I also replaced the thin copper interconnectors between ultracapacitors with proper, clean busbars. I wanted to box up the parts to provide a reasonably robust and neat finished product. Pele on 1st Jun 2013 You have a control on your timing circuit that's labeled as Pulse Time Control and you also say that you didn't use an SCR like others do because you need both on and off control. As such I'm not really familiar with how much weld current or energy is required for that! This was also a good time to test the TP4056 I will be using to charge this up. Each electrolytic capacitor has around 0.008 Ohm of internal resistance, so the theoretical maximum current will be I = 16V/0.008Ohm = 2000A during the discharge. Thanks for your comment. I'm not familiar with how the equivalent is done on Arduinos, but hopefully Google can tell you how to enable pull up pins on the Arduino! azzythehillbilly on 28th Dec 2012 Very nice blog. Did you do up a PCB for the controll board? Do you know other material that do the same job? Please help.I am not new to Arduino and have done fews projeccts. I'm guessing it's because they are lower voltage than your IRFP4668.I'm not sure yet, so I looked up the IRFP4668 ones and can't seem to find but 2 at the most on anyone's shelf do you know any suppliers in the states that carries them, or something as good? I noticed most DIYer would just simply call theirs a schematic also, and I figured I would just do the same. electric diagram on 5th Jan 2013 Can i have the electric diagram and the bill of the component of this spot welder? To solve this 'off line' Id suggest just loading up the u8glib example to your Arduino and getting that working first. I used a 128 x 64 LCD and mounted it behind the panel. That said the physical layout got tested thoroughly when I was developing it as a motor controller and I can confirm that the devices share the load well, even at much faster switching than the spot welder. SO I dont think you need and it may hinder output current drive of the driver as it has to charge that cap in addition to all other mosfet gates.The 0.1uF should be connected as close to pins 1 and 4 as possible and another 0.1uf should be conected the same way over pins 5 and 8. https://www.youtube.com/watch?v=ohmOjtgKFj8, is there a mistake in the comment line of, U8GLIB_ST7920_128X64_1X u8g(13, 11, 12); // SPI Com: SCK = en = 18, MOSI = rw = 16, CS = di = 17, if so it is starting to make sense how to connect lcd, Reply I just use Adhesive on the little led to hold that in place. As for SCRs, the problem is that you can't turn them off once they start conducting, the current has to stop flowing by itself, so would have no choice but to discharge the ultracap entirely - which is a lot of energy! it cost me a lot. I used a transistor to drive as I was not sure the arduino could provide the current to drive this (Arduino is limited to 40mA from memory), 3) 3 x 10k Liear multi turn Potentiometers - connected to A4, A5& A6, NB: The 1uF capacitor across the footswitch to "debounce" the input to the Arduino. Easiest option may be to build or buy a 1 Farad capacitor as per their designs! With this one, instead of using a Tab Welder, or soldering the batteries. I'll get MIC4452 as replacement. Six might be a better number to work with so you can crank the voltage up a little if necessary. With a bigger Cap, you have more lead way. The tip is held in place with a 3mm grub screw. Everything, but the (2F to .6F), of the Capacitor, tested right. Energy is of course power (or volts x amps) x time, so bumping up the time can compensate for lower power delivery. Basically, unfortunately I can't see a way to use ultracaps with an SCR switch. In less than 2 welds, I had the pressure down. Phoebus Sparos on 30th May 2013 For what kind of weld spots do you use this? Do you think I have any chance to succeed? About: I mainly take on projects I have seen here and put my own twist on them. everything's going well. I know with Circuits, I would draw out a schematic and with a Build like this, I would simply add smaller Pictures to represent the component used. Have you looked into these for either welding or for your vehicle motor controllers? Here I show the connection to the capacitor bank from the benchtoppower supply. What I have found with the Capacitor welder, and this might be because of its small Capacity. Any advice from a better electronics person than me would be good! With this figure you can work out how much voltage and capacitance you will need for each weld, based on the formula for energy stored in a capacitor: Hence at 15V, I would need about 1.8 Farad per weld. does the order of the 11,12,13 matter? Am I correct ??? studs ? Ian Hooper on 24th Mar 2013 Hi Lionel, I haven't tried it with stud welding, no. They use an SCR switch and you use MOSFETs. When cutting these holes, I like to use a StepBit. This makes me wonder about the failures that you experienced. That was great! These PCB's are entirely Ian Hooper's design. If a MOSFET were to fail it would be a mini nightmare to find out which one had failed! I Turn everything off with the cap charged. arran on 22nd Aug 2013 Hey thanks for the great tutorial and good to see you still check back here often. NB: DO NOT add the capacitor on the PCB - In this design the gates are driven from the Arduino whereas in Ian's welder the gates are 'held' open by these capacitors until all their charge has been dissipated into the weld. I didn't buy the buzzer I harvested it from a defunct piece of equipment. meguit@rist on 12th Jul 2013 I'm thinking of disconnect the power source during spot. I just measured where to drill for screws, and superglue the mount in place. I did a bit of research on the options for a 1F high power capacitor bank, and for my money I'd go with 20x Panasonic 16V 47000uF. BackStory Hi, my name is Kina and I do sensor and datalogger development for with the University of Alaska in Fairbanks. I tried 4*27000uf+1*100000uf which is 208k in total & the results is better than the super cap. Keeping the schematic close by, I started combining wires according to the page. Then add the 3 capacitors. With a quantity of K2 26650EV cells sitting in my workshop, orphans from a cancelled project, it seemed like a good idea to build myself a CD welder such that I could assembly these cells into packs suitable for use in my various electric vehicle projects. I was keen to use the basic set-up that Ian has developed but I liked the idea of potentially refining it to include some features available on commercial machines. 6) 2 resistors for the voltage divider, 1 @ XXX ohm and 1 at YYYohm. there's another in series that will still be able to turn off, and that that can often prevent what may well otherwise (and here i'm particularly fuzzy) have been the death of all the mosfets. Capacitors are charged with large amounts of energy. I also figured out that the Buck Converter will fit perfectly where I planned on the face. Could this have caused one transistor to handle the welding current before any of the others switched on. Portlablepowerman on 22nd Jun 2013 Thanks a million! Kyriakos.
Capacitor Discharge Welding Machines Supplier | Taylor Winfield Answer All other smaller parts and pieces should seem to work where I might place them. This is also when I decided that the UPS case would work perfectly, as I saw one used in another Youtube Video.I also like to lay out the face design. I have subdivided it to make it easier to understand. I noticed a huge difference when I cleaned the oxide layer off the copper interconnectors in my build and added contact grease (Noalox), which showed me how critical good connections are with this design! Will try IRFP3206 soon. Followed up by a 1/8 drill bit.
Also added is a resisitor from the Arduino Pin6 to limit the current that the Arduino can supply. Did you make this project? And, probably safer.
DIY Spot Welder Can Join Anything Together, Even Copper Thanks for the great write up on your CD welder. I wasn't to worry about cleaning everything up. Could it be the cheap 2.5F super cap not as super as 2.5F? Granted the current and switching time differences might not seem like much, but could they have been contributing factors to the failure? The hardest part to duplicate would probably be the power stage as you probably won't have suitable PCBs on hand, but can just solder large wires straight to the legs of the MOSFETs. This was able to weld 0.5mm stainless steel plate. I have read that the spot weld itself needs about 200 joules - not sure if that's per spot or for a pair, but at any rate it's clear that the equipment is soaking up most of the energy rather than delivering it to the weld. All the high power wiring is 8AWG, which has a resistance of around 2mohm per metre. kyriakos on 5th May 2014 Dear Ian
Thank you very much for your prompt and really c o m p l
e t e from any aspect response. Ian Hooper on 24th Mar 2013 Hi John, they would have plenty of energy and low enough resistance for the job, but you may need more than four for sufficient voltage.. I actually can't get IXDD414s anymore in my country (Australia) either! I hope I could help. Adjustable pulse time with potensiometer 25-250 ms.
8 IRFB7430 in parallel mount on their respective heat sinks
The whole thing wired on thick wires especially the out put starting from the negative (-) terminal of the capacitor bank to a common (unique) ground - negave bar, then to the sources of the 8 mosfets, then the 8 exiting drains in parallel from mosfets to the negative black prod. This driver chip is easily available as a SMD component. Just messing around, I knew i needed to make a battery pack for the SCR and small Voltmeter(Capacitor Voltage). These batteries can output several Amps, are those spot welds wide enough to transfer such current?I did not made any calculation, but let's consider 10Amps @ 3.7v, it would require around 1.5mm2 of surface (equivalent to 16 AWG).I think that a certain size & number of spots must be used, depending on the involved current, to prevent overheating and losses!Cheers , Answer Hence why I used MOSFETs, which can be turned off on command and do a timed pulse, whereas R.Thompson and P.Pemberton's designs have smaller capacitance which discharges fully so the SCR can turn off. And I use them Daily on certain projects. (The ones I'm using are 2.7V each so 16.2V theoretical max, but I only needed to charge them to 10-12V for welding; plenty of headroom for variations in voltage.). The SCR will drop a lot the voltage that means you will need higher voltage capacitor which is expensive. For those outside the United States, shipping is pretty expensive (if available at all). The person I got the idea for the old APC UPS case, used a Hockey Puck Style for his and he gets pretty close to the same results. It's pretty straight forward. My Next Instructable is a very simple welder I made in less than a few hours(after the case was dry or set in 48hrs, Of Course..LOL). ok, i can not find any real understandable info so someone please help? I took his suggestion and had them made at Seeed studio - great experience - I highly recommend it, all you need to do is submit the Gerber file, choose how many PCB's you want (I choose 20 as I might make 2 machines)! I expect you'd need a lot more power to weld 0.5mm material! Not wanting to spend thousands. Ian Hooper on 3rd Jan 2013 That capacitor internal resistance should work well, but it's hard to keep the rest of the circuit low resistance, e.g 1 metre of 8 gauge wire for the probes has about 2m resistance, and each connection adds a bit, etc. Before I add the leads, I wanted to run this through a quick checklist to make sure it is working correctly. On the front, I flip up(on) the little switch on the left, this turns on the smaller LED, that gives me the Capacitors voltage. Also, got the code to program with arduino 1.4 via my arduino uno as isp. Could the difference between the paths of the first and last transistor on that bus bar caused one transistor to handle more current than another? It gave me more satisfaction by readint it than dismantling
the entire Project. In the Arduino program I have used the library U8Glib The pins used are Digital Pins 10,11 and 13, 2) Buzzer - (optional but it is uselful)! After I tighten the screws, the Buck converter stay steady. I think he even got one of those fake 2F caps, that's actually only 0.6-0.4F also. !Check out my upgrades to this build here:https://www.youtube.com/watch?v=OtCiorlYP1UTIME CODES:SCR GATE WIRING:http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=1m37sGATE TRIGGER SWITCH :http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=3m20sCAPACITOR SELECTION AND POWER CONSIDERATIONS:http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=4m25sCHARGING:http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=6m26sWELDING @ 15.10 VOLTS:http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=9m28sWELDING @ 15.90 VOLTS:http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=12m25sBLEED RESISTORS:http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=14m25sNUGGET TEST ON WELDED AAA PACK:http://www.youtube.com/watch?v=TNclCrfsgJQ\u0026t=14m53sComponents:Nippon Chemi-con 1 Farad 16 Volt capacitorChinese 100 Amp silicon Controlled rectifier30\"X2 8 gauge wire6 gauge solid wire for electrodestactile/momentary switch scavenged from a wifi routerCharging:15 Volt 1100 milli-amp DC converterboost converterConstant current, constant voltage buck converter I also like to use graph paper for all my schematics. Thanks for reading my instructable and don't forget to vote. To me, it was not quite a pictorial, and Not quite a schematic.Thanks for the comment. Normally, one would consider the resistance of the bus bar to be negligible. For me, PB2 gets defined when you include the header file "io.h". You are unforgettable. However I'm hoping the machine will give years of good service for about 10% of the cost of a commercial unit. I set the Buck Converter to 16V and 3.2Amps, and the Boost Converter I set at 25Volts(later changed to 30V)Amps full open. You are really unforgettable. If you look at the Schematic/Pictorial I created. I imagine a shower of sparks, and/or things getting burned. 2) The negative link - to be connected to a bench top power supply. Kyriakos on 16th Jan 2014 Dear Mr. Ian Hooper,
Thanks verry much for your yesterdays' quick response. He uses a LM317 psu and the APC transformer to power his. Including electrode leads, I have about a metre worth in the welding circuit. Thanks again for your insight. I have made these welders in just about everyway I could think of, except the China Circuit I have seen showing up here and there. John on 24th Mar 2013 Hi! This switch isolates the battery supply for the control PCB. There are some pretty serious power levels involved which can make a mess if things aren't working right. Will these capacitors sufficient for welding battery tab? These capacitors feature very low internal resistance, so can deliver very high discharge current.
DIY Capacitive Discharge Welder - YouTube Ian Hooper on 21st Jul 2013 Yes, it is plausible that the Equivalent Series Resistance of the cheap 2.5F cap is too high for it to output the required current. I don't normally prep the components until assembly, but this one, I wanted to use Screw Terminal Barrier Connectors on all connections. Sorry
Kyriakos. 10F is certainly more energy than required for a single weld and things will happen pretty fast so it might be hard to weld consistently if you are using yourself as a timer!