Bjorn Dahle

Bjorn Dahle has submitted responses to the following questions.

Competing Reflow Oven Zones
You express two problems, and they are interlinked. The first is to define the process window for your tin/lead paste. ...

Reflow Oven - 5 Zone or 8 Zone
For modern quality reflow ovens, the longer ovens with more zones tend to be required primarily for higher throughput. If ...

Challenges with 01005 Components
In general, the miniaturization of components leads to smaller and smaller pads on the PCB. The printed solder paste will ...

Rechecking Thermal Profiles
If you have requirements for thermal process traceability, or if you want to integrate MES into your production line, you ...

Lead Free Reflow Oven Zone Count
There are differences between oven brands in terms of thermal capabilities, but in general more zones tend to make it ...

Puzzling PCB Reflow Delamination Problem
As per the description, the PCB had already been through several thermal excursions by getting baked, going through the HAL ...

Soldering Quality & IPC Standard?
Here are my thoughts. Not sure if it is valid, as it based upon minimum information that is provided. Looks ...

Reflow for Metal Core PCBs
The fundamental reflow process for a MCPCB is the same as for a FR4 PCB. You have to identify the ...

Need for Reflow Profiles
Whether you need to run a profile on every different assembly depends on your requirements, and what you would like ...

SPC for Reflow Ovens
The first question to decide upon is whether you want to run SPC on the machine itself (reflow oven) or ...

Tombstoning Dilemma
Tombstoning happens due to imbalance in the surface tension forces exerted on the terminations of small passive components. The imbalance ...

Oxidation on pads causes poor solder joints
Oxidation on the surface mount pads is due to the exposure of the copper to the atmosphere. The degree to ...

IR Reflow Issue
The following could be the possible reasons for this failure. 1. Board support in placement and the placement pressure. Too ...

Through Hole Soldering on 24 Layer Board
The problem seems to be that there is probably not enough flux that is wetting the entire barrel including the ...

Wave Soldering Problems
It appears that there is probably not enough flux that is wetting the entire barrel including the top side. Better ...

Solder Components to Thin Flexible Circuits
Solder will not attach to non-metallic surfaces. Therefore the component body need not be masked. On the other hand solder ...

Solder Deposits on Components During Wave Soldering
Solder will not attach to non-metallic surfaces. Therefore the component body need not be masked. On the other hand solder ...

Solder bridging on BGA's
Solder Bridging in BGA packages could be due to any of the following reasons PCB RelatedPad Size and Spacing No ...

How many zones are adequate for lead free profile
The number of zones in a reflow oven is only one of many aspects of the oven that will influence ...

Eutectic reflow for Pb-free BGAs
Yes you can. The most important aspect of this reflow is the melting of the Pb-free solder balls of the ...

Optimize Temperature Profile for High Mix Board
My name is Bjorn Dahle and I am with KIC, a company that makes profilers and thermal optimization software. The ...

Flux Deposition
The cause is most probably the lack of flux, provided all the reflow parameters are as per specifications. It is ...

Tg and Td for lead free process
Tg and Td are important material properties, as they influence the resin system in organic substrates. In lead-free processing,Peak assembly ...

Tombstone problems
The primary reason for tombstone defect is the difference in wetting action / surface tension of the molten solder on ...

Using tin-lead solder on RoHS parts
The RoHS gull wing or J leaded components and passive components with end terminations should not have any issues. They ...

Using non-RoHS components in RoHS process
Here are some generic considerations to keep in mind when combining components: PCB: 1. Is the PCB capable of withstanding ...

Books or Publications of today's electronics assembly
Here are a few reads, in order of difficulty. SMT Principles and Practice - By Ray Prasad Electronics Packaging and ...

Reflow parameters for lead-free BGA
Since the paste is 63/37 eutectic solder paste I would recommend the following ... A Preheat temperature of around a ...

Lead-free soldering problem
Answer to Question 1 The primary root cause for this could be inadequate melting of the bump and the solder ...