GregValiant

I think that you have two problems to solve. One is the build surface size and the other is a problem with the model. The actual printable area is determined by a couple of things. Within Cura, go to "Monitor / {your printer} / Manage Printers / Machine Settings" and check that the build plate size is correct for your machine. It should be a rectangle 350 x 350 and "Origin at Center" should NOT be checked. On the printer LCD check the Home Offsets. I don't know for sure but they should be something like X=-10 Y=-10 Z=0. The printer can have two zero positions. One is the absolute machine zero that Auto-Home uses, and the other is a relative zero that is the position of the head when it is at the Home Offset position. When a Gcode file is read, it uses the home offset position as zero. It calculates MaxX and MaxY by adding the numbers (350 and 350 in your case) to the home offset. That means that when you send the print head to X175 Y175 the nozzle should be dead nuts in the middle of the build surface. If it isn't you'll need to adjust the Home Offsets. Regarding the model, the gaps between the members of the array don't matter. Cura understands that they are gaps. Your individual model (that you have arrayed) is the problem. You can try to slice one model (single member of the array) just as a test. I believe even one model won't slice because of internal issues. If Cura 4.6 puts polka dots on the model or highlights particular faces of the model then Cura will refuse to slice because of problems in the STL file. I think there is a Mesh Fixer plugin for Cura in the Marketplace but I have never used it. Hopefully somebody else here can point you in a direction to check that model.

When that G28 auto-home is processed by the printer, it sends the print head up against the three axis switches. That is 0 absolute. The printer does NOT know where the bed is though. If you hand level the bed, then it will be below absolute 0 and there is no way for the print head to hit it because the print head is hard against the Z switch and can't go any lower. I'm thinking there is something going on with the G29 Auto Bed Leveling command (that is executed right after auto-home) and that your bed is above absolute Z=0 when the print starts. Two problems - one mechanical and maybe a second one in the firmware or software or maybe even with the BLTouch gizmo. I would start by leveling the bed manually to insure the nozzle can't drag. There are Youtube videos galore on that. In Cura, check for a setting called "Bed Adhesion / Z Offset" and make sure it is 0. On the printer LCD, check the Home Offsets. X and Y will be smallish negative numbers(Ex: X=-10 Y= -7). Z should be 0. The "Home Offset" defines a relative zero location and is what a running print uses as zero.

Do a search for YouTube videos on How to Calibrate the E-Steps. I would think that is all you need. Keep in mind that not all YouTuber's are equal. You may want to view a couple of different ones. CHEP is pretty good if you can find one by him.

I have written an Excel interface I use to talk to the printer. There is a section on print recovery that can generate a script (that can be run from within Excel) to re-start a print from any point in a file (using the Byte Offset). So long as your print isn't in the way of the auto-home position it will work. I'll put it and the instructions up if you would like. If you know some VBA you alter the code to suit your needs. There is a link in the file to download a trial version (freeware) of SComm32.ocx that Excel will need to communicate through the USB/Serial port to the printer. I use hairspray as an adhesion assist. Sometimes I have to use an air hammer to get the print off the glass. Other times it pops right off once the glass cools. It isn't consistent enough to count on to hold a print while cycling from hot to cold to hot again.

Being line-to-line with the build surface size may be an issue (where 349.99 x 349.99 may not be an issue) . If you have set up for a brim/skirt/raft then that detracts from the surface size as they take up room outside the model. Non-manifold means Cura is having issues with the model file itself. If you post the model file here someone will take a look and suggest fixes for it. A non-manifold model cannot be sliced by Cura because there are gaps in the model (it isn't water tight).

Did you try printing from the memory card?

Ender 3 Pro. Stock hot end, Orion BB hot end fan. 1.1.5 silent main board. Aluminum extruder assembly. In March the nozzle threads stripped out of the heat block. Repaired with a heli-coil. Filament is from Matter Hackers. I've had it since December. After the initial growing pains the machine has been printing perfect. Now it has a new trick. After printing for 35 - 60 minutes it stops extruding (with PLA at 210. Using PETG at 245 it happens faster). Doing a filament pull results in what you see in the image. What you can't see is that from the extruder to the hot end, the filament looks like an accordion. It is difficult to remove from the Bowden tube until it comes free with a slight pop. There is a lot of friction from the accordion shape. After pausing to clear the blockage and resuming the print, it happens again within 5 minutes. Practically speaking - the machine no longer prints. This started 5 days ago. Since the issue started I have: Put heat sink grease on the inside tube of the hot end. Added a thin aluminum plate to the backside of the heat sink. The fan is clean and sounds like it is reaching operating rpm. The hot end is assembled correctly. There is no leakage. The nozzles are clean. The PTFE Bowden tube is new. The tube fittings are new. The extruder stepper motor runs cool. Retractions do not slide the Bowden tube around. Print speed has been varied from 60 down to 20mm/sec. Retraction has been varied from 6mm down to 2mm. Temperature for the PLA has been varied from 215 to 195. Calibration has been double checked. None of that has made a difference. The extruder starts to skip steps on "prime" moves, and within 1 minute starts skipping constantly. Spring tension appears good as witnessed by the accordion shape. The filament appears to be getting shoved hard into the tube, but there is a blockage formed at the hot end of the bowden tube. I have ordered a stock replacement hot end. I do not have high hopes that it will cure the problem so I am looking for thoughts and ideas. June 30 and the new hot end is in and it's better, but still not right with either PLA or PETG.

There is a setting in Cura under "Quality" called "Initial Layer Height". It sets the height for Layer 1 and I think the default is .28mm. It does not change automatically when you change the regular layer height. If the setting isn't visible, slide the cursor across the Quality bar and click on the gear icon. Then check the box for Initial Layer Height.

There are a bunch of parameters that have an effect on flow. #1 is Extruder steps/mm. There are videos on how to calibrate it and you need to start there. After that, calibrate the XYZ. I use a digital caliper to measure those. Essentially, you measure where the head is from a fixed point, then tell the head to move 50mm and then measure again from the same fixed point to see if it actually moved 50mm. There is a quick formula for calculating the steps/mm based on the measurement. (Move Expected / Measured movement) * current steps/mm). Again, there are YouTube videos. These machines can be superbly accurate and it all starts with being parallel, square, and calibrated. Back to flow, there are settings in Cura under Material that allow you to change the flow for different areas of a print. I suggest you take a look at them and set all of the percentage based ones to 100%. Later you can customize. There should also be a menu on the printer LCD for Tuning. Under Tuning there will be a menu to adjust the flow % on the fly while printing. Flow is dependent on numerous variables. Nozzle size, line width, and of course speed are the main ones. If you are printing at 20mm/sec the flow rate will be 1/2 of what it is at 40mm/sec. A .4mm nozzle at a layer height of .2mm means that 1mm of filament pushed in will produce 30mm of extrusion coming out of the nozzle (IF things are calibrated correctly). At 30mm/sec print speed that is 1mm of filament/sec. There are people who claim to be printing at 150 or 200mm/sec. My Ender 3 would never keep pace with that kind of speed. The hot end just isn't efficient enough to pass plastic through at that speed. I plod along at 50mm/sec for most stuff. Slower gives better results and I get down to 25mm/sec for fancy stuff with a lot of stops and starts. If the extruder motor is clicking and snapping backwards it is skipping steps. That can be a lot of different things from temperature, to heat creep, to a clogged nozzle, to being too close to the build surface, etc, etc. etc. Finding out what is causing the missed steps and under-extrusion is a "Joy of 3d Printing" and you can't get a good print unless plastic is getting pushed at the correct rate. And if all that isn't confusing enough, speed in Cura is expressed in mm/second while speed in a Gcode file is expressed in mm/minute.

There may be something wrong with the model, or at least something that Cura doesn't like. In Cura - what does it look like in Preview? That will be what is sent to the Gcode file. Have you tried to export the file in a different format? (something other than .OBJ that Cura will open)

Have you tried "Spiralize Outer Contour"? It doesn't like horizontal surfaces but anything VaseLike comes out very well. You would need to look at the preview very closely to see if there are areas where the lines are so widely spaced that they don't make contact and you are printing on air.

"Your model is not manifold" error. It can't be sliced because it isn't a solid and it's not closed. You'll need to do something in Fusion to create a solid model. I don't know Fusion but in other programs you could make a solid base and then do Surface Cuts and eliminate the areas that aren't part of the car.

PLA essentially doesn't warp. Long narrow parts may test that statement but I don't see a need to raise the parts off the bed. IF warping happens that's a problem that can be dealt with. I don't want to get you down, but right now all you have is a mess. Keep it simple. Do one part at a time. Put the part on the build surface. Give yourself the best chance at being successful.

Careful is the key word. Heat up the hot end to soften the mess. I try and pick away at it with tweezers. If you have to use a knife make very sure you don't nick a wire.

What happens when you use one of the grips to pull the part?

You need something more accurate that a ruler to perform the measurements. A vernier caliper works well. I think that not enough people pay attention to the frame of the machine. Everything needs to be square and parallel. A carpenters tri-square comes in handy. If (for example) the X beam is at a slight angle then your prints will be off no matter how well the steps are calibrated. Or if the two upright beams aren't parallel then the part will twist as it gets taller. After the machine gets a few hours on it you will want to re-visit the calibration again as things loosen up.

I would start with the slots clear of the raised areas by .25mm constant all the way around. So if a raised area is 1mm x 5mm I would have the slot at 1.5mm x 5.5mm. You can make up a small test piece with some slots on one half and matching raised areas on the other half. Print it and cut it apart and test fit them together so you don't have to print both of the real pieces. If things still don't fit together go to .35 all the way around. Once you have it dialed in then make adjustments to the real parts and print them up.

When printing with wall line count at 3 I've had the infill kinda show through. Increasing the wall count usually gets rid of the marks. At a wall line count of 5 I rarely see it. I've never played with Infill Overlap Percentage but it sounds like the kind of setting that could have an effect on low line count walls and marring of the surface by the starts and stops of the nozzle when putting the infill in place.

Once there is heat damage to the bowden tube it doesn't go away by itself and doesn't care what material is run. BUT...Looking at the video again, it looks like a normal retraction. The motor is turning so slow it's hard to get a feel for what's going on. After the motor starts back up does it start from that retracted position? It's supposed to go back to the previous position. You might check the "Travel / Retraction Prime Speed" setting in Cura. I think the default is 45mm/sec.

Another thing would be how much clearance you left (in the model file) between the raised portions of the yellow piece and the slots in the black piece.

That's the extruder skipping steps when it can't provide enough torque to push the filament. You are clogged in either the nozzle or hot end. I'll put my money on the hot end. The higher temps required by PETG put heat stress on the bowden tube material that is within the hot end. Over time that changes the shape of the inside diameter and causes jams. The good stuff (Capricorn PTFE tubing) holds up better but it will still give out. I've had to replace the bowden tube twice. If you carefully remove the bowden tube and put it in backwards (extruder end into the hot end) maybe you can bring it back to life for a while. Make sure the ends are cut perfectly square. It needs to provide a seal against the back of the nozzle.

From one old shop rat to another...you're welcome.

And now you're learning differential calculus and why PI is a never ending fractional number. At the top of the sphere the angle of a tangent line starts to approach 0 degrees. Cura considers the area under the nozzle as a rectangle with 90 degree sides. When it calculates a layer, it pushes the rectangle up against the side of the sphere. When it calculates the next layer it can't slide the rectangle over quite as far. That leaves a little gap that is your step. Lowering the layer height is all you can do. If the layer height was .00001mm you would still have a step. It would be a really small step, but it would be there. As the layer height approaches zero the step width approaches zero but it never can get there. The same thing happens on inclined surfaces but the steps are all the same size and are all triangular when viewed as a cross section.

The easiest way to get to know this stuff is to play with it. Download files, slice them this way and that. Open up Gcode files with Notepad and get familiar with what kind of codes are being used for printing as opposed to routering because there will be differences. Most download files will be stereolithography STL files that you will open in Cura to slice. Cura will know how big your build volume is. If the model comes into Cura too big for your machine then Cura will put zebra stripes on it and tell you it can't be sliced. There are no dimensions in Cura. The only way to tell how big something is would be to slice it with say .1 layer height and check how many layers there are. Then re-slice the way you want the thing printed. On the left side of the Cura screen are some tools. Click on the model and then select the "Scale" tool. You can enter numbers in the boxes or just grab a handle on the model and drag it. Either way you can get the thing to fit your build space. If the model was drawn in English units it may come in really small. The scale then is 2540% to get it to metric which Cura uses. If the model is to be part of an assembly than all parts would have to be scaled the same so they would fit together. Now repeat after me..."I [insert name here] will NEVER blindly trust a Gcode file that somebody else created." When you download a Gcode file you have no idea what the machine parameters were when the thing was sliced. You can open Gcode files in Cura and it will be shown in preview mode but the file cannot be changed from within Cura. You would still want to open the file in Notepad to look at the opening code and make sure there isn't something in there (like M190 or M140) that your machine won't like. (Any line in a Gcode file that starts with a semi-colon is a comment and is ignored by the printer.) And you have to check the G1 and G0 lines for any X and Y values that are negative numbers. Your machine won't like that either but it will try to print WAAAYY over there and bang into your end stops. A Gcode file is just a simple text file. You copy it from the hard drive and save it to the SD card in a normal Windows or Mac way. You should keep Gcode file names short because most printers don't deal with long file names very well. After you print a Gcode file you can throw it away. As you get familiar with the software, you'll get better at slicing and if you wanted to print the thing again, you'd want to update the slicing anyway.

The geometry of a part is part of your problem. Cura knows it missed spots and goes back and fills them. You can see them in the preview view. They will be little areas of yellow infill amidst all the red and green wall lines. The more sides a piece has the less noticeable the problem is. When you have only three sides and your nozzle is round, it can't get tight into the corners and the software knows that. For structural soundness, filling those gaps is the thing to do. There are settings that will cause it as well. I know Combing will run the head all over as it tries to avoid printed areas. I haven't used Fill Gaps Between Walls but it sounds like the kind of thing that will cause a lot of running around also. Hopefully a moderator will chip in with some ideas for you.