Electrical Engineering

Questions tagged [solder-paste]

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Solder paste is used to connect smd's to the lands on the pcb.

54 questions
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2answers
165 views

How do i solder qfn package using soldering iron?

I don't have any soldering station but I need to solder the qfn package chip so how I solder it using a normal soldering iron.
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2answers
120 views

LGA parts and hot air soldering

Does the solder pattern on these huge pads indicate what might be going on ? The parts would not work about 80% - 90% of the time. I am trying to follow the ramp_up-soak-reflow-ramp_down curve to ...
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2answers
1k views

Double-sided Assembly

I'm going to assemble a prototype PCB which have components on both sides. I have access to a reflow oven with profiling control, solder paste and stencils (from OSH-Park) In the reflow process for ...
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2answers
178 views

Is the solder paste file necessary for through-hole components?

I have designed a PCB. There are only through hole components on the top layer, and only surface mount components on the bottom layer. Is TOP SOLDER PASTE file necessary to send to the PCB fabricator,...
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1answer
110 views

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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1answer
53 views

Solder Pad and Stencil Mask Data Sheet - Confused

I am using Autodesk Eagle. Need to create a footprint for CREE LED XHBAWT which is in the XLAMP XH-B series. I do not understand the Datasheet drawing of the footprint, attached. Are the lower views ...
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2answers
1k views

Can aluminum solder paste be used in electronic circuits?

Is a paste like Solder-It Aluminum Solder Paste ALP-21 suited for electronics? Are there going to be any issues with the solder under constant current due to chemicals in the paste or something like ...
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2answers
98 views

Solder paste stencil

I am ordering the stencils and I do not know if I shuld order .12 o .1 ones. There are some TQFP64 ISs and 0603 passive elements. I'd like to avoid bridges. Thank you Peter
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2answers
1k views

Thermal Paste on Cold Side of Peltier Freezing and not transferring “Heat”, what gives?

I am running a peltier element, and on the cold side an aluminum heat sink to effectively spread out the cool surface to the maximum possible surface area. I just bought this new thermal paste: ...
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0answers
104 views

Assemble a 9 * 9 * 0.05 mm steel foil and castellation PCB using standard pick and place

I have a hybrid PCB where I want to assemble a very thin steel foil on a PCB using standard pick and place SMT process. the picture below describe how the foil is like: The orange area is only hold ...
2
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1answer
621 views

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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1answer
410 views

How to clean solder paste needles?

I am looking for a good method to clean used solder paste needles immediately after usage. I know they are for one time use, but at this moment I have to clean the needles. Currently, I clean them in ...
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2answers
1k views

using plumber's copper solder as a “solder paste” for SMD components

Can I ? :D It is what I currently have plenty of lying around and, well... it says S-Sn97-Cu3 at composition If not, could I use regular solder wire, coat the SMT ...
1
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1answer
399 views

Is there any risk in storing solder paste and flux in living space?

I have solder paste and flux that I regularly use. A lot of times I keep them in my drawer. The solder paste go dry and flux leaks out from the syringe. I have not thought about health risks ...
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9answers
6k views

Is it important to file a new soldering iron tip before tinning?

I bought a cheap soldering iron. After reading articles and watching videos, I learnt that cheap irons get their resistor burnt easily. And many a times the iron becomes black as soon as you start ...
3
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1answer
258 views

Should mounting holes have solder bumps?

There are many discussions on if mounting holes should be plated or if they should include vias. This is not asking about those issues. I've seen suggestions to add solder to the annular ring on the ...
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5answers
5k 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 ...
4
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2answers
371 views

Good practice when designing a PCB and stencil?

While I generally use nothing smaller that SOIC chips or 0603 passive components, I have to design a PCB with a WSON-14 IC with tiny 0.5mm pin spacing and with an exposed pad. While I generally use a ...
0
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1answer
118 views

Solder paste for stencil

I'm going to solder a small pcb with reflow process and I'd like to use a stencil for that because the components are too tiny for hand soldering iron. The pcb has a QFN32 (0.5mm pitch and exposed pad)...
3
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2answers
625 views

Applying solder paste through stencil and with a machine dispenser

I am trying to apply soldering paste to a PCB using stencil but I am having issues with S-PQFP-G80 package with 0.5mm pitch. Whenever I try to apply the paste through the stencil I end up with paste ...
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2answers
810 views

Should I refrigerate solder paste?

I have a syringe of solder paste that is leaded, no clean. I've had it a while and don't use it very often. But I usually keep it in the refrigerator. Is that necessary? Or, can I just leave it my ...
4
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1answer
893 views

BGA package, should I add some solder paste?

I've found that BGA balls actually melt. I've read that some say that it's advised to add some paste, some say to add flux and some say just to put the chip in place. At the hobbiest level, without ...
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3answers
2k views

Solder paste not wetting at all

I have an issue with solder paste, I would like to know its origin so I can fix the problem and solder by components properly. I use a lead free Sn42/Bi57.6/Ag0.4 solder paste, manufactured by ...
0
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1answer
895 views

Altium - How to Convey Pin-In-Paste Technology in Design

I am working on the first board design I've done with a connector that requires pin-in-paste (aka. "paste-in-hole") soldering. We are trying to expedite the manufacturing process so we are leaning ...
4
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1answer
2k views

How to Clean Solder Stencils?

I have had great success in the past using the reflow soldering method, using a syringe and needle to apply the paste to the board. However, I found myself repeatedly making the same boards so I ...
3
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1answer
64 views

Solder balls and routing out of pad corners

I was approached the other day by a co-worker who claims he avoided routing out of corners of smd pads due to higher odds of solder balls forming. I have so far been under the impression that it is ...
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3answers
3k views

Preparing solder paste for syringe-style dispenser

I've been hand soldering SMD components for years and recently decided to buy a cheap solder paste dispenser hooked up to an air compressor. One of these with a 30cc syringe: I don't know much ...
6
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2answers
2k views

How to avoid solder bridges between LGA-16 pads (paste applied manually)?

I made a breakout board for an LGA-16 part (LIS3DH) and two attempts at soldering failed with a solder bridge between two pads. Top view of the PCB: The land pattern was created according to ST's ...
3
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2answers
299 views

Low Melting Point solder paste reflow profile adviced

I've found a low temp solder paste with a melting point of 140°C. I want to use it with some SMD parts. I've looked for some reflow profiles and didn't found nothing with this low melting point. Can ...
0
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1answer
461 views

Does a PCB circuit work without soldering the paste?

So the case is simple. I have to tune a Pi antenna matching network (a simple LC filter). That means I have to place and unplace a couple of pasives back and forth until I find out the right pair of ...
0
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1answer
195 views

Who is responsible for panelizing solder paste layers?

When creating small PCBs, it is often convenient to panelize them for higher volume production. In my package of gerber files, I include all the layers for one image, and then include a PDF detailing ...
5
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2answers
472 views

Potential pitfalls/caveats for developing a stencil for solder reflow

I'm developing a project that requires ICs that are in a QFN package, some have a slug on the bottom of the IC. Since these are QFNs, I'm not interested in hand soldering these; so I'm leaning toward ...
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2answers
205 views

Soldering problem when changing component on tablet board [closed]

I needed to change demaged Schottky SMD diode (2.2x1.2mm) at chineese tablet board. But I was not able to melt solder even I used hot gun at 400°C or soldering tip at 480°C. Finally I more or less "...
3
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2answers
3k views

Consequences of mixing lead and lead-free alloys when soldering

Would it be a problem to use a lead solder paste to solder lead-free BGA package parts? Are there contamination/compatibility issues? Does it affect the physical connection integrity between the board-...
2
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2answers
1k views

Consequences of not following reflow profile

I found many questions about how to perform reflow soldering, but my main concern is What are the consequences of not following the recommended reflow profile. Would there be any risk going the ...
3
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4answers
9k views

How to make a solder paste more liquid-like

I recently purchased Kester EP256 solder paste. This is the first time I am working with it, and placing it on the PCB is very difficult. I do not know how viscous it should be, but it seems to be too ...
2
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2answers
114 views

Fattening metallic ends of jump wires

I am trying to fit a umo wire into a ac power transformer. Turns out the jumper wire is just a little too thin. Any practical ideas on how to fatten them? I considered dipping them into molten solder....
1
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1answer
190 views

Is it possible to hand solder a component with a peak temp of 250 C?

I'm trying to mount an RF module that has 33 edge castellation pins. The data sheet says that the peak temperature is 250°C. I'm using 60/40 lead solder for a lower melting point but the solder will ...
4
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1answer
569 views

How to apply solder paste with stencil in a 2 sided PCB?

I have seen lots of tutorials about how to apply solder paste using a stencil, but all of them only show how to apply the stencil to one side of the PCB. My current project is 2 sided and I would like ...
3
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1answer
788 views

Is there a pitch limit to applying solder paste through a PCB stencil by hand?

I've ordered two stencils from two different companies, two different materials. Both times I've been completely unable to effectively apply solder paste to the pads of a QFP-64. I end up with a mess ...
0
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1answer
74 views

Double sided board w/ d2paks, solder paste?

Can you use paste on a double-sided board w/ d2paks on both sides? There is a small area below the tab but it seems like not really enough room for paste. If not, then how the heck do you do a double ...
6
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1answer
254 views

Non-wet open solder fault on the same ball of two different devices of the same part?

Sophisticated PCBA, with a DM6446 using two 16 bits DDR2 devices to implement a 32 bit memory space. On some boards, we see a stuck bit on either bit 24 or bit 8, which map to the same BGA ball (C8) ...
3
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1answer
1k views

Sane default for Altium pastemask expansion?

I am rather new to layout work. I am asking this question to sanity check that: The pastemask expansion is supposed to be negative (paste area smaller than the pad), right? My vendor said to use "0....
2
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0answers
605 views

Solder paste issues

I am using the smallest sized readily available lead paste I could find (15-25 micron size) and printing using a metal stencil with the smallest pitch being .5mm pitch qfns. Reflow is with a SMTmax ...
3
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5answers
2k views

Why not reflow a PCB before placing parts?

A standard reflow method for low-volume assembly is: Method A Apply solder paste (using stencil or syringe) Hand-place parts (using vacuum pickup pen or tweezers) Oven reflow - But what happens if ...
14
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1answer
26k views

Solder Mask and Cream in Eagle

I've got this part specification for the Paste Mask excerpted from the datasheet: There's a lot of lingo in this short paragraph that I would like to better understand conceptually. Specifically I ...
32
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4answers
78k views

Solder does not stick to tip of soldering iron?

Basic question here, but it's driving me insane! The solder does not seem to stick to the tip of my soldering iron. After the iron heats up, the tip appears black (sometimes on all sides and ...
6
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3answers
522 views

An idea for well-aligned component placement during PCB assembly

(Note: This question is in particular for low-volume self/manual assembly, i.e., without automatic pick and place machine). Generally, stencils are used for well-aligned application of solder paste ...
9
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1answer
1k views

Soldering 0.5mm pitch ICs using stencil and reflow oven

I'm new to SMD soldering, and tried to assemble a couple of boards, using a reflow oven. I 'm using a stencil (Kapton - mylar) and so far it worked fine except for the LQFP48 devices (pitch 0.5mm). In ...
14
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4answers
9k views

Questions on mass-production soldering

Wave soldering I am trying to understand how wave soldering works. Unfortunately the Wikipedia article has has left me unsure about the process: Is the entire board with its components quasi-...

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