Author Topic: kWeld - "Next level" DIY battery spot welder  (Read 97972 times)

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Offline anishkgt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #375 on: September 16, 2017, 06:22:19 pm »
Oh Tatus i had begun this project of mine a year back and they are not based on the capacitve discharge welding, rather they work on ac and determining the amp drawn was harder where the ac had to be rectified and then fed into the MCU and again there would be voltage drop down the way.

I brought this question up because it was done here http://avdweb.nl/contact/12-contacts/1-avandalen.html and wish to know how true it was by asking for others opinion. It had nothing to with your project and in fact am not going to add it into my either though the approach to it is totally different. Was only shedding some light to it so maybe yourself or others could make use of it.

Secondly i know how hard to sell something to some pennies out of it. I had sold quite a few of earlier spot welders. I have the second version pcbs with me that i had posted here in the forum http://www.eevblog.com/forum/manufacture/some-china-pcb-manufacturer-recommend/50/.

I too am a dad and a husband but this is not my primary job i work in the IT industry and these are just my hobby which am interested in with that said i do not copy and paste ideas, i try to do it my way with my own ideas. So Tatus need not worry about copy your ideas or designs into mine. :)


Hope that clears your mind.
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Offline anishkgt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #376 on: September 16, 2017, 06:55:41 pm »
Impressive project by the way Tatus :clap:. Seems one of a kind and i hope this would bring you fortune. :-+ As far as i have read, growth and fame has always begun in a closed small room, a grage or in the basement.
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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #377 on: September 16, 2017, 07:20:52 pm »
Impressive project by the way Tatus :clap:. Seems one of a kind and i hope this would bring you fortune. :-+ As far as i have read, growth and fame has always begun in a closed small room, a grage or in the basement.
Thanks, in this case it would an attic  8)
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Offline anishkgt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #378 on: September 16, 2017, 07:22:18 pm »
Impressive project by the way Tatus :clap:. Seems one of a kind and i hope this would bring you fortune. :-+ As far as i have read, growth and fame has always begun in a closed small room, a grage or in the basement.
Thanks, in this case it would an attic  8)


ha ha ha  :-DD that is a close match to 'closed small room'
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Offline mazzic518

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #379 on: September 17, 2017, 10:11:58 am »
I definitely want one looking forward to the second batch.
 

Offline Mikko Saarisalo

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #380 on: September 19, 2017, 04:45:10 am »
+1 for the waiting list for next production run.  I would not mind making and paying a pre-order for one or two units.

(Just registered to this site for this very purpose... :) )

cheers
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Offline mcinque

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #381 on: September 25, 2017, 03:07:30 am »
SirJMD, my compliments to you about how you're handling this little issue with your customers  :-+

Can I take advantage of this post to ask you the role of this three components (D16,D6 and D7-12, TVSs and zener) in your schematic? TVS are there to clamp voltage of course, maybe to manage the wiring inductance kickback? And why the zener on the mosfets? Of course to protect them from overvoltages, but are they needed because of the inductive kickbacks coming from the welding pulses?

Sorry for my ingorance  ;D
« Last Edit: September 25, 2017, 03:50:15 am by mcinque »
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshit :)
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #382 on: September 25, 2017, 09:51:39 pm »
SirJMD, my compliments to you about how you're handling this little issue with your customers  :-+
Thanks  ;)

Can I take advantage of this post to ask you the role of this three components (D16,D6 and D7-12, TVSs and zener) in your schematic? TVS are there to clamp voltage of course, maybe to manage the wiring inductance kickback? And why the zener on the mosfets? Of course to protect them from overvoltages, but are they needed because of the inductive kickbacks coming from the welding pulses?

Sorry for my ingorance  ;D
Yes, the TVS is there to reduce the stress that the transistors see during inductive kickback at turn-off. The zeners are there to protect the MOSFET gates from overvoltage. As I had to assume fast transients at their drains, and the gates are only loosely driven, I am afraid of gate overvoltage from charge build up through their Miller capacitances.
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Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #383 on: September 25, 2017, 10:55:51 pm »
When dealing with high energies, the 'belt and braces' approach is more than justified  :-+

I would place TVS diodes all over the unit if I thought it were needed, but you have already come up with an excellent robust design.

Sadly my kit is still in its box awaiting its turn on my to-do list.

Off topic but maybe of interest ?

I was demonstrating my Chinese Transformer based battery tab welder to my neighbour at the weekend. My first weld resulted in a loud BANG, from inside the unit and its lights went out. I thought I had blown the fuse but no, it was fine. House power was still on as well. The give-away was the lack of the neon light on the power switch ..... no mains power was getting to it.

A quick look inside revealed no smell of burning or obvious failure. A continuity check proved that the mains power cable Neutral wire was open circuit. Further investigation revealed that the blue insulation on the wire after it entered the units case looked slightly discoloured white in a couple of places. I pulled on the cable and the insulation could be seen to stretch ! I cut open the wires insulation and found just white powder inside at two separate locations. The copper wire had turned to powder ! No signs of heat damage.... the copper was gone. I looked at the cable quality and found that the manufacturer had used really low current cable with very little copper cross sectional area and very fine strands in the insulated wires. I am not certain of the failure mode, be it corrosion or gradual erosion of the fine wires, but it gave up in the end. I am fitting decent quality 13A rated cable to it instead.

Fraser
« Last Edit: September 25, 2017, 11:08:50 pm by Fraser »
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #384 on: September 27, 2017, 04:50:39 am »
Sadly my kit is still in its box awaiting its turn on my to-do list.
Then it's time to let the Tiger out  ;)

a loud BANG, from inside the unit and its lights went out.
That reassures me to continue my work! I am busy sourcing components for a 100 unit production batch.
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Offline Southerner

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #385 on: September 27, 2017, 05:32:11 am »

That reassures me to continue my work! I am busy sourcing components for a 100 unit production batch.
Do you have an estimated cost for the next batch?  I would be interested in one.
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #386 on: September 27, 2017, 05:33:43 am »

That reassures me to continue my work! I am busy sourcing components for a 100 unit production batch.
Do you have an estimated cost for the next batch?  I would be interested in one.
I'll publish that once I have all prices from my suppliers. I expect that to be completed in 1-2 weeks from now.
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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #387 on: September 27, 2017, 06:32:59 pm »
Guess what this will become  8)



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Offline Bratster

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #388 on: September 27, 2017, 06:40:57 pm »
Capacitor charging interface for a server power supply?

Sent from my Nexus 6 using Tapatalk

 

Offline Kjelt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #389 on: September 28, 2017, 12:27:23 am »
A raspberry pi / beaglebone  kWeld shield?  :popcorn:
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #390 on: September 29, 2017, 07:56:34 am »
Capacitor charging interface for a server power supply?
Bang on!

A raspberry pi / beaglebone  kWeld shield?  :popcorn:
Would that be another product idea?  ;)
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Offline anishkgt

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kWeld - "Next level" DIY battery spot welder
« Reply #391 on: September 29, 2017, 07:58:56 am »
Curious, which cad do you use to get those 3D images ?


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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #392 on: September 29, 2017, 08:53:25 pm »
Curious, which cad do you use to get those 3D images ?
I'm using old-fashioned Eagle and export into Sketchup.
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Offline anishkgt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #393 on: September 29, 2017, 09:00:50 pm »
Oh ok well that is a lot of work to do. Eagle is fine but moving it to sketchup is some work. I guess kicad is better with 3D but have to manually link the symbol to the layout.


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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #394 on: September 29, 2017, 09:09:48 pm »
Oh ok well that is a lot of work to do. Eagle is fine but moving it to sketchup is some work. I guess kicad is better with 3D but have to manually link the symbol to the layout.
the export/import is automatic, you just have to download or draw the objects. I get most of them through the warehouse, some of them are STEP files from the manufacturers. For this project, I didn't draw a single object from scratch. The biggest work was refining the heat sinks, as the manufacturer model only had a solid block instead of the fins.

I only wish that I had done that before ordering the PCBs. Look closer how the large connector's pins poke through the board :wtf:
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Offline anishkgt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #395 on: September 29, 2017, 09:13:20 pm »
Yea can be quite hard. I guess some day I'll have to start with kicad just because of the new licensing of eagle and the advantage of 3D rendering of kicad. If altium was cheaper would have taken that.


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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #396 on: October 01, 2017, 10:46:35 pm »
Capacitor charging interface for a server power supply?
The boards from Elecrow have arrived much earlier than I expected. Ordered on 23rd, received on 27th. :-+

Although I have to work on sourcing components for kWeld, I couldn't resist to build and power up one. It instantly came up with all four phases, and voltage regulation also works already ;D

Target specs: output voltage 6-10V adjustable (the design can do 0-12), current 0-80A adjustable. The design can operate in CV and CC modes. It fits all HP DPB800GB DPS800GB server PSU models that I found so far on the internet.

Apart from being a high power super capacitor charger, it can also be used to build a 12V / 80A current limited PSU for less than 100€.

I'll have to see how much current the design can do continuously, but it has a temperature monitoring circuit that linearly reduces current and regulates a max temperature. This makes it suitable for permanent short circuit under all load conditions.


« Last Edit: October 02, 2017, 12:41:09 am by tatus1969 »
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Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #397 on: October 01, 2017, 10:55:15 pm »
Nice work Frank  :-+

Very neat design.

Fraser
 

Offline anishkgt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #398 on: October 01, 2017, 11:08:04 pm »
Good job frank. With a little mode I guess it should fit other psu as well. But don't you think the power supply for kweld is a bit oversized. Just my opinion.


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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #399 on: October 02, 2017, 12:37:48 am »
Good job frank. With a little mode I guess it should fit other psu as well. But don't you think the power supply for kweld is a bit oversized. Just my opinion.
I want the system to allow welding at 50J with one second repetition rate. This means that the PSU needs to supply 50J / 0.1 * 1sec = 500W on average. (The 0.1 is the system efficiency)
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