Reducing diagonal lines on horizontal surfaces

Hi new hear and I am sure this has been discussed many times, but searching returns more about random lines or focused on using the ironing function in Cura which is not what I am after.

I have attached what I am talking about and have a feeling that this is never removed, but perhaps reduced?

I understand that 3d printing works by extruding so the lines it leaves when printing on the top surfaces are part of 3d printing in general. The layer lines are actualy quite good with my settings.

This is on an Ender 3 Pro with Creality ST-PLA. I am using 195 degrees nozel and 60 degrees bed (creality glass bed)

However I have noticed that printing slowly seems to reduce those lines but this isn't really an option as I'm talking really slow as in 5mm/sec

Is there any way to reduce those lines that appear all over the top surface other than slowing down or using ironing? Is it something to do with printing too cool so the filament doesn't melt and flow, or is it because I am not extruding enough material and need to turn the flow up a bit?

Small adjustments of those two don't seem to fix the diagonal lines. I'm not talking random ones, I am talking the lines it leaves when printing

Switch to injection molding. You are using FFF and that is what the top of a Fused Filament Fabricated item looks like. Your print looks really nice, there is nothing to fix.
Sorry for the awakening, but if you want a smooth top you will need to post process and fill, sand and coat with some sealer to make a smooth surface. Google "3d Printing Post processing" for more ideas

Also the original test print of a dog I did was nice and smooth. Although that had a lot of curves so might have hidden the lines. I didn't have the settings for the test print as it was on the supplied sd card in gcode. Was hoping that some magical settings would reduce it and considered looking into the gcode to see what settings they used...

But I'm very new to this that's as far as I've got.

I don't doubt what your saying and I have lots to learn, was just hoping to minimise the affect without post processing.

I remember thinking that same thing.. flat tops look like what you have in your hand. Here is a picture of a 2 layer extrusion calibration test print, and a couple of PETG mounts

So what you showed is normal yes? And only way around it is to either print at lower layer heights, print slow (not sure but that and increased nozel temp on first layer looked better for me which I only did to get better adhesion), using something like ironing in cuda, or post processing is the suggested ways to reduce? I found that increasing temperature for me caused rough, almost hairy/rough in spots in places for the St-pla from creality I'm using..

I really should play around with various test prints rather than real life prints huh? So I can experiment with various settings on prints that don't take long to print. I jumped straight into real prints so maybe I should take one step back.

No, I think printing things you need and are actually mechanical is the way to go. This is a process to prototype, not make finished items.. You can make finished items but they are not going to look like an injection molded part.. I quickly learned that a mechanical part that is strong and accurate trumps one that looks nice..