Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

SMTnet
»
Electronics Forum
»
Faster Reflow?

Faster Reflow?

Subscribe to Thread

We have a PCB rework dilemma involving a reflow profile. Th... - May 13, 2021 by reworkexchange

How are you specifically reflowing the boards now? You say... - May 13, 2021 by OptoGuillermo

Thanks for the reply. We are ramping up using soldering tec... - May 14, 2021 by reworkexchange

Could you setup bga rework style machines with custom nozzle... - May 15, 2021 by RobD

What about dispensing SMT epoxy (cures at much lower tempera... - May 24, 2021 by SMTA-64387687 SMTA

With a reflow oven or BGA Rework Station I doubt you will ge... - Jun 05, 2021 by Dennis O'Donnell

100k units a year/month? that's quite alot. What exactly are... - Jun 07, 2021 by OptoGuillermo

Never mind I reread your question and realized my mistake. ... - Jun 07, 2021 by OptoGuillermo

reworkexchange

#86634

Faster Reflow? | 13 May, 2021

We have a PCB rework dilemma involving a reflow profile.

This is a SAC305/Low Solids (aka no clean) process where we are currently hand soldering (5) components that were DNP. The boards have an acrylic coating and we take off the acrylic at the part add locations.

The 5 component body types are : 0402 resistor 0402 ceramic capacitor 1812 resistor SOT 23-3 SOT 23-5

We are wanting to locally dispense solder paste and reflow. The challenge is getting the paste into reflow as fast as possible as the reflow heat cycle is 2.5X the time of other processes and is a currently the process bottleneck. Based on DOEs we have done the fastest hot air cycle time is approximately 2.5 min. One of the limiting factors is the ramp in which do not want to exceed a 3 deg C/sec ramp (It takes 75 seconds from room temp to 240 C peak) and then the TAL of 45 sec (mfg suggested) and ramp down of 30 sec makes it a 2.5 minute process at best. The question is : "How do we make this process faster?".

We have eliminated laser reflow (board damage possible), mass reflow (due to being coated) and convective reflow (not repeatable, not suitable for a robot, labor is in short supply). IR might be another option.

reply »

OptoGuillermo

#86636

Faster Reflow? | 13 May, 2021

How are you specifically reflowing the boards now?

You say convective reflow is not repeatable/suitable for a robot(which I'm not sure is true but I do not know what you mean by for a robot) but you also say that you are using "the fastest hot air cycle time"

The easiest way to overcome your bottle neck is just to add a duplicate process to what you are doing now. You will get about twice (depending on handling and some other factors) the throughput.

reply »

reworkexchange

#86650

Faster Reflow? | 14 May, 2021

Thanks for the reply.

We are ramping up using soldering techs and convective hand soldering. We have investigated w/many soldering robot vendors. The number of units is over 100K.

We will be automating using a dispense+pick and place for greater consistency and less skilled labor. Thus the reflow question.

reply »

RobD

#86652

Faster Reflow? | 15 May, 2021

Could you setup bga rework style machines with custom nozzles? Assuming your manual convection process consists of technicians with hot air pencils, and depending on part locations, this could potentially replace the manual part of that process.

reply »

SMTA-64387687

#86696

Faster Reflow? | 24 May, 2021

What about dispensing SMT epoxy (cures at much lower temperatures, than solder reflow), p+p components, run through the oven to cure, and using a laser selective solder robot to solder the pads?

This message was posted via the Electronics Forum @ SMTA SMTA

reply »

Dennis O'Donnell

#86741

Faster Reflow? | 5 June, 2021

With a reflow oven or BGA Rework Station I doubt you will get better than 2.5 minutes. Using a hot air pencil with about a 1/4" nozzle you can probably get 30 to 60 seconds depending on the density of your PCB?

reply »

OptoGuillermo

#86743

Faster Reflow? | 7 June, 2021

100k units a year/month? that's quite alot. What exactly are you making? PCBS or something else?

Is there a reason a traditional reflow oven will not work for you?

reply »

OptoGuillermo

#86744

Faster Reflow? | 7 June, 2021

Never mind I reread your question and realized my mistake.

Your best bet is just to either get more labor to rework and up your output that way or to make a custom machine that has the hot air nozzles fixtured and timed. Then load up multiple boards and run it at that same reflow rate.

Have you tried vapor phase reflow? maybe that would work with your coating?

reply »