Ishikawa Metal Co. Ltd is Lead-free solder manufactuer and sales in Osaka

石川金属株式会社

TÜV RHEINLAND認定

Management System
ISO 9001:2008
ISO 14001:2004

  • 7-21 Chikkoh Hamadera Nishimachi Nishi-ku Sakai City, Osaka 592-8352, Japan
  • TEL:072-268-1155 FAX:072-268-1159
  • info@ishikawa-metal.com

Wettability issues (Solder pastes)

Wettability problems

Poor wettability makes less bonding area and bonding reliability.


Causes of wettability issues

The causes of wetting issues include reflow profile problems and deterioration of components and boards.


Concept of reflow profile

"Trapezoidal profile" is long preheating and main heating. The melting point of the solder is about 220 °C, while the heat resistant temperature of the parts is around 250 °C. Long preheating zone eliminate the temperature difference due to the size of parts, it prevents wettabiliy issues due to heat shortage of large parts and failure due to overheating of small parts.

Reflow profile
Reflow profile
  • ①Heating zone 1
  • ②Preheating zone
  • ③Heating zone 2
  • ④Main hearing zone
  • ⑤Cooling zone

Deterioration of the solder paste in preheating

Generally the preheating temperature is 150 to 180 ° C and the time is 90 to 120 seconds. During preheating, the flux of solder paste starts the reaction by heat, gradually loses its activity and the wettability decreases. So it is ideal to preheat at as low a temperature as possible and in as short a time as possible within the range where the temperature of the part rises to around 240 ° C during main heating.


Measures against wettability issues

We use the optimum activating agent according to the preheating temperature and main heating temperature, in the flux of the solder paste, You can achieve more accurate information about solder paste and recommended profile by accurately communicating parts, shapes and dimensions of the mounted parts to the solder maker. We have a wide range of preheating temperature and solder paste which shows good wettability with various parts so please contact us.


Measures for Void (Solder paste)
Void issues

The void at the soldered part occurs that the gas remains inside which is generated in soldering. The voids of up to 25% in area of joints are allowed in the IPC-A-610, an industry standard, but voids reduction is required for parts such as power devices, in order to improve heat dissipation efficiency and bond reliability.

Void issues
Void occurred in the lead of QFP

Causes of void
Causes of void are as below
  1. ① Air bubbles remaining in unwetted parts
  2. ② Decomposition gas of flux remaining in solder
  3. ③ Decomposition gas caught in unwetted parts
Causes of void
Cause of void(example of QFP)Enlarged view

Measures of void

To prevent voids, necessary not to make unwetted parts on boards and parts. It is important to adequately manage so that deterioration such as oxidation and moisture absorption does not occur during storage.

We have a less void type solder paste using materials with good wettability and less gas generation, so please contact us.


Wettability issues, bridges, spikes (Flux cored solder wire)
Wettability issues, bridges, spikes

Wettability issues, bridges, spikes are caused by flux activity. The flux loses activity over time, due to the heat during soldering, We can reduce these problems by reviewing work procedures and selection of flux.

Wettability issues, bridges, spike
  • Wettability issues
  • Bridges
  • Spikes

Changes that occur in flux during soldering

It is the active agent in flux that directly affects wettability and activity of solder during soldering, the activator will decompose and volatilize with heat and be consumed. It is important in preventing wettability issues to suppress volatilization of the active agent and always supply fresh active agent to the soldered part.

Changes that occur in flux during soldering

Review of soldering work

The supply timing of solder is very important, regardless of manual soldering or robot soldering.
Fresh active agent always exists in the soldered part and realizes better wettability by supplying it little by little, than a large amount at once, especially, in case of robot soldering, the finish greatly changes.

Good soldering
Review of soldering work
  • Supply little by little while advancing the iron
  • Excellent wet and spreading

Selection of solder materials

The active agent in the flux is selected according to the application of each product and reacts at the optimum temperature.
It is important to consult with the solder maker and to use solder adapted to the packaging and construction method.
We have flux cored solder wires that shows excellent wettability with wide temperature range and mounting products. In addition to ordinary components, it can be used for high difficulty mounting products such as through-hole boards, transformers, large connectors, etc


Flux spattering, solder ball (Flux cored solder wire)
Flux spattering

The flux spattering is a most problem in soldering with flux cored solder wire. The appearance of the product will be impaired. In addition, flux adhered to the liquid crystal screen, camera unit, switch contact point leads to defects in the product.

Flux spattering

Causes of flux spattering

Flux spattering occurs when the low boiling point and low decomposition point components in the flux are boiled and gasified by the heat during soldering and exploded simultaneously with melting of the solder.
Factors that flux spattering is likely to occur are as follows.

  • · Not selected suitable solder for the work
  • · Too high iron temperature
  • · Too fast solder supplying
  • · High work area altitude (low ambient pressure)
Flux spattering
Flux spattering

Solder ball

Solder ball easily occurs at the same time as flux spattering. Generated accompanying the flux spattering in extreme supplying, too severe movement of the soldering iron, even too much amount of solder.

extreme supplying, too severe movement of the soldering iron, too much amount of solder
  • extreme supplying
  • too severe movement of the soldering iron
  • too much amount of solder
Solder ball
Solder ball

Selection of solder materials

It is possible to reduce the spattering by solder material, by increasing the melt viscosity of flux, using materials with less gasification, etc.
At our company

  • · Manual soldering
  • · Laser soldering
  • · Robot soldering
  • · High altitude (high altitude place, low atmospheric pressure place)

We have low spattering type flux cored solder wire suitable for each and please contact us.


Flux spattering, Solder ball (Solder Pastes)
Flux spattering and the issues of Solder paste

Flux of solder paste may occur spattering in reflow heating.
Flux adhering to the connector part or contact part of memory socket may cause poor conduction and malfunction.

Flux spattering, Solder ball (Solder Pastes) 1
Less spattering type
Flux spattering, Solder ball (Solder Pastes) 2
Ordinary type

Causes of flux spattering in solder paste

Causes of flux spattering is the rapid boiling of flux.
In reflow heating, gases are generated in the flux as the solvent evaporates and the activator decomposes.
The temperature of the solder paste rises rapidly in the Heating zone 1, which is from the start of reflow to preheating, and in the Heating zone 2 which is from the end of preheating to main heating.
It generates gas from the flux at once, boils and causes spattering.
Also, when a large amount of gas is generated after melting the solder,Gas tends to accumulate in the molten solder, and spattering is likely to occur when this gas escapes.

Measures against flux spattering in paste

Measures against flux spattering in paste

Measures against flux spattering are as follows.
<By reflow profile>
· Decrease the temperature gradient of temperature rise zone 1 and temperature rise zone 2.
<By solder>
· Change the active agent in the flux to one with a wide decomposition temperature range.
The generated gas does not accumulate inside the molten solder, and it escapes every time, so it hardly leads to spattering.

We have less spattering type solder paste, so please contact us.


Solder ball

Solder ball is a phenomenon where solder powder is left behind around the soldered part after reflow.
In addition to appearance problems, insulation resistance value will decrease if the amount generated is large.

Cause of solder ball

Causes for solder ball are from both devices management and solder paste.
<from devises management>
· High temperature inside the printing press, high humidity
· Cleaning failure of metal mask
· Misalignment of metal mask
· Clearance defect of metal mask
· Reuse the paste once used
<from solder paste>
・Oxidation of solder powder


Measures against solder ball

Management and maintenance of printing presses are important to prevent solder balls. On the other hand, adding an appropriate activator to the flux of solder paste reduces solder balls. Our solder paste has taken measures in flux to reduce solder balls.

Solder ball
Transparent residual flux, corresponding to LED board
Color tone of flux

The various rosin used for the flux has different colors from transparent to brown one. Also, some some active agents and additives are colored due to heat during soldering.


LED lighting board

In LED lighting equipment, white resist is applied to the entire board, and brown flux residue impaires the appearance of the product.


Affect on appearance inspection

On the Board displayed by silk, brown flux residue the visibility deteriorates due to the residue flowing to the display area, especially the visual inspection load to increase.

Affect on appearance inspection1
Affect on appearance inspection2

Selection of solder materials

We have solder materials which weakened the color of flux residues to light color by using light color rosin and less coloring activator, so please contact us.


Residue cracking
Residue cracking

Residual cracking is a phenomenon in which cracking or peeling occurs due to the application of forces such as heat shrinkage and bending to the flux residue.

Use in low temperature environment, Mounting on flexible board
  • Mounting on flexible board
  • Residue cracking
  • Use in low temperature environment

Problems of residue cracking

Cracking in the residue causes moisuture absorption at the cracked part, and leads to a decrease in electrical reliability. Also, peeled flux enters switch contact etc, which may cause malfunction.


Measures against Cracking in the residue

Measures against cracking in the residue are washing of substrates and coating of coating agents, but in both cases cost problems arise. In order to solve these problems, resilient flux has been developed and put to practical use. We have residue cracking prevention type solder paste and flux cored solder wire, so please contact us.

Printing problems
Printing problems
  • (1)Transfer problems
    A required amount of solder paste is not transferred to the board, causing insufficient wetting and strength at the soldered part.
  • (2)Sagging in printing
    The shape of the solder paste collapses after printing or solder paste is transferred excessively, causing chip side balls or bridges at narrow pitch parts.

Cause of Printing problems

The cause is viscosity change of solder paste. Increase in viscosity may cause transfer problems, decreasing may cause sagging in printing.


Measures against Printing problems

There are measures with solder paste and equipment setting, respectively.
(a) Measures with solder paste
By using solder paste with little change in viscosity even if continuous printing for a long time, it is possible to take measures against both transfer problems and sagging in printing.
(b) Measures with equipment setting
You can take measures by managing the temperature and humidity inside the printing machine.
When the temperature inside the printing press is high, the viscosity of the solder paste temporarily decreases and print sag is seen. Over time, the viscosity increases due to the chemical reaction of the flux and the solder powder, resulting in transfer failure. On the other hand, when the temperature is low, the viscosity of the solder paste decreases and transfer failure occurs.
If the humidity inside the printing machine is high, deterioration of solder paste due to moisture absorption, viscosity increase occurs, transfer failure occurs. Also, if the humidity is low, the solvent in the flux volatilizes, which increases the viscosity of the paste, which may cause poor transfer.


Solder paste with stable printability

We have solder paste with low viscosity change and stable printability even for long time printing so please contact us.

Low Ag solder · no Ag solder
Requirement for low Ag of solder alloy, role of Ag

The most widely used lead-free solder is Sn-3.0Ag-0.5Cu, which contains 3% Ag.
Ag, which is a precious metal, is expensive and price fluctuations are intense, so we have high risk of material cost and cost fluctuation in packaging.
Low Ag solder (reduced Ag content), and no Ag solder (not using Ag) are being introduced for this reason.
Ag in the solder has the role of lowering the melting point of the alloy, improving the wettability, increasing the mechanical strength, fatigue strength, creep strength, and so on. For this reason, there are packages that can be used with low-Ag solder and packages that are not applicable, and we need to proceed with the introduction taking this into account.


Introducing examples of low Ag and non-Ag solder

The packaging that can be introduced with low Ag and no Ag has the following features.

■Parts with large dimensions and large solder amount
TV · home appliances, LED lighting, battery pack
■Stress-free parts are soldered after mounting
Coil part of the motor (no stress occurs as the coil bends)

Complement of wettability and workability by flux

Since low Ag and no Ag solder contain a small amount of Ag, wettability and workability of them are inferior to ones of Sn-3.0Ag-0.5Cu solder. However, complementing with sufficient wettability flux ensures performance close to that of Sn-3.0Ag-0.5Cu.

We have solder paste and flux cored solder wire, corresponding to low Ag, no Ag, so please contact us.

(JEITA鉛フリー化活動成果報告2007より)
Halogen free solder
Background about Halogen free

In the case of solder material, halogens such as Cl, Br, etc. are used in the flux to improve solder wettability and workability. However, dioxins, which is harmful to living things, may be generated when incinerating an electronic board containing halogen, Cl or Br.
Halogen free is for measures of dioxin, to try to regulate the halogen to be used for the electronic board.




Halogen free standard and our halogen free type products
Standard Contents of standard Compliant product
JPCA-ES01
IEC61249-2-21
IPC4101B
Halogen content in the copper-clad laminate
Chlorine (Cl) content: 900 ppm or less
Bromine (Br) content: 900 ppm or less
Total amount of chlorine (Cl) and bromine (Br) content: 1500 ppm
JEITA_ET-7304A Halogen content of solid content in solder material flux
Fluorine (F) content: less than 1000 ppm
Chlorine (Cl) content: less than 1000 ppm
Bromine (Br) content: less than 1000 ppm
Iodine (I) content: less than 1000 ppm
Laser soldering
Characteristics of laser soldering

Two major reasons why laser is used for soldering are listed below.

  • · Non-contact heating and less maintenance
  • · Small variation in solder amount, stable mounting quality
Laser absorption rate

Infrared laser is used for soldering, and characterized by higher absorptivity of organic matter than metal.
Therefore, in soldering, before the solder alloy reaches the required temperature, the flux may evaporates or deteriorates, because of higher temperature of the flux.

Laser soldering

Issues of laser soldering

There are the following problems accompanying light heating and short-term rapid heating, in laser soldering

  • · Not enough wettability
  • · Flux, solder spattering
  • · Degradation of laser output due to lens contamination

Function required for laser solder material

As a solder material for laser, dedicated flux cored solder wire and solder paste are prepared. In case of flux cored solder wire, it corresponds by using base material which is hard to evaporate. Also, in the case of solder paste, it corresponds to by adding a material that is hard to cause heat sag at high temperature, respectively.

  • Totally covered with flux

    No reach with deteriorated flux

    Totally covered with flux No reach with deteriorated flux

    Totally covered with flux

    No reach with deteriorated flux

We have solder materials suitable for point soldering, SMT, printing, dispensing and various mounting forms, so please contact us.

Stainless steel soldering
Can stainless steel be solderable ?

Stainless steel is a base material that can be soldered.
Sn in the solder and Fe, Ni in the stainless steel join together to complete the bonding.

The difficulty of soldering is high due to the behavior of the oxide coating of stainless steel.


Phenomena occurring on the surface of stainless steel during soldering

Oxide coating of stainless steel has a function to prevent rust, but hinders soldering.
In soldering, the oxide film on the stainless steel surface is removed by flux, while a new oxide film grows due to heat and oxygen in the air. So we have to complete the soldering in a short time before the oxide film grows thick.


Actual work

We need sufficient heat capacity in a soldering iron or solder pot, in order to operate in a short time.
In case of soldering iron, set at 400 ℃, apply soldering point at the same time, supply sufficient amount of solder at a stroke and continue heating until spreading.
For soldering such as board materials, heat capacity is insufficient even if you use a soldering iron sold by a home center. In this case, please use gas burner or gas torch.
In case of solder pot, set to 250 ~ 300 ℃, apply flux to base metal, quickly dip in molten solder and hold until wet.

We need sufficient heat capacity in a soldering iron or solder pot, in order to operate in a short time

Solder for stainless steel

We have non-cleaning type flux cored solder wire for stainless steel, so please contact us.

Measures for fine wire erosion
Cu erosion, fine wire erosion

It is a phenomenon that the line becomes narrow in soldering, when soldering a coil wire such as a relay part, an earphone, a microphone etc. Depending on the degree, it leads to failure such as disconnection

Soldered Cu urethane wire in 40㎛

Cu erosion, fine wire erosion
  • a little erosion
  • much erosion

Copper of coil wire diffuses to solder
Copper of coil wire diffuses to solder

Cause of copper erosion

Copper erosion causes the copper of the coil wire makes a compound with Sn in the solder and diffuses into the solder.
Since Pb-free solder contains a lot of Sn, it is easier to make erosion.

Cause of copper erosion

Copper of coil wire diffuses to solder


Measures for copper erosion

Adding a large amount of Cu into the solder alloy enables to lower the diffusion rate of Cu from the coil wire and to reduce copper erosion. We have flux cored solder wire and solder bar for measures against copper erosion, so please contact us.

Aluminum soldering
Uses of solder for aluminum

Small aluminum motor
Aluminum voice coil

Aluminum soldering1
Aluminum soldering2

Price and features of aluminum

The price of aluminum is about one-third that of copper, which can lower procurement costs. Since it weighs about a third, we can reduce the transportation cost and the environmental load on shipping.
The characteristic of aluminum is ecology and economy.

Aluminum soldering

We made it possible to solder to aluminum which was difficult until now.
The surface of aluminum has a strong oxide film, and it is impossible to remove the oxide film with ordinaly flux.

Aluminum soldering3
Price comparison of aluminum and copper
No washing

We succeeded in removing a strong oxide film of aluminum with special fluorine compound activator in our flux cored solder wire EAN series.
It can be used without washing flux residue as well as ordinary flux cored solder wire.

Low melting point solder
Uses of low melting point solder

Low melting point solder is used for mounting weak heat resistant parts such as camera modules.
These parts were retrofitted with flux cored solder wire, and now we are studying low temperature soldering and laser heating for further low temperature and automation.

Issues of low melting point soldering

For low melting point solder, we need dedicate flux according to its melting point,
and you can not apply what you currently use as it is.
In addition, since the alloy contains Bi, caution is required for use in parts requiring high reliability such as in-vehicle parts, medical equipment, industrial equipment.

Low melting point solder

Low melting point solder in Ishikawa metal

We have syringe type solder paste with many market results including halogen free type, so please contact us.

Fine powder paste
Demand and necessity of fine powder paste

The particle size of the solder powder used for the solder paste must be selected according to the mounted product. The miniaturization of parts used for compact mounted products has progressed, and along with this, in order to stably apply a small amount of solder to the mounting substrate, we need to narrow the inner diameter of the dispense nozzle and the metal mask opening, and fine powder is used.


Issues of fine powder paste

The surface area per unit weight increases, in addition to reducing the diameter of the fine powder.
These results in problems below, and we need dedicate flux which solved it.

  • ・ Increase in cost
  • ・ Degradation of wettability
  • ・ Increase of solder ball
  • ・ Degradation of stability during use (continuous application)

Fine powder paste in Ishikawa metal

We have syringe type solder paste using Type 5 (10-25) powder and it has a already been adopted by customers.

Solder dross
Amount of solder dross

Lead-free solder generated the twice amount of dross in the dipping process and flow process, as that of Sn-Pb solder.

Amount of solder dross

Recycling of dross

Dross is the solder alloy involved in the oxide film, most is composed of solder.
We separate them and enable to take out solder from the dross, which was waste, and enable to resell it as valuables.


Easy separation of solder from dross with recycle machine

Our solder recycle machine enables to take out solder easily from dross,
simply by pressing the warm-up operation and separation start button after dross injection,
no special training or knowledge is required.
Already used by many users

Ultrafine solder
Demand for ultrafine solder

Fine adjustment of solder supply amount is required along with miniaturization of various packages and finer pitches of boards.

Our ultrafine flux cored solder wire correspond to wire diameter 0.10 mm.
It can help you toincrease the application range of flux cored solder wire greatly.


Ultrafine solder is used for small mounting products such as camera modules, OIS modules and fine cables.

Also, in the case of Sn-3.5Ag-0.5Cu solder,
It also corresponds to a high flux content of 6%
and enables fine adjustment of solder supply amount and wettability.

Ultrafine solder

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