Best way to create CNC file for a neon sign.

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
karnov
Posts: 4
Joined: Thu Mar 23, 2023 11:53 am

Best way to create CNC file for a neon sign.

Post by karnov »

Hello everyone,

I am relatively fresh FreeCAD (0.20.2, linux) user with not much experience in 3D and design. Since I have a woodwork hobby, about 1 year ago I bought a Stepcraft machine (CNC router) and have been using it ever since. At first I was using Blender with blendercam to create some projects and it was OK, a bit painful but I managed to work it out, it never got very convenient though. At some point about 3-4 months ago I decided to try something else and luckily went for FreeCAD which made a huge improvement when working with my projects, the sketcher, part maker and the path desktops are great. I am still struggling with a lot of things but I feel I am making good progress. The first outcome was a modular cat house for a local shelter :D

I usually try to look up tutorials and it works out most of the time but I came across a problem that I cannot really figure out (or don't know how to ask proper question). I would like to create "a placeholder" for a neon LED strip, i.e. to cut "a path" in a piece of wood that would allow me to push the neon strip in so the shape is well preserved. The neon strip is about 5mm wide and I want a 5mm deep path for it. There are some letters and a lot of curves. What I did so far, for the letters I created image from the font, imported it into FreeCAD and drew shapes in sketcher making sure the shapes are about 5mm wide. That seemed to work but the next part is more complex - I have a simple drawing (a cat in glasses) that is quite irregular and creating a shape path is still possible but then I have no idea how to make sure the distance between the lines is 5mm everywhere (actually made it 0.55cm). See the attached file - I know it's not constrained and super messy but at that point I just wanted to see if I can draw the desired shapes).

So the fonts may be close to "ok" but the cat shape is getting super messy, I just tried to create some points where I insert 0.55mm distance constraint but as you may see there is no way it really works well. I.e. I have no idea how to effectively create (curved) "inside" wall that is always a 0.55mm distance from the outside wall.

I was also thinking, if instead of trying to create closed shapes I could just draw a path and then just use a 5mm router bit - it would do the work as well but I have no clue if that is even possible to do (i.e. use just lines to create CNC path grbl file).

So I would like to ask if anyone could give me some advice on if and how this could be done in some clean way.

Best regards,
Le
kotel-neon-1.FCStd
(140.6 KiB) Downloaded 22 times
chrisb
Veteran
Posts: 53930
Joined: Tue Mar 17, 2015 9:14 am

Re: Best way to create CNC file for a neon sign.

Post by chrisb »

Hi and welcome to the forum!

FreeCAD itself has no image tracing capabilities. A frequently used workflow is to use Inkscape for the image tracing, and to simplify the path, then import the SVG into FreeCAD.

If you have a font, you can use it directly in FreeCAD, see e.g. here: https://forum.freecadweb.org/viewtopic.php?t=36623.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
karnov
Posts: 4
Joined: Thu Mar 23, 2023 11:53 am

Re: Best way to create CNC file for a neon sign.

Post by karnov »

Hi,

Thanks, that is what I did actually - i.e. converted a PNG to svg in inkscape and imported into FreeCAD to draw shapes on top of it (because the "neon shape" is not continuous I create the "hollows" where I'd push in the LED stripe). My issue is that I fail to make curved shapes that have equal distance in between their walls and I need exactly 0.55cm so the LED strip sits in there nicely and keeps the shape.

Lets say I draw a heart shape in FreeCAD, I want that shape to become the object's outside wall, how could I create an inside wall so its exactly like the outside one but smaller and the distance between the walls is always 0,55cm?

Le

p.s. thanks for the font link but in this particular case I do not need an exact font shape to be cut but rather a guide for cutting the hollows where the LED strip sits - this is the reason why in the file I drew those hollows over the general font shape.
chrisb
Veteran
Posts: 53930
Joined: Tue Mar 17, 2015 9:14 am

Re: Best way to create CNC file for a neon sign.

Post by chrisb »

karnov wrote: Thu Mar 23, 2023 1:40 pm My issue is that I fail to make curved shapes that have equal distance in between their walls and I need exactly 0.55cm so the LED strip sits in there nicely and keeps the shape.
There are tools for this in FreeCAD: Thickness in Part and PartDesign, 2D and 3D offset in Part, Offset of SubShapeBinders in PartDesign. These tools are picky and fail in certain cases, and these are not too exotic. If they fail, then remains only the maual way.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
User avatar
papyblaise
Veteran
Posts: 7870
Joined: Thu Jun 13, 2019 4:28 pm
Location: France

Re: Best way to create CNC file for a neon sign.

Post by papyblaise »

I traced the kat in a single thread and used the wall function of Arch Wb
it is necessary to leave attachment points so as not to have separate islands
Attachments
kotel PPB.FCStd
(163.63 KiB) Downloaded 13 times
kotel PPB.JPG
kotel PPB.JPG (34.8 KiB) Viewed 1720 times
User avatar
Shalmeneser
Veteran
Posts: 9475
Joined: Wed Dec 23, 2020 12:04 am
Location: Fr

Re: Best way to create CNC file for a neon sign.

Post by Shalmeneser »

:roll:
Attachments
kotel-neon-1_SHALM.FCStd
(170.01 KiB) Downloaded 19 times
Petit chat2.svg
(3.84 KiB) Downloaded 18 times
chrisb
Veteran
Posts: 53930
Joined: Tue Mar 17, 2015 9:14 am

Re: Best way to create CNC file for a neon sign.

Post by chrisb »

From what I see you definitely have simplified the cat in Inkscape. You can use the automatic function or remove some points yourself.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
karnov
Posts: 4
Joined: Thu Mar 23, 2023 11:53 am

Re: Best way to create CNC file for a neon sign.

Post by karnov »

Thanks everyone,

I'll look up how to find and use the mentioned tools. And the modified files are very close to what I wanted - thanks!

Le
karnov
Posts: 4
Joined: Thu Mar 23, 2023 11:53 am

Re: Best way to create CNC file for a neon sign.

Post by karnov »

Thanks everyone,

Using your advice allowed me to do what I wanted. I guess it's bit of an overkill for a garden cat house but it surely was fun :D


IMG20230403200944_result.jpg
IMG20230403200944_result.jpg (212.72 KiB) Viewed 1417 times
User avatar
papyblaise
Veteran
Posts: 7870
Joined: Thu Jun 13, 2019 4:28 pm
Location: France

Re: Best way to create CNC file for a neon sign.

Post by papyblaise »

it's great :!: , it makes you want to go purr
Attachments
ronron.png
ronron.png (120.86 KiB) Viewed 1400 times
Post Reply