Minimum adequate boss diameter to hold circuitboard?

[alexg]

Hi All, I have a question that only those with experience making functional plastic parts can answer, the theory in internet does not quite answer this.
I am designing a small plastic case for a small device that look similar to early 2000s cellphone, that will hold circuit board inside, due to space constraints circuit board will be supported by 1 boss at each corner and maximum boss diameter I can afford is 2.8mm, hole diameter is 1.12mm because I am going to use M1.4 screw. Hole depth is 3.3mm. Is this boss going to be strong enough to hold PCB in place?
Thanks in advance.

[Suhas]

Do you have space to put ribs for support?
So to understand this: Is the thickness of the wall 2.80 - 1.12 = 1.78 mm? If yes, that is good if you choose a material such as a ABS or a PC ABS.
Regards,
Suhas

[alexg]

Do you have space to put ribs for support?
So to understand this: Is the thickness of the wall 2.80 - 1.12 = 1.78 mm? If yes, that is good if you choose a material such as a ABS or a PC ABS.
Regards,
Suhas

Its less, over all boss diameter is 2.8 so boss wall thickness is (2.8-1.12)/2 = 0.84mm and yes I can add ribs in three directions, please take a look at the attached dimensions.

I can increase overall boss diameter to 3mm.

170

[Suhas]

Those ribs are very thick. You will get sink on the other side of the part. My advise is to show it to a professional plastic designer and get it done. Will save you a lot of trouble. It will not be that expensive either.
I am sure if you show it to your molder, he will suggest the changes.
Suhas