Still not working

For some time now I haven't done much 3D printing.  The machine is giving every time I start a new print....problems with underextruding..   Sometimes I think that the 3d model that is underlying the  Gcode can be the reason for this problem.

Again underextruding

I am planning to print a Solartracking device which I found on Thingiverse.com.  All the electronics I have already just now I need to start printing.  The item which I printed sofar and which are ok you can see on the next image.

 But I got problems with underextrusion....  Here is an image of a big part which started underextruding just at the end of the print....

So I am doing again a Atomic Nozzle Clearing....    I use a piece of white pla filament so I can see clearly if there is dirt in the nozzle.   The first piece came out quite clean......no visible dirt....  Then I did it a second time and on  the piece that I got out were minor irregularities.  The third time went ok. 

Direct after this I started a test print......
After 16 minutes and 32% done the test print went good.

And after 46 minutes it was ready.... good till the end.

So tomorrow I will try another time the items for the solartracker...