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Altium 0402 Resistor Footprint
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jnbrown View Drop Down
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Joined: 13 Jan 2020
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Points: 40 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jnbrown Quote  Post ReplyReply Direct Link To This Post Posted: 14 Jan 2020 at 3:53pm
I am noticing that in Library Expert Pro the pad corner radius is set to 25%,
but when I import the footprint the radius ends up being 50% in Altium.
However looking at footprints the radius looks the same in both programs.
Why is the radius value not the same in both programs?
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Tom H View Drop Down
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Points: 5716 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 14 Jan 2020 at 3:58pm
It's 25% per corner or 50% overall. 

You can adjust the Corner Radius in the "Rules" tab. 
  • Corner Radius Size (% of pad width)
  • Corner Radius Limit
  • Corner Radius Size Round-off
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ransonjd View Drop Down
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Points: 139 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ransonjd Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2020 at 10:39am
I don't know if it's still an issue, but as of 17.1, the Altium IPC Wizard didn't follow the IPC standard for the spacing between pads on chip components.  This was what I found and filed with them 3 years ago:

"Altium is setting the spacing between pads based on the minimum length of the component, minus twice the maximum band width of the component.

The correct spacing between pads should be based on the nominal length of the component, minus twice the nominal band width of the component, minus the RMS sum of tolerances. This is per section 3.1.1 of IPC-7351."

They acknowledged it as a bug and then I never heard anything more.
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LaserAlex View Drop Down
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Points: 27 		Post Options Post Options   Thanks (0) Thanks(0)   Quote LaserAlex Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2020 at 10:46am
Originally posted by ransonjd ransonjd wrote:

I don't know if it's still an issue, but as of 17.1, the Altium IPC Wizard didn't follow the IPC standard for the spacing between pads on chip components.
. . .
They acknowledged it as a bug and then I never heard anything more.

Yet another reason to use PCB Library Expert instead of the Wizard in Altium.
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ransonjd View Drop Down
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Points: 139 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ransonjd Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2020 at 10:58am
It looks like V20 still uses what I believe is the wrong formula for minimum heel spacing. Tom, can you verify that the minimum heel spacing calculation is not calculated by "subtracting twice the Maximum Bandwidth Range from the Minimum Body Width Range."?
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ransonjd View Drop Down
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Points: 139 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ransonjd Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2020 at 11:01am
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Tom H View Drop Down
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Points: 5716 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2020 at 11:14am
I did hear about this issue, but everyone should know that Land Pattern Calculators are very complex to create and then you must maintain them as new technology emerges. And we do that every day. 

In the case of Altium, in 2005 when they created the Altium Footprint Wizard, the 0201 and 01005 packages were not even on the market yet and the 0402 was brand new. 

Every chip package size requires a different solder joint goal and even IPC-7351 does not support that theory. But it's true. 

There are documents on your computer in this folder - 
C:\Program Files (x86)\PCB Libraries\Library Expert 2019\Documents
  • Library Expert Solder Joint Goal Tables.xlsx
  • Library Expert Surface Mount Families.pdf
  • Library Expert Through-hole Families.pdf
These are the Library Expert default solder joint goals as tested and approved by the 100,000 users of Library Expert worldwide. They are all User definable in Preferences and everyone has the right to edit the default values to work best for you. 

IPC-7351 has been downgraded to a Guideline because even IPC and their Land Pattern Committee doesn't know anymore what solder joint values are best for each terminal lead style. 

Micro-miniaturization of component packages are changing everything and it's hard for everyone to keep up unless you are 100% dedicated to do so. And PCB Libraries, Inc. is 100% focused on Land Pattern technology. Yesterday, Today and Tomorrow. 
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Tom H View Drop Down
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Points: 5716 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb 2020 at 11:27am
I don't understand why anyone would use the Altium Footprint Wizard when we give away a Free Library Expert Pro that supports 25 CAD tools and produces perfect high quality 3D STEP models simultaneously. 
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