Paul Austen

Paul Austen has submitted responses to the following questions.

Full Aqueous Clean or Local Spot Clean
The standards say get it clean, they do not say how, for the most part. How clean depends on the ...

Trays for MLS Baking
What material to use for baking trays will depend on the temperature you use to do the bake. For sure, ...

Storage To Prevent Corrosion
Actually a combination of low RH atmosphere and nitrogen (low oxygen) will be the best at preventing corrosion. If your ...

How To Remove Oxidation On SMT Components
If oxidation is the only impedance to solderability, a “good” flux should remove it. Ask your favorite flux/paste manufacture for ...

Baking Old PCBs Prior To Reflow
I would NOT make it a hard fast “rule” to always bake boards. Baking can exacerbate oxidation (IPC J-STD-033D 4.2.7.1) ...

Twisting Multi-strand Wires
To twist or not to twist? Looks like you should always "...restore the original lay..." before tinning per IPC standards ...

Design Considerations and Impact on Assembly
An oft forgotten (until testing starts) design consideration is the spacings required by regulatory agencies (UL, VDE, etc) between “mains” ...

Components Falling Off During Reflow
A visual example of how too much paste (solder) on the bottom side components is a dripping faucet. The drop ...

Can a Few Contaminated Joints Cause an Assembly to Fail RoHS Compliance?
J. S.; L. L. above said it best, "...dilution is not the solution..." to passing RoHS, otherwise any assembly could ...

Moisture Barrier Bag Calculation
The most common way to find the volume of an irregular shape is to submerse it in water and note ...

BGA Component Cleaning Spec
IPC/EIA J-Std-001 "Requirements for Soldered Electrical and Electronic Assemblies" section 8, "Cleanliness Requirements" address these post soldering cleaning which I ...

Pre-bake in a Vacuum
Vacuum assisted baking can hasten moisture extraction from boards and components. However it could also cause the problem you are ...

SOT (Small Outline Transistor) Body Cracks
There are several unanswered questions, the main one being: At what point in the assembly line is the cracking noticed? ...

Challenges Placing RF Shields During SMT Assembly
Reflow solder pallets. There are many creative pallet fixture manufactures out there that can develop pallets to hold your RF ...

Seeking Advise for a Solder Reflow Recipe
A thermal profile will be the best tool to help you find the right oven recipe. One thing for sure, ...

Lifted Lead on SOT Component
From the image supplied, it appears the component lead did not "wet" (AKA: head in pillow) either because: the component ...

Mixed MSL Baking
Unless you plan to re-heat the entire PCB assembly to reflow temperature during the re-work process, you only need to ...

Baking After Cleaning Hand Placed Parts
Any Moisture Sensitive component, which has exceeded its Floor Life, and will be subjected to a soldering process, must be ...

Question About Dry Storage of PCBA's
Dry Storage is a great way to keep the assemblies dry after mass solder (reflow). Moving them from reflow, after ...

Can Solder Joint Geometry Change Resistance?
Assuming the circuit (device under test) drawing the current is the same when powering with a Battery vs a Supply, ...

Critical Part Fixture During Reflow
Fixtures for holding components in place during reflow, or other soldering processes, are very common and highly recommended. And, if ...

Aluminum Trays and Rapid Static Discharge
Static is tricky. There is a lot of "tribal knowledge" spread around about it. Some is good and some is ...

Water Wash vs. No-clean
If the assembly is NOT conformal coated and meant to be used in "reasonable" environmental conditions, a no-clean solder process ...

Maximum Allowable Time Prior to Washing When Using Water Soluble Paste
Many water soluble paste fluxes are acidic. I would not leave it on my board one second longer than absolutely ...

Shelf Life Limit for Soldering Old Components
I am not aware of an IPC standard that suggests that the age of a component is a reason to ...

EMI Shield Reflow Soldering Techniques
Fixturing the shield during reflow is the best way to hold it in place. It must be as light weight ...

Looking for Long-term Component Storage Options
J-STD-033D, "Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices" offers three methods. Here is a brief summary: ...

Cleanliness Standards for Electronic Components
The IPC is the best source for standards for our industry, Electronics Assembly. In your case, a standard for cleanliness, ...

ESD Ground Wire Gauge
You are right, ESD protected areas have what is called "Equipotential Bonding Systems" which tend to be very high resistance, ...

Competing Reflow Oven Zones
Ovens do their best to maintain isolation between zones. But there are practical limits to what they can achieve because ...

Reflow Profile for Mixed Lead-Free and Leaded
The lead free board does not care about the thermal profile (temperatures on solder joints) or the oven recipe (zone) ...

Reflow Oven - 5 Zone or 8 Zone
For the most part, ovens with more zones (thus longer length conveyors) allow you to increase the conveyor speed and ...

Moisture Sensitive Components in Flooded Storage Facility
Unless the moisture exposure has damaged the component or the packaging mechanically or aesthetically, or there was direct contact between ...

Reflow oven testing and calibrating concern
There is now a standard, IPC-7801 "Reflow Oven Process Control Standard" which could help address C.J's question. ...

Moisture Sensitivity Level for Bare Boards
The moisture sensitivity of printed board design will depend on the resin system. Whether anyone has assigned an MSL number ...

What Is This Contamination?
From the picture, it is difficult to be sure. I would suggest there is a corrosive contaminant under the epoxy ...

Is Solder Mask Considered an Insulator
IPC standards are, for the most part, focused on quality, quality programs and the protection of the environment [http://www.ipc.org/ContentPage.aspx?pageid=Mission-Vision-and-Goals]. There ...

Stainless Steel Benches and ESD
Metal benches, if grounded correctly are not an ESD hazard, in fact grounded metal is the best sort of ESD ...

Selective Soldering Frame Causing Cold Solder Joints
"Selective Soldering Frames" can "pull" large amounts of heat from the solder wave at the point of contact, effectively lowering ...

Floor Life of MSD Parts
J-STD-033C has a provision for repeated short term exposure(open bag) of parts in paragraphs: 4.1.2.1 and 4.1.2.2. Repeated exposure is ...

Solder Paste Prep Before Use
Although thismethod of preparing your solder paste is definitely acceptable, there arechances of running into a few issues. The main ...

Tiny Solder Balls After Reflow
One possible cause is the board itself. Air, moisture or even the alcohol you use to clean the board, can ...

Production Floor Temperature and Humidity Loggers
One should not challenge an auditor, however it would be fair to ask, what standard indicates that more than one ...

ESD Grounding - 1 Meg Ohm Resistor
To prevent the user from being electrocuted should their wrist strap come into contact with a live mains voltage. 1 ...

Rechecking Thermal Profiles
It is very important to know you have the right oven recipe to correctly solder your customer's products. This can ...

Soldering Station Calibration
Yes I agree! Anything used in critical manufacturing processes can and should be calibrated. Calibration is often confused with, adjustment ...

Suggested Limit for PCBA Heat Cycles
I would "suggest" no more than two heating cycles, to solder reflow temperature. Most assemblies can be soldered in one ...

Burned Chip Repair
Surface mount components can be safely removed and a new component can easily be replaced using the same tools. This ...

What Causes Component Rotation During Reflow?
This is likely caused by an uneven rate of heating; one pin(pad) is melting the solder a little faster than ...

Profiling for Double Sided BGA
The fact that you are asking this question means you care about your soldering processing and the impact they will ...

Reflow Causing Warp
You must run a thermal profile first to find where the temp differences are on the board. Warp is caused ...

ESD and Humidification
Elevated relative humidity (RH) is known to help reduce the concentration or buildup of electric charge (potential difference). This can ...

Jumper Wire Gauge
Jumper wires on circuit boards can take a couple of forms. If you must use through hole, bent solid wire ...

Long Term Component Storage
Most all manufactures ship their products having a Moisture Sensitivity Level (MSL)> 1 in a Moisture Barrier Bag (MMB) containing ...

Reflow Oven Calibration Schedule
The oven manual or the oven manufacture is the best source for a recommendation on the calibration frequency. However, many ...

A Generic Reflow Profile
You are correct in your thinking that different board types, thicknesses and component densities may demand different oven recipe settings ...

Zip-lock Bags vs. Heat Sealed Bags
The question of the quality of the seal in somewhat mute once you open a sealed component bag. Once a ...

Silver Solder for Audio Circuits
All elements of the conductive path for audio signals have the potential for adding"noise" (aka: hiss, buzz, hum, etc) to ...

Insufficient Barrel Fill on Through-hole Components
This is a difficult number to find in the "standards." I can tell you that board designers have a "rule ...

Test for Flux Penetration
The tried and true method is to lay a flux sensitive paper over an unpopulated board and pass it over ...

Deionized Water Sample Testing
Deionized water is a very "hungry" acid. However, it's hunger is very easily satisfied.DI water fresh from a DI bed ...

Soldering Multilayer Ceramic Chip Capacitors
It would be best if you could solder both ends of the cap at the same time, using a hot ...

Unusual Component Lead Contamination
Here is one possible cause to check on before you apply the failure to the component. As with most solder ...

Lead Free Reflow Oven Zone Count
More zones offers more flexibility in the board or solder paste target thermal profile "shape" because you have more places ...

Board Spacing During Reflow
All ovens behave different depending on the amount loading. It is more important to load the oven consistently for a ...

Lead-Free Profile Using Leaded Paste
Mixing solder alloys on the same board is never a good idea, but it is a cleaver thought. It won't ...

Need for Reflow Profiles
Thermal profiling is the only way to prove to your customers that your oven settings (the recipe) are such that ...

SPC for Reflow Ovens
What most people mean when they ask, "what is the best way of running SPC" on most any process is, ...

Adding Weights to Small BGA's During Reflow
Be sure you understand the thermal profile of the environment under this component before you try a mechanical remedy as ...

Through Hole Component Phase Out
Most electronic gadgets are designed to interface with humans in some fashion. We humans are very abusive to most electronic ...

Problems with Insufficient Barrel Fill
Good soldering needs 3 things: Solder, a "wetable" surface(s), and heat. I suspect you have the solder, so that's not ...

Polarity on LED SMT Components
Tradition for many years has made the cathode of diodes the feature to marked with a band or other indicator ...

What Is the Life Span for a Profile Board?
You are fortunate to have profile test boards and I applaud your efforts to make sure your ovens are producing ...

Tombstoning Dilemma
Tombstoning is often caused by one end of the part reaching liquidus temp just before the other end. The surface ...

Issues with BGA Components Near PCB Edges
Thermal Profiling is the key to determine if you are going to have a reflow problem with a BGA, or ...

Solder Joint Explosions
First make sure the temperature that the board's solder joints are being subjected to are within reasonable temperature limits by ...

Problems with blow holes
Blow holes have many causes. One possible cause is air escaping from between the layer of the PCB through pin ...