How do I improve this print?

I am printing using the PolyLite PLA from Polymaker. I am using a TAZ 6 and Cura software with standard settings, but 1.5mm shell width as the only overridden setting.

The photo shows the side facing the bed on the top and the side facing the head on the bottom.

On the bed side, the print shows tiny gaps between the lines. Actually, it appears that the lines simply are not squished together enough.

On the head side, the lines are getting squished together enough, but some lines are not as flat as the rest.

Are there suggestions as to what I can do to get smoother results on these two sides?

-Tony

Hi
I also use a TAZ6 to print with.
On your top photo, the BED side, Your Z offset is a bit loose.
I had exactly that on all of my prints for about 6 months until I adjusted the Z offset.
My original Z offset was -1.17mm
I started adjusting it by very small increments and ended up using -1.3mm Z offset to
get my prints squished tight to the bed with most of the lines being eliminated.
I was somewhat afraid of adjusting this, but the end result works very good for me.

As for your extruder side;
I see exact same anomaly you are having.
I haven’t figured out how to completely eliminate that.
I’ve noticed that different filaments and colors affect that top layer.

Bed side you are under extruding. If you looked you will see that the extrusion is not even width during printing, and pretty much quits flowing sometimes.

I got this printer a week ago, so I am new at this. I used the translucent red version of the same filament and it had a good firt layer. But this green version has a poorer first layer. The top layer looks well fused together, presumably this is a first layer only problem. I am using the default “standard” settings except a 1.5mm (instead of 1.0mm) shell thickness.

Looking at the Cura settings, I see that I can set the “initial layer thickness” which defaults to 0.425mm I tried 0.25mm instead and this did not appear to fix anything.

There is “initial line width” which defaults to 125%. If I increased this, would it provide more “squish”? in the first line?

I had been told that I might adjust my Z axis offset a little bit, but I don’t see a location to change the Z axis settings.

How would increasing the extruder temperature a little affect things? Would it allow the first layer to flow better? Would it make the subsequent layers too hot to extrude properly?

-Tony

Some filament manufactures require different temps for different colors of filament. So one color may need different temps than another color to get the same results.

So, maybe I should increase the extruder temperature? The other layers seem to be better fused than the first layer. Is it possible or worthwhile to set the first layer temperature to be different (higher) than the succeeding layers?

-Tony

Hi again
It would appear that you do not know where to look on your new TAZ6 to find out how to
change your Z offset.
It’s quite scary, but very necessary.
The only way I know to change the Z offset is from the LCD display.
Your problem, as I see it, is that your nozzle is not quite close enough to the bed.
If you change your z offset in small increments, On your LCD display panel, will, I believe truly
solve your problem.
It did for me.
The only thing I’ve noticed in cura when changing extruders etc. is that nothing changes other than
the message displayed on the LCD.
I change between FlexiStruder and the original extruder quite often.
It appears to me, that the only change that happens thru CURA is the message on the screen that displays
for about 3 seconds when you power it up again.
You need to actually use the LCD to change your Z offset.
That is your trouble.
Try it.
Don’t make major changes, only very small ones.
Under extrusion, in my opinion is not your trouble.
Once you get the proper squish of your filament to the Bed plate, Your troubles will mostly be Gone.

I made the decision to change my Z offset when my Ninjaflex parts had loose layers on the build plate.
That was not acceptable when building faucet washers and kitchen spactula parts.

I hope my comments will lower your anxiety and enable you to do this very simple thing.

Just my 2 cents worth.

I did adjust my Z-offset. It was easy, as you said.

The initial setting was -1.200mm I changed it to -1.300mm and tried a single layer print (30mm diameter disk with 100% infill.

In this case I am running PC-Max filament, which had a worse first layer than the PLA. I had upped the first layer line thickness form the default 125% to 130% as well.

The print at -1.300mm seemed excessively squished and the top surface of the first layer had grooves/furrows where the head was dragging. So, I reduced it to -1.250mm.

At this setting it was quite good, but maybe not enough squish. So, I changed it to -1.275 and this seemed a good balance between good contact on the bottom, and leaving too much furrow on the top.

QUESTION: Is this always a trade-off between obtaining a full contact of the individual lines on the bottom and furrows of excess plastic on the top of the first layer?

Question: Do I need to adjust other settings to further optimize the quality of the bottom and top of the first layer?

Hi again
It’s a good thing that you tried and now understand z-offset settings.
For the parts that I usually print, the bottom layer is the most important thing for me.
I do see anomalies as you described in earlier post on Extruder side of my parts.
I find that changing the Filament Flow % and how fine the Z axis resolution is set appears to affect
the extruder side of the print.
I get better extruder side quality when I reduce the Z axis resolution to something like 0.22mm or smaller.
I also get better extruder side quality when I reduce the Filament Flow %.

The quality I look for when printing is that the parts are as strong as possible.
As a result, I tend to over extrude.
The outward appearance is not usually a concern to my particular applications.
I’m very happy with the quality of my current prints and my TAZ6.

The bottom layer rates set up by CURA seem to affect only the bottom 2 layers,
So if I give an extrusion rate of 98% or 95%, usually I don’t notice a difference on the printer bed side.
After the first 2 layers are layed down, I do see a difference in the print quality with 98% or 95% extruder extrusion rates.

I also found out that no matter if I switch filament types, (ABS, nGen, PCTPE, PLA) that the Z-axis bottom layers are always
pretty much the same.
I have not changed my z-offset settings since I got them dialed in that one time.

I use my prints pretty much as they come off the printer with almost no cleanup or surface prep.
Sometimes I will Paint some parts that will be used outside in the weather, but I’m not sure if that adds extra life
to parts used outside or not.
I don’t look for injection molded quality on parts that I make.
I rather like the fact that my parts look 3D printed.

I hope these comments help you in some manner.
Gary

Gary, thanks for the feedback. I don’t mind a 3-D printed look. And, like you in many cases strength is a goal. When I use PC-MAX I am looking for strength and as high temperature tolerance as reasonably possible. Those parts are going to be used in an anvironment that will be at least 70c and maybe get up to 120c. I have not actually tested the printed parts under those conditions… yet. Right now I am trying to get the printer dialed in to give as good LOOKING parts as possible. Then I will test temperature tolerance

PC-MAX has a lower printing temperature than some other polycarbonate filaments. I looked up the MSDS on PC-Max and done me that it is only 70% PC. No word on what else is in it!!! 30% seems like an awful lot to gloss over in the MSDS!

I had been using Garolite G10-Flame retardant bars and then cutting and drilling. That material is easily able to handle the environment but it is expensive to buy and finish. The printed parts will cost less than $0.50 each compared to about $2.00 depending on the cost of labor to do the finish work.

-Tony