What are the pitfalls with building my own manufacturing facility?

Building your own manufacturing facility may make sense under some circumstances where you need a tight control on quality.  However it also comes with some issues. 

• This is almost always the most expensive way.
• You may not have a consistent enough pipeline to keep the staff utilized at a high level.
• You will almost certainly miss something fundamental – such as manufacturing test, as a separate discipline from manufacturing engineering, as a separate discipline from assembly and test technicians.  Either you don’t know the difference, or you cannot afford to get people with these skillsets. So you make do and quality and consistency suffers as does your ability to manage engineering changes.