Hi, I’m using the vertex for small production series of structural elements. 3D printing is of course very flexible technology but slow. With some trial and error I managed to get reliable prints in about one third the printing time (10hour print now in 3h45min).
As you probably have experienced boosting the print head speed ony gives marginal faster prints and greatly increases the risk of things going wrong. I keep print speed below 80mm/s. In the past I also tried drilling the stock nozzle to 0.5mm, with bad result (filament blobs).
The trick is increasing the layer thickness: while the manual mentions a max layer thickness of 0.2mm, I’ve set it to 0.35mm (nozzle diameter), the max my slic3r software allows. One would think it leads to bad surface finish and poor interlayer adhesion, but none of that… I’m printing with the velleman ABS (doped ABS since you can’t finish it with acetone) on a 80°C heated bed. One would be surprised how much filament you can push through that little nozzle. I use the slic3r ‘constant volumetric speed’ function and manage to print reliable at 6mm³/s, with 0.35mm layer thickness. I guess you can do the same with PLA, but maybe you need to use a heated bed ~45°C for good interlayer adhesion.
One important trick is for a good interlayer adhesion is I altered the printer: I disconnected the main centrifugal fan, since I want my printed part and print bed to remain hot (interlayer adhesion!), and the ‘isolator tube’ as cool as possible for not having filament jams. For that I place a ‘fan shroud’ https://www.thingiverse.com/thing:3095662 , the short version where only the isolator tube gets cooling air, the hotend should not be cooled. the small fan at 100% is all I need.
this setup will work for ‘simple’ parts with <45° vertical perimeters and no or only short (~6mm)bridges. The only downside I have is that infill seems to sag a bit so your top solid infill is not perfectly flat, it hangs a bit. I tried using a 100% infill every 5 layers which gives improvement but doesn’t solve the issue completely.
here you can see my printer in action: https://drive.google.com/open?id=14gUM3Eo20001HYYyAVsjI-4EpwH9_yQV
good luck