Noob Question: How to improve this print (Calibration Cube)

[firefist235 0]

Hi all,

I am an absolute 3D printing beginner, so I am i little overwhelmed with all the settings in cura.

I used the Cura extension "Calibration shapes" to print some calibration cubes with my Anycubic Kobra Max.

 

I am not really satisfied with the result.

The top is not good looking

the corners aren't really sharp

you can see horizontal and vertical "ghosting" from the "X" and "Y" all way around the surface (even on the sides were there is not even a letter) 

 

The first two cubes are printed with 80mm/s. The second large one with 40% Speed.

I also tried the cube with enabled and disables acceleration and jerk control in cura.

 

Can someone give me a hint what knobs i have to tune to improve my prints?

 

Thank in advance

[GregValiant 1,408]

Whether the printer came as a kit, or assembled from the factory, there are a couple of things to do to the machine itself to insure the mechanicals are adjusted.  Do not assume that because certain parts were assembled by Anycubic that they were assembled correctly.

Use a carpenter square and a straightedge and go over the frame.  You want the 3 axes to be as close to 90° to each other as you can get them.  My ender came with a 2° angle between the X and Y and that was a factory assembled piece.  Don't be afraid to loosen some screws and make some adjustments.  These are basically simple motorized machines.

Next is the X beam.  You have dual Z screws and motors with a timing belt across the top.  You don't want the two sides fighting each other.  The same is true for your bed trolleys.  The beams the bed travels on need to be precisely parallel or there will be binding and your prints will suffer.  The vertical Z beams also need to be exactly parallel or the X beam will rotate as it rises.

With the machine cold - wiggle the nozzle.  There shouldn't be any movement but loose hot ends have been known to happen (one of those factory things).

Each set of trolley wheels should have one that is mounted on an eccentric cam so it is adjustable.  You should be able to just rotate an wheels with your fingers.  If you can't then the adjuster wheel needs to be moved away from the slot.  If it is too loose then the adjuster wheel needs to be moved in to the slot.

When all of that is done then the printer should make nice square prints.

The Extruder motor may need calibration.  Within the gcode files you print are "E" values and they are in "mm's of filament".  When a command tells the extruder to deliver 100mm of filament then exactly 100mm of filament should come out of the extruder.  There are a ton of videos out there on how to calibrate the E-steps.  This is likely what is wrong with your top surfaces.  Going along with this is an exact measurement of your filament diameter.  That number goes into Cura and is used to calculate the volume of an extrusion.  When people talk about 100% Flow they are talking about the ratio of "Volume of Filament extruded" to "Volume of extrusion at the nozzle".  When that is even steven you have 100% flow.  If your filament says 1.75mm on the package but is actually 1.72mm when you measure it, and Cura has 1.75 as the filament diameter, you will have a built in 4% under-extrusion.

Use a flat topped calibration cube and scale it to about 75 x 75 x 1mm thick.  Slice it and print it.  Top surfaces are the best for checking the flow to see if you are under-extruding (gaps between adjacent extrusions), over-extruding (ridges and the nozzle looks to be bulldozing plastic) or just right which looks....just right.  A magnifying glass can help.  Remember these are practices and can be aborted when you see something and recognize that you want to make a change.

 

Non-square corners can be caused by loose machine parts.  Extrusion problems can be from E-steps being out of whack.  Ringing is usually a speed/accel/jerk thing.  It's hard to tune ringing out.

You never really turn Accel and Jerk control off.  You can set them in Cura to certain values but if you don't "enable" the accel and jerk in Cura then the printer will use what it has saved internally.  Right now don't worry about it but you should enable both in Cura (500 accel for everything and 8 Jerk for everything) so you can start building a baseline for your settings.

 

There.  Now you have something to do tonight.

Edited November 20, 2022 by GregValiant

[firefist235 0]

Thank you very much,

i hope i find some time this weekend to get this done 😉

[firefist235 0]

Add: I try to connect my printer to my PC but all i get is "device descriptor failure" in the device manager. I tried many different attempts to solve this problem, but without any success so far 😕

Edited November 27, 2022 by firefist235

[GregValiant 1,408]

That might be because the USB to Serial drivers aren't installed on the port.  Have you tried other USB ports on the computer?  When Cura was installed it should have installed the port driver.

In the screenshot you can see that the USB port is listed under "Ports (COM and LPT)".  The "USB-SERIAL CH340" is the driver and in my case my printer is connected to COM11 which is the port name.

 

[firefist235 0]

Thanks for that, but i have installed the driver, tried various ports and also another PC. No luck 😕

[GregValiant 1,408]

I've written this little app.  It's more versatile than Cura in regards to communicating with the printer as you can actually view the responses from the printer.  It checks the baud rate up to 250,000 and the Com Ports from COM1 to COM40.

 

It's for Windows only and is unsigned (that costs money) so if you decide to try it you would have to fool your anti-virus into letting it install.

 

I've been under the hood on this today.  If you use it please let me know if there are glitches.  This does not send Gcode files over the USB but rather controls printing from the SD card from the computer keyboard rather than the knob on the printer.

 

Connect the printer to the computer and then start the app.  There is a readme file.

 

Greg's SD Print Tool

Edited December 2, 2022 by GregValiant

[firefist235 0]

Thanks alot. But i don't think this would work because my PC dont even recognise the printer correctly. I think there is some hardware failure