Unanswered A couple of questions from a Newbie

Ok - Just when I thought I was getting the hang of this, I am having some issues. I printed all day yesterday with no problem. My settings were 198/50 for PLA with -.2 Z offset. All was great. Went to print some stuff tonight, having changed nothing I am aware of, and a Z offset of -.2 prevents me from extruding. I reduced it to -.01 and it is now printing at least, but I tried it with 0 Z offset and the base layer looked just lmage here : https://all3dp.com/wp-content/uploads/2015/11/ucg5niL-1024x576.jpg

Which supposedly means I am too far from the bed. We'll see if -.1 works, but I don't know what changed from yesterday...Any thoughts?

 

Think I found at least part of the problem. I forgot that I did lift the bed up earlier today BEFORE I started printing anything. I think one of the magnets was probably not fully seated, playing havoc with the leveling and extrusion. Here is a pic.


I am using PLA tonight but it is the Robo3D Metallic SIlver. What is a rough guess as to what the Z offset should be? I am -.3 now and it still seems that it is not far down enough. Pics are below. It also seems to either be bubbling up from the bottom or something else is going on. Thoughts?

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Starting increasing my -z offset to -.5 Here's what I got.



I'm really at a loss. Where should I start?

 

I think I am getting tot he root cause. In several of the pictures, the print won't print (or certainly not well) on the right side of the bed. I think I still may not have it sitting properly, though I have no idea how to fix it because the magnets appear to be in the slots and again, it was obviously aligned and working yesterday just fine. Any ideas?

 

Does anyone have the link to the site that shows what the first layer should look like? I think it was something printed in blue.

 

Thanks Geof. I appreciate it. I actually am in the middle of my first somewhat successful print of the day. It's not perfect and I need some advice on what to look at, but it is definitely a million times better than the other attempts. It looks like one of the magnets (or more) was not properly seated after it was moved and it was causing all kinds of problems as shown above...

I'm going to post pictures of the latest print as soon as it finishes to hopefully get you guys' advice!

 

YUp! Thats's the one. Thanks! Also - and this may sound like a dumb question - is there a trick or easy way to ensure that the bed is level and the magnets are in the slot as they should be?

 

Ok - here's the latest pics. A few things I am noticing:
1 - Bottom is not smooth as it should be - to be more clear - yes, it is physically smooth, but the layer is not straight lines as you would expect. Does that make sense?
2 - Think I need to increase the infill overlap because it is not going all the way to the perimeter in a couple of locations
3 - This is only printed in medium quality, but should the individual lines be visible on the top or should it just be a smooth and together?You can see where it made each of the passes. It feels smooth of course and there are no high areas, just not sure if it;'s normal and how to fix it if not.

 

It should be - it was printing fine last night. That said, how do I check that?

 

What does this pic mean Geof? Too high a temp, extruder down to low?

 

I changed the Z offset from -.3 (which gave me the above picture) to -.2 (which I used to print out the heart above a few posts back). So I assume the picture above means the -.3 was too low and too close to the bed. Is that correct?

I then printed the below first layer of the batarang. I started out at 200/50. About 2/3 through the way with the first layer, I bumped the temp up to 210. Not sure this was needed or right, but I am still trying to figure out why I keep getting the texturing in the bottom layer. It might be the filament since it is a metallic silver, so I am going to try some other stuff again...

What are your thoughts on issues with the below pics?

 

Also - I have been using 200/50 as temps. Do you think those are too low?

Do you see in the picture above how the line of filament being extruded seems to not be flat/round, etc, like normal, but rather looks like it's got ridges?

 

I also found at least one of my problems. I am fairly certain I am UNDER-extruding. I did the procedure at this link - https://www.matterhackers.com/articles/how-to-calibrate-your-extruder - and measured from the top of the extruder - just where the filament enters - and measured up 120mm. I extruded 100 mm, and when I measured again, there was 30 left. There should have only been 20. So that is under-extruding - correct?

Which value do I use to calculate the step difference and where do I enter it? I am asking because the link, I assume, is outdated since the mattercontrol EEPROM screen doesn't look like that. I don't have one step/mm value, I have 4 listed.

I am going to try the test again in the morning just to make sure I have consistent results. Would under-extruding explain some of the issues above?

 

This video shows how as well. I just updated the firmware e steps and flashed the board. Under and over extrusion Carey their own set of issues with prints. It is well worth going through the calibration steps to make sure it isn't part of the issue.

 

Thanks guys - I appreciate it. Amazing how dumb I feel right now but I can't seem to figure a couple of things out.
1 - I did follow Tom's video - right up until I have to change the step value. He uses Octoprint to edit his and I don't even know where to start with that. Can I change the value in Arduino and reflash? If so, is this the 723.38 E setting listed in configuration h?
#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,800,723.38} // default steps per unit for RoBo 3D R1

If so, I assume I am replacing the 723.38 with the new calculated value based on the calibration - correct? How do I calculate what the new E value should be? In my case, my test showed I only extruded 90 instead of the 100mm of filament that should have been extruded.

2 - In his video he talks about extrusion speeds. The only place I see extrusion speed is under "retraction" in MC and it says 33mm/s. Is that correct?