I've only been 3D printing for a few weeks and most of my prints seem to come out fine, but when I try to print models which require a small clearance between sections of the model, e.g. various tolerance/clearance tests and some others, I can't get them to separate when they should because the bottom layer is a solid plate with no gaps.
For most models, this seems a good feature as they stick well and the final surface is completely flat, but for some, I want parts to be separable, so there should be some clearance on the first layer..
From some research, I suspect it may be either that the nozzle is too close to the bed or that the bed (or nozzle?) temperature is too high.
I have an Ender-3 and use PLA with a 200 °C nozzle temp and 60 °C bed temp. When leveling, I've been using a post-it note to set the nozzle clearance. I've tried dropping the bed temp to 45 °C and even 30 °C, but this didn't change the first layer printing of the Maker's Muse tolerance test, which still came out with a completely solid first layer and hence was basically a brick! I also tried using a raft, but the result was that the raft couldn't be removed from the model so this changed nothing.
What should I try to improve this?
I'm using CURA 4.4.1 with as far as I can tell mostly default settings. I've tried the profiles Standard Quailty 0.2 mm and Super Quality 0.12 mm but this doesn't change things. FYI, as you might guess, I haven't changed the default nozzle so it's 0.4 mm.
The main reason for the question is that I don't know where to start with adjusting the settings, so had hoped someone would ask for the value of specific settings rather, than a full lisy, since most of the seem to do with the structural integrity of the body and shell of the model rather than the base, but here goes...
Shell: Wall Thickness: 1.2 mm Wall Line Count: 3 Top/Bottom Thickness: 0.8 mm Top Thickness: 0.8 mm Top Layers: 4 Bottom Thickness: 0.8 mm Bottom Layers: 4 Horizontal Expansion: 0 mm Infill: Infill Density: 20 % Infill Pattern: Cubic Material: Printing Temperature: 200 °C Build Plate Temperature: 60 °C Flow: 100 % Wall Flow: 100 % Outer Wall Flow: 100 % Inner Wall Flow: 100 % Top/Bottom Flow: 100 % Infill Flow: 100 % Skirt/Brim Flow: 100 % Prime Tower Flow: 100 % Initial Layer Flow: 100% Enable Retraction: [Yes] Speed: Print Speed: 50 mm/s Travel Speed: 150 mm/s Initial Layer Speed: 20 mm/s Initial Layer Print Speed: 20 mm/s Initial Layer Travel Speed: 100 mm/s Travel: Avoid Printed Parts When Traveling: [Yes] Avoid Supports When Traveling: [On] Travel Avoid Distance: 0.625 mm Z Hop When Retracted: [No] Cooling: Enable Print Cooling: [Yes] Fan Speed: 100% Support: Generate Support: [No] Build Plate Adhesion: Build Plate Adhesion Type: Skirt Dual Extrusion: (No settings - single nozzle) Experimental: Tree Support: [No] Printer Settings: X(Width): 235 mm Y(Depth): 235 mm Z(Height): 250 mm Build Plate shape: Rectangular Origin at Center: [No] Heated Bed: [Yes] Heated Build Volume: [No] G-Code flavor: Marlin Printhead Settings: X min: -25 mm Y min: -32 mm X max: 32 mm Y max: 34 mm Gantry Height: 25 mm Number of Extruders: 1 Start G-code: M201 X500.00 Y500.00 Z100.00 E5000.00 ;Setup machine max acceleration M203 X500.00 Y500.00 Z10.00 E50.00 ;Setup machine max feedrate M204 P500.00 R1000.00 T500.00 ;Setup Print/Retract/Travel acceleration M205 X8.00 Y8.00 Z0.40 E5.00 ;Setup Jerk M220 S100 ;Reset Feedrate M221 S100 ;Reset Flowrate End G-code: G1 E-2 F2700 ;Retract a bit G1 E-2 Z0.2 F2400 ;Retract and raise Z G1 X5 Y5 F3000 ;Wipe out G1 Z10 ;Raise Z more G90 ;Absolute positionning Material is Generic PLA: Default Printing Temperature: 200 °C Default Build Plate Temperature: 60 °C Retraction Distance: 6.5 mm Retraction Speed: 25 mm/s Standby Temperature: 175 °C Fan Speed: 100 % Standard Quality Settings: Quality: Layer Height: 0.2 mm Initial Layer Height: 0.2 mm Shell: Wall Thickness: Calculated Top/Bottom Thickness: Calculated Support: Support interface Thickness: Calculated Super Quality Settings: Quality: Layer Height: 0.12 mm Initial Layer Height: 0.2 mm Shell: Wall Thickness: Calculated Top/Bottom Thickness: Calculated Support: Support interface Thickness: Calculated
As you may already know, there are lots of other settings which, by default, are not visible. If you need the value of one of these, I'll turn it on and see what it is.
I've also got a few of the failed pieces out of my junk box and added a couple of photos/ As you can see, the underside is beautifully flat and solid.
I also tried this test, but the only reason I got one of the pegs out was it broke off the base layer!
Not an answer to the original issue, but I found a workaround in that there is an option in CURA to turn off the "drop model to build plate" option, so the whole model can be made on supports. This then doesn't have a 'solid' first layer and I get a test piece which shows I can print down to a separation of 0.2mm and have the parts remain free; 0.15 doesn't free up.
Original attempt, new version and the support.