Printrbot Simple Metal Fan Shroud

50an6xy06r6n's version 7.1 didn't fit all too well on my Simple Metal. It scraped the first print layers off the bed and was about 1.4mm too long towards the Z-probe. As a result, the Ubis hot end was offset from the centre (towards the fans side.) It also hit the printer frame above the X-motor when homing Y and Z.

I have modified his design slightly so that my hot end is centred within the shroud.
I decreased the profile by approximately 1mm in order to better clear the bed and not scra