Ask the Experts Member

EH Lim

Managing Director, Asia Pacific
ECD

EH Lim has been in the PCB Assy industry since 1985, starting at Thomson/Singapore for 5 years before moving to Electrovert Asia Pacifc. Lim was Sales Director for Vitronics Soltec prior to joining ECD in 2007 as Managing Director for Asia Pacific.

EH Lim has submitted responses to the following questions.

Reflow for Metal Core PCBs
MCPCBs usually use aluminum as their base material, which absorbs a lot of heat. Thus the reflow process will have ...

Solder Bridging Problem on Header Connector
Try to rotate the direction of the pcb flow by 90 deg, ie, have the connector parallel to the conveyor ...

SPC for Reflow Ovens
One of the easiest ways of running SPC on a reflow oven is to use our ECD's OvenRIDER, whereby the ...

Options for Reducing Dross
Options to reduce dross in wave soldering systems are: Use nitrogen blanket over the waves, depending on cost of nitrogen ...

Cause of Pin Hole Rejects
Check the solderability of that component. An x-ray at the pin hole location will reveal more (ie how deep is ...

Problems with Insufficient Barrel Fill
Possible causes of insufficient fillings are: Incorrect (ie insufficient or excessive) preheat on the board, throughout the pcb thickness, insufficient ...

Delamination dilemma
You should verify the temperature profiles of your pcb assy during the reflow process. If they are confirmed within tolerance, ...

Wave solder process issue
Are you using nitrogen gas in your air knife or just compressed air? Nitrogen gas will produce shiny joints, while ...

Pre-Bake Standard for Rework
No, it is not a common practice to pre-bake an assembled PCB prior rework, unless the PCB storage conditions (eg ...

Hand Soldering vs. Selective Wave for small LCD
I would recommend soldering the LCD glass display with 44 pins to the PCB using a selective wave soldering process, ...

Oxidation on pads causes poor solder joints
Oxidation on surface mount pads could be caused by poor pcb material manufactured (i.e. there should be a layer of ...

When is oven drying mandatory
Blisters after reflow could to be caused by wrong reflow profile in the reflow process. Check the temperature profile first, ...

Lead Free Dross Removal
Dross in the lead free wave soldering process can be reduced by as much as 90% by having a nitrogen ...

Wave Soldering Problems
Voids and insufficient top side fillet happened in PTH due to one or more of the following causes: Materials:Improper curing ...

Free Newsletter Subscription
Circuitnet is built for professionals who bear the responsibility of looking ahead, imagining the future, and preparing for it.

Insert Your Email Address