Surface finish with FDM

Hi,
A question to all 3D printer owners here. I requested a sample from a famous brand and I received this :

Attachment 668Attachment 669

Now, as written in the letter in attachment, the print parameters are quite explicit : time was of the essence. The total print time was 22min, and the print layer thickness 0,25mm.

The lateral surfaces of the bolt are quite OK, but is it possible to obtain a smoother finish that the "M" face where you can actually see the tool path ? What is this representative of ? Large extrusion nozzle ?

I'd be grateful for your interpretations.

you'll always see lines and a toolpath but that does look under extruded. i generally get a top surface thats 100% solid across. in your sample the edges of the lines arent touching. also the bottom or surface of the m should have a top solid surface on it and it does not. that is simply the fault of the slicer. the threads and sides of the bolt look good