Sorry I forgot to attach files !!!!

Hello All,
I have fabricated a plate type heat exchanger. Currently, I am doing a different heat exchanger design. The heat exchanger plates have 2mm channels of semicircular cross-section. Please check the attachments for details. Plate 1 gives the overall plate, plate1a shows the semicircular c/s channel at one of the corner holes (start point), plate 1b shows the partially cut (not semicircular c/s) at the diagonally opoiste corner hole. Following are the steps that I followed to get the channel
a) Draw plate of given dimensions
b) Extrude cut holes on the four corners of the plate
c) Sketch the path of the channel
d) create a plane at one of the corner holes and sketch a semicircle on that plane of radius 1mm
e) Extrude the semicircular sketch (to arbitrary depth) to create the profile and use that to sweep cut along the path sketched in (c)
here is where I have the problem: when I sweep cut, at the end of the path (which is the diagonally opposite corner hole) I do not have semicircular cross-section). In other words, it does not cut fully. I am wondering if anyone can help me find a way out of this. Thanks in advance,
Besides, I have around 12 channels on a single plate. Can I somehow use linear pattern and avoid the tedious task of doing it for all the 12 channels ? The channels have a pitch of 2.5 mm. Pls let me know.
Sai