CorelDraw X8 Suite Print size and image size is not same how to fix it ?

Hi

We use EPILOG LASER for engraving  so we use COREL for  Art Projects.  Other day we got new order and its very specific  size. I draw my project in 6inches but when i print it its never come 6 inces.Its always 5.86-5.90 but never 6. So i doubled check about if my page size and piece size are matched; yes they are matched. I checked about layout and it on this setting: AS IN DOCUMENT.  Where do i make mistake ? should i change dimension setting ? Please and thank you