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Questions tagged [reflow]

Reflow soldering is a type of soldering where solder paste is applied to the pads, after which the components are placed on top and then it is baked in an oven.

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What is the best solution to keeping heavier components on a double-sided PCB while going through second pass reflow?

I am trying to do some research as I have many customers who face this issue with their parts falling off the board during the second pass. What has worked for you? Many applications are different ...
RMT's user avatar
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Is there flux that doesn't brown under heat?

Adding flux (MG8341) to rework a component is resulting in ugly brown stains as shown in the picture below; this is a flexible circuit board with white cover-lay. The flux started to turn brown add ...
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Soldering with SAC on a glass PCB

I’m having trouble getting the solder paste to wet my glass PCBs. I am using SAC305 solder. Funny that it works fine on FR-4 but with glass it just balls up. Maybe it is because glass conducts heat ...
Eitan Benchabbat's user avatar
3 votes
2 answers
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Cheap vs. expensive reflow oven

I am trying to build my capacity to solder SMD onto two-sided boards. As far as I understand, for example from this post, a reflow oven is better than a hotplate for reasons of uniformity in ...
villaa's user avatar
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2 votes
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Reflow oven control technique

I am developing a DIY reflow oven using a 10L common electric oven with quartz heating elements. Below is a graph that represents the oven's step response (open loop response): In blue: oven's step ...
Emanuel M's user avatar
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Should I throw these boards with soldering issues out?

I've just baked some boards. The first two looked normal, but upon closer inspection I noticed that paste did not melt under one chip with exposed pad package. I used a slightly different profile with ...
Maple's user avatar
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PCB warping during Reflow

I have design a PCB size about 100x60mm it reflow very nice on the hot plate but If I convert my PCB to a panelization 2x3 quantities size became 200x180, the edges began to lift up due to expansion ...
mehmet's user avatar
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4 votes
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Reflow soldering with decreased footprint size fully within pad

So the original footprint is first, followed is the edited footprint to allow for inner pads to be accessed. As you will notice the extended pad footprint is smaller than the pad. Will this cause ...
Tony's user avatar
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Solder SMT/SMD with a rework preheater?

Is it possible to solder SMT/SMD chips using a rework preheater (e.g. a Model 5040-XR3)? What "gotchas" go with this method of SMT/SMD soldering? I know it's best to use a real reflow oven, ...
P_B's user avatar
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1 answer
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Disobeying recommended pad size of 0603 LED

I need to pack a cluster of 0603 LEDs (https://docs.rs-online.com/c349/0900766b81180479.pdf) as close together as possible on a PCB. The datasheet recommends a pad-to-pad width of 2.3mm. As the board ...
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What glue to use for edge bonds on a laptop NB

I'm trying to reball the northbrige of my HP Pavilion DV4-1212LA because it stopped working from one day to the other. I've checked, and all of the voltages are present. The laptop itself posts the ...
fpp's user avatar
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9 votes
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How do components not get knocked off or fall off during reflow?

I am looking at reflow ovens. A lot of them have a metal conveyor belt the boards sit on. On a double sided board, when you put the board on the metal belt, won't the metal belt knock components off ...
SA_A30's user avatar
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Re-reflow of older car radio's PCB

I have a 2006 Jeep WK/H REC/REJ, depending on region, the screen of which has ceased to function. It has been suggested to me that reflowing the Nav board (only accessible PCB in the unit) may - at ...
VibratingBird's user avatar
11 votes
1 answer
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Do electrolytic capacitors lose lifetime during soldering in reflow oven?

Electrolytic capacitors service time is based on maximum operating temperature, among other things. When they are inside an SMD soldering oven, the temperature increases to over 375°C. Most of the ...
Sadat Rafi's user avatar
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4 votes
1 answer
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SMT Reflow solder quality issue with SN42/BI58 paste

I have been doing hardware design and PCBA prototyping for a while and I have issues with quality of reflow soldering. I have a small lab including a pick'n'place machine, stencil printer (eC-stencil-...
D_Dog's user avatar
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3 answers
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How are surface-mount parts held in place for hot air soldering?

I've found myself having to solder a bunch of XGL6060 and XGL4040 inductors lately, which have to be reflowed as there's no way to get a soldering iron to the pads underneath the chips. I don't have a ...
Hearth's user avatar
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Solder reflow pure nickel strip to PCB ENIG pads

I've arranged for a custom shaped strip of pure nickel that I intend to solder to ENIG pads on a PCB using reflow/paste. Will we have problems getting the solder to adhere to the nickel? Is there a ...
Dan's user avatar
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SMD pad size for custom component

I'm trying to reflow a custom shaped strip onto a PCB, but I'm unsure about what size pad I need on the PCB. The strip is 13mm x 6mm x 0.3mm. The PCB surface finish is ENIG. The pad is likely to be ...
Dan's user avatar
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1 vote
2 answers
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Reflowing circular, non-BGA pads

I ordered this IC and a corresponding test PCB: From the drawing pad lettering I was expecting a BGA device with balls, and my test PCB has pads matching the size of the pads on the IC (as ...
user1850479's user avatar
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Type of tray to use to bake integrated circuits in DIY reflow oven

I just recently started getting into surface mount components with a Controleo3 reflow oven. I usually buy extra components for projects I build, and end up with extra integrated circuits that have ...
buchankn's user avatar
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BGA reballing and reflowing, how to actually repair dead GPU chips?

To my understanding BGA reflowing is a technique which aims to reconnect bad solder joints on a BGA chip, BGA reballing is a technique to desolder and then resolder a BGA chip both aim to do the same ...
icyli2's user avatar
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1 answer
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Mini reflow oven advice

Hey all I am venturing into making a DIY reflow oven. Been looking at many different types/styles over the last couple of years and feel now is a good time to start one. I originally planned on ...
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Is 35g/in^2 a good "rule" to use for upside down reflow surface tension?

I have one assembler that gave me their "rule" of 35g/in^2 for reflow parts falling off upside down or successfully hanging on. Are there any sources that point to this being any more than ...
mint branch conditioner's user avatar
2 votes
3 answers
810 views

How do I get pin headers to reflow flat to the board?

I work for a small company as an apprentice. We build mostly mass produce double sided PCBs. We are having trouble keeping the pin headers flat to the PCB through the reflow oven process. The first ...
Korb's user avatar
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2 votes
2 answers
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Reflow temperatures vs chip removing temperature

Is "Reflow Temperature" the same as "Chip Removing Temperature"? It says lead free solders melt at 250C. I tried to remove a chip at this temperature and heated it for 30 minutes ...
Mb B's user avatar
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Flux to lower solder ball melting point

Is there any such flux? I find the balls on BGAs very hard on my home made oven. From what I gather, mixing up solder types in order to lower the melting point is not the best idea, especially when ...
kellogs's user avatar
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16 votes
4 answers
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Can leaded BGA chips be reflow soldered with lead-free process?

We have a board with two BGA chips. Due to the current shortage of many parts, one of the chips is next-to-impossible to find; except that we found a supplier with a good stock of the non-RoHS / ...
Cal-linux's user avatar
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How many times FR4 can be put under a reflow process?

I have a board with several designs, one component did not arrive so half of the PCB cannot be fabricated. In order not to waste time I would like to manufacture the designs that can be done but I don'...
Smart_Celery's user avatar
4 votes
2 answers
347 views

Re-reflow SMT boards

A SMT supplier messed up the reflow process of several PCB, though I have to urgently ship. As seen on the picture, the reflow temperature was too low and thus the solder did not properly flow on some ...
Damien's user avatar
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Determining reflow oven temperature wave and best practices

I am new to reflow soldering and am wondering the general approach for determining reflow wave setpoints. The solder paste I am using is MG chemicals data sheet and am using several decently ...
Feynman137's user avatar
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1 vote
2 answers
245 views

Do I need to re-reflow this board?

I had given a few boards for manufacturing and this is how they’ve come back from the fab. Do I need to reflow these again? Would it be safe to do so? I checked and the pins are not shorted but what ...
user3418620's user avatar
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1 vote
0 answers
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Do I need to alter my reflow profile for a PCB with thicker copper?

I have always been working with pretty standard 1 oz. copper PCBs and using a Controleo3 reflow oven with great success. However I am now working on boards that will potentially have 3oz or 4oz copper ...
VanGo's user avatar
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1 vote
1 answer
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what is the pitch for vssop-8?

I recently took on a personal project that requires a vssop-8 chip:ADC081C021. In order to help me solder the pins on the pcb, I ordered a vssop-8 stencil online. But when it arrived, I found the ...
user1402154's user avatar
1 vote
1 answer
636 views

Reflow with Heat Gun - WLCSP

I need to solder a WLCSP chip (FAN3852) to a DIP breakout board. Since the WLCSP chip already has tiny solder balls, would it be possible to hold the chip in place on the breakout board with tape and ...
Joel's user avatar
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1 vote
0 answers
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Can I expect a solderpaste circle to reliably reflow onto a smaller circlular pad?

For various reasons, I need to pad a bit more solder paste onto a fixed-size pad, and I cannot change the stencil thickness without messing up other footprints. The pad is a 1.2mm diameter circle, and ...
Conor Patrick's user avatar
3 votes
1 answer
174 views

Connection problems or burned chip?

I am assembling a board for a wireless charger based on this evaluation module (see here) I own a preheat bed, a hot air gun and a quality soldering iron. I am afraid that after soldering the chip and ...
bem22's user avatar
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1 vote
1 answer
461 views

Which type of surface finish to use for low-temperature SMD soldering?

I have designed a two-sided (components on both side) 4-layer SMD PCB that I will reflow with my solder oven. To do so, I am planning to use high-temperature leaded solder (MG Chemicals 4860P, ~250 C) ...
Swapnil Saha's user avatar
3 votes
2 answers
2k views

Going over IC max temp in reflow oven?

I'm a beginner-ish in PCB making and I want my workflow to be faster by using an oven instead of doing all the solder by hand. I searched for few hours without answer to my question. A low temperature ...
s.1.618's user avatar
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1 vote
0 answers
2k views

Repairing an SSD using a soldering iron vs oven reflow?

I'm trying to recover data from a cheap kingspec ssd that stopped working some months ago. It is not recognized by the computer at all. I get some messages saying the computer is trying to connect to ...
Meruje's user avatar
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2 votes
1 answer
290 views

BGA VCC and VSS shorted after desoldering

I am really confused with working with BGA chips. I am new to this but have been following other guides so I thought I should give it a try. I am using a DIY pre heater that has a 800watt IR bottom ...
speedstr's user avatar
2 votes
1 answer
108 views

Do I need to Reduce the Width of a Power Trace for Thermal Relief When it's Passing Through a Pin on the Chip?

I'm routing a PCB. Currently, all power traces are 20 mils. A QFP chip on the board requires multiple voltage rails to operate, I found the easiest solution is passing a power trace through a pin on ...
比尔盖子's user avatar
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0 votes
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Desoldering SMT components with a reflow oven

I'm wondering if it's possible to desolder all smd components on a PCB using a reflow oven? My plan is to hang the PCB upside down over a piece of aluminum foil, use a standard reflow profile and let ...
Jon's user avatar
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-1 votes
1 answer
168 views

SMD reflow oven baseplate material

I’m (for fun and hobby projects) making a DIY reflow oven (box, not conveyor) based on resisting heating elements and convection. I initially used a base to hold PCB made of steel wire, but that ...
Alexey Kamenskiy's user avatar
1 vote
1 answer
227 views

Should I apply soldermask over SMT thermal pads?

On page 8 and 9 of the following datasheet, there's a description of thermal pads for this MOSFET: https://www.vishay.com/docs/63302/si2342ds.pdf What I am wondering is: I will design the footprint ...
Spatial Effects's user avatar
4 votes
1 answer
522 views

How to solder large smd components on a PCB with 2oz copper

I’ve got a large inductor that needs to be soldered to my board. The pads are hidden underneath the component so hand soldering is not an option. The data sheet says to reflow at 260c for 40 seconds ...
Ryan's user avatar
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0 votes
2 answers
3k views

Reflow Soldering at home

I’m trying to solder my TSSOP-16 chip to the DIP adapter. I’m planning to apply solder paste to the adapter’s pads, put the chip on the adapter and then use my kitchen oven to melt solder paste and ...
beginner's user avatar
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9 votes
8 answers
3k views

Assembly of PCBs containing a mix of SMT and thru-hole parts?

I have a batch of beta PCBs which we have to assemble in our lab. We have an APS manual pick-and-place machine and a tabletop reflow oven so I thought assembly tomorrow would be easy and straight ...
Doug12745's user avatar
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3 votes
4 answers
2k views

Solder bridging when reflowing QFP

Today I attempted to reflow solder a board using a solder paste mask and a hot air station but for a QFP chip, I got a of solder bridging. This has generally been my experience with trying to solder ...
Emil Eriksson's user avatar
4 votes
1 answer
182 views

Small DFN chips come out twisted from the oven

This is a 2 x 2 mm chip with 12 no lead contact points. Half of the time I get it out of the reflow oven, it's twisted like in the image below. I am using a stencil in order to lay the paste down and ...
kellogs's user avatar
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2 votes
1 answer
107 views

Can a castellated PCB/module have electrolytic capacitors in it?

We're designing a small module (3in x 3in) that will have castellations on the edges for connection. I just watched a video on castellation PCB design. The video talked about the module going thru ...
Rodo's user avatar
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