What's wrong with my printer?

[Gerrardh 1]

Hi All,

 

I have a CR10S that is all standard - save for a few 3D printed tweaks. I've just spent the better part of a 3 day weekend trying to print a few relatively uncomplicated parts, but facing non-stop issues along the way.  Issue number one, was nozzle blockage - I suspect the nozzle was just old, but that may be related to my current, and currently unsolved problem. After the fist completed print of the weekend, I came home today to find that the parts were complete except for nasty looking surfaces. There appears to be two separate issues - firstly the top surface (only) of the round parts is broken and opened in places, secondly the vertical edges of the taller two parts has a nasty case of stringing... This is the first time I've seen either of these problems, and I've successfully printed from the same models before... For what it's worth, I'm generally pretty happy with the printer - I've put the better part of 3kg of filament through it since I've had it, and the prints are usually really good... 

 

I've replaced the nozzle, cleaned the hot end, checked the bowden tube for restriction, re-checked the calibration of the extruder, tightened the extruder clamp... What have I missed?

 

Thanks in advanced.

[geert_2 557]

I don't know your printer, so this is just educated guessing.

 

The gaps in the disks look like the top layer is way too thin. I would print such a thin disk between 80% and 100% filled, and with a top layer of at least 1mm.

 

The strings could be non-optimal retraction settings, too hot temperatures, or just the material. Maybe other causes too?

 

[Gerrardh 1]

It's the educated guess I'm looking for... I've exhausted all my experience, so looking for suggestions...

 

I agree that the top layer LOOKS too thin, but it's the same thickness I usually use... 0.6mm, I only did that print with 10% infill, but I just re-did this same print with the same top layer thickness, but with 20% infill and it's turned out OK... not brilliant, but OK...

 

I hadn't considered print temperature... I've been printing at 200degC on all my filaments, but I'll try dropping it a few deg to see if there's a difference.

 

Thanks for the advice...