Pad on Pad

[gavinkenny]

Hi,

I am trying to make a simple mounting board, to mount computer parts on as a prototyping setup. So all I want is a base plate with some small columns on it at specific locations and then on top of each column I want a smaller column which would clip through the mounting holes on the pcb's I have.

I thought this would be simple - stupid me. I had my baseplate setup (simple square - padded) and I had an initial set of base columns, again padded, but when I went to put the upper columns on top everything went weird. I now have a situation where I have somehow "grown" a mirror off at a 90 degree angle, which I don't want at all, and am no closer to working out how to add the 2nd padded column on top of the first.

What am I doing wrong?

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4 (GitTag)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)

[drmacro]

No idea how you might have done it...but, the Dependency Graph showed a back/cross reference.

Sketch had the attachment changed to Pad001...

I remapped Sketch properly to XY_Plane and FlatFace and it seems ok now.

(Just for example, I also simplified the constraints on Sketch001.)

pi_board.png (90.7 KiB) Viewed 534 times

[gavinkenny]

Thank you so much.
To go back to my original problem, is it possible to map a new sketch onto the face on the current columns so I can add a 2nd set with a smaller diameter?

[kisolre]

Yes, but for now you should avoid it. Mapping sketched to generated items (faces, edges, ...) is prone to topological naming issues - faces could be renamed at any time and then the mapping will fail or not be where it was intended. In your case you chould map that sketch to base plane and offset it accordingly. For this you can also use expressions to link the offset to sizes of previous features (sketch.z = pad1.length+pad2 length).

[chrisb]

I don't offset in such cases, where the added pad is smaller than its base below. I map it to the main plane and increase the length appropriately.

[gavinkenny]

Thanks guys, I'll give it a go. Really appreciate the help

[vocx]

... is it possible to map a new sketch onto the face on the current columns ...

Topological naming problem