Unresolved Can you identify the cause of the issues present in this print?

Hey guys! I'm looking to really dial in my printer so that it's as reliable as possible. I printed a large vase to see what issues were obvious.

Can you tell me what you think of the overall quality and can you tell me how to solve the issues present?

To begin with; I am printing at 195C with PLA. 35mm/s, no heated bed and one cooling fan.

Issue 1: Strange ringing pattern. It isn't the classic 'ghosting'. It's some sort of weird angular resonant pattern. Can't pin this one down and it's been there for months. I'd love to get rid of it. Examples are shown in the 'Curved Ringing' images. It's not the obvious large single curve. I'm not sure what that is. If you look really closely you'll see what I mean. The surface of every model I print is covered in tiny wavy ripples.

Issue 2: Layer transition seams. Large and obvious scar up the side of the vase. Is there any way to hide the point at which the z-axis moves up each layer?

Issue 3: Rough pattern at the top of the vase either side of the layer seam. I'm not sure why that's only near the top.

If the ringing was gone and the seam was no longer apparent, the only issue left with my printer is the fact it doesn't like printing overhangs at all. This print does not display that as there are no overhangs but if you have any advice on that I'd appreciate it. I can't fit a second cooling fan on my printer as I have started using jim3Dbots IR height sensor which replaced my second fan.

 

Hi Mark. Thanks for the feedback!

What do you think of the quality of the print? Compared to yours?

I'll randomize the start points and try. I think when I did that last it created lots of little pock marks but that was a while ago.

Resonance in the axis drive. Hmm.... I tried using vibration dampeners to make the x and y steppers quieter. I removed them but maybe I didn't tighten screws correctly. I'll take a look.

I'm not sure #3 is related to #2. By #3 I meant the rough pattern shown to the left of the seam on the flat plane in the image titled 'Defect near the seam'.

Overhangs fail as the layers droop on each other. I'm sure it's a cooling issue but it happens when I print at 180C with my fan on 100%. Similar to the pink image attached. I'd love to print overhangs and have them come out like the other image.

 

I feel like the printer should be able to cope with that overhang though. If one printer can do the image on the left I can't imagine why a Robo can't do it. Same principals apply surely?

I have a duct but I don't think it's very good. It's all that would fit with my e3d v6.

 

So since I can only mount one fan, I'll need a much stronger one I'm guessing. I've already tried printing at 175C. I'll have to modify the firmware if I want to print colder.

How do you mean commodity hardware? I've had my Robo for 2 years now and sunk $1500 dollars extra in to it to get it this far. Hopefully I'll be able to get the cooling sorted and be happy with the quality of prints! I think I've earned it at this stage, haha.

 

I don't think I can. Left of the extruder is the endstop screw. Right is the barrel cooling fan. In front is the part cooling fan and behind is the IR sensor. Can't get another fan in there without losing print area I think.

 

That's what I used to have until I got rid of the fan on the left side of your picture so I could install the IR sensor. Now that spot is occupied.

 

They were never good. I assume I just bought cheap fans though. I'll look for a nice strong one this time and use this fan shroud: http://www.thingiverse.com/thing:409483 if I can make it fit.

With regards to temperature, I have poor results down to 180C. I will modify the firmware so I can print even cooler and see what happens.

Thanks very much for the input, Geof! I appreciate it.

 

I tried randomising the starting point and ended up with lots of little burrs and scars on the print. Should you not be able to tell where a layer starts?

Also, with regards to cooling; now that I only have one fan mount, I've printed the following shroud http://www.thingiverse.com/thing:409483 and want to buy a good fan to compensate for only being able to have one. Is this a good fan? Seems pretty strong: https://newpowersupply.com/dynatron..._3_pin_model_df125020sh-pr-1224-c-46-p-1.html

 

Okay, and with regards to the fan?

I also had a print fail yesterday because the Zebra Plate bed came loose. I'm having trouble finding a way to secure it to my glass bed due to the 5mm space between the housing and the side of the glass bed. Is a metal binder clip with the handles cut off safe to use with the glass or will I crack it? It's the only thing I can thing of that will fit through that gap.

 

Okay great. Thanks for the quick replies, Mark.