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Edward Zamborsky
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Regional Sales Manager
OK International Inc.
Mr. Zamborsky serves as one of OK's technology advisers to the Product Development group. Ed has authored articles and papers on topics such as; Low Volume SMT Assembly, Solder Fume Extraction, SMT Rework, BGA Rework, Lead Free Hand Soldering, Lead Free Visual Inspection and Lead Free Array Rework.

Edward Zamborsky has submitted responses to the following questions.
Tough Hand Soldering Problem
Usually this type of application requires a large amount of power to be applied directly to the thermal load. Glass ...
Soldering Station Calibration
Most facilities will test soldering systems for repeatability others will calibrate. These are two very different topics and can involve ...
Package-on-Package Rework
The rework of POP devices with our micro oven tweezers nozzles has been very successful for many companies for many ...
Double Sided BGA
When you are reworking double sided PCBs with BGAs, it is important to select a convection rework system that features ...
Toe Fillet Requirements on Gull Wing Components
The NASA requirement is the width of the end solder joint (toe) must be greater than 75% of the lead ...
Syringe Dispensed Solder Paste for Hand Soldering
Using syringe packed solder paste is a very common application for SMT rework. Some of the key things to control ...
Cleaning Reballed BGA Components
This is an acceptable proceedure as long as your baking time meets the requirements of the package that you are ...
Wave Solder Pot Contaminated with Lead
The easiest would be to add new pure solder to the bath. This will reduce the percentage of lead contamination ...
Contract Assembly in a Prison
The transition from leaded components to the packages you describe is very different then going from Thru-Hole to SMT. The ...
BGA Corner Ball Bridging
This is a classic symptom of too much top heat. This excessive heating causes the weaker corners of the BGA ...
Cold Solder Joints on 0603 Components
It would seem that by exceeding the 12 hour setup usage time you changed the flux chemistry of your solder ...
Solder Balls During Hand Soldering
You don't mention if you are using solder wire or solder paste for your 8 lead SMT components. If you ...
Devices for Soldering Iron Tip Cleaning
We supply all of our Metcal and OKi branded soldering systems with both the traditional soldering sponge and the Brass ...
Solder Paste Mixing After Storage
I would think that a centrifuge would cause the metals to migrate to the bottom of the jar and the ...
Batch Reflow vs. In-line Reflow
Having supported both types of ovens; my recommendation would be the conveyor oven. The batch may be fine for your ...
J Lead Overhang Specification
This user needs to refer to IPC-2221 section 6.3 "electrical clearance". ...
Best Way to Eliminate Dross?
Keep the temperature of the pot as low as possible and turn off the wave whenever possible. The addition of ...
Square vs. Round
Round apertures are easier to etch and etch more accurately. In addition, you get better paste release from round apertures. ...
BGA Rework Residue Concern
This sounds like flux residue from either the original process or flux being added during the rework operation. Contact the ...
Intermittent BGA Test Problems
Assuming the BGA components are good, it sounds like a reflow profile that is either too hot or too cold. ...
Application of Flux for Hand Soldering
You can buy your flux loaded into 10cc or 35cc syringes. Use a time pressure dispenser and you can select ...
Most Important Factors for Screen Printing
Solder paste volume and stencil alignment are both key factors to successful screen printing operations. Fortunately these variables can both ...
SMT Components Popping Off During Reflow
If there are indentations in the remaining solder, it sounds like the component has a solderability problem that is causing ...
Options for Reducing Dross
I would suggest you contact your solder supplier, most supply a dross reducing fluid that is specific for your formulation ...
Through Hole Component Phase Out
When we started developing SMT tools in the late 1980's the phase out of thru hole components was just around ...
What Causes Chip Component Blow Out
From what you describe, it sound like too rapid a temperature increase is causing the fluxes to boil off and ...
What is the Shelf Life for a Syringe of Solder Paste
Most of the latest syringe samples that I have encountered have an expiration date stamped next to the manufacturing date. ...
Humidity Inside Our Screen Printer
Check with your Solder Paste Printer Manufacturing Company, they may have a fan or A/C unit built into the system ...
BGA Rework Flux Recommendation
All the major brands have a BGA Rework specific tacky flux formulation. I would start with the vendor you currently ...
Lead-free Assemblies Reworked with Leaded Solder
This is a very common situation. The most important thing is that you MUST remove all traces of the old ...
Contamination Prior to Conformal Coating
I would say that if there was some type of release agent applied during the manufacturing process of the anti-static ...
Is Baking Required After Aqueous Cleaning?
Only if the board is going to be heated to reflow temperatures. ...
Most Difficult Components to Hand Solder
0201 Rework with a soldering iron. 15mil QFP hand soldering. ...
BGA Shifting During Reflow
I would check the level of the oven, and the velocity of the convection fans. Before I got too crazy, ...
Tombstoning Dilemma
This can be caused by many factors: To rapid a rise in the preheat section of his oven. Solder paste ...
SN96 Solderability Issues
It is possible that you damaged the plating by operating your soldering stations at too high a soldering temperature. I ...
SMT Component Lead Oxidation
I would suggest you contact your solder supplier. They can evaluate the solderability of your components and recommend a suitable ...
Concerns Using Hand Sanitizers
If you are using original scent hand sanitizers which are mostly alcohol I would think that it would be OK. ...
Hand Soldering Alternative
It sounds like your current soldering system is not able to keep up with your process needs. My suggestion would ...
Tacky Flux Residue Problem
Sounds like you are applying too much tacky flux during the assembly operation. Try using a Flux Transfer Plate that ...
Issues with BGA Components Near PCB Edges
From the PCB design side, with BGAs close to the edges, you may have problems routing the traces away from ...
Solder Joint Explosions
It sounds like you have found out the problem, humid PCB storage. To salvage the remaining boards you should pre-bake ...
Components Lifting During Wave Soldering
I am assuming that you currently cut the leads on the PTH parts prior to reflow. Perhaps the simplest operation ...
Hard Water Contamination
If it is hard water stains, I would try a solution that will suspend the mineral deposits. The Axarel sounds ...
Solder Joint Rework Question
If you try to touch up from the top side, you could create a void within the plated thru hole. ...
Mysterious Solder Balls
It sounds like you are overheating the previously reflowed side of the board, during the second reflow operation. This is ...
Small chip cap rework advise
The fastest method would involve a bottom side convection pre-heater, a board holder, and a direct power soldering system equipped ...
Reworked BGA component bridging at the corners
The warping you describe can be caused by moisture in the component or more likely too high a reflow temperature ...
SMT Component Shift
Assuming that there is one placement line feeding two ovens, I would expect that the "problem" oven is either off ...
Estimated SMT component placement cost
This would be the loaded hourly cost for your facility divided by the average component placement rate per hour. This ...
How to Clamp Odd Shaped Circuit Boards
Check with the manufacturer of your auto routing machine to see if they offer a tooling plate with tooling pins. ...
Technology to Measure Oxidation Levels
There are several companies that specialize in Solderability Testing. I think that would be a better place to start. ...
Blow Holes on Clinched Radial Lead Components
Sounds to me that the tight clinch is acting as a dam preventing the flow of both the flux and ...
Which term to use, PWB or PCB?
Most of the industry uses PCB. So that would be the term for me. ...
Measuring component height after reflow
I would suggest using a VPI-1000 from Easybraid. Once the assembly is reflowed you can simply measure the height. ...
Ideal humidity for circuit board assembly
The low humidity could cause the solder paste to dry out prematurely, but your bigger concern with the low humidity ...
Conformal Coating & Humidity
There are several conformal coatings that are advertised as waterproof, search for MIL-SPEC conformal coatings and then you can sample ...
BGA Replacement limit
It depends on many factors; leaded solder will provide you with additional cycles where a lead-free application will reduce the ...
Wave solder process issue
From what you describe, it sounds like the hot air knife may be too cold and it is causing the ...
Micro-balling with lead-free HASL and SAC alloy
It sounds like your reflow process is too aggressive. Try reducing the ramp rate so the fluxes don't burn off ...
Double Sided Reflow
Side One: Stencil Solder paste Dispense Adhesive Place Components UV cure the adhesive Flip the assembly Side Two: Stencil Solder ...
Solder Bump QFN's
It is nearly impossible to accurately "solder bump" these components back into place on your PCB. Sure you might have ...
Opens on BGA solder joints after reflow soldering
From what you describe, it sounds like flux residues that are being left on the pcb. This can occur from ...
Rework Circuits Under BGA's
It would depend upon the type of BGA and the component you wanted to place underneath it. For example; if ...
Lead Free Flux
Yes, due to the higher reflow temperatures and longer soak times if you tried to use eutectic flux in a ...
Voids in leadless packages
The main cause for voids in BGA solder balls is too low a ramp temperature or to fast a ramp ...
Through Hole Soldering on 24 Layer Board
The best process to use would be a direct power iron combined with a convection pre-heater under your board. Without ...
Reflow BGA's with CSP's
There are two common solutions; one would be to apply solder mask over the open vias, and the other is ...
Recover Solder from Dross
If you are going to create a system to recover solder, then before you start I would look at this ...
BGA Rework
Based on the information that you have provided, you are stenciling onto the PCB. In this case you would want ...
Multiple Lead-free Profile
It appears that you are describing a multiple ZONE lead free profile. Multiple zones are required for production soldering to ...
What is Jell Flux?
Looks to me that "jel-flux" may be a trade name for high viscosity flux used in the manufacture of jewelry. ...
Solder Components to Thin Flexible Circuits
Once the flex circuit material is secured, you can align the component by hand, apply liquid flux and using a ...
Leaded Solder on ROHS Compliant Parts
No, using leaded solders on a lead free application will work just fine. You might notice a small difference in ...
How many zones are adequate for lead free profile
For REWORK you need a minimum of 4 independent top and bottom zones for heating and one zone for cool ...
Solder bridging on BGAs
When you inspect with an X-Ray you can diagnose the different causes of the bridges that you observe. For example; ...
Reduce voids in QFN pb-free reflow process
I would check my reflow oven profile and possibly adjust the soak zone to allow for the flux to be ...
Carbon Dioxide generated and trapped by conformal coating
While I am no expert on aerospace assemblies and coatings. I would expect that these carbon dioxide bubbles would react ...
Eutectic reflow for Pb-free BGAs
No, because the reflow temperatures in the eutectic process will not be hot enough to melt the lead free solder ...
Bake for Repair
I would suggest you check the PCB bill of materials and base your bake time and temperature on the MOST ...
Lead Float
Due to the light weight of these components and the surface tension of the solder this may be causing the ...
Flux Deposition
The easiest system to use for flux inspection is the VPI-1000 manufactured by Easy Braid Inc. It features up to ...
Cause of BGA Solder Joint Bridging
Typical causes of the bridging you describe is excessive top side reflow temperatures. I would suggest you reduce you top-side ...
Pre clean boards before printing
Most PCBs are cleaned and then packed in moisture proof packaging. The key here would be to keep them in ...
Part Movement During Reflow
This is a pretty common problem with this type of component. The secret here would be to reduce the center ...
Rework Metal BGA's
The problem you are facing is due to the IR energy bouncing off the reflective surface of the metal topped ...
Voids in BGA's
Voids are caused by trapped flux and flux vapors within the solder balls. They can be caused by improper thermal ...
Component Shift During Reflow
Too rapid a rise in temperature can cause the fluxes to boil off too fast causing the components to move ...
Wave soldering LCDs
Assuming the LCD is not going face down into the wave, wave soldering should not be a problem for this ...
Keep package in place during reflow
The only way to secure them is with an adhesive. While you mention you do not have a glue machine, ...
Clean before wave soldering
This would only be required if there were heavy deposits of grease or other contaminates on the PCB. Otherwise the ...
Coating or encapsulating tin-lead solder joints?
If you are not exporting your product, or if you are exempt then you do not need to do anything. ...
Solder Paste Hang up
Make sure the solder paste is fresh. Make sure the solder paste has been brought to room temperature before printing. ...
BGA Rework - with or without solder paste
The best process is to remove the component, remove the old solder from the board using desoldering braid and a ...
Voids in Solder Balls
Typically solder voids will be formed during the reflow process. They are usually acceptable providing they do not exceed 25% ...
Wire stripping insulation prior to tinning
This is a good idea. Leaving the stripped end on the wire protects it from damage as it is moved ...
BGA re-balling process
Winslow automation have an excellent process for reballing. ...
Tombstone problems
You can try gluing the parts on the bottom side of the board. Or you can reduce the subzone temperature ...
Hand soldering process
A short dwell time reduces the amount of heat transferred up the lead and into the body of the component. ...
Stencil printing process problems
Could be that with warmer temperatures the paste is sticking to the blades. You might need to try a different ...
RFID Technology for Pick and Place feeders
The use of RFID feeders should help to eliminate component mixups during change overs and kitting. Will it increase the ...
Should we buy new low cost assembly equipment
While the benefit of purchasing capitol equipment is lower prices, the downside is the support network that is NOT present ...
Plating thickness for lead-free HASL
While I cannot provide a specification, thicker would be better as the high tin content in the lead free solder ...
Lead-free connector rework
There is only one method I can identify for this type of application, the pcb will require substantial bottom side ...
Books or Publications of today's electronics assembly
Join the Surface Mount Technology Association and then you can use their website. ...
Wave solder and reflow 0805 capacitors and resistors
As long as you are careful with the preheat zone so that you do not ramp up too quickly you ...
Temperature Time Transformation
See the following links to answer this questions. Kester Lead Free Reflow Profile Standard Solder Paste Reflow Profile for Kester ...
Lead-free soldering problem
Answer to Question 1 It looks like your peak reflow temperature is too low, perhaps your thermocouples are out of ...
Double sided SMT
The best way to look at double sided SMT assembly is to break it down into 2 single sided SMT ...
Cleaning PCB Boards with window cleaner?
Since my bottle of Windex doesn't list any ingredients, you would need to contact the manufacturer for details. ...
Small component rework
This is a common solution for removal of two sided devices in the rework area. Some of the common reasons ...
Hand soldering skills
I would suggest a company called Soldering Technology Inc. they specialize in solder training and they also supply soldering training ...
Tombstone problems
The increase in body thickness will also increase the wetted area of the component body. This can result in the ...
Proper hand soldering settings
The important factors for any hand soldering application are temperature, repeatability and thermal response. You need to solder at the ...
Hand soldering for Lead-Free
The only hand soldering system that is available where you can measure power is the OK International line of Metcal ...
Coating to stop tin whisker growth?
No, tin whisker growth cannot be stopped with conformal coating. Conformal coating if properly applied will prevent the electrical shorts ...
Hand-held XRF system question
RMD Instruments manufacturers the LPA-1 LeadTracer handheld XRF system. The LeadTracer is a state of the art XRF spectrum analyzing ...
Regarding lead free, can I use the reflow ovens I currently have in production?
Typical ovens of this vintage have 5 heating zones, most newer ovens have a minimum of 7 zones. While it ...
Average Temperature/Humidity for an Electronics Assembly Facility?
Typically in the normal human comfort zone. 68-75 degrees F with a Relative Humidity of 45-55%. ...
RoHS existing products vs. new products
You have misunderstood the word "new". All products sold into the EU must be lead free with certain exceptions. Just ...