Author Topic: kWeld - "Next level" DIY battery spot welder  (Read 53831 times)

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Offline cs.dk

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #150 on: July 22, 2017, 06:11:15 PM »
Thanks for the link, Fraser.. I though hydraulic crimpers were a lot more expensive..  :-+
Had to buy this one; http://www.ebay.co.uk/itm/322465802286
 

Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #151 on: July 22, 2017, 08:49:20 PM »
Yes I was surprised as well. I considered the 16T version but it lacked the smaller 4,6 and 8mm dies that I would find useful. If I ever need to crimp the larger sizes I will certainly buy the 16T version as well.

Fraser
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #152 on: July 22, 2017, 08:53:57 PM »
I decide that a simple hydraulic crimping tool would be useful to have in my tools collection so I have bought one this evening.
It is likely not that great for serious work but should meet my needs and those of this project. I also intend to use it as a mini hydraulic press once I have made up some flat face 'dies'.

There are two very similar looking versions on eBay. One is rated at 8T, whilst the other has a stronger head and is rated at 10T. The 8T comes with 8 dies and the 10T comes with 9 dies. I went for the 10T version.

The cost is £21.99 delivered from a UK warehouse. They are cheaper direct from China but I did not want to wait.
Mine is a pure mechanical one, limited to 50qmm. It is less versatile as it has a fixed revolver style tool set, which is not milled but punched. But it has one advantage, it is quick to use.
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Offline cs.dk

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #153 on: July 22, 2017, 09:05:35 PM »
For 4 and 6 mm i usually use DuraSeal ringterminals. Not lugs like the bigger (battery) ones. I've never seen a 8 mm2 cable. In Denmark we go from 6 mm2 to 10 mm2, that i'm aware of. Thats why i supposed i don't need em.

Mechanical ones are fine for most things, i use one at work everyday. But for a 70 mm2, you really need to push hard.
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #154 on: July 22, 2017, 09:53:57 PM »
For 4 and 6 mm i usually use DuraSeal ringterminals. Not lugs like the bigger (battery) ones. I've never seen a 8 mm2 cable. In Denmark we go from 6 mm2 to 10 mm2, that i'm aware of. Thats why i supposed i don't need em.

Mechanical ones are fine for most things, i use one at work everyday. But for a 70 mm2, you really need to push hard.
We had to do 6 x 150qmm on a ship once, to supply a 500kW hydraulic power pack. That was luckily done by the shipyard, they have no problem with that  ;)

the wire gauge that I use for the welder's electrode cable is an important part of the electrical system, also because it mainly defines the maximum pulse current level. If you choose to use cables with a larger cross section, then you'd have to pay attention to the total resistance budget, and make sure not to exceed the 2kA absolute maximum current level. Two days ago I made a(nother silly) mistake during my tests with the new electrode holder, by using a 5mm thick flat steel bar as weld material "simulator". I forgot to separate the electrodes by at least 20cm and placed them close to each other instead as I would do for a normal weld. I fired four or five times until I noticed that this was more than one second of continuous 1.2kA current flow. The battery didn't like it, and the Deans battery connector that is still there, even less. The welder has no problem with this, except that it realizes that the weld spot resistance is very very low and most of the energy goes elsewhere, which causes it to keep the current flowing until it times out or the energy was delivered at last.
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Offline cs.dk

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #155 on: July 22, 2017, 09:59:51 PM »
Just courious about your product, but can you reliably weld 2 thicker plates together, lets say 0,8 mm sheet metal? If so, i could in deed be interested in one.
 

Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #156 on: July 22, 2017, 10:00:52 PM »
Interesting to read about the 8mm2 size. That explains why that size is not present in the 8T version of my crimper :) I wanted the smaller sizes for when I do projects that require a metal tube to be crimped down onto a cable or rod. The tubes can be non standard diameters so having the 8mm2 die just looked to be useful :)

For smaller automotive type terminals I use the insulated ones and have the correct good quality crimping tool to compress them. The crimper even indents the plastic sleeve with the die details ! That crimping too was quite expensive but when dealing with automotive electrical connections, I take no chances.

I managed to get nice quality bootlace ferrule crimping tool a few years ago. Using bootlace ferrule crimps certainly tidies up my terminal block connections. Love that tool :)

Fraser
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #157 on: July 23, 2017, 08:46:36 AM »
Just courious about your product, but can you reliably weld 2 thicker plates together, lets say 0,8 mm sheet metal? If so, i could in deed be interested in one.
I'm afraid but I have no experience with that. Do you know what current levels and pulse times are required for that? The power switch of my welder electronics can reliably withstand 2kA for 200ms.

I found this interesting site: http://www.portablewelders.com/spot-welding-technical

It suggests at least 6kA for 200ms. The switch resistance of my welder is 120 microOhms. A current of 6kA would result in a power dissipation of 4.3kW, or 720W per transistor (assuming equal distribution, which is not the case). According to the datasheet of the used transistors, they allow a maximum pulse duration of 10ms at this power level. Which means: no, the kWeld circuit cannot do that for the required 200ms.

I managed to get nice quality bootlace ferrule crimping tool a few years ago. Using bootlace ferrule crimps certainly tidies up my terminal block connections. Love that tool :)
I'm still searching for the one that crimps well and is affordable. I have very good professional work experience with the Knipex 5512, that is in my opinion the one and only. Because that one is very expensive, I bought a "clone" for personal use - and I am quite disappointed. It is not machined precisely enough to do >=22AWG crimps.
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Online Kjelt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #158 on: July 23, 2017, 05:43:38 PM »
The even more expensive knipex with six crimpsides was half price on amazon a half year back perhaps still. The reason was they made a new one that went two steps in awg further but who needs that. So scored one for 105 euros instead of al ost 200 and every crimp is a pure delight.
 

Offline cs.dk

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #159 on: July 23, 2017, 05:45:46 PM »
I'm afraid but I have no experience with that. Do you know what current levels and pulse times are required for that?

I have no idea - But you have a working device next to you ;)
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #160 on: July 23, 2017, 06:57:53 PM »
I'm afraid but I have no experience with that. Do you know what current levels and pulse times are required for that?

I have no idea - But you have a working device next to you ;)
That, yes. But no .8mm sheet metal :-//
Your living is determined not so much by what life brings to you as by the attitude you bring to life; not so much by what happens to you as by the way your mind looks at what happens.

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Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #161 on: July 25, 2017, 06:47:18 AM »
My 10T hydraulic lug crimping tool arrived today.

I must say I am very impressed with it. How do they manage to make such a relatively complex tool and sell it for so little ? The tool is well designed and made from what I can see. The pump action Is quick as apparently the design provides fast initial movement until resistance is felt, then the action slows down. Turning the pressure release knob results in very quick retraction of the lower die and piston. On the10T version, the die locating pins appear to be a better design than those seen on the 8T version. They snap into the die holders and the dies remain well retained and aligned.

For occasional use, I can certainly recommend this tool.

Fraser
« Last Edit: July 25, 2017, 08:37:45 AM by Fraser »
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #162 on: July 25, 2017, 08:26:07 AM »
My 10T hydraulic lug crimping tool arrived today.

I must say I am very impressed with it. How do they manage to make such a relatively complex tool and sell it for so little ? The tool is well designed and made from what I can see. The pump actio. Is quick as apparently the desig. Provides fast initial movement until resistance is felt, then the action slows down. Turning the pressure release knob results in very quick retraction of the lower die and piston. On the10T version, the die locating pins appear to be a better design than those seen on the 8T version. They snap in to the die holders and the dies remain well retained and aligned.

For occasional use, I can certainly recommend this tool.

Fraser
I already regret it that I went for the cheaper option... |O
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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #163 on: July 25, 2017, 08:37:19 AM »
A quick progress update on this project:
- production of 25 copies electronic module is progressing well. I had a delay of one week here waiting for the microprocessors from Arrow, but the parcel is now at customs clearance here in Germany (there was some annoyance regarding export control restrictions, I had to calm Mr Trump that I will not be building any rockets from them). The PCBs have been manufactured in the mean time.
- I have completed the firmware update functionality. All that is needed for that is a terminal program that can talk YMODEM (extraPutty and TeraTerm do this job well), an adapter cable (will be added to the shop for a few €), and an Arduino style FT232 USB->UART adapter configured for 3.3V operation (I will also sell them via the shop for convenience).
- I have designed a housing for the welder, see these pictures and please tell me how you like it. I'll upload it so that anyone can print it. I'll not be selling them in my shop, as I don't have a 3D printer.

I still wait for the new battery and some parts to make a video showing the new stuff, hopefully by this weekend  :D

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Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #164 on: July 25, 2017, 08:45:03 AM »
I like the case. Very nice design.

Thank you for the update on the first 25 modules :). I am in no great rush as I have other projects in flow along with selling off my excess test gear on eBay :) I will be happy to receive my module whenever it is convenient for you to ship it. I am just pleased that I have pre-ordered one to ensure I get it.

Fraser
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #165 on: July 26, 2017, 05:51:18 PM »
I think that it will still be possible to keep delivery by mid August, I will keep you updated. Had to call DHL customs yesterday to hear that they have high workload and would have eventually contacted me the next days because they need an EORI number from me.  :wtf:
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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #166 on: July 31, 2017, 10:08:24 AM »
I've been working on the assembly manual, and have just uploaded a first (incomplete) version to the kicksurfer website. I have made this a downloadable product in my store that is free of charge for all registered users: https://www.kicksurfer.de/index.php/product/assembly-manual/  That'll not help much against far east copiers, but maybe a bit...

And I have tested a different approach to manufacture the bus bars, the brass bars are just too expensive to finish. I have attached first pictures. These are laser-cut from 4mm x 12mm x 75mm aluminum bars. The first tests are very promising, the switch resistance goes up from 0.12 to 0.145 micro-ohms. That is just 25 micro-ohms more. They don't heat up noticeably during heavy firing.

Their price is quite good, so that for all people who have already purchased the brass bars, I can offer the following:
- if you have ordered them "raw" you can choose to receive the finished aluminum bars at no extra cost
- if you have ordered them "finished", I'll additionally refund the labor cost

Of course it'll also be okay to leave an order untouched.

I'll create a separate mail to all customers to ask for their wishes.


« Last Edit: July 31, 2017, 10:12:36 AM by tatus1969 »
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Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #167 on: July 31, 2017, 09:00:59 PM »
My only concern regarding using Aluminium for the buss bars is the high reactivity of aluminium with the atmosphere. Aluminium oxide is a very poor conductor. Brass will also oxidise. Copper buss bars may be the best option, but also the most expensive.

I was considering what protection the bars may need to prevent such oxidisation becoming an issue over time. The old trick was to cover the area around the contact surface with an air excluder such as vaseline petrolium jelly. This may need to be considered but I do not think it is good to use it on the actual contact surface itself.

Fraser
 

Online Kjelt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #168 on: July 31, 2017, 09:31:36 PM »
I've been working on the assembly manual, and have just uploaded a first (incomplete) version to the kicksurfer website. I have made this a downloadable product in my store that is free of charge for all registered users: https://www.kicksurfer.de/index.php/product/assembly-manual/  That'll not help much against far east copiers, but maybe a bit...
Great  :-+ , I just can't find the download button but ordered it so I expect you will mail it ?  :-//

Quote
And I have tested a different approach to manufacture the bus bars, the brass bars are just too expensive to finish.

What was the problem, the milling is it to tough or does the bit bite into the metal? It might be good as Fraser indicates to switch to Copper, but I will look into this myself.
Can you provide me (us) with the exact mechanical layout (thickness, length, wideness, and position of the holes and diameter) of the bars, than I can look at my local metaldump if I can find a suitable copper donorpiece and already start cutting it up and working on that  :) 
Do you think it would matter if the barr is made out of two or three parallel parts or perhaps made thicker, since it is the overall resistance that counts right?
 

Offline Fraser

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #169 on: July 31, 2017, 09:41:30 PM »
Kjelt,

You need to 'order' the manual and go through checkout as if you were buying it. You then see a link to click for the download in your checkout receipt. No charge is made to you and no card/PayPal is needed. It just requires you to log in.

Fraser
 

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #170 on: July 31, 2017, 09:42:35 PM »
Yes thanks, the email had some delay but it is all clear now  :-+
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #171 on: August 01, 2017, 12:06:42 AM »
Kjelt,

You need to 'order' the manual and go through checkout as if you were buying it. You then see a link to click for the download in your checkout receipt. No charge is made to you and no card/PayPal is needed. It just requires you to log in.

Fraser
thanks for helping me out  :D
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Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #172 on: August 01, 2017, 01:24:32 AM »
My only concern regarding using Aluminium for the buss bars is the high reactivity of aluminium with the atmosphere. Aluminium oxide is a very poor conductor. Brass will also oxidise. Copper buss bars may be the best option, but also the most expensive.

I was considering what protection the bars may need to prevent such oxidisation becoming an issue over time. The old trick was to cover the area around the contact surface with an air excluder such as vaseline petrolium jelly. This may need to be considered but I do not think it is good to use it on the actual contact surface itself.
I've got the same feedback on other places, and I have started investigating it. I found a shop that sells galvanic articles, and it would be possible to add chemical zinc, and then galvanize with gold. That would be a good match for the gold PCB traces.

On the other hand, I have built an audio amplifier decades ago, and I still have the bulk capacitors with screw terminals that are connected with aluminum bars. The capacitor's screw terminals were made from tinned brass.

That makes me think: would it prevent contact corrosion if I would order tinned PCB's instead of gold plated next time?

What was the problem, the milling is it to tough or does the bit bite into the metal? It might be good as Fraser indicates to switch to Copper, but I will look into this myself.
Can you provide me (us) with the exact mechanical layout (thickness, length, wideness, and position of the holes and diameter) of the bars, than I can look at my local metaldump if I can find a suitable copper donorpiece and already start cutting it up and working on that  :) 
Do you think it would matter if the barr is made out of two or three parallel parts or perhaps made thicker, since it is the overall resistance that counts right?
I indeed had problems with drills biting into the metal, but meanwhile I have specialized soft metal drills that perform much better. The work steps on the brass bars are the following:
- cut to length
- measure and centerpunch all drill positions (I will use a template instead for "mass" production)
- drill 4.5mm holes
- drill 6.5mm holes
- deburr with countersink drill
- sand all faces

That sums up, wich was why I decided to set the price for that work relatively high. Also to prevent myself from drowning in machining work.

Here are the dimensions of the original brass bars. The new aluminm bar is identical but is only 4mm thick (the maximum that my provider can laser with this contour).


« Last Edit: August 01, 2017, 01:26:11 AM by tatus1969 »
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Online Kjelt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #173 on: August 01, 2017, 01:54:27 AM »
Thanks for the info Frank  :-+ Itsure takes time if you do all those steps,almost time for a CNC  ;)
 

Offline tatus1969

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #174 on: August 01, 2017, 01:56:13 AM »
almost time for a CNC  ;)
definitely!!
Your living is determined not so much by what life brings to you as by the attitude you bring to life; not so much by what happens to you as by the way your mind looks at what happens.

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