Improving a T-962A Reflow Oven Part6

[@martyjohnston700]

Amazing how a different perspective can have huge impacts, on this project, we really have to think inside the box. Awesome work, I hope you keep sharing and teaching. Limited budget and after all the reviews read, I purchased and was expecting to firmware upgrade. Unboxed, quick inspection of the model, short test with just paste on a bits of foil, I thought the profiles were manageable for a small board, find the right tray location, I am happy for the cost outlay, bargain really. I feel like I made the right choice for my hobby. Investing in this questionable Reflow Oven, with small manageable modifications, without risk. The potential for my hobby to expand has increased.

[@freznelite]

Thanks for the tips. I am impressed with the level of dedication you gave to making this unruly contraption work. Without your suggested modifications, I don't know how you could depend on one of these ovens. I added a recirculation fan and wires beneath the heating elements on my T-962 (the smaller oven). Baffles were preinstalled in the rear so I did not need to perform this step. The upgrades kept the temperature spread under 20 deg C during ramp up and less than 10 deg C at the peak. I reprogrammed with Unified Engineering's T-962 controller firmware, which allowed me to calibrate the thermocouple offsets and achieve higher accuracy (40 deg C during heating). I tried a lot of different positions in the board, but it was very sensitive and seemed to wildly diverge with even small changes in position. Instead, I added a tiny bit of Kapton tape to the ends of the thermocouple probes to increase the amount of radiant heat they receive. This seemed to significantly improve their accuracy at peak temperatures and reduced their sensitivity to position. The Kapton tape reduced the temperature difference between the probes and the PCB to

[@joyztik]

Thank you Jerry. I know many were waiting for this video for ages, myself included.

[@Difool80]

Hi Jerry, Many thanks for these very detailled explanations !

[@johnleclair663]

Great video ! I have been looking forward to this last installment. After watching your series, I created a temperature test board with 8 thermocouple tips laid out like yours, and designed an arduino board with eight MAX31855 ICs to acquire the data . I calibrated all channels using a single NIST Digital thermometer. The MAX aren’t super precise, but after calibration and with your extensive analysis and modifications I should be able to come close to duplicating your oven results. Although, I am still baffled at how the bananas were produced. Thanks again for this video series. I hope to run some boards containing large FPGA BGAs through soon.

[@JerryWalker001]

Yes the bananas are a mystery, They are supposed to be apples. Please let me know how you get on with the BGA's (You may need to preheat the boards as the oven does not have an underside heater).

[@danarobotmaker3396]

John, how did it work out? I'm right where you where in 6 months ago. I wanted to test the base unit first with a few probes on one small PCB near each other. This to eliminate a probe issue. The PCB was behind the screen displayed profile F1 by over a minute. It did seem to track the profile, somewhat. Stayed at peak temperature much longer than it should have. The cooling phase is totally inadequate. Not even close to the profile.

[@jaxxmason5081]

i dont mean to be so off topic but does anybody know a trick to log back into an instagram account..? I somehow lost the password. I love any assistance you can offer me

[@jaxxmason5081]

@Boden Nathaniel I really appreciate your reply. I found the site thru google and I'm trying it out now. Seems to take a while so I will get back to you later when my account password hopefully is recovered.

[@jaxxmason5081]

@Boden Nathaniel It worked and I now got access to my account again. Im so happy! Thank you so much you saved my account :D

[@danarobotmaker3396]

Jerry, I was recording several temperature probes on a small PCB and soon realized my graph was minutes longer then the T962A display. At first suspecting the recorder I checked using a stop watch. A stop watch recorded 1:35 minutes : seconds for each T962A minute. Yikes! That is pretty bad. I'll contact the seller.

[@paulgallagher2937]

I've got a similar model to this. I found that its almost useless for any critical reflow. Even on a 100mm board, the temperature is too inconsistent. I thought about doing exactly the modification you did, the fan on top. Glad to see it actually works. I guess I need to do it now. Its a shame they don't make such a basic improvement themselves.

[@JerryWalker001]

Yes I totally agree. Even if they added the £5.00 it would cost to make the change it would be well worth it. I found the oven pretty much useless without modifying it.

[@paulgallagher2937]

@@JerryWalker001 100mm PCB, the edge of the board are burned, and the paste in the center not melted. Definitely useless as is.

[@symeonkrizias2534]

Hello Jerry,greatful for your job!!! could you please be more specific about the sensor mod., i.e. whats the length it protrudes within the chamber,same as in previous position? why we have to put it within a tube and not leave just as it was before,just moving it in its new position,as it happens to that one not moved??manythanks!

[@irgski]

Can you provide: 1) the “fan” blade dimensions 2) the motor shaft extension dimensions 3) the motor specs or possible sources Thank You!

[@Ender_Wiggin]

Could you make a playlist for this reflow oven I want to share it with some buddies

[@JerryWalker001]

Done

[@Ender_Wiggin]

@@JerryWalker001 Thank you!

[@larayronica2456]

Thanks for all the amazing research. I could use a little clarification though. You originally started with some "shadow" baffle strips under the heating elements that looked about 6-7mm wide, almost as wide as the heating elements. In this recap you described them as 1mm wire, and I think I read 0.8mm wire elsewhere. Do you mean that these very thin wires cast a sufficent "shadow" to even out the IR distribution? It ask because it hardly seems that would be much of a shadow. I'm trying to order some appropriate wire form mcmaster if thats really all you ended up using. Could you confirm the diameter of the heating elements in your particular unit as well (if it's handy)? I notice they sell this wire in matte or mirror finish. Any thoughts on that? Thanks so much.

[@JerryWalker001]

It depends entirely on how far from the heaters you fit them.The aim is to case a 'shadow' at the pcb level which is around 50% the width of the heater and is directly below the heater centre line. I suggest you draw it to scale as a cross section and use the emissive diameter of the heater as the 'source'. Note that this is not the same as the heater diameter and depends on the type of heater fitted. As a general guide use 75% of the heater diameter. The wires should be high enough so that they only affect the heater they are under and do not create secondary shadows for the other 3 heaters.

[@wescoast]

Any rough idea of what RPM the added "stirrer" fan was operating at? Trying to gauge what type/specs of motor to be looking for.

[@garyfry7813]

Great work! Thank you for sharing. Top banana!

[@snivesz32]

Would this oven be suitable for soldering mosfets that use solder filled vias for thermal management? How about BGA, because those might not heat up if they are in the shadow of the chip?

[@hazimjauhari5188]

Hi jerry. can u share with us the dimension / marking for those improvment? especially on the drawer baffle & exhaust fan baffle? regards.

[@engsam7759]

great vid many thanks , subscribed . does these modifications apply to the new T962A+

[@JerryWalker001]

I have not seen a T962A+ so do not know how it differs from the T962A. The spec states that it has air recirculation so they may have added a circulation impeller but you would need to investigate it to be sure. If not then the modifications I show would certainly help.

[@engsam7759]

@@JerryWalker001 yes and it reaches 350 degree temperature what might be worse or better . and has larger working area

[@SantanderDiogenes]

Excellent analysis and video series!! I'm wondering if placing one of the TCs in contact with a PCB would help to have a more accurate PCB temperature measurement? That would need a longer and more frexible TC cable. Also. Do you think that instead of installing the ceiling blower, it would have a similar effect by keeping the rear fan running slowly throughout the process (maybe using PWM) and ramping up to full speed when the controller needs to drop the temperature?

[@sm6fie]

Hi, I have watched all your KZbin videos about the improvement of the T-962A Reflow oven. This is a very impressive, well-illustrated and professional work. Thanks! I have now purchased a T-962 Reflow oven, the little brother to the T-962A. I want to make a warning about the device. When unpacking and testing the device and measure the voltage between the device case and the mains ground I got about 94 volt AC! After doing all the device ground modifications this voltage completely disappeared. My question to you is if you did measure the change in Cold Junction temperature when operating the device. If so how big difference did you note. Furthermore, if I understand it correctly, you never did any firmware upgrades or change the electronics. That was not necessary to get the oven to work correctly as I understand it. Can you please confirm that? Regards, Bo, SM6FIE

[@williamsteele]

Is that an upgraded model that keeps growing bananas?

[@nameredacted1242]

So, ever since Video 2 I had an independent thought right away of moving the board back and forth inside the oven to change incident angles of infrared radiation... Using stepper motors outside, pulling on wires, with wires moving the PCB inside... You said you were going to attempt that... Any results on your "conveyor" concept???

[@JerryWalker001]

I discuss this in a later video. I did try a 'conveyor' system in which I fitted a motor with a sine drive to move the board by half the spacing of the heaters to simulate a conveyor. This did improve the performance but not by enough to make it worth the complication. The simple changes I describe in the final video were sufficient to get good operation and consistent results. My goal was to get the temperature in the chamber to follow the programmed profile and also to be consistent across all areas of the chamber and the changes I describe meet this target so I did not retain the mechainical movement. If you are interested the way I did this was to fit a motor/gearbox with a cam outside the chamber in the space next to the fan at the back. Inside the chamber I fitted a sliding platform with a spring pulling it to the rear. A pushrod ran through a hole to the cam so that the drawer could be opened (The plate moved to the rear as the pushrod came off the cam). So no direct link between motor and plate. The cam gave 50% of the travel compared to the heater spacing and it rotated at 10 rpm. It worked well but was not really needed.

[@nameredacted1242]

@@JerryWalker001 Thank you for the detailed technical explanation of your attempt, and its results!!!

[@simonraybould3021]

Hi Jerry, these videos are great and I’m having the same issues with my T962A, some areas too hot and others too cold so I’m now getting the parts together to make the changes you made, mainly the baffles, stirrer motor and TC relocation. Out of interest, what spot welder did you use for this? Kind Regards, Simon.

[@jero1836]

The simpelest solution i reckon is to have your board rotating under the heaters. Probably solves the problem without all the trouble of millimeter arranging elements etc etc. My 2 cents. a commercial oven the board travels so it aint get spot heated. since you cant do that in this enclosed case so rotating may be closest you can get. Just like it does in a microwave oven :) dont even have to invent the wheel again, get the rotating mechanism of a dumpster one.

[@JerryWalker001]

Unfortunately that would not work. Yes commercial ovens have conveyors but that is not the same as rotating under linear IR heaters. I did try this to see the effect but it was hopeless and gave very poor results. You also then have the problem of having a moving platform in the hot area and the resulting loss in effective capacity. For example the board I used would not be able to rotate as the diagonal size is greater than the width of the chamber. Also the heaters do not heat to the ends . The centre of a rotating board would be subject to very different conditions to the outer edges. Overall the solution I describe is very easy to implement and does not require precision parts and gives very good results. You are of course free to modify your own oven in whatever way you choose. If you can get a rotating system to work then posting a video of the result may help others.

[@JacobChrist]

I think my oven is broken, I don't get bananas when I open it.

[@colydeane]

Another great video, thank you. Are you interested in making a video on how to improve a cheap eBay signal generator? i.e. Signal Generator Module DIY Kit Sine/Triangle/Square Wave 1Hz-1MHz

[@JerryWalker001]

Do you have a link to it?

[@colydeane]

@@JerryWalker001 This is the one I bought but my guess is they're all the same and all use the fake XR2206 www.ebay.co.uk/itm/UK-Signal-Generator-Module-DIY-Kit-Sine-Triangle-Square-Wave-1Hz-1MHz-Frequency/383610825951?hash=item5950fcacdf:g:Kw8AAOSw7P1e-bNN

[@alo1236546]

Anyone try air fryer

[@nameredacted1242]

So, I am DYING to know: you spent months trying to tune this crap of a product (design-wise and build-wise)), you have lots of toys (=you have some funds), and you seem to have the space from your business. Why in the world would you NOT go for the T960 reflow conveyor oven instead of this tabletop unit???

[@JerryWalker001]

I have the resources to carry out this investigation and in my business I do not need a desktop oven at all. I make these videos to try to help those that maybe do not have access to more expensive equipment but still need a working unit. My goal way to attempt to provide some simple and low cost modifications that anyone could apply to these cheap ovens so that they would have a useable oven. If my advice was 'buy a more expensive oven' then I do not think that would have been quite as useful.

[@nameredacted1242]

@@JerryWalker001 No major disagreement. Good work!