This is the best diy implementation of a spot welder i've seen so far, the software with calibration and measurement features is like a cherry on top, really nice.
thanks :-) There's a new cherry: the latest model also supports an anti arcing feature that protects you from burning a hole in the battery when accidentally triggering a plasma arc due to dirt, corrosion or too little contact pressure.
It's very nicely designed and constructed. The part I like the best are the large, clean, shiny bus bars on the PCB connecting the mosfets. It's a work of art!
I like how we are dealing with energies instead of pulse times, as well as having the circuit's own resistance measured and used in self-calibration. Will look into this further :)
I have been looking at getting a small spot DYI spot welder for a while. I really like this one. I'm heading to the store now. Great design and explanation.
Still haven't actually used mine for what I bought it for ( replacing the 18650s of my Philips Robust Collection HR1379/00 Hand Blender ) but just viewing this video again after watching the reviews of more recent - made in China - spot-welders _really_ calms my soul about buying _this_ Kit back then 😗
I am happy to announce that the next batch of kWeld is in production. I accept pre-orders through my shop. All pre-order products are on sale with a 10% discount until Nov 30.
This is excellent!!! This machine is a steal at this price. I've been looking at aluminum spot welders for >10k USD but will very likely buy yours instead. Keep up the good work; I bet once you get a shiny case and warranty you'd be able to sell this for over 500 USD easily.
Thanks, but I wasn't the first to attempt this. This part of my product was "proudly found elsewhere". My contribution is to turn this into an easy to assemble, easy to use and robust kit. The energy metering approach is also a novel, I haven't found this even in much more expensive industrial units.
Thanks :-) Yes, I focus on the KISS principle. Antoine de Saint-Exupéry: “Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.”
Ziemlich witzig die Preisdebatten zu lesen, hab den Spotwelder durch eev entdeckt und der ist auf jeden Fall das Geld wert. Ausserdem, nur meine Meinung warscheinlich, verkaufst du es sogar unterm Wert. Falls du das nicht gesehen hast, Dave hat auch ein video über das bepreisen von Produkten gemacht.
It works well with lead acid batteries, some users are using them. I am collecting info about suitable supplies here: www.kicksurfer.de/index.php/2017/08/29/kweld-power-supply-recommendations/
Thanks a lot! I am working on sourcing the next batch of 100 kits, I will open for pre-orders soon. I will inform about this through the (spam free) newsletter at kicksurfer.de, I suggest that you subscribe to it.
I loved seeing the lead wiggle at 8:46 - wires don't usually move when conducting DC current (but i suppose this is more like AC for the duration of its test.
It is the Lorentz force that causes the leads to attract. This is always there between two conductors carrying DC current, but you normally don't notice it. Different here, because the current is approx. 1300A.
Nice look forward to it.. i might be just starting in the electrical world as i call it .. or as a Linux nurd calls it ..but i hope i can learn a lot not to work in the field don't see my self starting over at 40..but building something with your hands and having other people enjoy it .. seems to me to be the best feeling out there..that's why i have a Mechanical keyboard kit ordered and a electronic alarm clock hahaha..
I know what you mean. Making things that do something in the real world (and if it's just ridiculous current flow) is one of my passions, that's why many of my projects deal with electric motors.
Im talking about the contact probes pressure. This needs to be consistent. I use spot welders at work. there are 4 different settings current, pressure,dwell (hold time) pulse (how many hits of current). yea i know this is not as fussy but these are just some of the things in spot welding...thanks
Sorry, I confused the battery that is welded on, with the Lipo power source. I thought, why should I apply pressure to the latter? Makes more sense now :-) My system does not require consistent weld spot force, and it does neither need nor use cleaning pulses. That is because it works differently from all other spot welders that I have seen before. I'll try to explain: Commercial spot welders fire pulses with a given duration. If there is not enough pressure, or if there is a bad contact from corrosion etc, then the spot's ohmic resistance is different from what it should be - the weld fails. My design measures the instantaneous power that goes into the spot, integrates this to obtain the so far deposited amount of energy, and stops the pulse when the set value is reached. Al this is done every 10 microseconds. This ensures that the amount of energy, or heat, that is dumped into the weld spot, is *always constant*, no matter how much initial pressure you apply, how much corrosion there is, how well the surfaces tough, and so on.
I totally underestimated the demand, and ran out of stock by just pre-orders in less than a week. I plan another batch right after having received the current one. I'll inform again through the newsletter. But in order help me estimate the demand, I have just implemented an "inform me on availability" button for the sold out products that puts you on a waiting list when you click it.
I guess I'm late to the party (as usual) but what I like most about this is the flash and weld are much more like a proper spot welder and look like they are generating minimal heat. One guy on RUclips has a video where he tests his welder with two tabs on a piece of wood. When he lifted them the wood had a big burn mark. I hate to think what damage he is doing to his batteries.
I have received my spot welder this week. Saturday ordered Tuesday delivered. Nice fast shipping. On Saturday I will assemble it. And then try it out. I hope it works with my SUNKKO HB-70B spot welder pen.
if i was the iventor , i just throw the clones my self on ebay first ;D. the price is to high for a piece of electronics. Sure its very useful and engeneered. But just my opinion a very experienced buyer, the value must be higher than the price you must pay. And this is not the case here. (Microcontroller,Mosfets, a PCB cant justify 150/213€) i would say at max around 66€ and a on "sale" price of 50€ would get him way more sales.
This is not true, as a service engineer. you would need something portable. If we would use this more frequent than this is perfect. just if would have a nice case and isolate probes. This is really a interesting device.
Its pretty interesting and compact. I could see it's use, but I think my diy mot will work great for what I want. I might consider something similar in the future, but at his price I would probably just make my own. I wouldn't say that it is highly overpriced, but I enjoy doing it myself and currently I still have the time to waste.
The assembled PCB is 110€, the prices that you state are for the full kit I presume. That includes all mechanical parts, some of them custom CNC machined, and all cable assembly plus work plus packaging. If you would want to sell that assembled PCB for 50€, then you would certainly have done your calculations wrong. Just the 6 MOSFETs, the microcontroller, and the LCD account for a bit less than 40€ at Digikey.
the fets alone will run 25 bucks at the moment. i really wouldnt hold my breath on that one. if you have a lithography set up and etch tank at home you might make it for close to that price...assuming you also have a battery or cap bank already
Hello very nice his idea, great presentation, please tell me how to buy the material i am in ITALY. You can buy it from her. Thank you I'm sorry for my english mail b.fargnoli@alice.it
sorry too, I didn't mean to harass you but it's very surprising at first. Maybe you could add an annotation (if youtube allows this). Anyway thanks for the video, it's a need device. Scary seeing naked fingers so close to high voltage tip btw :p
I can check. It does not make much sense to add a note in the comments though, because many people including me don't read them by default. These are no high voltage tips. The unit is supplied from a 11.1V Lipo battery.
Thanks for great video just shame i can not afford your kit as love to build it nbut thanks to your video and some others i now have a idea how a spot welder works
A very nice piese of equipment !!! And professional mecatronic-design, with many well-thought details !!! ;-) Only the slices in the brass-tipholdes could maybe be smaller...
I'm a noob when it comes to electronic. A 40yr old noob hahhaha I watch great scots vid and saw this awesome welder. Who knows perhaps one day I can buy a kit from you to diy repair battery packs. But I would just want to run it out of mains power perhaps that's a bad idea.
kWeld has actually been featured in his one of his most recent videos: ruclips.net/video/b2sBhDxmPmA/видео.html as I had send him one for his ebike work.
yah i know that was great to see.05:50 ;-) i also so him trying to create his own hahaha..was cool to watch.. There are lot's of cheap Chinese bulky and not so trust worthy solutions out there. and since i live in a apartment your compact solution has a high wife approval factor ..also designed tested and build in Germany finishes the stamp of approval .. for once i'm happy to live in The Netherlands and not having to pay customs crap..But the kit will have to wait for a while until i finish my current projects studies and lot's more...my compliments btw..
that is because I have a reseller in the US, and you should have seen a corresponding message on the checkout page. In case that this didn't show up, please leave me a message through the keenlab.de contact form and I will send you his contact.
Würde ich sofort kaufen wenn es nich so Teuer wäre! Für meinen Geschmack und das bischen was ich damit machen würde tuts bei dem Preis auch ne Billige Alternative aber sehr schön umgesetzt großes Lob dafür mfg
Danke :-) Der Preis wird noch deutlich runtergehen, wenn es klappt und größere Stückzahlen möglich sind. Im Moment mache ich alle mechanischen Arbeiten selbst und muss den Preis dafür relativ hoch ansetzen, um nicht überschwemmt zu werden. Es macht jetzt noch keinen Sinn, irgendetwas rauszugeben. Es lohnt sich hier selbstbauen, die Rohteile insgesamt dafür kosten dafür etwa 149€. Viele haben aber bereits einiges davon da, z.B. Fußtaster, Kabel oder Schrauben, dann lässt sich der Preis auf 99€ reduzieren. Vorsicht bei dem einen oder anderen Bausatz, vieles ist sehr knapp kalkuliert und "stirbt" schnell. Dieses Gerät ist deshalb teurer, weil es mit Reserve dimensioniert ist und auch noch 2000A klaglos schalten kann. Und die Energiemengensteuerung ist auch einzigartig im DIY-Bereich.
If the FETs stay on for some time, the current should accumulate due to inductance to some maximum value, when the FETs are then switched off, so ZCS switch on. But at switch off you have maximum current and maximum switching losses, and without a flyback diode how is this energy depleted? Like I see what looks effectively like a buck converter without the freewheeling diode. The freewheeling circuit will be half of the power since it starts at the peak current and decreases to zero. I thought that was what was killing my cheapo $25 ebay special along with poor gate drive. At least on one occasion, a FET failed so spectacularly that it somehow welded itself to the PCB and removing it required lots of heat and force with pliers. Chipping away at the plastic encasing and the stuck metal tab that welded itself to the copper despite being soldered.I did get a chance to see the silicon die on those and was impressed with how huge it was. So used to thinking of transistors as microscopic things but seeing the die that was maybe 4mm by 6mm was just amazing!
in kWeld, this is handled by an array of large TVS diodes. As you have experienced, the MOSFETs alone cannot handle the amount of inductive kickback at these current levels.
Looks good I been finding transformers to rewind the secondary to get the most current at low volts .....it don't weld a good as this tho .....very nice
Is the circuitry in this effectively similar to the car jump start battery pack? Not seen much for tear downs on them but they also use MOSFET's. Otherwise from a safety stand point it could be a good idea to cover the leads with some kind of insulating material where you are holding them.
AFAIK those Lipo jump starter packs are basically just the battery and a schottky diode for reverse polarity protection. There is no power switch, you just connect them to your battery. The current is typically also lower, a few 100A. This unit is much more complex, as it has to reliably switch up to 2000 A.
Ich habe heute damit 2x 0,3mm= 0,6mm Hiluminband übereinander auf einen Akku erfolgreich geschweisst. Einstellung 200 J Delay 0,7s 1390 Ampere. Hab gar nicht geglaubt, dass man solch dickes Band damit Punktschweißen kann. Hatte mich zuerst langsam herangetastet mit den Einstellungen. Ich werde übermorgen versuchen 3x0,3mm Übereinander = 0,9mm damit Punktschweißen. Als Stromversorgung habe ich 13,8 Volt / 240 AH Lithium-Eisen- Titanat Akku (LTO) angeschlossen. Dieser liefert auch 3000 Ampere wenn er soll.
Really good construction idea and innovation! May i suggest just one improvement idea for the electrode holders: when i saw the big gap between the cable connection and the round electrode i first wondered why. Then i saw you need the disconnection to get the pressure to the electrode by screwing them down. But you only need to cut one peace to achieve the same result and have a better connection with a lower resistance. May not matter much here, but every percent counts :-) Are you in mass production already? I am about to build a bigger spot welder for stainless steel - about 2 - 2.5 kAmps :-) Triggered by two SSR's and inrush current control for the primary winding of the transformer (rewound from an old traditional welding transformer around 4 - 5 kVA).
Thanks for your suggestion. Sadly that electrode holder is already obsolete, I didn't like the machining effort that had to go into it and found a simpler solution. I hope to upload the next video by this weekend showing this and other improvements.
what sheet metal thickness do you aim at? 2.5kA is not a lot for this. Professional sheet metal welders can easily go up to 15-20kA. BTW, my design is calculated for 2kA max for 200ms.
Hi there, i doubt that a LiPo-battery can give you 2 kA - did you check the amps? I know that industrial spotwelders can deliver up to 30 and 40 kA, but i used an old welding transformer and replaced the secondary by 4 windings of 120 mm2 copper cable giving me up to 4 V at around 2,5 kA (for a few seconds). That should be enough for 1 - 1.5 mm stainless stell i guess. More would be better tough...
I measured the amps through a defined section of (brand quality pure copper) AWG8 wire with known resistance. Modern high amperage race Lipos are well capable of delivering these currents. I just received a fresh Turnigy nanotech 3S / 5Ah pack. That is rated for 130C discharge current, which is 650A. "Continuous"!
Fantastic work. It can deliver up to 500J, but you show 18650's require only 150J. Could you make a less expensive version with fixed 150J output? Then you could downgrade all components, thinner cables, fewer mosfets, smaller battery, no pot (cuz fixed), etc. I don't need 500J. I think you would find a lot of buyers for that. Thx.
It's the current handling capacity (2000A) that makes the components expensive, and the reliability that my design stands for. Battery spot welding needs at least 1000A to work properly. The amount of energy is varied by adjusting the pulse duration. However, the numbers in this first videos are wrong (current measurement was inaccurate at the time of making it). The series product can do up to 200J, and needs 50-100J for 0.3mm nickel strips.
This is really fantastic to me, and the amazing realization is that no high voltage is necessary only 11.1v! Why people user a high voltage is now a mystery to me. Perhaps the weld happens a millisecond faster with a higher voltage?
Where did you see high voltage in a resistance spot welder? For this kind of welding, you just need insanely high currents. The resistance of a weld spot is low, maybe one milliOhm. And you need to heat it up such that it melts.
many people use a microwave transformer- but actually I guess in adding a large secondary they are actually using a low voltage at the weld. So the big difference then is just using wall current versus battery current, and to produce the hundreds of amps needed a relatively high primary to secondary ratio is needed. But I always thought that arc welders use high voltage- but maybe no.
Yes, the microwave designs also produce low voltage, around 1-3V on the secondary. But hundreds of amps is not enough yet, also these are able to do >1000A when made well. Their advantage is that it is much easier to switch the current, but their disadvantage is that they can only chop the welding time into 10 millisecond intervals (one half AC sine wave). I need much better resolution to implement my energy based pulse control and therefore chose DC supply and MOSFET switching. I think that arc welders are using higher ignition voltages, but this one is not an arc welder. This is called resistance spot welding.
3d print an electrode holder. Would be nice if it could use power tool battery packs. Then you could build a full case and have a fully portable welder.
Electrode holder: secondlifestorage.com/t-Easy-to-3d-print-K-Weld-electrode-housing-files (community contribution). Power tool battery packs won't work, as the welder needs at least 1000A (better 1500A).
I guess you missed the link at the end of the video, and in the video description. That's where my webshop is: www.keenlab.de/index.php/product-category/kspot-welder-kit/
This is the best diy implementation of a spot welder i've seen so far, the software with calibration and measurement features is like a cherry on top, really nice.
thanks :-) There's a new cherry: the latest model also supports an anti arcing feature that protects you from burning a hole in the battery when accidentally triggering a plasma arc due to dirt, corrosion or too little contact pressure.
WOW! A very elegant design. A little pricey, but a very nice piece of kit.
It's very nicely designed and constructed. The part I like the best are the large, clean, shiny bus bars on the PCB connecting the mosfets. It's a work of art!
Thanks :-) I also like that, that's why I used a picture of this area on the main product page at keenlab.de :-)
I have one of these welders and I'm very happy with it. Very well made and it works great with my Turningy lipo nanotech 5ah battery.
I admire your ingenuity and business sense. Good luck! I hope you sale a ton of them.
Thanks for the Kudos!
I want one............ The best I have seen so far. Great design and features.
Just check out the video description, there's a link to the shop where I am selling these.
Decent approach in term of invention way! That's really cool
Excellent and clever design and logic. Chapeau.
That looks fantastic . Very portable , adjustable and easy to use ! I want one !
I have one in stock for you :-))
I like how we are dealing with energies instead of pulse times, as well as having the circuit's own resistance measured and used in self-calibration. Will look into this further :)
you have made a very good high current design. Excellent. very good engineering, both electrical and mechanical.
Thanks a lot :-)
I have been looking at getting a small spot DYI spot welder for a while. I really like this one. I'm heading to the store now. Great design and explanation.
Still haven't actually used mine for what I bought it for ( replacing the 18650s of my Philips Robust Collection HR1379/00 Hand Blender ) but just viewing this video again after watching the reviews of more recent - made in China - spot-welders _really_ calms my soul about buying _this_ Kit back then 😗
Nice job. This looks like a winner to me. I think you can sell these with no trouble.
New video online showing some substantial improvements! ruclips.net/video/rQnODV4VQjU/видео.html
Where can we find PCB schematic, firmware etc ? :)
I am afraid but this one is not open source.
Fascinating and at the same time well documented, excellent engineering both electronic and mechanical....I have subscribed............
Bloody brilliant !!!! I have 5 trades under my belt but not electronics .
A very neat tidy and functional unit . . . . I like !
Make more please. Its so frustrating to see something so nice and not be able to buy it. :D
I'm working on it, I will place an order for a larger production lot next week. As soon as I have a delivery date from them, I will let you know.
Just bought one! Looking forward to trying it out!
great job on the design of the spot welder glad you got the funding to make it to production seems like you thought about what features to add.
Thanks, and yes a good product should be continuous improvement. Do you have an idea of what could be added?
Simply the best! Am saving money for this
Very nice project, best luck in the future!
This is very nice kit! You basically made a micro UniSpot welder! I may just order one.
Thanks :-)
Very cool,great work!
When it all begun.
I am happy to announce that the next batch of kWeld is in production. I accept pre-orders through my shop. All pre-order products are on sale with a 10% discount until Nov 30.
ship to USA?
How much it cost to USA???
How can I order this or the parts to build it to Chicago, USA?
One of the best electronic projects I've ever seen on YT!! I will be ordering a kit!
This is really nice and a badly needed product! Very well done!!!
This is excellent!!! This machine is a steal at this price. I've been looking at aluminum spot welders for >10k USD but will very likely buy yours instead. Keep up the good work; I bet once you get a shiny case and warranty you'd be able to sell this for over 500 USD easily.
Interesting idea to use a battery as the source of power instead of a microwave transformer like everybody else. Thumbs up!
Thanks, but I wasn't the first to attempt this. This part of my product was "proudly found elsewhere". My contribution is to turn this into an easy to assemble, easy to use and robust kit. The energy metering approach is also a novel, I haven't found this even in much more expensive industrial units.
there isn't much to it is there!
not saying there is anything bad about it. looks like a simple functional design. just how I like it!
Thanks :-) Yes, I focus on the KISS principle. Antoine de Saint-Exupéry: “Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.”
Ziemlich witzig die Preisdebatten zu lesen, hab den Spotwelder durch eev entdeckt und der ist auf jeden Fall das Geld wert. Ausserdem, nur meine Meinung warscheinlich, verkaufst du es sogar unterm Wert. Falls du das nicht gesehen hast, Dave hat auch ein video über das bepreisen von Produkten gemacht.
MAN! that is so well made! i loved it. i think i`ll make my own but with lead batteries...
It works well with lead acid batteries, some users are using them. I am collecting info about suitable supplies here: www.kicksurfer.de/index.php/2017/08/29/kweld-power-supply-recommendations/
Wish this was cheaper to get to the usa. I want one so bad! Amazing job!
Have you noticed that I have a US reseller? Infos right at the beginning of the product page.
I just ordered mine from the USA.
Aha!! found you!
You'll be getting that order now
this definitely is the next level.
thanks :-))
You did an absolutely magnificent job on this!
Thanks for sharing and I'll certainly be ordering the kit.
Thanks a lot! I am working on sourcing the next batch of 100 kits, I will open for pre-orders soon. I will inform about this through the (spam free) newsletter at kicksurfer.de, I suggest that you subscribe to it.
@@wearethewatt2950 how could I get one?
I'm finally beginning to assemble it today after playing lazy for a couple of weeks.
great! Let me know if you have any issues.
I put it together, but won't be able to use it until next month when I move into my home. If I have any issues then; I'll let you know, thanks.
I loved seeing the lead wiggle at 8:46 - wires don't usually move when conducting DC current (but i suppose this is more like AC for the duration of its test.
It is the Lorentz force that causes the leads to attract. This is always there between two conductors carrying DC current, but you normally don't notice it. Different here, because the current is approx. 1300A.
wires will twitch anytime a heavy load like that is working. AC or DC..
yeah, they use that property to de-ice aircraft wings. one huge pulse of current thru a wire and the wire jumps and breaks the ice.
Hope to get mine shortly!!!!
Cool welder dude
Thank you for the demo of a portable DC powered spot welder.
This is very impressive
Glad you took my advice on board, well executed!
that is a fantastic welder thumbs up to you from Ireland :)
Very impressive. Best of luck
Wow! Excellent work! I would love to order one but you are sold out. I'll get on the newsletter mailing list so I don't miss out on the next run!
excellent project. very useful spot weld device.
this project is soo amazing and smart
Beautiful. To high of cost for most.
Very cool, I'm waiting for it to be available, awesome work :)
Next level for sure! =)
Excellent presentation. Added this welder to my wishlist.
Very nice work.
And I guess it gets the energy right by measuring the resistance of the tabs before each weld? That's quite clever and makes a lot of sense.
Almost! It is doing this continuously while welding, at a very high update rate thanks to the powerful microprocessor.
Impressive! I might order one when they're back in stock ;)
This is the next level
Btw I'm also impressed will check the channel good job mate greetings from the Netherlands
Thanks! I have some video footage to cut and will publish new videos very soon :-)
Nice look forward to it.. i might be just starting in the electrical world as i call it .. or as a Linux nurd calls it ..but i hope i can learn a lot not to work in the field don't see my self starting over at 40..but building something with your hands and having other people enjoy it .. seems to me to be the best feeling out there..that's why i have a Mechanical keyboard kit ordered and a electronic alarm clock hahaha..
I know what you mean. Making things that do something in the real world (and if it's just ridiculous current flow) is one of my passions, that's why many of my projects deal with electric motors.
Im talking about the contact probes pressure. This needs to be consistent. I use spot welders at work. there are 4 different settings current, pressure,dwell (hold time) pulse (how many hits of current). yea i know this is not as fussy but these are just some of the things in spot welding...thanks
Sorry, I confused the battery that is welded on, with the Lipo power source. I thought, why should I apply pressure to the latter? Makes more sense now :-)
My system does not require consistent weld spot force, and it does neither need nor use cleaning pulses. That is because it works differently from all other spot welders that I have seen before. I'll try to explain:
Commercial spot welders fire pulses with a given duration. If there is not enough pressure, or if there is a bad contact from corrosion etc, then the spot's ohmic resistance is different from what it should be - the weld fails.
My design measures the instantaneous power that goes into the spot, integrates this to obtain the so far deposited amount of energy, and stops the pulse when the set value is reached. Al this is done every 10 microseconds.
This ensures that the amount of energy, or heat, that is dumped into the weld spot, is *always constant*, no matter how much initial pressure you apply, how much corrosion there is, how well the surfaces tough, and so on.
That is beautiful. Nice work.
I totally underestimated the demand, and ran out of stock by just pre-orders in less than a week. I plan another batch right after having received the current one. I'll inform again through the newsletter. But in order help me estimate the demand, I have just implemented an "inform me on availability" button for the sold out products that puts you on a waiting list when you click it.
I guess I'm late to the party (as usual) but what I like most about this is the flash and weld are much more like a proper spot welder and look like they are generating minimal heat. One guy on RUclips has a video where he tests his welder with two tabs on a piece of wood. When he lifted them the wood had a big burn mark. I hate to think what damage he is doing to his batteries.
Definitely, considering that the can is filled with plastic to the rim, which, should it fail, creates a short circuit.
I have received my spot welder this week. Saturday ordered Tuesday delivered. Nice fast shipping. On Saturday I will assemble it. And then try it out. I hope
it works with my SUNKKO HB-70B spot welder pen.
Nice job.
Now to wait for the 50$ clone from ebay :-)
if i was the iventor , i just throw the clones my self on ebay first ;D.
the price is to high for a piece of electronics. Sure its very useful and engeneered. But just my opinion a very experienced buyer, the value must be higher than the price you must pay. And this is not the case here.
(Microcontroller,Mosfets, a PCB cant justify 150/213€) i would say at max around 66€ and a on "sale" price of 50€ would get him way more sales.
This is not true, as a service engineer. you would need something portable. If we would use this more frequent than this is perfect. just if would have a nice case and isolate probes.
This is really a interesting device.
Its pretty interesting and compact. I could see it's use, but I think my diy mot will work great for what I want. I might consider something similar in the future, but at his price I would probably just make my own. I wouldn't say that it is highly overpriced, but I enjoy doing it myself and currently I still have the time to waste.
The assembled PCB is 110€, the prices that you state are for the full kit I presume. That includes all mechanical parts, some of them custom CNC machined, and all cable assembly plus work plus packaging. If you would want to sell that assembled PCB for 50€, then you would certainly have done your calculations wrong. Just the 6 MOSFETs, the microcontroller, and the LCD account for a bit less than 40€ at Digikey.
the fets alone will run 25 bucks at the moment. i really wouldnt hold my breath on that one. if you have a lithography set up and etch tank at home you might make it for close to that price...assuming you also have a battery or cap bank already
lovely clear video - what camera do you use?
actually.... my outdated smartphone that I had at that time :-)
very very nice work
You could wire 2 of those batteries in parallel to increase the discharge rate if you need extra capacity.
yes, that would be an option. But I have found a more suitable battery as I discuss in my more recent videos.
Can it weld copper tabs?
That is the end all, be all, of battery spot welding.. Absolutely beautiful unit either way.
no, can't do copper. Thanks for the Kudos :-)
Nice and clean
molto bello ed interessante ottima presentazione
Hello
very nice his idea, great presentation, please tell me how to buy the material i am in ITALY.
You can buy it from her.
Thank you
I'm sorry for my english mail b.fargnoli@alice.it
That noise gate you used on the sound is really annoying, I would prefer the background noise vs the constant gate switching.
I'm sorry for that. Unfortunately RUclips does not allow modifying a video after it has been uploaded. My newer videos on this topic are better :-)
It's so "strong" I thought my headphones we failing.
sorryyyy, I would re upload it with better sound but RUclips doesn't support this...
sorry too, I didn't mean to harass you but it's very surprising at first. Maybe you could add an annotation (if youtube allows this). Anyway thanks for the video, it's a need device. Scary seeing naked fingers so close to high voltage tip btw :p
I can check. It does not make much sense to add a note in the comments though, because many people including me don't read them by default.
These are no high voltage tips. The unit is supplied from a 11.1V Lipo battery.
Thanks for great video just shame i can not afford your kit as love to build it nbut thanks to your video and some others i now have a idea how a spot welder works
you're welcome!
A very nice piese of equipment !!!
And professional mecatronic-design, with many well-thought details !!! ;-)
Only the slices in the brass-tipholdes could maybe be smaller...
Thanks a lot :-)
Thanks for the video and welcome to my DIY channel)
Ready to market product wow perfect
Yes this is next level.
I'm a noob when it comes to electronic. A 40yr old noob hahhaha I watch great scots vid and saw this awesome welder. Who knows perhaps one day I can buy a kit from you to diy repair battery packs. But I would just want to run it out of mains power perhaps that's a bad idea.
kWeld has actually been featured in his one of his most recent videos: ruclips.net/video/b2sBhDxmPmA/видео.html as I had send him one for his ebike work.
yah i know that was great to see.05:50 ;-) i also so him trying to create his own hahaha..was cool to watch.. There are lot's of cheap Chinese bulky and not so trust worthy solutions out there. and since i live in a apartment your compact solution has a high wife approval factor ..also designed tested and build in Germany finishes the stamp of approval .. for once i'm happy to live in The Netherlands and not having to pay customs crap..But the kit will have to wait for a while until i finish my current projects studies and lot's more...my compliments btw..
Thanks! When I saw him trying to build a spot welder that was actually when I decided that I had to donate one to him ;-)
That's very nice!
Thank you for sharing this nice video.
That is superb!
new stock is coming, and I've just opened for pre-orders at the shop! --> www.keenlab.de/index.php/product-category/kspot-welder-kit/
Trying to pre-order but tells me no shipping method chosen I am in USA no shipping info is populating in the cart?
that is because I have a reseller in the US, and you should have seen a corresponding message on the checkout page. In case that this didn't show up, please leave me a message through the keenlab.de contact form and I will send you his contact.
can i buy one from you? i live in USA and i would like to buy one.
please leave me a message through the website contact form, I have a U.S. reseller that I can forward you to then.
Nice job!
Brilliant!
Würde ich sofort kaufen wenn es nich so Teuer wäre! Für meinen Geschmack und das bischen was ich damit machen würde tuts bei dem Preis auch ne Billige Alternative aber sehr schön umgesetzt großes Lob dafür mfg
Danke :-) Der Preis wird noch deutlich runtergehen, wenn es klappt und größere Stückzahlen möglich sind. Im Moment mache ich alle mechanischen Arbeiten selbst und muss den Preis dafür relativ hoch ansetzen, um nicht überschwemmt zu werden. Es macht jetzt noch keinen Sinn, irgendetwas rauszugeben. Es lohnt sich hier selbstbauen, die Rohteile insgesamt dafür kosten dafür etwa 149€. Viele haben aber bereits einiges davon da, z.B. Fußtaster, Kabel oder Schrauben, dann lässt sich der Preis auf 99€ reduzieren.
Vorsicht bei dem einen oder anderen Bausatz, vieles ist sehr knapp kalkuliert und "stirbt" schnell. Dieses Gerät ist deshalb teurer, weil es mit Reserve dimensioniert ist und auch noch 2000A klaglos schalten kann. Und die Energiemengensteuerung ist auch einzigartig im DIY-Bereich.
If the FETs stay on for some time, the current should accumulate due to inductance to some maximum value, when the FETs are then switched off, so ZCS switch on. But at switch off you have maximum current and maximum switching losses, and without a flyback diode how is this energy depleted? Like I see what looks effectively like a buck converter without the freewheeling diode. The freewheeling circuit will be half of the power since it starts at the peak current and decreases to zero.
I thought that was what was killing my cheapo $25 ebay special along with poor gate drive. At least on one occasion, a FET failed so spectacularly that it somehow welded itself to the PCB and removing it required lots of heat and force with pliers. Chipping away at the plastic encasing and the stuck metal tab that welded itself to the copper despite being soldered.I did get a chance to see the silicon die on those and was impressed with how huge it was. So used to thinking of transistors as microscopic things but seeing the die that was maybe 4mm by 6mm was just amazing!
in kWeld, this is handled by an array of large TVS diodes. As you have experienced, the MOSFETs alone cannot handle the amount of inductive kickback at these current levels.
Looks good I been finding transformers to rewind the secondary to get the most current at low volts .....it don't weld a good as this tho .....very nice
Thanks :-) I opted against transformers, because a) no way to turn that into a kit for sales, b) less control as you say.
WeAreTheWatt oh yeh I don't plan on selling just for own quick use
I like the electrode holders
Is the circuitry in this effectively similar to the car jump start battery pack? Not seen much for tear downs on them but they also use MOSFET's. Otherwise from a safety stand point it could be a good idea to cover the leads with some kind of insulating material where you are holding them.
AFAIK those Lipo jump starter packs are basically just the battery and a schottky diode for reverse polarity protection. There is no power switch, you just connect them to your battery. The current is typically also lower, a few 100A. This unit is much more complex, as it has to reliably switch up to 2000 A.
wow, thats slick!
nice video, thanks for sharing bro.
Quick easy I'm interested
Ich habe heute damit 2x 0,3mm= 0,6mm Hiluminband übereinander auf einen Akku erfolgreich geschweisst.
Einstellung 200 J Delay 0,7s 1390 Ampere. Hab gar nicht geglaubt, dass man solch dickes Band damit Punktschweißen kann.
Hatte mich zuerst langsam herangetastet mit den Einstellungen. Ich werde übermorgen versuchen 3x0,3mm Übereinander = 0,9mm damit Punktschweißen. Als Stromversorgung habe ich 13,8 Volt / 240 AH Lithium-Eisen- Titanat Akku (LTO) angeschlossen. Dieser liefert auch 3000 Ampere wenn er soll.
Super! 1390 Ampere ist mitten im "sweet spot" des Geräts.
Quite a steep price for a DIY. But still - nice work.
Really good construction idea and innovation! May i suggest just one improvement idea for the electrode holders: when i saw the big gap between the cable connection and the round electrode i first wondered why. Then i saw you need the disconnection to get the pressure to the electrode by screwing them down. But you only need to cut one peace to achieve the same result and have a better connection with a lower resistance. May not matter much here, but every percent counts :-)
Are you in mass production already?
I am about to build a bigger spot welder for stainless steel - about 2 - 2.5 kAmps :-)
Triggered by two SSR's and inrush current control for the primary winding of the transformer (rewound from an old traditional welding transformer around 4 - 5 kVA).
Thanks for your suggestion. Sadly that electrode holder is already obsolete, I didn't like the machining effort that had to go into it and found a simpler solution. I hope to upload the next video by this weekend showing this and other improvements.
p.s. yes I am in mass production, if a first batch of 25 can be called that :-)
what sheet metal thickness do you aim at? 2.5kA is not a lot for this. Professional sheet metal welders can easily go up to 15-20kA. BTW, my design is calculated for 2kA max for 200ms.
Hi there, i doubt that a LiPo-battery can give you 2 kA - did you check the amps? I know that industrial spotwelders can deliver up to 30 and 40 kA, but i used an old welding transformer and replaced the secondary by 4 windings of 120 mm2 copper cable giving me up to 4 V at around 2,5 kA (for a few seconds). That should be enough for 1 - 1.5 mm stainless stell i guess. More would be better tough...
I measured the amps through a defined section of (brand quality pure copper) AWG8 wire with known resistance. Modern high amperage race Lipos are well capable of delivering these currents. I just received a fresh Turnigy nanotech 3S / 5Ah pack. That is rated for 130C discharge current, which is 650A. "Continuous"!
Perfect tool!
Fantastic work. It can deliver up to 500J, but you show 18650's require only 150J. Could you make a less expensive version with fixed 150J output? Then you could downgrade all components, thinner cables, fewer mosfets, smaller battery, no pot (cuz fixed), etc. I don't need 500J. I think you would find a lot of buyers for that. Thx.
It's the current handling capacity (2000A) that makes the components expensive, and the reliability that my design stands for. Battery spot welding needs at least 1000A to work properly. The amount of energy is varied by adjusting the pulse duration. However, the numbers in this first videos are wrong (current measurement was inaccurate at the time of making it). The series product can do up to 200J, and needs 50-100J for 0.3mm nickel strips.
impresive work
This is really fantastic to me, and the amazing realization is that no high voltage is necessary only 11.1v! Why people user a high voltage is now a mystery to me. Perhaps the weld happens a millisecond faster with a higher voltage?
Where did you see high voltage in a resistance spot welder? For this kind of welding, you just need insanely high currents. The resistance of a weld spot is low, maybe one milliOhm. And you need to heat it up such that it melts.
many people use a microwave transformer- but actually I guess in adding a large secondary they are actually using a low voltage at the weld. So the big difference then is just using wall current versus battery current, and to produce the hundreds of amps needed a relatively high primary to secondary ratio is needed. But I always thought that arc welders use high voltage- but maybe no.
Yes, the microwave designs also produce low voltage, around 1-3V on the secondary. But hundreds of amps is not enough yet, also these are able to do >1000A when made well. Their advantage is that it is much easier to switch the current, but their disadvantage is that they can only chop the welding time into 10 millisecond intervals (one half AC sine wave). I need much better resolution to implement my energy based pulse control and therefore chose DC supply and MOSFET switching.
I think that arc welders are using higher ignition voltages, but this one is not an arc welder. This is called resistance spot welding.
oh ok thanks for explaining- interesting that yes- it must be that 60hz is only 16ms I see your point about a higher switching frequency.
Great project. One suggestion. Don't use a Deans connector for the battery. An XT90 connector would be much better.
Check my new videos on this, I've already improved that :-)
Still not XT90 though ;)
No. I have them here, but it is very difficulty to mate them with AWG8 cable. Therefore I decided to use XT150 instead.
3d print an electrode holder. Would be nice if it could use power tool battery packs. Then you could build a full case and have a fully portable welder.
Electrode holder: secondlifestorage.com/t-Easy-to-3d-print-K-Weld-electrode-housing-files (community contribution). Power tool battery packs won't work, as the welder needs at least 1000A (better 1500A).
I want to buy one. Please do let me know the procedure and price.
I guess you missed the link at the end of the video, and in the video description. That's where my webshop is: www.keenlab.de/index.php/product-category/kspot-welder-kit/
Well done