Scaling problem with slicer software

[TFilbert]

First post! I am new to 3d printing at home, My wife bought me an I-mate S for Christmas, and I'm using the QIDI slicer software that came with the printer. Upon installation of the slicer software, I was immediately prompted to download the newest version, which I think is 5.6.12? My problem:The QIDI slicer software is not properly scaling my parts. I intend to use this to print precision tolerance parts for prototyping purposes prior to having parts milled or laser cut out of steel. So If I model a part to the thousandth of an inch, I need the print to come out to the thousandth of an inch.To test print and learn the software, I created a 2" diameter x 7" tall cylinder with .125" wall thickness. The part was modeled in AutoCAD "Inventor" software, since that's what I have available at work. I exported the part in several formats not being sure what the slicer software will be happy with. When I open the part in the QIDI slicer, each file type opened up at a different size. None seemed to keep the original dimensions. I noticed that the part loaded with metric dimensions and not inches. I found a button to click that said "Scale inches to MM" When I clicked that, the part exploded and went from way too small to way too big. All the manuals and instructions are very poorly translated to English and offer very little help.What is the secret to modeling a precise part, and opening it in the slicer software so that it maintains the precise dimensions? Picture 1 shows how the part imports at different sizes based on file type. one is .stl the other is "3d part file" (I can't see the extension type) Both file types were exported from Inventor from the same part model.Picture 2 shows how the dimensions seem random. it says 5mm x 5mm x 18.08mm (Keep in mind, it was modeled to be a 2" diameter, 7" tall cylinder.)Picture 3 shows what happens when I click "Scale inches to mm" and it blows up so big it wont fit in the print space.What gives!? How do I print exactly the size I modeled without having to do guess n check work?!