GregValiant

When you use a single extruder printer then there must be an air gap between the top of the support and the actual print. If there wasn't then the support would become part of the print and be near impossible to remove. Adaptive Layers aside, Cura works with a fixed Layer Height and so the minimum air gap is 1 layer thickness. You can play with the other settings but you are going to end up pretty much with what you see in your photos (which really isn't too bad). If your layer height is .20mm and you have a .20mm air gap then you have extrusions calculated for a .20 height that are going into a .40mm gap. They are not going to squish like they would with full support. This is a primary reason people go to dual extrusion printers. Extruder 2 would be for support with a non-compatible material. That means no air gap and the support interface can be 100% density. One alternative is to print separate pieces and bond them together. I use short pieces of filament for locating pins and have matching 2.0mm holes in the mating parts. Location is very accurate and Cyano-Acrylic glue works very well on both PLA and PETG.

Back in the day I was very into U-Control and then RC airplanes and I still maintain some interest. Now I'm retired. I'm too much of a wus to go fishing when it's 40 degrees outside and so I wander into my office a few times a day and check here to see if I can add something useful (or at least humorous). I started working with Gcode in 1969. This allows me to claim that I have some understanding of it. You can find the listing of the Marlin Gcode commands HERE. The RepRap WIKI is a bit more extensive and is HERE. You don't need to know all the G and M codes but some come up a lot and those you should be familiar with. When you install a printer in Cura, Cura uses a "Printer Definition File" which was put together by either a member of the community, or supplied by a printer manufacturer. That file sets certain "maximums" and "defaults" within Cura. Many of those settings can be found when you load the "Printer Settings" plugin from the MarketPlace. Those "Maximums" and "Defaults" assume that the settings within the printer are also the defaults. But many of those settings can be changed in the printer and so the Printer Definition File may not be up to date and so Cura may not be up to date. The only thing those Max's and Defaults affect are the settings boxes in Cura. If a box turns red when you enter a number then you have made an illegal entry (according to the definition file). There is no interaction between the printer and Cura other than a gcode file. If you go to Printer Settings and change the Maximum XY Acceleration the printer will not be told. You would however be allowed to enter a higher number in the Speed / Acceleration settings boxes and it would be accepted by Cura. The only way to tell what the printer settings actually are is to send an M503 to the printer and to view the response. You can do that with "Pronterface/Printrun" or with my "Greg's SD Print Tool" that is a Windows App that I'll include below. Either way you need a working USB connection to use them. I wrote the app for Marlin but many commands cross-over with RepRap. Greg's SD Print tool. Let me know if you come across any issues or bugs. I was only a 3.8 student.

If you set a limit in the printer using M201 then that will be the upper limit. Let's say you set a limit of M201 X1000 Y1000 in the printer. In Cura you ask for 2000mm/sec. That would go to the printer as an M204 S2000 in the gcode. When it gets to the printer the printer would impose the M201 limit of 1000. (Think about what that means for Cura's "Estimate Print Time" when the actuality of the printer is different than the theoretical of the gcode.) This is part of my printers response to M503. echo:Maximum feedrates (units/s): echo: M203 X500.00 Y500.00 Z50.00 E50.00 echo:Maximum Acceleration (units/s2): echo: M201 X3000 Y3000 Z100 E1000 echo:Acceleration (units/s2): P<print_accel> R<retract_accel> T<travel_accel> echo: M204 P1000.00 R1000.00 T1000.00 echo:Advanced: S<min_feedrate> T<min_travel_feedrate> B<min_segment_time_us> X<max_xy_jerk> Z<max_z_jerk> E<max_e_jerk> echo: M205 S0.00 T0.00 B20000 X10.00 Y10.00 Z0.40 E5.00 You can see that my limit in M201 is 3000 for X and Y. In the M204 line you can see that I had Cura set for "Print" and "Travel" acceleration both at 1000. In this case the printer would use 1000 since it is below the limit set in M201. If you set a limit in the printer then the printer won't go over it, but you can set Cura to whatever you want. You can change the limit by adding an M201 line to your startup followed by M500 which would save the setting to make it the new default after which you could remove the lines from the StartUp. If you don't enable Acceleration and/or Jerk in Cura, then the printer will use whatever it has in M204 with an eye on the limit set in M201. For Jerk it will use whatever it has in M205. Jerk is different in that there is no way to set Jerk except by changing the Maximum limit as M205 is the only command that applies. If you tell Cura you want Jerk at 100 it will gladly tell the printer to use 100 and the printer will gladly accept it. My printer is an Ender 3 Pro so it's a bed slinger. If I'm printing something tall and thin I will manually add a M201 Y350 line at about layer 300. That will soften the starts and stops so the print doesn't break free of the bed. When I shut the printer off and turn it back on the default of M201 Y3000 is back in place.

Scale the model to 250% in the Z. Set the model on the build plate and slice it. Look at layer 1. I think you will see that there is no divider until Cura prepares for that wall. This is layer 2 with the model at Z=64.75 tall. No divider. On Layer 3 the divider shows up.

This is X-Ray view in Cura. You can see that there is a problem surface within the model. I didn't notice anything odd when I sliced it though. I was able to repair the model with MS 3D Builder. Is it supposed to look like this? I think the "dividing the first layer" may be because that outboard part is so thin. It's only a couple of layers thick and then the wall starts. I think Cura is preparing for the wall support.

OK that is not infill showing through but Support Interface. I understand. Have you tried printing those with Adaptive Layers turned on? As the bowl areas rise they develop "feather edges" that will want to curl upward. That can often cause a deformed look to certain layers. Cooler temperatures can help and shorter layer heights mean not as much heat is being imparted to layers below.

Good Luck.

I have some analysis tools I've written. I read a gcode into AutoCad to check geometry, and into Excel to analyze extrusions/retractions/Line Widths. Using your 3mf file to generate a gcode everything looks very good. Line Widths are generally right at 0.40mm (there is some variance as would be expected given "variable line width"). The speeds are on the money. I don't see any issues in the "flow". Within AutoCad everything is where I would expect it to be. The layers have concentric extrusions. The side view shows a basic hemisphere. Certainly nothing like what printed for you.

When I zoom in to your images it does look like some under-extrusion. On the bowl in particular, there is very little material covering the infill. Calibrating the E-steps falls under "it can't hurt". Another thing are the black flecks on the bottom of the bowl. Could that be burned material from inside the hot end? Maybe you just need to clean out the nozzle and hot end. A partial clog where the bowden tube meets the back of the nozzle is a popular problem on Creality printers. You could try trimming the hot end of the bowden tube by 5 or 6mm and re-installing. That would put the teeth of the fitting onto new plastic. Make sure it is a nice square cut. I looked at your settings in the 3mf file. They look fine. I would change some things, but they would be "personal preference" rather than something that is amiss. I like higher "support density" and higher "support interface density" when there are arcs and circles. The extrusions stay where they are put instead of getting dragged towards the center.

Yes, you will need to use surface mode. Here we are looking straight down a gap between the internal ribs and the upper and lower skins of the wing. A bit of over-extrusion would glue them together, but not by much.

In Preveiw mode, if you look at the underside of a model you will see surfaces colored red. Those are the areas that will need support (according to the overhang angle you set). Those red areas must be covered by a support blocker in order to block the support. The blocker doesn't need to go down to the build plate, just cover the red surface, or in some cases, part of the red surface. Here there are three blockers that I've made 30mm in the Y There are no supports where they've touched the red overhang surface.

Try it with a 0.4 nozzle at 0.35 Line Width. I thought it looked pretty good. I usually print boat hulls thicker at .8 line width as they aren't near as fussy about weight. If you wanted to print this at 0.6 line width you could do that by jacking up the flow in Cura, or just adding an M221 S150 line to the beginning of the gcode file. If you try to do it with the line width then Cura will skip areas. This is at .35 Line Width. (BTW the bottom of the model isn't flat. That's why the skirt is cutting across short of the leading edge.)

I can guarantee they are not gcode bugs. My Ender never prints like that. Load the model and set Cura up to slice. Use the "File | Save Project" command to create a 3mf Project File. Post the 3mf Project File here. All Creality printers need the E-steps calibrated. Did you do that?

The convention is to use G0 for moves with no extrusion and to use G1 if there is an extrusion. The oddity in Cura is when Z-hops are enabled. It may be because Z-hops are related to retractions/primes and so a Z hop move will be with a G1 even though there is no E value in the line. "Lately however that went away and now it's just +0.2" I think it's a firmware issue. A line like "G0 Fxxxx Xxxx Yxxx Z0.2 should send the print head to Z=0.2. IF there is some sort of compensation for the bed leveling written into the firmware, then the firmware may be adjusting that, but the command states to "travel to Z=0.2". G29 has some parameters that can be applied. Which parameters is likely dependent on your firmware. The same would be true for M420. The Marlin definitions are HERE and the RepRap definitions are HERE. When you use Search and Replace to make changes it has the option to "Use Regular Expressions". That option can make the Search very specific. Search: ;LAYER:1\n Replace: ;LAYER:1\nG0 X0 Y0 Z0\n Use Regular Expressions: TRUE The search criteria with the "\n" newline character would be limited to Layer:1 (rather than Layer:1, Layer:10, Layer:11, Layer:100, etc.) Rather than using the G1 line it might be better to use the "G92 Zx.x" line to set the Z position for the file. That way every Z value in the file would be adjusted. A third possibility would be to use M206 and adjust the home offset Z.

If you are using "Pause at Height" then you have at least two options regarding the actual Pause command. "M0" is the normal Marlin command and should send the message "click to resume" to the LCD. When you are ready to restart then a button click on the LCD should resume the print. An alternative is "BQ/M25". The M25 is "pause SD print". Sometimes the LCD will say "click to resume" but sometimes (depending on your firmware) you may need to click on "Pause" before clicking on "Resume". How the printer reacts to a command is a function of your firmware. If a command is not supported by the firmware then it is usually just ignored by the printer.

No matter how you do it - if you level the bed and the initial "Z gap" is exactly "0" then the line G1 F1000 X0 Y0 Z0.2 would set the nozzle at exactly 0.2 above the build surface. For an ABL system the commands are often: G28 G29 and then either purge lines or printing start. The printer is supposed to go where it's told. If the initial gap is too high (or too low) then there is something going on with the ABL settings and the Z-offset. The only other real possibility is that there is a problem in the Z system that causes the printer to NOT go where it was told, but that has a very low probability. Manual leveling is different. You Auto-Home the printer, level the bed, and then start the print. Almost every printer definition file puts a "G28" in the StartUp gcode. What that does is to reset the Z=0 location. Considering the quality of parts on my printer, I found that the Z=0 was often a different height than the Z=0 of my first Auto-Home. That changed the height of my first layer. The bed didn't move, the nozzle height was changed by a Z-stop switch that isn't very "repeatable". Changing my Startup Gcode to "G28 X Y" solved the problem. The "Z" location I leveled with is the "Z" location I print with.

Here is the gcode file you posted. I don't see anything weird in it other than it's not the one you had analyzed. Have you formatted that memory card lately? It needs to be done every once in a while. Here is the one you posted opened in Cura. I read it into AutoCad as well and that one looks just like this one. The lines on the left are your purge lines and the angled line is from 0,0,0 to the start of the skirt/brim. There is also the wipe-out move at the end of the print. I think there is a better than even chance you have a bad sector on the memory card.

The Walls setting "Zseam Location" and "Z seam relative" along with the Travel settings "X Layer Start" and "Y Layer Start" can be fiddled with to get what you want. I like to start the skirt near the left front corner so no string gets pulled across the build area.

"initial_extruder_nr" is the extruder that Cura has figured out will start the print. I can see that if the skirt/brim is set to T0 then that is what will start the print. If you don't intend to use T0 for the print have you tried disabling it? It looks like if T0 is enabled then the build plate adhesion defaults to it. I guess you either need to manually set the skirt/brim to T1, disable extruder T0, or disable the Build Plate Adhesion.

Hello to both of you. Try enabling "Connect Infill Lines". It will get better but I couldn't get them to go away. They appear to be appended to the ends of all the infill lines.

There is always a Zseam as the nozzle must start the outer wall someplace. Settings like "Outer Wall Wipe Distance" can make it less. I have found that disabling "Retract before outer wall" can help because with no retraction there is no "prime". Coasting can help, but it also has drawbacks as extrusions after coasting can start out under-extruded. Printing with the wall order "Inside to Outside" is better. Round parts are the toughest because there aren't really any corners to hide the Zseam in. You can make it "random" but then there are zits all over instead of lined up nicely where they are easier to sand off.

Playing with the firmware is a long slippery slope. There are numerous posts on the Ender 3 board on Reddit regarding botched firmware "upgrades". That would be a better place to start though. This board is pretty UM specific when it comes to the hardware side. If you have a specific idea regarding commands that your firmware doesn't currently support and that you think you would find useful then you can try compiling your own firmware. You have a fixed amount of memory available on the board and every added function will eat away at that memory. You will get to a point where the firmware won't fit into the board do to memory constraints. You need a good idea of what functions will fit, and what might have to be disabled so something you want can be enabled. I run a stock Creality 1.1.5 8bit board with Marlin 1.8 and the machine prints really well. M0, M600, and G2/G3 are all enabled so I can use Pause at Height, change filament, or use Arc Welder with no problem. Have you tried changing the thermistor on the bed? It's the only control there is for the bed temperature. It tells the thermostat on the board whether to turn the bed on or off. The LCD display should just be reflecting what it's told. There is a firmware option in Marlin that will not turn the Hot End fan on until it hits 50°. You would need to recompile to enable it. "Start and End sequence" commands are in your StartUp and Ending gcodes in Cura. There is no need to recompile to change them. That includes the heating order of the bed and hot end.

The coasting is there, it's just very small and hidden by the white "Start" squares. The skirt coasting is obvious but you have too look close to see it in the walls. This is with your settings. Here I've dropped the "Minimum Volume Before Coasting" to .1mm³. When I inserted a cube next to your model the cube looked like I would expect with gaps where the coasting occurred. Somehow your model is confusing Cura. Maybe it's all those short line segments around the curves??? The skirt looks fine with gaps as expected. This is your model scaled up to 300%. Everything looks good here.

You could try T{initial_extruder_nr} At the end of your StartUp Gcode. Cura will put in the number of the first tool used in the print. You will need to work out the heating arrangement for it to insure you don't get a cold start. I think that: M109 S{material_print_temperature_layer_0} T{initial_extruder_nr} should work. You will need to test that. You may have to activate the tool before you can set the temperature.

The words "Dead Simple" and "Computer Software" are mutually exclusive. The proper terminology is "Why won't this #$%^ POS do what I ^%$##$@ want it to do???". Most people find that at this point a cutting torch and sledge hammer are required to move forward.