Smooth bottom layer

[Modified_Gemini 2]

I feel like im beating a dead horse in the mouth with this topic. Ive tried searching and found most of the same and nothing that displays this problem and I feel these are software issues.

I have a Monoprice Maker Select, now using Cura 2.3.0 Ive been printing for quite a few months now. My print bed is level, slight drag of a piece of paper, and holds level pretty good. I print directly on glass with hair spray and with a raft i don't have any problem with adhesion.

Im trying to get off of printing on a raft to create a smooth surface. So after a bit of googling it finally made sense to me, raise temp and increase flow rate to fill the gaps. Duh!! So I played around with the tweak at Z. Raise heat to 235, and extrude rate to 125%. But here is where problems came. Not much to understanding the gcode, so when i started looking at it between different settings, I found there is a layer 0. Layer "0" is completely normal in the computer world, but it appears to be a skirt/brim layer that does not say so. So when I try to tweak layer 0 I get this.

;LAYER:0

M106 S255.000000

G1 F1500.000000 E-1.00000

G0 F2160.00000 X93.355 Y93.359 Z0.200

;TweakAtZ V5.1: executed at Layer 0

M117 Printing... tw@L 0

M104 S235.000000 T0

M221 S125.000000

;TweakAtZ V5.1: reset below Layer 0

M104 S210.000000 T0

M221 S-1.000000

;TYPE:WALL-INNER

So it does the tweak, but immediately reverts settings, plus my machine shows only a 25% flow rate, because of the "M221 S-1.0". Problem 1 (it took me a couple frustrated months to realize this, believing I kept clogging up, because somewhere down the line I realized a certain combination of other settings also reset the flow to 25%(more bugs?) )

I can tweak at Layer 1, and then it shows and does a successful tweak but only after it completely printed "layer 0"... e.g. a raft/brim is a new layer below the print. A 3mm test, plus a .2 skirt/brim, and a paper thickness bed leveling, plus some error Im at 3.4mm, not to mention with a little effort I can pry away the ugly base lines - closer to the shell they are glued pretty good (ill work on getting pics if needed). Taking the skirt/brim to a 0 count also creates the same results as it still created a new bottom layer, except there is nothing beyond the print foot. Im Hoping im just missing something, I cant believe a simple tweak would be this complicated.

Much appreciated.

[neotko 1,417]

IMO you can't get a smooth surface using raft unless you use dual extrusion and the raft is soluble, because as soon raft is a printed part you will need to break it away, making a bad surface.

Do you really need the raft?

[Modified_Gemini 2]

I do understand that, and that took me a while to understand. I printed so great on a raft that i never strayed. But to print smooth on a raft would inherently cause bonding issues. Im not trying to print on a raft. these issues are otherwise.

[neotko 1,417]

I see. Maybe even when the paper calibration looks ok you just need to get closer to the bed. Also setting a first layer of 0.25 and printing it slow helps. I see a lot of people using higher temps for the first layer but I never needed that.

Maybe show pictures of your current bottom layer could help.

[Modified_Gemini 2]

I will work on getting pics. But they will look like every other "bottom layer issue" i have seen.

I do not have a problem with leveing my bed, or the distance of leveling. my problem is in the settings. i included the gcode copy showing how the tweak changed, and right away, the gcode went back..

[Modified_Gemini 2]

immediately after executing the tweak, the next lines of code reverted to original settings, plus it grossly modified my flow percentage down to only 25%.

[DaHai8 74]

Ok, let's level-set on what is a good, smooth bottom layer.

I consider this to be a near perfect bottom layer (others may disagree ):

You can still see the filament lines but it is all uniform with no gaps and no blobing and butter smooth.

Now we need to see what your bottom layer looks like.

On the other points in your post:

Without a Raft: Layer 0 in the gCode is the same as Layer 1 in Cura (don't ask me why its done this way, 'cause I dunno). So Layer 0 is a real printed object layer, not an 'extra' layer, but part of your print. Skirts and Brims are printed on the same layer as the first real layer of your object (not a layer below it).

Increasing the filament temperature is not necessarily the best option in getting a smooth bottom layer. I print at 200c nozzle and a bed heated to 75c (PrintBite bed, not glass). Glass is good, though, better than Blue Tape! Higher than required printing temperatures can lead to blobbing, stringing and holes.

Having to over extrude the bottom layer may just be covering up another issue. Perhaps your Extruder is not calibrate correctly and is always under extruding. You should not need to over extrude the bottom layer to get a smooth finish. Something else is amiss there.

Look at your Speed settings in Cura. The first layer should print at a slower speed than the rest of the layers to improve adhesion. This automatically slows down the extrusion rate to account for the slower speed on the first layer. Here are the settings for the Prusa I3 MK2 as an example:

Check you Speed setting and your Material Flow rate (should be around 100%).

You could also be dealing with a partially clogged nozzle. If you manually extrude filament (with the nozzle at printing temperatures), does the filament come out in a nice smooth straight line or does it get all twisty around the nozzle? Twistyness indicates a partially clogged nozzle.

[Modified_Gemini 2]

Yeah I understand how computers count, 1 is actually 0, except in some code language , I forgot what one. and after looking a little more, it is not adding another layer, I might have got confused. But here are some pics.

 

This is layer 0, printed directly on the glass, freshly leveled, and no clogs, material flows out smooth and straight. Its pretty clear that there is gaps. My machine shows a 100% flow rate, so im assuming in the cura engine, its giving different calculations for a bottom later?

Here is after the completed print, I can usually get my finger nail in there and scrape quite a bit of the bottom layer off. And only the bottom layer, I don't have any other adhesion problems with any other layers

I would like to tweak at layer 0, but i run into the previously stated problem. I know i can mod the gcode myself, but would like cura to recognize layer 0. Also forcing a tweak at z only masks the problem im having. I would like to get it figured out.

[Modified_Gemini 2]

Here is the top layer. A little ridgy, but its completely bonded with no gaps. cant get anything in there or separate anything. So if my e-steps were an issue, you would think I would have the same issue on the top layer also?

[neotko 1,417]

That bottom layer shows a bad bed calibration, that or your belts are wrong. There's gaps between the perimeters

[DaHai8 74]

I would suggest you run through the calibration steps in this guide:

Triffid Hunter's Calibration Guide

Like you said, overextruding the bottom layer is not the answer - you should never need to do that.

All the layers look poor (sorry).

What printer did you select in Cura to base your Maker Select on?

Not sure selecting the wrong one could make this much of a difference, but best to examine everything...

[DaHai8 74]

Also...just as a sanity check: Check all your wires and connections to make sure they are solid and firmly in place. It's quicker and easier than running through those Calibrations and may turn up something amiss...

[Modified_Gemini 2]

Ive done lots of calibrations, but this guide is a bit more technical than others I found, after I get off work ill use the weekend to see if its really a calibration issue. Ive never taken off the hotend to truly calibrate the esteps, but if that was really the problem I feel this issue would be print wide, not just bottom layer. As for the x/y I do have like a .2 difference in the outside dimensions, but this is a set number meaning is like a .2mm if its 5.2mm or 100.2mm changing esteps would create a percentage problem over different size prints so I feel that's in the belts or something? I would also like to figure this out also but I just try to compensate in the design phase when I need to precise fit.

My z height is pretty damn spot on when I print on a raft. Since I been trying to get off of a raft ive noticed a slightly taller print, which brings me to the z-endstop? As I just learned of this and have not hardcoded a z-0.1, could this be my problem?

Also what about chances of a different size nozzle? Maybe I have a wrong size than thought? Supposedly its a .4mm, when I raise head and extrude a section of material I want to say it shows like a .56mm or something. If I remember correctly I did try to print with a .5mm setting, and it just spaced the nozzle further creating larger gaps.

As for the base printer, I selected the pursa i3.

I thought my other layers were good :( haha! live and learn and now something more to strive for!

[DaHai8 74]

You don't necessarily need to remove the nozzle for the extruder test - only if you don't want to 'waste' filament. Personally, 100mm of filament used to ensure the extruder is properly calibrated is not a waste to me.

Have you posted your issues on the RepRap forurm? There might be someone there with more experience with the Monoprice Maker Select:

RepRap Forums

Or contact the seller/manufacturer. Maybe a defective part?

Have you tried other filaments? Maybe you got a bad roll...

I've not had to set a z endstop on my printer, so I'm not even sure what/where to do that.

Your filament is extruding much to wide for a .4mm nozzle. Either your extruder is not calibrated correctly, or you really do have a .5mm nozzle. My .4mm nozzle extrudes at .41mm

I'm running out of ideas :(

Edited November 19, 2016 by Guest

[Modified_Gemini 2]

I have 8 rolls of PLA from 3 different manufactures, stored in a huge ice chest with a 300g silica canister. HA (when I get into a hobby I go hard in the paint). So that rules out a bad roll and me unwilling to use filament for productive purposes.

I took off my extuding motor and found out my Esteps were WAY off, but in the wrong direction :( Most likely altered them to mask a previous problem. I was at 108 when I needed to be at 95. As I don't know hot to program small steps, but now im about a half step much in a 300mm sections.

Sooooooooo. in reducing my extrusion, ive created and solved some problems. My top layer is much more smoother, however there is a little bowl lip? My O.D. went from a +.2mm to a -.35mm? Ive read there is shrinkage, so I assume this is a good thing?

And because Im extruding less, I couldn't even get a print started. I just drag filament around because not enough comes out to force contact adhesion. Which is why im glad for your advice on calibration tips! I was able to hardcode a G92 Z0.1 , but, there is still huge gaps in layer 0, as well as bad (but not as bad) adhesion between layer 0 and layer 1. Also layer 0 lines are about a .64mm!! which boggles my mind because if im supposed to be printing .4mm lines, why am I getting .64mm and gaps in between? Thus I truly believe this is a software issue, Cura engine is over spacing layer 0.

Which brings me back to the nozzle diameter, I think its a .4mm. When I use my machine to extrude I do get a .65, but when I had my motor off, I used my hand to push it out slower and got a smooth consistent .41mm. I really

appreciate all of your help, I love bouncing ideas around, keeps the mind open.

And for new pics.

New bottom layer stand alone.

New Top Layer/ bowl lip.

New Bottom Layer Completed print

This is a 20mmx3mm disc, printed at a .2mm resolution. Im working on priming/temp issues. On the bottom layer one of the cross lines is actually some skirt filament that didn't adhere and was dug across previous to printing.

Once again Thanks, for everyones help, wish it didn't say this post was answered because its not. lol and I have now been looking in the reprap forums, thanks to your link.

[Modified_Gemini 2]

As for a bad part, im still within warranty, ive had my machine for 8months of 1yr. There is 21days/ 20hrs/15m of print time extruding 1,931.3m. When I took my extruding motor off, the cog was not worn down or jammed with filiment in the teeth. There is still great tension on the roller, as to whats expected im unsure. Maybe ill buy a pull gauge and work on a tension/slippage method?

Ive done some of what I thought were really nice prints that took 48hrs.

 

http://www.thingiverse.com/make:216997

but on a raft, and im trying to get off a raft.

[Modified_Gemini 2]

I found an old disc I printed with old settings, I had beautiful bottom lines, but my outside as you can see has the bowl lip going on. Also decided to dig my fingernail in, and come to realize I had improper bonding to the next layer. And again they are about a .60 width, but you can clearly see gaps in whats supposed to be a .4mm line width.

Edited November 20, 2016 by Guest

[Modified_Gemini 2]

Woohoo!

Well after some number crunching, I realized it wasn't a software issue.. My bad... After some thinking and my inability to tweak layer 0. I modified the gcode in order to compensate. And its working! First I in Cura I changed the initial layer to .27mm then I added this to the beginning gcode.

G28 X0 Y0 ;move X/Y to min endstops

G28 Z0 ;move Z to min endstops

G92 Z0.1 ; reset 0 to .1

G1 Z0.2 ;raise hot end to prime

G1 F1500 X100 E15 ; traverse x, prime extruder

G92 E0 ; reset extruder to 0

M117 Alakazam

I believe with a little more tweaking, I can get a glass finish on the bottom. I hope others will find this useful and I appreciate the help and guidance.

[DaHai8 74]

Looks much better!

How do the sides and the top look?

Glad you're making progrees.

[Modified_Gemini 2]

Sorry about the late reply, but my printer took a crap. lol. Still in warranty so I got a brand new printer in the mail!! This one has longer linear bearings, I really want to say smaller stepper motors? thicker build plate (moot cuz I print on glass anyways), larger cooling fan, threaded rod guides seem to have more meat on them. I also noticed some internal settings were changed, their e-steps were re calculated to what I had manually input. Ill work on getting this thing dialed in and see if I can provide some good pictures for your critiquing. Also hope this thread helps others as well.