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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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 ...
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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 ...
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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 ...
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2 votes
3 answers
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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 ...
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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 ...
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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 ...
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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 / ...
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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'...
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4 votes
2 answers
314 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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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3 votes
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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 ...
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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) ...
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2 votes
2 answers
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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 ...
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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 ...
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1 answer
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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 ...
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1 vote
1 answer
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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9 votes
8 answers
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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 ...
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1 vote
2 answers
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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 ...
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4 votes
1 answer
145 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 ...
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2 votes
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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 ...
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Causes of burning solder paste

I’ve recently acquired a modified T962A reflow oven and have been experimenting with profiles. I’ve had to really ramp up the peak temperature and time at peak temperature to even have any chance at ...
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Reflow soldering, pin longer than pad?

I was designing the footprint for this FPC connector: Datasheet The recommended land pattern is shown here: The issue I encountered is that the pins on one side protrude outside of the pad: I ...
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4 votes
1 answer
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When I rework an SMD capacitor or resistor, it will sometimes stick to the soldering tip. Does this high temp then destroy it?

When I rework 0402 capacitors, then often stick to the tip of the soldering iron. My iron is set at 350. I then discard the cap because I am worried the sustained temp for a few seconds has destroyed ...
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5 votes
1 answer
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Do SMD resistors have to be reflowed black side up, or is black side down okay?

I reflow my own boards in a toaster oven. When I drop my resistors off the paper tape, I always flip them over to black side up before I place them. Should I bother if it doesn't really matter?
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1 vote
2 answers
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Burned PCB with reflow soldering

I made a homemade reflow oven and used it for the first time to solder a board. As you can see in the image below, I botched the job and burned the solder connections (not surprisingly, the board does ...
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reflow oven issues with RO4003 PCB

Im trying to reflow some RF pcbs in a legit reflow oven. The PCBs material is "Rogers RO4003 305 Um" and 3 layer. (Its a very thin pcb) If temperature is high enough to reflow the paste, the pcb ...
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3 answers
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Makeshift SMT Station. Any suggestions? [closed]

I am trying to do some surface mount soldering for my project and have hit a few snags. My hot air gun works perfectly fine for most of the PCBs I am making but one type in particular is problematic....
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1 answer
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How to prevent a low duty cycle load from flickering lights

This is a follow up question to this: Alternatives to Large Transformer or PSU for Driving DC Heater I've hooked up 120v AC to a zero crossing SSR and a 3.2 ohm resistive load. To get my desired ...
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Alternatives to Large Transformer or PSU for Driving DC Heater

I have a 3D printer heated bed, instead of 3d printing I want to use it for reflow soldering. The bed is intended to operate at 70c, using 12v or 24v. It can be wired in series or parallel depending ...
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1 vote
1 answer
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Transitioning to lead-free reflow and soldering

I have recently been thinking about moving to a lead-free process for my production and though I've been reading up, I was hoping someone more knowledgable than me would be able to point me in the ...
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6 votes
1 answer
644 views

Rule of thumb for surface tension when placing components on the secondary side of a board

I've been working on my first multi-layer PCB design, and have been placing a variety of components on the secondary side of the board (mostly decoupling capacitors and QFN ICs). However, some of ...
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3 votes
3 answers
303 views

SMD solder failure due to probing? How to solve it?

I was visually inspecting a board that had functional problems, and I have noticed a strange pattern in the pads surrounding the IC. Upon electrical inspection, there are two pads that are shorted ...
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3 votes
1 answer
381 views

LEDs lighting up while being baked inside a reflow oven

This is a board with 80 3535 LEDs on it just after completing the reflow cycle in my home-made reflow oven. Why are the bottom corner LEDs lit up? Rather, how is this happening?
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exploding cartridge heater

I bought this cartridge heater for my reflow oven. Since this was rated for 220VAC I connected it to my mains through an SSR which is in turn controlled by the reflow oven firmware. The firmware goes ...
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2 votes
1 answer
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Should I spray some flux on my board before putting it in the reflow oven?

I am using Tin-Lead solderpaste to make my prototype circuits. This is the exact solder paste: ALPHA OM-5100 (https://alphaassembly.com/Products/Solder-Paste/OM-5100)     ...
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10 votes
1 answer
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Can you program a surface mount IC with flash memory and then reflow solder them?

I know that many chips, such as the ATMEGA328P-AU list flash storage lifetimes at certain temperatures, but they usually cap out at 100° C. I know that, ideally, one should include leads on their ...
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2 votes
2 answers
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Baking SMD integrated circuits for prolong time

I recieved samples of AD7175-2 and AD5684R with an instruction: If these samples are to be subjected to solder reflow or high temperature process, they must be baked for 24 hours at 125°C prior ...
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1 vote
0 answers
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FR-4 discoloring in reflow oven

Is it normal for exposed (no solder mask) FR-4 to blacken during reflow? We're using a fairly ordinary profile with a max at 233C, about 5 minutes total and only about 60 seconds above 200C. I ...
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7 votes
5 answers
11k views

Using a home oven for solder paste

I'm doing a project and I have a PCB which needs surface mount components attaching to it. One component has already been attached, and I have some 138deg solder paste in a syringe. This is possibly ...
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