Advice for small reflow plate?

[jmf11]

Hello,

I would like to by a cheap reflow plate, for PCBs in the 50x50 to 100x100mm range. This is mainly for prototyping.

There are several models on Aliexpress or Amazon. Are some of those "proven OK in use" than others? Some recommended model?

Or should I go to something like https://github.com/AfterEarthLTD/Solder-Reflow-Plate ?

Best regards,

JMF

[jmf11]

I have up to now 2 candidates:
- UYUE 946-1010: with a 100 x 100mm surface,
- Maechanic iX5 (smaller platform, seems 80 x 60 mm)

I don't know if the plate shall be the same size or bigger than the PCB to work on, or if one can slide the PCB over the plate to solder PCBs bigger than the plate (and what would be the best).

JMF

[thm_w]

I don't know if the plate shall be the same size or bigger than the PCB to work on, or if one can slide the PCB over the plate to solder PCBs bigger than the plate (and what would be the best)

Its best if the plate is the same size or larger than the PCB. Sliding it around can work but its wasting your time waiting for areas to heat up, uneven heat, and probably more chance it will fall off.
If you are reworking/removing parts maybe the smaller size would work, eg miniware MHP50. But I don't know, I feel like 80 or 100mm is a more appropriate size.

https://maidavale.org/blog/uyue-946-1010-hotplate-review/
https://www.reddit.com/r/flashlight/comments/rm1otz/psa_uyue_9461010_hot_plate_has_a_secret_menu_that/

[m98]

Get one of those that have the PID controller module:
https://www.amazon.de/Vorw%C3%A4rmstation-200X200mm%EF%BC%8C500W-LED-Mikrocomputer-Schwei%C3%9Fer-Heizplatte-SMD-Nacharbeitsheizung/dp/B07XY3BTC1

[jmf11]

The 200x200mm 946C is too big for my applications and storage area. But Web tests/feedbacks of the 100x100mm 946-1010 are not very encouraging.

I found several hacks to replace the controller by one allowing temperature profiles. This may not be mandatory but is industrial practice.

I'm not set yet on a model...

[selcuk]

I was looking for a similar product as well. This one got my attention due to the price for a 15 cm unit. But I couldn't find any review video about its reflow soldering performance.

BY1515 on Aliexpress

[artag]

You can slide the pcb around. I do this with the MHP30.

However, there are caveats :

1. It takes a while, and you will expose adjacent areas to heat for longer than strictly necessary. I haven't so far had a problem with this but you need to think about it.

2. It's difficult to balance the pcb on the small plate. I am using a circular pcb ~55mm diameter with ws2812 leds close to the edge. I don't expect full temperature right to the edge - especially through the pcb thickness - so I overhang the board by almost half it's width.  Moving around is also a problem - heat is conducted to the edge so you can't do it with fingers, and it's easy to accidentally knock it away with tweezers.

The optimum if you have to do this is probably to build a heat-resistant platform all around the plate to support the overhang. However it needs to be accurately set to the same height to avoid creating a gap between pcb and heater.
I have recently bought a 200mm square plate which will probably be more successful, though I will have to find out how to remove the pcb without knocking all the parts off. I assume this is a solved problem though.

The one I got was similar to the centre photo in https://www.aliexpress.com/item/1005005362421956.html but the BY1515 might have been better. Or the 100mm square plate on the left which appears to have an unheated surround.
 

[coppercone2]

why not a chemistry lab plate if you can afford it, their better built because they are meant to be used in the most harsh environments for electronics.

Great ones have a die casting and a external thermocouple instead of some shitty box


IMO its like getting a alibaba plastic box chinese power supply vs a HP

I see nice robust PCB, thick wiring, heavy chassis and good terminations inside of laboratory hot plates.

[thm_w]

IMO its like getting a alibaba plastic box chinese power supply vs a HP

Yes but OP specifically asked for cheap, and you didn't even bother to link an option.

Here is a lab hot plate that goes to 300C for $154: https://www.aliexpress.us/item/3256802486677292.html but the display thermocouple unit is $300
This one is cheaper and more watts: https://www.aliexpress.us/item/3256804743142551.html

But not clear what the hot plate is made off. Ceramic hot plates have incredibly uneven heating, regardless of price.

[coppercone2]

ebay old lab equipment with aluminum tops and give it a sanding


OP might not be aware that there are great deals to be had if you spend some time looking and researching that will pay off more then buying something from a manufacturer.

I decided not to do the equivalent of linking a top-of-the-line commercial cost factory direct keysight-type power supply, because its fairly ridiculous for a home lab

And with the really basic ones, you can PID control them like anything else to make a truly top of the line heater

[CaptainBucko]

And with the really basic ones, you can PID control them like anything else to make a truly top of the line heater

I have two of these, rescued from eWaste. I do need to work out how to PID control them, but for now, I have a table of knob positions vs temp, and its reasonably accurate.

[coppercone2]

I think I saw a project, just keep in mind if its slow like that kiln I found it just needs P.


All you do is set it to max if it has a thermostat or if its a duty cycle oscillator then put a short over ride switch to give it 100% power when on (1 extra switch).

Then you can plug it into a thermal control box thing (generic) or your own box.

The hard part I think is figuring where you put the thermocouple... but if you just have 100% maximum, for testing all it can do is over shoot. I think your challange or risk comes from potentially finding a tight wad hot plate where its not possible to put a thermocouple in the heating element. Or just make it slow enough that the board matches temperature and kapton tape it to the board for reflow



Or the precise way might be to put a aluminum plate (thick) on the hot plate with a machined channel for the thermocouple to go into. it should spread the heat nicely, but be slower to heat up. I think generally the problem is that the top plate might be too thin to spread heat evenly? This should be the equivalent of putting a big ass filter capacitor on a rectifier supply.

[thm_w]

ebay old lab equipment with aluminum tops and give it a sanding

If its old, the chance of having temperature control + digital display is very low

OP might not be aware that there are great deals to be had if you spend some time looking and researching that will pay off more then buying something from a manufacturer.

I looked and didn't see any deals.

I decided not to do the equivalent of linking a top-of-the-line commercial cost factory direct keysight-type power supply, because its fairly ridiculous for a home lab

And with the really basic ones, you can PID control them like anything else to make a truly top of the line heater

But top of the line is not relevant here, we are talking cheap. Why spend time and money adding a PID controller to some old beat up 200W lab hot plate when you can buy a premade 850W unit for $60? https://www.aliexpress.us/item/3256801916875035.html

[selcuk]

I was looking for a similar product as well. This one got my attention due to the price for a 15 cm unit. But I couldn't find any review video about its reflow soldering performance.

BY1515 on Aliexpress

I ordered this one and it came today. Part number on it is BY1510 but it looks like identical to BY1515. 15x15cm hot plate and 500W. It melted lead free solder on PCB after setting to 240 C. I will test it with populated PCBs and actual parts later.

[coppercone2]

I found a Chinese low cost lab hot plate in similar enclosure in the trash. I took it apart and promptly threw it out, it was IMO dangerous build quality.


At the very least I strongly recommend you pop the hood and take a look


mine had a bundle of point to point solder blob construction. might be marginally acceptable for a AA battery device. 

meanwhile a VWR or Thermolyne looks like it might survive a drop out of a plane

[selcuk]

I found a Chinese low cost lab hot plate in similar enclosure in the trash. I took it apart and promptly threw it out, it was IMO dangerous build quality.

At the very least I strongly recommend you pop the hood and take a look

mine had a bundle of point to point solder blob construction. might be marginally acceptable for a AA battery device. 

meanwhile a VWR or Thermolyne looks like it might survive a drop out of a plane

Thanks for the recommendation. I shared the product in "What did you buy today" topic. I received a similar warning and took an internal picture. It looks like a decent product for its price range. It has some sort of a controller board, high temperature cables and a through white paint.

https://www.eevblog.com/forum/chat/what-did-you-buy-today-post-your-latest-purchase!/msg5591537/#msg5591537

[exmadscientist]

I've never had good luck with scientific hot plates. High thermal mass, uneven surfaces, and even magnetic stirrers (liquid solder + Alloy 42 leadframes + magnets = sadness) make them poor choices. I'm not trying one again.

Ironically enough, the best results I've ever gotten have been from a kitchen electric griddle. But if you can get your hands on a "reflow toaster" converted toaster oven, they're much better still.

[coppercone2]

there is something to be said about thermal mass it is greater because they deal with boiling stuff and that means sudden drastic changes in load.

But it also means it won't suddenly decrease temperature when your solder melts. That is a phase change, and the flux evaporating. It might mean higher quality joints because its more stable... but like a toaster oven, it means it won't cool off as quick. I don't think that is bad for the solder joints, just the plastic parts might take a bigger beating.

[DaneLaw]

But not clear what the hot plate is made off. Ceramic hot plates have incredibly uneven heating, regardless of price.

The MHP30 which has a ceramic plate, seems extremely even in its heating area.. (+37 sec)




Though, more a novelty, proof of concept, and likely too small &  expensive for what it is' for most buyers.
The temp-accuracy, seems to cycle with a few degrees around the selected..
it overshoots a tad, when selected fx 200 degrees, where it will jump up to fx 205 and then dial down to 200, and then cycle around the selected.
The MHP30 display will keep informing the actual value, so when it overshoots while raising in temp, the display does show it, whereas other models (incl. soldering irons) will just show the selected when met, and not a given overshoot.
Temp 200* and 280* degrees examples.

[thm_w]

The MHP30 which has a ceramic plate, seems extremely even in its heating area.. (+37 sec)

MHP30 is either brass or copper, which does the heavy lifting.
The ceramic coating is just a thin plating, so in this case won't affect even heating.

The lab hot plates that I am talking about have thick 2-5mm layers of ceramic. Then steel or something underneath?

https://www.fishersci.ca/shop/products/corning-pc-410d-stirrer-digital-display/07770151#?keyword=

Thermal conductivity of that is like 1W/mK (aluminum is 237).

[DaneLaw]

MHP30 is either brass or copper, which does the heavy lifting.
The ceramic coating is just a thin plating, so in this case won't affect even heating.

Exactly, it's a ceramic coating that Miniware got on their hotplates and gives the best of both worlds..
It keeps the heating uniformity known from aluplates, while also giving the benefits of ceramic.