Author Topic: KiCAD custom board shape  (Read 5706 times)

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Offline Rerouter

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Re: KiCAD custom board shape
« Reply #25 on: September 17, 2018, 12:46:35 am »
I mentioned a 1.6mm board because some people see a 2mm slot and think a 2mm thick pcb is the best choice.

A chamfer is a straight line cut off corner. Making 2x 45 vs just 1x90. But rounding off gets a similar effect

In these enclosures you will likely be making holes in the end plates for your connectors to the outside world. So drilling mounting holes through an end plate is not uncommon. The studs I mentioned are essentially a solder on nut. Generally to suit a 2-3mm machine thread screw that secures your pcb to an end cap.

The other way is to just make the board fit the enclosure length. Then it cannot really go anywhere
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #26 on: September 17, 2018, 06:58:13 am »
Since I am firm believer in hard fixing everything, I tried to think about more solutions. Here is what I got:

1- using spacers

https://www.banggood.com/300pcs-M3-Nylon-White-Hex-Screw-Nut-Spacer-Stand-off-Varied-Length-Assortment-Kit-Box-p-984548.html

Another option: https://www.aliexpress.com/item/50Pcs-M2-5-M3-M4-Hex-Nylon-Standoff-Spacer-Column-Flat-Head-Double-Pass-Nylon-Plastic/32817236078.html

But now I have to buy these sets from aliexpress, which is mendoksai!

Using this kit I can put 2-4 spacers under the board on the bottom part of the enclosure and glue them there... then put holes in PCB and use screw with a nut to secure it. It won't be precise but kinda will do the job.


2- Soldering joint

put 2 soldering pads (no connection) at the end of the PCB near the back plate, and make 2 pads on the back plate (which is a pcb)... stack then next to each other and solder them.


I am looking forward to your opinion. I wonder how professionals do it.
« Last Edit: September 17, 2018, 07:48:44 am by VEGETA »
 

Online bson

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Re: KiCAD custom board shape
« Reply #27 on: September 17, 2018, 07:02:43 am »
I will use 1.6mm as it is the default. I don't know why you mention it.
Because as a rule it's better to repeat something someone already knows than to fail to mention something they don't.

1.6mm isn't a universal norm anymore, especially for two layer boards.  I just ordered a bunch of 4 layer boards, and the default for them was 1.2mm from JLCPCB.  That's a bit thin for my uses, so I upped it to 1.6, but 1.6mm is a pretty thick board these days.  I think it added 2 days to the turnaround, so 1.2mm would have been a little quicker and I would have gone with that if I didn't need something that can be manhandled.
 

Offline Rerouter

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Re: KiCAD custom board shape
« Reply #28 on: September 17, 2018, 08:24:24 am »
On previous boards, I have just has a T shape routed in the board edge. Dropped in a 4mm nut in the top of the T. Solder it to the board and left the down stroje of the T for the screw to come throug. If I can find the design files I'll try and upload a render of what I am talking about. Made for dirt cheap mounting hardware.

Just have to be aware the routing bit of choice at fabs will be 2-3.2mm in diameter. So for inside corners I made my edge cuts dig in a bit deeper at those corners so they could fabricate something that the nut would friction fit in.
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #29 on: September 17, 2018, 10:41:46 am »
On previous boards, I have just has a T shape routed in the board edge. Dropped in a 4mm nut in the top of the T. Solder it to the board and left the down stroje of the T for the screw to come throug. If I can find the design files I'll try and upload a render of what I am talking about. Made for dirt cheap mounting hardware.

Just have to be aware the routing bit of choice at fabs will be 2-3.2mm in diameter. So for inside corners I made my edge cuts dig in a bit deeper at those corners so they could fabricate something that the nut would friction fit in.

I tried to imagine this but failed miserably.  :-DD

Do you mean the nut sits inside the T pointing towards the end of the board? meaning, if screw is attached to it then it would be perpendicular to the back panel?

then you would need to attach the screw to that panel or even if it is perpendicular on the bottom part of the enclosure you would still need to attach it somehow which returns to the first problem.

 

Online sokoloff

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Re: KiCAD custom board shape
« Reply #30 on: September 17, 2018, 11:03:11 am »
Rerouter's idea is slick.

Imagine you wanted to use a screw through the back panel to fix the board front to rear. Near the back of the PCB, create an east-west slot (along a line from side-slot to side-slot on the enclosure). This slot will hold the nut vertically. Now, create a north-south slot from the back edge of the PCB to the slot you created above and a little beyond (towards the front of the device). This will allow the screw to come through the back panel, engage the nut in the east-west slot (fixing the PCB mechanically), and then a little extra space so you can have the thread come fully through the nut and have a little space for full engagement and to allow you to buy screws with slight variance in length during production.
 

Offline Rerouter

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Re: KiCAD custom board shape
« Reply #31 on: September 17, 2018, 11:32:41 am »
I was not able to find the design files for the final version, but this should give you an idea on what I meant.

Later on i set it back 1.5mm away from the pcb edge, leaving a 3mm gap for the screw so the board did the supporting, not just the solder,
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #32 on: September 17, 2018, 12:09:53 pm »
nice idea!

However, how should I attach it to the back panel?

I don't want to make anything visible from the outside, thus I need something neat from the inside without making holes in back panel.


One idea is to have a solder pad on back panel which gets soldered to this nut, but I think you already rejected this idea.
 

Offline Rerouter

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Re: KiCAD custom board shape
« Reply #33 on: September 17, 2018, 12:26:42 pm »
Well now your just making things hard :P

My first suggestion would just be countersunk holes and live with flush, but visible.
Be aware the case will have 4 countersunk holes per end that hold the case together

The other is much more crafty. use a folded spring battery terminal on the edge of the PCB, it can take up 1.5mm of slack,

But seriously, you have no connectors on the top or bottom??
« Last Edit: September 17, 2018, 12:31:00 pm by Rerouter »
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #34 on: September 17, 2018, 12:38:59 pm »
Well now your just making things hard :P

My first suggestion would just be countersunk holes and live with flush, but visible.

The other is much more crafty. use a folded spring battery terminal on the edge of the PCB, it can take up 1.5mm of slack,

But seriously, you have no connectors on the top or bottom??

Top or bottom what? the PCB? it is through hole components.

As for front panel, it is gonna be drilled to fit a panel meter and input plugs and possibly an on\off switch.

As for back panel, I will fix the heatsink on it. Maybe use the provided screw holes to fix the heatsink and back panel together and also with enclosure as a whole. Or drill 2 holes for the heatsink (but then the original screw holes will be unable to be used.).

BTW, can I use nylon\plastic screws to fix the heatsink to this aluminum enclosure? the mosfets are in an isolated package but if one item is not isolated then it will be shorted to the whole enclosure. I wonder if there is anything to isolate the metal\ss screws or any form of screws that are isolated but still withstand heat. this is important.

the mosfets will be fixed to the heatsink by cutting a rectangular hole on the back panel to let the cabling reach them... so basically all our suggestions are not valid in this case simply because I forgot to mention how heatsink will be mounted.  :-//

but it is a nice addition to my knowledge for the next project. looks like more questions emerged in this post.
 

Online MasterTech

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Re: KiCAD custom board shape
« Reply #35 on: September 19, 2018, 12:04:55 pm »
I'm having trouble importing a dxf file into kicad to create a board outline

In inkscape I design a rectangle as follows,



Then after converting the object into a path, exporting to dxf and loading into kicad gives me this,



DFX file is attached, corners are not imported. Is it because kicad will only import straight lines?
 

Offline Rerouter

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Re: KiCAD custom board shape
« Reply #36 on: September 19, 2018, 12:09:08 pm »
V5 currently only supports segment based DXF, if you have splines, which your arcs are probably encoded as it gets unhappy,

Picking an older DXF specification is the fix.
 

Online MasterTech

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Re: KiCAD custom board shape
« Reply #37 on: September 19, 2018, 01:52:41 pm »
The thing is, it is not trivial to close two lines with an arc in kicad, it seems to be very picky about where the lines cross. In 3d view then it gives error messages about it...
 

Offline Clear as mud

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Re: KiCAD custom board shape
« Reply #38 on: September 19, 2018, 04:03:38 pm »
The thing is, it is not trivial to close two lines with an arc in kicad.

It was easy in the July 2013 version (the one that for more than two years was the most widely available version for Windows).  I haven't worked with KiCAD in three years or so, but I used to make edge cuts with arcs at the corners all the time, and I don't remember if I did anything special to make the ends exactly line up.  I think as long as they got close that was fine.  Either that or there was some easy way to make them line up.

Now that I'm thinking about it, I think what I usually did was work in "snap to grid" mode and set my grid at an acceptable size, then create a 1/4 circle snapped to the grid at the ends at each corner of the board, then join the 1/4 circles with lines.
 

Online MasterTech

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Re: KiCAD custom board shape
« Reply #39 on: September 19, 2018, 04:49:34 pm »
The thing is, it is not trivial to close two lines with an arc in kicad.

Now that I'm thinking about it, I think what I usually did was work in "snap to grid" mode and set my grid at an acceptable size, then create a 1/4 circle snapped to the grid at the ends at each corner of the board, then join the 1/4 circles with lines.

That was it, I was using a grid too fine, and the start and endpoints of each segment have to be 'exactly' the same
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #40 on: September 22, 2018, 07:32:55 pm »
I think I am settled on this one: https://www.aliexpress.com/item/YGS-005-88-38-120mm-WxH-L-anodized-aluminum-small-aluminium-extruded-project-electronic-enclosure-pcb/32826456213.html

I will choose 82mm to be the board width and 100mm to be the length, as heatsink will be mounted outside. I will try using freecad or something similar to create the outline then import it to kicad since this is the easiest way.

I could draw it inside kicad but no way I can verify if it is correct or not, or can I?
 

Offline donotdespisethesnake

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Re: KiCAD custom board shape
« Reply #41 on: September 22, 2018, 08:47:56 pm »
Of course you can, click on the line and look at the properties, use the relative coordinates, or the measure tool.

In the 10 days since you first asked, you still haven't tried it in KiCad? It would take a few seconds to draw the outline...
Bob
"All you said is just a bunch of opinions."
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #42 on: September 22, 2018, 11:02:08 pm »
Of course you can, click on the line and look at the properties, use the relative coordinates, or the measure tool.

In the 10 days since you first asked, you still haven't tried it in KiCad? It would take a few seconds to draw the outline...

I drew a rectangle and yes it worked with me but I didn't know such a tool exist. In the coming days I will begin to do the PCB, as I decided the enclosure.
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #43 on: November 03, 2018, 07:15:36 pm »
After changing the panel meter, I needed a taller enclosure... then I found this: https://www.aliexpress.com/item/Plastic-Electronic-Project-Box-Enclosure-Instrument-Shell-Case-DIY-130x170x55MM/32869861591.html

As you can see, the problem is that they don't specify the drawing for this thing! I don't know where the holes will be! So I guess the only solution is to get them then measure stuff to determine it.... after that make the PCBs.

The other solution is this: https://www.aliexpress.com/item/1pc-Aluminum-Enclosure-Case-Silver-DIY-Electronic-Project-PCB-Instrument-Box-Mayitr-100x100x50mm/32818002759.html

Here no measurement to be taken except for the board itself. I guess making it something like 95x80mm is gonna be enough, right?

I think going for the 2nd option is better overall. What do you think?
 

Offline VEGETA

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Re: KiCAD custom board shape
« Reply #44 on: November 03, 2018, 08:09:26 pm »
latest version PCB is in attachments.

I didn't start the layout yet.
 


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