PCB: Center of Mass - Moment of Inertia

Get the specs of all the major components, weight + H.W.L. and a base outline of the board. A suitable 3D cad package is needed to draw the board with tracks and holes etc and place the components and assign materials. This is I think the only way to calculate it without a major headache on the math... Solidworks and solidEdge are what I would use. But Autocad may have a system as well..

What about a cheap CAD software as TURBOCAD? Can do the job ?

I'M planning to design a layout of switching power supply using a cheap software as TURBOCAD, what is your advice ?

I personally do not use turbo-cad, so I can not advise you however I do know that if it has 3D capability it will have inertia and mass calcs i don't know about material . However there are many here that will. You will get a better response if you register so people can relate to you.. there are hundreds of guests..

Thanks merc600sec

I will need a software. In fact I have already started the model using Solidworks (My company does not have CircuitWorks, :( . However I still have a doubt. An integrated package is made of ceramic and it has also metalic parts. It would be a good simplification consider all my integrated packages as a simple homogeneus parallelepiped?

I suposse that I have to simplify the model.

Another problem is that I still can not find the exact ceramic material for each integrated that I have.

You don't need to know more that the weight of things and the essential dimensions.

Assigning a standard material in SW is "easy" if it is a single material part - and on the list. But I rarely get to use that - now extensive - list.

And DS have cut out the old 'user friendlies' in this area.

So: SW '98 techniques; brought forward;

Model the 'body', and in this case, full as supplied legs.

Go to properties - find the volume of your 'as supplied' part.

Go to the spec sheet (or manufacturer), find the exact mass.

(for tiny stuff g/1000, or 10k, is usually available)

Pick up your calculator (or Excel) - compute the density (specific gravity)

Plug that SG into a "custom material" - which I think The Last Mohican of, now lurks in plastics. (i.e. mine is not on at the minute, and I have to open something to find out how f^c* I do it).

Don't be put off that it's a custom "plastic" - programs are stupid. They don't know what anything actually is.

If you build the components passably accurate - but most importantly: assign the right SG, you get all the numbers you need.

SO CHECK! - SW does return the exact component mass. Well to around 4 decimals in metric, if you're talking 50g all-up and a bunch of stuff.

Lots of component suppliers put their products on Global or 3D content or SW search (top RH corner) will give you stuff for download.. helps with the construction so no just do the searches and then adapt your models or draw new ones.. and the plastics area is good for assigning materials and colours though you can do it elsewhere depends what version you have.. Good luck

Hope this helps

Always glad when my posts 'help with construction'

I think it is complicated and unnecessary issue.

...What would be expected acceleration of the pcb? would it have any heavy components like low frequency transformer, or ferromagnetic cores? etc? Would it accelerate towards one direction or all three directions? Perhaps it would rotate? Perhaps rotate and move towards one direction? If you can answer these questions than you can eliminate these components that are ultra light from consideration and perhaps the board itself is much heavier than all the components mounted on that board, so you neglect components and calculate inertial momentum of the board only, but it could be risky so add 20% and prey that these board would survive mo0vements within certain acceleration and speed range. Sometimes intuition does more than calculations. Good luck buddy!

GUEST...Are we to bow to your Superior knowledge on this.. I think not I have 50 years of design work to call on.. It is not a question of doing it for this board or these components but being able to do it for anything. In SW I can scale stuff up to tremendous dimensions and mass.. and that is how I work for small delicate peices..then shrink them back to size.. and your remark "Sometimes intuition does more than calculations. Good luck buddy!" is ok for baking a potato on a open fire but not so good for anything else.. and your lack of intellect on this is about the same as your inability to register and be part of the solution not the problem...Register and face me on equal terms.

If board is not designed, it's going to change anyway so why bother.

If board is designed it's simpler to just build it and test it.

More of a problem is resonance of the board to a constant mechanical frequency.