[Solved] Problem with multiple 3D models into a footprint

[s.besso]

hello,

I have the need to represent a horizontal TO-220 THT package with an AAVID Thermalloy 577102B00000G (19x13 mm.) heatsink under it.

To accomplish this task, I have first created a new horizontal TO-220 footprint with the heatsink contour around it. So far, so good.

Nevertheless, a first sign of the problem pops out in the 3D tab of the footprint, where it’s evident that the metal tab of the TO-220 package is not visible:

After having saved the footprint all the same, I have updated the PCB and I have observed the result in the 3D viewer.

While the plastic body of the TO-220 package is rendered correctly, respecting the thickness of the heatsink (the following two images show the right part, near the pins)…

…the metal tab of the TO-220 is literally melted inside the heatsink, as shown in the last image:

For the TO-220 part, I have used the standard model supplied with KiCad, while for the heatsink I have downloaded a 3D model available on Mouser (.step format).

What is wrong with my attempt? Any help will be appreciated.

Salvatore

[s.besso]

In this image, I have reduced the opacity of the heatsink and the problem (melted tab) is now evident:

I have used the term “melted”, but I could also say that the metal tab of the TO-220 package has been rendered in the wrong place, at the same vertical level of the heatsink.

Salvatore

[maui]

you need to add a z offset on your first 3D model

[mf_ibfeew]

look at the left side of your picture. You have 9 fields to manipulate scale+rotation+movement of every 3D step model individually.

[s.besso]

Wow! Perfect. I have added a +1.25 mm. Z offset to the TO-220 package that is equal to the thickness of the heatsink.

Sorry for the noise, but it’s my first attempt to create something that is not available in stock files installed with KiCad.

I have also downloaded and installed FreeCAD, but it will be far more difficult for me I think, since I’m not a mechanic

Thank you to both.

Salvatore