Homemade Reflow HOT Plate - Version 2 | Low Cost

hey guys so this is a low-cost reflow hot plate for smd components and as you can see is homemade and if you remember a few weeks ago i've made another reflow hot plate using a clothes iron of 3000 watts and also a solid state relay and an arduino and other components anyway that works great but it's a bit expensive it's too big for me and also has way too much power that i want and this time i'm using this heating plate here that only costs seven dollars and the rest is also very low cost because a few more dollars for the arduino the screen and the relay a few more dollars for small components such as buttons a switch a fan and some wires and the case as you can see is 3d printed and i'm sure that you wonder if the plastic goes well with a hitting plate well actually it does and i'll explain in this video have designed this case in such a way that the heat from the plate will never reach the plastic case and that is quite interesting so i will show the components that we need to make this project how to assemble everything and we'll make some tests with some pcbs so what do you think guys will this project be able to reflow my pcbs stick till the end to find out so let's get started [Music] video sponsored by pcb way look at those great gold finish pads their pcb quality is amazing and for so low prices so if you want to get your own pcb design manufacturer all you have to do is to download the gerber files from your designing platform such as ltm kitkat and so on then go to pcbway.com click the code now button and insert the board settings such as thickness size and finish then upload the gerber files and apply the order and for just five dollars plus shipping you'll receive amazing pcbs with professional look and great finish select up to 14 layers different color for the solder mask different finish for the pads and more on pcbweight.com what's up my friends welcome back let's go over the part list first and then we make the project we go over the code and finally we test it so what do we need well remember that in my previous reflow hot plate project i was using a clothes iron as a heating plate and this has a lot of power a lot more than we need especially if you want to use low temperature solder paste the problem with this was that measuring the temperature was a little bit difficult and very slow and why was that well because first i was using a thermocouple with this amplifier module and this module could send a measurement only 200 milliseconds so if you need faster reading well you can't and second the heat propagation was quite slow so till the real hit was reaching the thermocouple the pid was already way behind so we always had over temperatures so i had to adjust the values manually but this time i will use this heating plate that i bought from aliexpress for just a few dollars and i still want to keep this project low cost so it will be cheaper than buying a reflow station this plate has an internal hitting resistor of around 450 ohms so at 360 volts it could deliver around 280 watts of power which is 10 times less than the other project if you remember because that one was of 3000 watts on aliexpress the plate was marked as 400 watts but i'm not sure that it could reach that but anyway i've realized that we don't need more than 300 watts the plate is made out of aluminum which will transfer the heat very fast and to control the power we will need a solid state relay you could use a big one like this one as we have used before but this time since we have less power i will use one like this one that could work with 220 volts and could deliver up to 2 amps of current and this could also be easily controlled with an arduino so obviously we also need an arduino which in my case it will be once again the arduino nano and to show the values i will use an lcd screen with the ice crusty communication module so it will be easier to control and this time i'll use the 16x21 instead of the 20x4 one as we have used in the previous project and to measure the temperature i will now use a thermistor instead of a thermocouple and this is just a simple resistor that will change its value according to the temperature so it's very easy and fast to read compared with the thermocouple and we will see how in just a moment we also need to use a fan like this one and you will see why when we assemble the project the heater plate will work at 220 volts but the rest of the digital part is working at 5 volts so to lower the voltage to 12 volts i will use this small converter and we can connect the output from this to the v in pin of the arduino and since the arduino already has a 5 volts regulator that's how we get our 5 volts for the rest and to switch the entire circuit on and off i want to use the switch which already has an integrated led and that's very nice to have i also want to add a buzzer like this one to use for alarm notifications and finally to assemble the case you will see that we need some sort of metal plate in my case i will use this one here and when we assemble a project i will explain you why and finally for the case it would be better to make it out of metal but my workshop is not prepared for working with metal yet so that's why i've made my design out of plastic and this was printed with abs so it will withstand more heat and the heating plate will stay here and it will never be in direct contact with the case also the only way to transfer the heat to the plastic case will be through these screws that we add below the plate and because they are long enough the heat will transfer slowly even more the screws will be connected to that metal plate before and only this blade will be in contact with the case and this metal plate will dissipate the heat even more and below will have a cooling fan also between the heating plate and the metal plate i also want to put some of this heat insulation cotton and this should protect the case even more from the heat of the top plate but above all that remember that our solder paste melting point will be 172 degrees and you could also find some paste that will melt at 138 and this temperature is still ok with abs that will melt at around 230 degrees or more the case has a few parts and i've designed it in such a way that everything will fit perfectly on this small part we can add the screen and the buttons so we also need four of these type of push buttons on the side of the main case we have spaces for the on and off switch and on the back we have another space for the cooling fan the metal plate will get screwed inside here and we have a small skirt of plastic around so it will keep it at the exact height and on the bottom part we can screw the pcb with the arduino and the relay on the side and that's pretty much it it took me a while but finally i had a good design so this is all that we need for this project so let's assemble it but please be careful because this project is working with high voltage from the main outlet so if you're not sure don't start this project and also use proper insulated tools and never touch the exposed wires so guys download the schematic from below and have it in front of you so you could follow the same steps first we need to secure and place the heating plate but for that we need to add the metal part below because if you try to add it later you won't be able because we will have these plastic parts that will get in your way so you must add the metal part first so inside the case we have four holes for screws so make sure that you make some holes in your metal plate as well four holes will be for the heating plate and four more holes for each corner for the plastic case now we add the plate and tie the screws on each corner like this now we take the heating plate and we add four long screws and we tighten up for each like this at this point we also have to secure and place the thermistor on the metal plate so we can measure the temperature we could use this kind of thermistor or if you want this other one that already has a metal cover and like that maybe it will have a better connection but in my case since i still have a little bit of space aside of the heater element inside i want to add this thermistor inside here so i secure secured in place inside with force and some kept on tape and this could withstand very high temperatures then we add four more nuts and this will define the maximum height before i add the heater inside i cut some of this insulation foam i cut it to size and also make the holes for the screws then i add it in place over the metal plate and now we can add the heater and make sure that you pass the power wires and the thermistor to the bottom side of the case because the electronics will be below here and now from below i tied four more screws and the heater is now in place and as you can see the plate gets a little bit above the plastic case so we could easily remove the pcbs okay now let's assemble this part here first we have to add the push buttons so get four of these push buttons and solder wires to each one like this i use one black wire for ground and the color one for signal each button will go behind this plastic pad and like that when we push the pad we also push the button below and to keep the buttons in place i printed this part that will get screwed here and support the buttons so i decide where each button will go and then i glue them in place on that small support part and now i screw that support in place with some very tiny screws now when i push the plastic pad the button is pressed and as you can see we can hear the click okay so now we can add the lcd in place once again we add some screws and tied some nuts so we have a little bit of clearance and then i place the lcd and add more nuts to keep it in place and remember to also solder some wires for the power and the ice crusty communication now i get a relay a prototyping pcb and the bottom 3d printed part i screenplace the relay and now i measure where the pcb will go in order to be screwed on these four holes and i cut it to size with the pcb in place i decide where to place the arduino and the 5v converter and also some outputs and inputs i soldered the arduino the regulator and the buzzer in place and four sets of pins for the lcd the buttons the fan and the thermistor and on the back of this pcb i make all the connections with some thin wires and also some ticker wires for power now let's make a small pause here and let me show you how to read a thermistor as you can see at room temperature its resistance is 10k ohms in this case but i also have another model that could be of 100k ohms anyway when i hit it up its resistance will go lower so if i connect this thermistor in a voltage divider with another resistor with a known value i can measure the voltage change at the output and then using a graph like this one i can measure the temperature as you can see here i have my thermistor and another 10k resistor in a voltage divider i supply it at 5 volts and measure the output and as you can see when i hit the thermistor the output will also change so all i have to do is to use the arduino analog pin and measure this voltage and then using a graph like this one we could know the temperature so as you can imagine this will be way faster and easier than using a thermocouple but using this we can go to very high temperatures okay so let's resume the assemble i get the on off switch and solder 3 wires and the one with the led also has a resistor to limit the current then i add the switch to the side of the case now i screen place the cooling fan on the back and i make sure that it will suck the air in i get the power cable and pass it through this hole here on the back and make a knot inside and also add some glue so it will stay in place and finally i make all the connections as in the schematic the main power goes to the switch and from here we supply the relay and the five volts converter the relay will then supply the hitting plate and so on so now everything is connected it's time for the code so download it from below and upload it to the arduino now let's take a look in the code we set the loop refresh rate with these lines and then we read the temperature using the library for the thermistor and according to the elapsed time and the real temperature we control the pid code that will control the power that goes to the relay and we try to do that to follow this curve here which will be the melting curve of the solder paste and then we apply that pid output to the relay using a pwm signal and with this we can try to keep the power in such a way that the temperature will follow the set point so once the code passes over all the stages it will start the cooldown and also ring the buzzer a few times in order to let know the user that the process is over but the plate is still hot so that's pretty much what the code will do i've uploaded the code and make sure that the temperature control is okay and also try some different pd values to have got decent results that was getting closer to this curve for my solar paste so now that the code is uploaded and we know that it works we can close the case so we take a few of these insertion nuts using my soldering iron we insert them into the holes of the plastic case and as you can see we only have holes on these two corners because the other two will be added using these parts here we have one for each corner and this will stay in place using the same screws that we used to connect the lcd part to the main case so now using two screws we make a sandwich between the lcd part the main case and the small parts for the screws and once we have them in place i use my soldering iron once again and add 2 more insertion nuts and now we can add the bottom part and close the entire case and the project will be ready so the final case looks quite good right but does it work now connect it to power and flip the switch the internal led of the switch should turn on indicating that power is connected and the lcd should also start and tell the user to select the mode on the screen we can see the temperature if the relay is on and when the mode is running we can also see the set point the pwm value and the elapsed time in seconds i prepare a testing pcb with some solder paste and i add a few components with the tweezers i place the pcb over the heating plate and from the menu i select mode 1 which is the only mode for now and then i press run the code will start with the ramp where we go to 150 degrees and then we have the soaked part and finally we go over that temperature and reflow the components but with the first test i had too much solar paste so the components merge together so i had to make another proper test once the components are soldered we enter the cooldown mode and at this point you can remove the pcb from the plate and the cooldown mode will end when we get below 40 degrees okay so for the second test i've used a solar paste stencil to apply the correct amount of paste and this time as you can see we have the correct amount now that we have good solar paste i added components using again some tweezers i put a pcb on the hot plate and run mode 1 once again and the refill process was okay but some components moved so i had to use the tweezers and put them in place but in overall the reflow process was a success and then i've made another test with another pcb and i've also played a pcb on the side with only the solder paste and as you can see the one without components started to melt faster and then we can see all the components getting soldered so the project is a success so guys what do you think the entire project is quite low cost since the heating plate was just a few dollars the arduino the relay and the small components as well and the case is 3d printed you have the full part list below and the price is in the description so do you like my project if so comment below or give this video a like thanks again and see you later guys hey so one more video that ends i hope that you like it okay so listen if you want to buy my merch my t-shirts you have the links below for my shop and i promise that i will make more designs and also maybe you would comment below which one you like more and what more designs you would like to see because in that way i could start designing them and post my new t-shirts so thank you for all the support and i'll see you in the next video

Channel: Electronoobs

Views: 52,932

Keywords: homemade, DIY, 3D printed, reflow, hot, plate, SMD, soldering, components, PCB, halogen, infrared, station, Arduino, SSR

Id: 9q0mh3y_XBc

Length: 18min 31sec (1111 seconds)

Published: Sun Oct 17 2021