FR-4 TG material - Page 1
Forum section: electronics / general

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 23, 2017, 08:26:01 am
content: HelloI want to order some PCBs.the PCB manufacturer said me the material is FR-4 standard. (TG130 or TG140)now my problem is:how much the maximum temperature can I use during soldering with a hot air (rework station) for such a PCB?I have some high speed ADC/DAC/Crystal OSC/ 0.8mm connectors/2.54mm male header... on my board.Thanks

author: ebclr
author_rank: Super Contributor
timestamp: December 23, 2017, 01:53:38 pm
content: http://www.surfacemountprocess.com/-pcb-delamination-during-reflow.html

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 23, 2017, 02:49:41 pm
content: Quote from: ebclr on December 23, 2017, 01:53:38 pmconsider the material is TG140 and thermal profile of a part is as shown:my board is controlled impedance to have 50 R impedance.how should I solder the part?

author: ebclr
author_rank: Super Contributor
timestamp: December 23, 2017, 02:59:54 pm
content: You need to know details of your solder paste, have many kinds, and this is a key point to decideHere somebody doing something similarhttps://youtu.be/2Z7nCAxS2Rg

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 23, 2017, 03:17:02 pm
content: Quote from: ebclr on December 23, 2017, 02:59:54 pmthe company uses FR4 (KB6160A TG130).I'm using the below solder paste:https://www.amazon.com/XG-Z40-Syringe-Solder-Paste-25-45um/dp/B077G79YRLplus I have some solder wire as below from ASAHI SOLDER company:0.3mm 63%SN(Tin), 37%PB(Lead)0.6mm0.8mm

author: ebclr
author_rank: Super Contributor
timestamp: December 23, 2017, 03:26:37 pm
content: Do you have a stencil, or will be by hand ?

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 23, 2017, 03:43:42 pm
content: Quote from: ebclr on December 23, 2017, 03:26:37 pmsoldering by my hand

author: ebclr
author_rank: Super Contributor
timestamp: December 23, 2017, 03:55:13 pm
content: Do you have a preheater ?Case not, you need to start with the hot air fair away +- 300C, +- 15 cm, and coming near to make a preheat +- 150C near the IC pads, do this until you see the flux poping out of the paste, after that coming down slowly until the solder start to melt.Another video as reference

author: vzoole
author_rank: Regular Contributor
timestamp: December 26, 2017, 01:14:50 am
content: If you have good quality PCB material you don't have to worry about reflow soldering.e.g. Eurocircuits useIsola IS 400orTechnolam NP-155Fboard (TG150) that delaminate at 260°C more than 1 hour.http://www.isola-group.com/wp-content/uploads/data-sheets/is400.pdfhttps://www.eurocircuits.com/wp-content/uploads/ec2015/ecImage/document/NP155F-D-5-2012.pdfIn case of china board the base material could be a big question and risk.

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 26, 2017, 10:01:18 pm
content: Can I uselead-freesoldering wire andlead-freesolder paste?I've heardlead-freeversion has a lower melting temperature.

author: mars01
author_rank: Contributor
timestamp: December 26, 2017, 10:11:11 pm
content: Quote from: xzswq21 on December 26, 2017, 10:01:18 pmIt's actually the other way around. Lead-Free solder paste and/or solder-wire has a much higher melting point than the leaded one.It's a pain to rework a PCB that was assembled using lead-free solder.

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 28, 2017, 10:02:02 am
content: Quote from: vzoole on December 26, 2017, 01:14:50 amare there any low price manufacturers in USA or Europe?

author: mars01
author_rank: Contributor
timestamp: December 28, 2017, 08:49:44 pm
content: Quote from: xzswq21 on December 28, 2017, 10:02:02 amIt depends on how you define "low price" and what are your requirements for the PCB. If your design has blind/buried vias, drills under 0.3mm, impedance control, more than 4 layers and so on, then even in China price per dm2 is going up quite fast.

author: xzswq21
author_rank: Frequent Contributor
timestamp: December 28, 2017, 09:07:34 pm
content: Quote from: mars01 on December 28, 2017, 08:49:44 pmthe minimum trace is 8 milclearance is 8 mil4 layers12/20 mils vias0.3mm holesimpedance control for the high speed ADC's LVDS Busbut the board size is 10x10cm

author: mars01
author_rank: Contributor
timestamp: December 29, 2017, 10:55:28 pm
content: There is a company in Bulgaria who do cheap PCB's (and the price for components is the best I could find in EU: actually the prices for passive are sometimes better than China and from good manufacturers, too). It's called Comet Electronics.http://www.comet.bg/?cid=92They do not do BGA's so for our need we ended up doing the PCB's for prototypes with EuroCircuits. But EuroCircuits might not fit in your idea of cheap.

author: asmi
author_rank: Super Contributor
timestamp: January 07, 2018, 07:48:13 pm
content: If you plan to do a reflow (even 2 reflows for double-sided placement of parts) as a primary soldering method (some manual soldering of thru-hole parts are OK), in my experience even cheapest Tg130 FR4 is going to be just fine for lead-free profiles. As long as you don't overheat your board, internal structure (and thus trace impedance) will not be affected much my soldering, but I strongly advise against manual soldering unless it's absolutely necessary (like for thru-hole connectors). And when you do manual soldering, always leave enough time for things to coll down between repeated heating.But again, unless you absolutely have to use lead-free process, I'd suggest you to stick to leaded one as it's much more forgiving and has lower melting point. Now - there is Bismuth-based low-temperature lead-free paste, but as far as I understand it is not recommended to be used for production - only for prototyping or repair/rework. It's also often used for non-FR-based boards some of which are very sensitive to heating.

author: xzswq21
author_rank: Frequent Contributor
timestamp: January 07, 2018, 10:29:03 pm
content: Quote from: asmi on January 07, 2018, 07:48:13 pmDearwhat do you mean "manual soldering"? I don't have any "pick up & place" machines.on my PCB I have1600 pads! many QFN / LFCSP/ 0402 0603 0805 ... Packagesconsider I have 10 pieces of a QFN-7x7 ICs.is the below instruction right?1-I should preheat the board to 100~150'C2- soldering the first IC with an How Air within 250'C.3-now I should wait to cool down the PCB to 150'C? for other ICs I should do the same?some tracks are LVDS and impedance controlled.the material is FR-4 TG140 and the board is 4-Layers.I don't want to use a lead-free solder paste bcoz the melting point is higher than Sn63Pb37 (standard solder paste)Thanks

author: asmi
author_rank: Super Contributor
timestamp: January 07, 2018, 11:11:14 pm
content: Quote from: xzswq21 on January 07, 2018, 10:29:03 pmExactly what it sounds like - manual soldering with an iron. I don't have PnP here as well, so I place parts manually and then reflow them in the oven.Quote from: xzswq21 on January 07, 2018, 10:29:03 pmMy latest 6 layer board had similar amount of components (all kinds of sizes from big FBGA-256 down to tiny 0201 capacitors).I use stencil to print the solder paste, then I manually place all SMT parts under microscope, after than I put the board in the oven for reflow. There is no way you will get the temperature right with hot air gun - not to mention the heating will be very uneven, so recommend you either buy or build an oven.Cooling down was mentioned for manual soldering (with an iron). Most boards contain at least some thru-hole parts (usually connectors and such), so you will have to do at least some manual soldering.Quote from: xzswq21 on January 07, 2018, 10:29:03 pmThat's fine for prototypes, but remember you will need to use lead-free process for production (unless your board is a hobby/non-commercial product).

author: xzswq21
author_rank: Frequent Contributor
timestamp: January 08, 2018, 05:58:33 pm
content: Quote from: asmi on January 07, 2018, 11:11:14 pmI have many components at the both side of the PCB.could you please explain more about the oven process?I mean once I should mount the components at the top layer and put into the oven and once again I do the same for the buttom layer?how much time does it take during a oven process?Thanks

author: mars01
author_rank: Contributor
timestamp: January 08, 2018, 07:01:32 pm
content: If you have big/heavy SMD components you'll need to use glue under them such as when you flip the board for reflow on the other side, your components will not fall. If your components are small then you may get away without glue.

author: xzswq21
author_rank: Frequent Contributor
timestamp: January 08, 2018, 07:13:43 pm
content: Quote from: mars01 on January 08, 2018, 07:01:32 pmI have many 0201, 0402, 0603, 0805, 1206, 1210, QFN7x7 (ADC), LFCSP (4x4)... components,Crystal Oscillator...Actually most of my ICs have ground PAD.I don't have any special glue... but I know a thermal tape like below:

author: asmi
author_rank: Super Contributor
timestamp: January 08, 2018, 11:39:40 pm
content: Quote from: xzswq21 on January 08, 2018, 05:58:33 pmMy board has only passives on the bottom side:So I place bottom side parts first and then reflow them. Once that is done, I make standoffs using M3 screws with some nuts, and then place components on the top side (take note of screws I used to make standoffs):As you can see, the top side has many parts, so by the time I placed them all the board will long be cooled down to ambient temperature. So I wouldn't worry about that too much. Again, my comment was mostly referring to manual soldering of thru-hole parts after reflow.I don't use any glue to hold bottom parts in place during second reflow, and so far no part has came off - I had everything from tiny 0201 to quite large "type D" (size 2917 IRC) sized parts (see first photo). Surface tension of molten solder is quite strong and keeps all these parts in place.Granted, I didn't try doing the same thing with parts in BGA package - for those you will probable need some glue. More experienced colleagues will hopefully pitch in and share their experience in that area - I would love to know that as it would allow me to make my boards more compact. For now I try to avoid placing anything other than passives on the bottom side - mostly out of concern that they would fall off/move and create shorts underneath, but also because I don't want to subject sensitive (and expensive) parts to second reflow if I can help it. At the end of the day, even if some of passives would come off, I can always solder them back into place manually, but this isn't so for things like QFN, or BGA.

author: xzswq21
author_rank: Frequent Contributor
timestamp: January 31, 2018, 06:12:22 pm
content: Quote from: vzoole on December 26, 2017, 01:14:50 amQuote from: mars01 on December 29, 2017, 10:55:28 pmwhat do you think about EuroCircuits quality?I have looked many companies but EuroCircuits has a good trad-off between the price and quality and other options.most of companies like Analog devices, Linear,... have been using FR408 material, but I couldn't find any suitable manufacturer for my prototype PCB.

author: mars01
author_rank: Contributor
timestamp: February 02, 2018, 11:51:10 am
content: Quote from: xzswq21 on January 31, 2018, 06:12:22 pmIt's difficult to give you a definitive answer because your boards will have, most likely, different requirements than mine. I did 6 layers boards, ENIG, blind/buried vias, 0.3mm holes and they were OK but I had no need for controlled impedance so I can't tell how this will be.