i see programs to convert from something to a step file or some other 3d design stuff but is there a program that can convert from 3d design software to something i could get a pcb from?
Have you tried the StepUp workbench for FreeCAD?
What exactly you need to do?
What does your 3d program define?
The outline is easy to get into KiCad with stepup. Positions of components (including mounting holes) is also reasonably easy with stepup.
Copper and other typical PCB layers are a lot harder. This is because there simply are no tools out there that do it. Not because it is more work to implement something like this but because there simply is not really a demand for it.
My 3D program drawings are all copper. 2 or possibly 3 layers. And vias ands some simple masking and that’s it. I’ll try stepup thanks but not feeling positive.
I would assume there is a reason why this board exists as a 3d model instead of being designed in a electrical CAD system. Could you give us these reasons because maybe there is a better option out there that would be easier to get to the PCB.
Oh and stepup can not really convert copper to a PCB. It can be used to push an outline to KiCad or to design complex footprint pads but not really to get a full PCB from FreeCAD to KiCad.
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aha. yes i found converting to gerber doesnt mean you can make a pcb out of it. ugh. please call me or write me if you want to make bucks converting my simple design into something a fab house can make
(removed by mod, us PM if you want contacts)
john
it still wont tell me upload any attachments as im new.
just 2 layer pcb with no components for batteries i later attach. just fat traces mirrored on both sides with thinner balance traces on the bottom as well. slots. holes. solder mask. thats it.
You can use Python.
You can also do it with GCC
But beware, there may be a steep learning curve 
steep and long. ive tried different software and out of effort to continue. but if youre good and quick its easy bucks
call me!!!
I have some experience with KiCad, and it should be fairly easy to import a DXF file into KiCad.
I’m not much interested in a big job, nor am I interested in money. But I’m willing to have a look at it, and if it’s a quick job for me I’ll do it for fun.
So the question is:
How much are you willing to donate to KiCad?
(Hopefully you can PM me the DXF. If you want I can also post it here for others to have a look at it)
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ill do that now. dont know what you mean by donate but happy to donate design or bucks
i cant seem to pm you. maybe thats limited too since im new?
Level up. Try now. …
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he got it going by writing me first
Around 23:40 we exchanged some PM’s and then it suddenly stopped…
hummie uses fusion360 and apparently he has some problems exporting (to any format). Probably one of the hidden features of fusion360?
@hummie, If you can verify if you can open a dxf with LibreCAD, then it’s fairly sertain I can also import it in KiCad.
Local time here in Europe is now 01:47 and it’s time to put one ear on a pillow for the next bunch of hours for me.
5.5 fat traces with balance traces ( no outline) v1.stl (36.8 KB) 5.6 26650 pcb Drawing v1.pdf (124.2 KB) 5.7 holes.dxf (138.2 KB) 5.7 holes.pdf (105.0 KB) 5.7 pcb w traces v1 Sheet1.dxf (150.1 KB)
We hope you put those files public on purpose…
At this moment I have a preliminary draft of your PCB.
The files you posted are not of much use to me.
The DXF files are scaled. the stl file is a “blob” which I do not know how to handle well. The PDF file has measurements, but there are lots of inconsistencies.
So I had to do some guesswork to make a PCB out of this.
I assumed the outside diameter of the PCB is 500*143mm (or is that the size of the pads?)
Instead of trying to scale and convert your DXF files I just took some coarse measurements, rounded most measurements down to whole millimeters and converted it to a native KiCad project.
Sizes I used for the pads:
- 31 * 160mm
- 73 * 78mm
- 31 * 80mm
I have put SMD pads on both top and bottom, and stitched them with rows THT pads.
I also had to make other guesses.
First guess is to what this PCB is actually used for.
I guess it’s for very big battery packs with a lot of 26650 cells.
I guess that each pad is for 6 cells.
I guess that 6*12 = 72 of these 26650 cells are stacked between 2 PCB’s.
I guess that multiple of these stacks form a larger complete pack.
I guess there may be hundreds of these 26650 cells in a complete battery pack.
Are these guesses correct?
What is the current rating of this battery pack? I guess that each (0.7mm) via is good for about 2 to 3 Amps, but have not researched it thoroughly.
At the moment the long pads have 122 via’s and the square pad has 112 via’s.
Some of the work I’ve done:
I started with making a schematic:
The schematic is of course very simple.
A connector (2.54mm spacing) for the sense lines, and 3 sizes of pads. I also added labels to the wires for ease of PCB routing.
After that I made custom footprints for the Pads.
Pads are on Top and Bottom of the PCB, and Top and bottom are stitched wit via’s:
I have also made a custom footprint for the “slots” and placed an array of them on the PCB. At the moment each slot is 9*1mm.
In KiCad’s 3D viewer it looks like:
As you can see I have not routed the board yet, KiCad is yearning for me to replace the white ratsnest lines with real tracks.
You put all the tracks on the same layer, Is it OK if I put some on the top, and others on the bottom?
But I will only route the board once the exact dimensions and locations of the pads are clear.
The easiest way is to have an DXF file of only the object. scaled 1:1 and inclusive the board outline (Is it 500x143, or is that the size of the outline of the pads?
Also, I think it’s now time to discuss my “fee”.
What is this design worth to you?
It took me a few hours, most of it was trying to understand what exactly you want to make, and some of it was to refresh some info of how to do things the KiCad way.
What is it worth to you to have this design in a quick manner?
What sort of production are you going to make of this? How many of these battery packs will you make?
At the moment I’ve put about 5 hours of work in it, inclusive communication and figuring out how to interpret the files you posted here.
Since you offered to pay for this design, I want you make a fair donation to the KiCad project for the worth of this design to you.
You can make a donation through:
https://funding.communitybridge.org/projects/kicad
I’m not sure, but I think this donation is tax deductible, but if that’s important to you, i’ll leave the details for that for you to figure out yourself.
I am also having difficulties with sizes and dimensions, because different files you made public here have different measurements.
For example:
- I would have expected 1:1 raw objects, no title blocks and such.
- Pdf says: 161.06mm long. (Top left pad)
- Stl says: 162.50mm long.
- Dxf says: 107.35mm long.
- PDF says: Pads 31mm wide, while the Stl pads are 30mm wide.
- Stl is only file with “accurate” measurements, but does not have board outline.
- Weird scale factors on drawings.
- It also seems logical you want rounded corners on the PCB. Maybe the same radius as the 26650 cells?
- How about the “ears” on the 2 short pads near the connector for the sense lines. are those important? (I can add them easily)
- Is my idea of via stitching around the edges OK? Do you want more or less via’s, and where do you want them?
- I am also not sure of the exact locations of the slots. At the moment I’ve set the pitch between the slots to 27.41mm. Is this an important measurement? If it is not important, then I prefer to work on a grid of whole millimeters. KiCad itself is not very good with measurements, and with whole millimeters it’s easier to work on a grid.
- On the pdf you have a measurement of 11.6mm Is this the center distance between the slots, or is this measurement for the distance between the pads?
- When the design is finished, is it OK if I post the whole project here, or do you want to keep it private (Then I’ll PM it).
I think it’s also a good Idea if you install KiCad.
KiCad is an open source program and this won’t cost you anything. Then, when you view the project in KiCad you can determine if it’s OK, and I can make adjustments before making the final Gerbers. (Or you can make the Gerbers yourself with a few mouse clicks).
Also, having the complete design as a KiCad project makes it easier for you to adjust the design for a different sized battery pack.
Last:
I’ve removed the border and titleblock of “5.7 pcb w traces v1 Sheet1.dxf” and then scaled it with a factor of 1.5, and now it fits reasonably well on the PCB. But I do not know if this scaling is correct. Ideally I ant a .dxf file with:
- Outline of the PCB.
- Location and size of all pads. (Is roudning to mm OK? Can all the “Long” pads be the same size?)
- Location and size of all slots. (Is rounding to mm OK?)
- Location and size of the connector.
- Circles for diameter and location of the 26650 cells. (these are not always exact the same size)
Is it possible the battery cells are in some ridgid frame with fixed dimensions? If so, is there a datasheet? (Post it)
Also some notes about your tolerances would be nice.
Are sizes of the DXF a maximum, a minimum, or plus and minus some distance.
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Now I realize the intention may be differently.
Could it be that just 2 of these PCB’s will form a single battery pack?
It may be a good Idea to use the back of the PCB to make series connections between the cells.
Maybe you want smaller pads on the back of the PCB to solder wires to?
Another idea is to put 2 holes near the connection of the sense wires.
If your intention is to solder the wires directly in the PCB, then some form of stress relief is required. with holes through the PCB, you can put tie-raps through the holes to secure the cable. (The cable may not bend at the solder connection. It is a stress concentration point).
Maybe these cells are supposed to be glued together.
Soldering is uncommon for Li-Ion.
Let me know your requirements and I can make adjustments.
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I have had experience with doing something like this. What amount of current do you want to draw out of the battery?
If it is more than a few amps then i highly suggest you go a different route than using a PCB.
The team i worked with made the experience that you really need copper inlays to be able to handle even currents in the order of 20 Amps. (Mainly because you really need to ensure that there is very little voltage drop within your battery pack as you otherwise draw differing amounts of power from your cells). Soldering to such copper inlays gets however really tricky.
And as soon as you use copper inlays you basically can also directly use nickel plated plates (same material as the strips that come out of your cells) laser cut to your desired shape allowing you to even have thin strips protruding bend over to make soldering easier or even better have them spot welded. Solder thin wires directly to these plates to then get the protection circuit and don’t forget to include space for temperature sensors.
And separate the different voltage zones by use of plastic plates (can be glass fiber reinforced plastic if you want the same component to add more mechanical stability).
For pure series connections there is an even simpler solution. Place your cells next to each other but rotated such that the minus pole of one cell is always near the plus pole of the next one. Tape them together by use of fire resistant tape (to be on the save side). Then solder them together without anything else in between. For mechanical strength put large shrink tubing on top of that.
This is how most commercial battery packs are made (the one for RC cars, planes, …)
You can also place rubber strips around the connection points to reduce the chances of short circuits in the case of mechanical damage to your pack (for example if it is dropped). The least you should do is put tape over them.
You can also buy one cheap pack and dissect it to see how it can be done.
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In his other post hummie plans to use 2OZ copper for this board.
There are also no connections on the back side. Top and bottom are symmetrical, which gives 4OZ copper total. I also assume the connection on the back will be in the middle, which helps current spreading and reduce voltage drops.
I do not know what’s going to happen with the back of the board.
A photo of a similar finished battery pack would be nice.
Also, is 5 hours of design time normal for a board like this?
What would be a fair price for such a board?
At the moment I don’t even know if this is for a mass produced commercial product, or a one-off hobby project.
Comments from any forum readers welcome.