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PCB Dimensioning
mnpebm , 06-26-2019, 09:11 AM
Could someone point me to a resource to show the proper way to dimension a PCB? Board size, relationships to holes, slots, etc? I see IPC-2615 is a place to start, but the spec is expensive.
Paul van Avesaath , 06-27-2019, 06:19 AM
your question is a bit broad.. my first reaction would be use common sence, but there probably is a standard or a reference out there.. usually you get dimensions from the client 
so sorry dont have a giftwrapped answer, maybe if you can be a bit more specific in what your facing..
so sorry dont have a giftwrapped answer, maybe if you can be a bit more specific in what your facing..
robertferanec , 06-28-2019, 02:19 AM
I have never really thought about board size and shape from an IPC standard point of view.
Usually, these are the factors what I use to decide on PCB shape and mounting holes and they depends on what kind of product I am designing:
- STANDARD: using a standard form factor format (e.g. COM Express, PC104, miniATX, ....)
- COMPATIBILITY: e.g. if I would like to stay compatible with Arduino, I use mounting holes and PCB shape from the original board
- BOX: If it is going to be a boxed product, I have a look at the box / enclosure what I would like to use (if you buy a standard existing box/enclosure, you may want to follow their dimensions)
- CUSTOM: sometimes I need to decide on the shape and mounting holes by myself. Usually then the board is created as small as possible.
In past I have designed boards with many very custom formats, now, I prefer to use more standard board shapes .... board shapes what are already used somewhere. Making completely custom size, shape, mounting hole positions makes it hard to be used in existing solutions and systems.
So, have a look how competitors products look and you may want your product dimensions to be compatible with them.
Usually, these are the factors what I use to decide on PCB shape and mounting holes and they depends on what kind of product I am designing:
- STANDARD: using a standard form factor format (e.g. COM Express, PC104, miniATX, ....)
- COMPATIBILITY: e.g. if I would like to stay compatible with Arduino, I use mounting holes and PCB shape from the original board
- BOX: If it is going to be a boxed product, I have a look at the box / enclosure what I would like to use (if you buy a standard existing box/enclosure, you may want to follow their dimensions)
- CUSTOM: sometimes I need to decide on the shape and mounting holes by myself. Usually then the board is created as small as possible.
In past I have designed boards with many very custom formats, now, I prefer to use more standard board shapes .... board shapes what are already used somewhere. Making completely custom size, shape, mounting hole positions makes it hard to be used in existing solutions and systems.
So, have a look how competitors products look and you may want your product dimensions to be compatible with them.
mnpebm , 06-28-2019, 04:30 AM
Thank you both for your help!
Yes. I do get the board outline from my customers, and then I dimension the rest. I was just asking about standard ways of doing this dimensioning, such as what point/line on the pcb acts as the main reference point. My common sense approach has been simply to use the left edge of the board as the main reference. Never have had any questions from fabricators, but thought there must be information other than buying the IPC spec.
Yes. I do get the board outline from my customers, and then I dimension the rest. I was just asking about standard ways of doing this dimensioning, such as what point/line on the pcb acts as the main reference point. My common sense approach has been simply to use the left edge of the board as the main reference. Never have had any questions from fabricators, but thought there must be information other than buying the IPC spec.
robertferanec , 07-01-2019, 04:51 AM
Ah, I understand now. Left bottom corner is very often used (but I am not sure if that is a standard).
Paul van Avesaath , 07-03-2019, 01:26 AM
yes left bottom, but i usually set my reference to one of the fiducials befor generating data.. i constantly move my origin point to not have to do math 
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