge is to make these devices more reliable. The package size of the devices is largely driven by the consumer industry with their sizes getting smaller making it harder to assemble and be reliable at the same time. For automotive and other high reliability electronics product, it is of the utmost priority to secure high reliability because it directly involves human life and safety. Challenges include selecting an appropriate solder alloy and having good reliability of the solder paste flux....

Improving Thermal Cycle and Mechanical Drop Impact Resistance of a Lead-free Tin-Silver-Bismuth-Indium Solder Alloy with Minor Doping of Copper Additive

Jul 11, 2018 | Takehiro Wada, Seiji Tsuchiya, Shantanu Joshi, Roberto Garcia, Kimiaki Mori, Takeshi Shirai

For a demanding automotive electronics assembly, a highly thermal fatigue resistant solder alloy is required, which makes the lead-free Sn-Ag-Cu type solder alloy unusable. Sn-Ag-Bi-In solder alloy is considered as a high reliability solder alloy due to significant improvement in thermal fatigue resistance as compared to a standard Sn-Ag-Cu alloy. The alloy has not only good thermal fatigue properties but it also has superior ductility and tensile strength by appropriate addition of In; however, initial results indicated a sub-par performance in joint reliability when it is soldered on a printed circuit board (PCB) with Electroless Nickel Immersion Gold (ENIG) surface finish. Numerous experiments were performed to find out appropriate alloying element which would help improve the performance on ENIG PCBs. Sn-Ag-Bi-In solder alloys with and without Cu additions were prepared and then tests were carried out to see the performance in a thermal fatigue test and a drop resistance test.to investigate the impact of Cu addition towards the improvement of joint reliability on ENIG finish PCB. Also, the mechanism of such improvement is documented....

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