Parameterized SOIC

[HiGreg]

Seeking input on my parameterized SOIC (small outline integrated circuit) model.

Constraints and offsets come from the spreadsheet. Is this the correct way to design a parametric model?

At some point, I need to put the origin on the lead bottom centered on the package so that the model exists at 0 Z and positive Z and symmetric around the Z axis.

FreeCAD file:

Parametric Package Model.FCStd

(83.87 KiB) Downloaded 144 times

ParameterizedSOIC.png (48.73 KiB) Viewed 2587 times

ParametersSOIC.png (18.15 KiB) Viewed 2587 times

Specification1SOIC.PNG (37.86 KiB) Viewed 2587 times

Specification2SOIC.PNG (26.59 KiB) Viewed 2587 times

FreeCAD and OS version details:
OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[Konstantin]

Beautiful. I like spreadsheets.

[triplus]

Nicely done.

[regis]

not much knowledge in that but I can assure you that the direction you are going is certainly a good one. provide more related information and context aswell for us who don't know what such things are and can be used for.

[easyw-fc]

Seeking input on my parameterized SOIC (small outline integrated circuit) model.

Hi Greg,
nice work...
I saw also your message at KiCAD forum...
just to avoid double work, I would let you know that recently most ICs and pcb parts have been already created for KiCAD using FreeCAD and parametric scripts...

You can have a look at the KiCAD official 3D mechanical repo
https://github.com/KiCad/packages3D
and at FC forum
https://forum.freecadweb.org/viewtopic.php?f=24&t=20892

You can contribute at KiCAD repo with PR on new models

Maurice

[HiGreg]

I appreciate all the feedback everyone!

Thank you for the links in info, Maurice! I did this as a sort of exercise of a parameterized model (the pin details were especially fun: angles and lengths, etc) and because the 3d model from KiCAD V4.0.6 release build for my part was slightly off and didn't match the footprint, but I'm not sure exactly why (I'm still new at KiCAD).

Once I try a few more, I might see if the scripts that generate the 3d models in your link are available and how they're put together.

For others, KiCAD is a PCB design and layout tool with a 3d viewer. An SOIC is a manufactured integrated circuit in a package (the package itself is called SOIC, but there are several names for similar looking packages). Maurice's forum link explains a lot of the excitement between KiCAD and FreeCAD working together for 3d views of PCBs.

I've updated the model to fix the pins on the package edge, and some of the constraints, and centered it too. If anyone is interested, I can post that model as well. Otherwise, I'll post after I test a little more.

[easyw-fc]

and because the 3d model from KiCAD V4.0.6 release build for my part was slightly off and didn't match the footprint, but I'm not sure exactly why (I'm still new at KiCAD).

Hi Greg,
your models seems more the SSOP_28_53x102mm_Pitch065mm than the SOIC28 as in your data sheet
I tried to load the kicad footprint and in fact the right model is SSOP_28_53x102mm_Pitch065mm and not the SOIC28 (which has picth 1.27 and different overall dimensions)

SSOP_28_53x102mm_Pitch065mm.PNG (242.59 KiB) Viewed 2478 times

the kicad 3D model attached is pretty similar to yours and it fits exactly the footprint

the scripts to produce the parametric 3D models are here
https://github.com/easyw/kicad-3d-models-in-freecad
some tips here
https://github.com/KiCad/packages3D/blo ... /README.md
Maurice

[keithsloan52]

I know some people have used OpenSCAD to create 3D parts.

In theory, one should be able to import the OpenSCAD part into FreeCAD and output to step, wrl, vrml as required by KiCAD.
But there is not much mention of this on the internet