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Topic: Qinsi QS-5100 IR Reflow Oven Manual in PDF (Read 23517 times) previous topic - next topic

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #15
Hi Ian -

Thank you for the info and YouTube video on QS-5100 reflow oven.  I was wondering if you could comment on your experience with using the QS-5100 with any BGA parts?  Any helpful tips / techniques for reflowing these parts? 

You also mentioned that the reflow profiles that you use now are different than what is recommended in the manual.  Could you you share what profiles that you use (and the specific solder paste).  Thanks for all your help!

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #16
Hi -

I just purchased a Qinsi QS-5128 the other day, the 1200W four tube one, and I'm having a few problems with it.

No matter what profile I seem to use I either brown the silkscreen or the paste doesn't melt properly.

I've tried two different pastes:

 - Lead Free: SAC305 NC257-2 http://www.aimsolder.com.au/index.php/s ... lder-paste
 - Leaded Paste: Sn63 NC254 http://www.aimsolder.com.au/index.php/s ... lder-paste
 
These should be high quality pastes, so I'm not expecting any problems with the pastes.

If anyone has any ideas of some good profiles I'd be really keen to hear (for any Qinsi oven) - at the moment I feel like I'm just banging my head against a wall.

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #17
An update to my adventures yesterday.

The best I seem to be able to do is the following profile:

Preheat to 150C for 60s
Heat to 198C for 120s, hold for 58s
Solder at 211C, hold for 31 seconds.
Keep to 190C
Cool to 120C

This doesn't match the solder pastes profile at all - it does seem to solder ok though.

It still leaves the silk screen a fraction brown - which I'm finding very disappointing.

The rear half of the oven (under the back two tubes) seems much hotter than the front half of the oven. I think a small fan might help with this.

I'd still be really interested to know if anyone can reflow in these ovens without "browning" the silk screen? If so what profile / tricks are you using?

Also interested if anyone has worked out a way to distribute the heat a bit more evenly.

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #18
I received my QS-5100 oven last week.  As Ian mentioned in his YouTube video, these ovens appear to be better quality than the T962 models.  I removed the top cover on my unit to inspect it and also ran some temperature tests to test its accuracy.  For their low-cost, it appears to be well built and insulated (with no masking tape inside!), and have nice control boards, fans, and sensors.

It does have one flaw that I observed when trying to baseline the temperature profiles.  The oven's thermocouple is placed right between the two IR heating elements.  The fact that the oven's controller is basing it's profile on the ambient temperature and that reading is is further influenced by the proximity to the IR heating elements make the desired profile and actual board profile very different.  You can check this by taping a thermocouple (from a multimeter) to a spare PCB and comparing the temperatures between the meter and the oven during a reflow process.  They're probably significantly off from each other.

Since reflow profiles are specified for the solder junction temperature and not ambient temperature, then the profile really needs to follow the board's temperature and not the ambient.  I ordered another thermocouple and plan to replace the oven's current one with a thermocouple that I can Kapton tape to my boards during reflow.  Hopefully this should allow for a more accurate and repeatable reflow process.

So if you're having trouble with dialing in the profiles, then I recommend getting a multimeter and thermocouple and compare the temperatures and work from what the board temperature is and not what the oven is perceiving from its ambient sensor.

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #19
Thredboguy,

I'd recommend placing a thermocouple directly on the board and paying particular attention to the Wetting stage (Reflow and Keep stages).  This is the most likely period when the boards are browning and needs to be tightly controlled.  The leaded solder paste profile indicates that the total time from 183C to 215C then back down to 183C is 60 seconds maximum.  You might try reducing the Reflow hold time (maybe to 15-20 seconds) and having Keep kick in at a higher temp (maybe 205C) to actively cool the temperature back down.  At least on my oven, the fan actively cooling is still within the 2-4 degrees C rate that is recommended for the cool down stages.

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #20
I'd agree helix I think the ovens are well built too.

Can I ask which thermocouple you purchased? I think you're idea has much merit and would be keen to give it a go too. Would love to hear how it goes.

I purchased a small fan I was going to try wacking under the unit in the hope it might help even out the temperature. I'm also contemplating buying a cartridge heater to mount under the tray. Would be extra cool if I can get it to turn on at the same time as the IR tubes. I'm thinking about this item: http://http://www.ebay.com.au/itm/Mold-Heating-Element-Cartridge-Heater-9-4-Wire-220V-200W-8mm-x-120mm-/390850245435?pt=AU_Business_Industrial_Industrial_Supply_MRO&hash=item5b007d733b

I'll also give your temperature profile suggestions a go, but probably not for a couple of weeks (very busy at the moment). I'll post back my results - success or failure!

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #21
The QS-5100 has a MAX6675 thermocouple amplifier on its control board that uses a K-Type thermocouple. It attaches to the control board via a Phoenix-style connector that allows wires to be removed/inserted via screw terminals.  I bought a cheaper set of thermocouples from Amazon for short term testing and a metal-shielded thermocouple for long-term installation.  Here are those:

Cheaper Sensors for short-term testing: (Amazon)
http://http://amzn.com/B00CQFTZ4E

Metal-shielded sensor for permanent installation: (AliExpress)
http://http://s.click.aliexpress.com/klk/zjiEmMJmA

If you are looking for something cheap as external measurement and do not have a multimeter that has temperature, then you might try this dual temperature meter:

http://http://amzn.com/B00FFYEPVQ

I received the cheap thermocouples from Amazon a few day’s ago and temporarily replaced the oven’s built-in one and attached it directly to the PCB that I was reflowing.  As expected, I could dial in the board’s reflow profile much more closely to the manufacturer’s specification and the results were accurate and repeatable.  There was some overshoot by the controller (expected), but that is easily mitigated by adjusting the temperature and time settings slightly.

I need to perform more testing, but I am pretty convinced that this will be a more accurate and repeatable method than the controller using the ambient temperature sensor.  I plan to permanently install the metal-shielded sensor into the oven once it arrives.  I’ll post more as I get a little more time and can work out the profiles some.

You might try aiming a low-output external fan (4-6 inches away) at the built-in fan opening on the back of the unit.  It seems to circulate the air in my small oven without interfering with the oven’s built-in fan.

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #22
Thanks for that info on what you're doing. I purchased some of the same shielded thermocouples and one of these too from ebay http://http://www.ebay.com.au/itm/1M-3-3ft-K-Type-Screw-Thermocouple-Temperature-Controller-0-800-Sensor-Probe-/141556343766?pt=AU_B_I_Electrical_Test_Equipment&hash=item20f56a63d6

Once they arrive I'll give them a go too - I'm enthused by your testing!

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #23
[quote author="helix"]I need to perform more testing, but I am pretty convinced that this will be a more accurate and repeatable method than the controller using the ambient temperature sensor.  I plan to permanently install the metal-shielded sensor into the oven once it arrives.[/quote]Did this modification prove worthwhile over the past few months use?

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #24
Sorry for the late reply Stryker. 

I have actually had very good success reflowing boards by placing the thermocouple directly on the PCBs.  I have consistantly been reflowing both lead and lead-free board profiles without burning boards.  I initially invested in the oven to be able to build boards with BGA parts on my designs.  I was skeptical that I would be able to, but it has been surprisingly easy to do.  I use a 100-pin 0.8 mm pitch part on one of my designs and a 256-pin 1.0mm pitch BGA on another design.  Even more amazingly, I was able place and reflow 624-pin 0.8mm iMX.6 processors on some once disfunctional boards from my workplace. I clean the BGA pads well, apply solder flux to the pads, and then carefully align the corners of the part on the board.  The flux holds the part in place and will self-align during reflow process provided that you are not off by a row of pins.

To derive my profiles, I empirically tested an average sized bare 4"x6" PCB over many cycles adjusting the ovens profile and comparing that with an independent thermocouple connected to a multimeter and then to the industry standard reflow profiles.  One thing that I noticed, was that the fan should kick on soon after the peak temperature has been reached.  The board's cooling rate is still within the recommended profile spec, but this helps prevent the board from burning.  I use "Mechanics" Solder Paste (AliExpress) for my lead solder, but have to use the lead-free solder (Sparkfun) and profile for boards with BGAs. 

For my QS-5100 w/thermocouple attached to PCB, I have the following profiles:

LEAD SOLDER PASTE PROFILE:
- - - - - - - - - - - - - - - - - - - -
PREH   140C   00:30
HEAT   175C   00:15
SLDR   212C   00:03
KEEP    212C   
COOL     70C   

LEAD-FREE SOLDER PASTE PROFILE:
- - - - - - - - - - - - - - - - - - - - - - - -
PREH   150C   00:30            
HEAT    190C     01:00
SLDR   240C    00:01
KEEP   225C   
COOL     70C

I hope this helps. 

Helix

Re: Qinsi QS-5100 IR Reflow Oven Manual in PDF

Reply #25
I know that it has been a long time since the original post and video... but hopefully this will help.

First thank you for your video.  It was super helpful.

I went through a bad patch of reflows using the oven... and I ended up switching to your profile.
preheat 150/60s
heat 180/58s
solder 210/30s
keep 180
cool 150

Last weekend I put a temperature measurement system into my oven and made a bunch of recordings. here is a plot of the data


It appears that the oven has 4 (or maybe 5) modes in the controller
1. Heater ON (seems to raise the temp at about 1.6degree/second)
2. Heat stable (do enough to keep the temperature "flat"
3. Heater off
4. Cool

For sure you can see "heat stable" during the "heat" and "solder" phase.

I wondered if maybe there is a partial mode which it uses during the preheat phase.

You can see it naturally cool after the solder finishes... then you can see the active cool as the curve bends sharply down at about 438 seconds into the reflow.


The only thing that looks like it might be a problem in the chart is the "heat" phase which is 186 degree.. .not 180... and that is above the melting point of solder which is 183... 

You can read more about it on my blog if you like http://https://iotexpert.com/2016/11/28/qinsi-qs5100-sn63pb37-solder-profile/

Anyway... I hope that is helpful.

Alan Hawse
www.iotexpert.com
@askiotexpert