MK4 IS profiles defaulting to grid infill is a mistake  

RE: MK4 IS profiles defaulting to grid infill is a mistake

At home my MK4 sets on a rock-solid bench. I had a print sliced with all stock IS settings that printed perfectly. 

Now I’m in a motorhome with the printer on a plastic tote resting on carpet. I tried printing the same bgcode. The printer jerks around reacting to every change in direction. The top of the printer is moving an inch in every direction. The nozzle kept hitting the grid infill making a mess out of the print. 

Point is that I wonder if most of the grid infill problems others are having are related to the printer not being on a stable surface?

RE: MK4 IS profiles defaulting to grid infill is a mistake

Can’t speak for anyone else, but my mk4 is on ‘rock solid bench’ too. A very heavy, low cabinet that actually has concrete weights in the base. And as stated, I’m seeing the infill issue.

RE: MK4 IS profiles defaulting to grid infill is a mistake

I can't see the bench having anything to do with it - the nozzle physically hits the overlapping/crossed sections of the grid infill. The base the printer sits on has no bearing on that. 

If it does, then Prusa should be supplying me with a recommended table to ensure my printer works as advertised! lol

RE: MK4 IS profiles defaulting to grid infill is a mistake

For my part, I have the printer on a very solid base, I even put it on the floor.

I am also exchanging emails with support and they have passed the incident to the slice department. Do we all use prusaslice or do we also have the same problem with other apps?

RE: MK4 IS profiles defaulting to grid infill is a mistake

I'm having similar issues, also using grid infill. It seems that when my Mk4 prints a straight line that bridges from one part of the grid to the next, the line fails to connect/adhere and lifts up, causing the nozzle to hit the print and make a noise when it passes over again. Also, the portions of the print made by the rapid zig-zag motion look choppy at the edges.

I found that slowing down the infill and gap fill rate seemed to help, but didn't completely fix the issue. The lift was drastically reduced and the nozzle wasn't making any noise as it passed over the problem areas, but I can still see thin lines and slights bumps. I'll try the same prints with gyroid infill tomorrow.

RE: MK4 IS profiles defaulting to grid infill is a mistake

Update:

Completed the same print without any mishaps using gyroid infill. All other settings were from the default IS SPEED profile. I could still see a few slight bumps in the print from the infill lifting/warping a bit but everything else came out fine, and I had no issues with the nozzle hitting the print.

I'm starting a larger test print just in case, but the grid infill pattern seemed to be the issue. Seems to be a common issue with IS according to this post, hopefully Prusa is working to fix it. I'm a little frustrated because I spent so much time tweaking other settings and checking my printer for calibration issues.

RE: MK4 IS profiles defaulting to grid infill is a mistake

Yeh Gyroid seems to be the way to go for now......

RE: MK4 IS profiles defaulting to grid infill is a mistake

there is an update for configuration, it's addressing the infill speed rate

RE: MK4 IS profiles defaulting to grid infill is a mistake

Where can I find more info?

Thanks

RE: MK4 IS profiles defaulting to grid infill is a mistake

Hi, here is the change log: https://files.prusa3d.com/?latest=slicer-profiles&lng=en_US

Posted by: @iftibashir

Where can I find more info?

Thanks

RE: MK4 IS profiles defaulting to grid infill is a mistake

Thanks for this, I've been seeing the issues described for some time now. In my experience some filaments seemed more sensitive to failure than others. I had moderate success with turning up the hot end temperature but still saw issues with skipping in the infill. I'm running a print that failed numerous times with Overture filament, this time with lower temp and rectilinear infill, so far so good.

RE: MK4 IS profiles defaulting to grid infill is a mistake

I see someone already commented, but it's caused from under extrusion because the infill speeds are too fast for most PETG.  Look up the volumetric for rate for the PETG your using.  They vary wildly.  For example Hatchbox is like 100mm/s where Polymaker is only 50.

I discovered this before the update because when I did some PETG prints with Polymaker PETG, that I had previously made with Hatchbox PETG, I saw the same issue with the infill. 

I could tell by looking at it that it was underextruding so I looked up the specs, and sure enough the default infill speed in PS was faster the Polymaker max speed. I lowered the infill speed and the problem was solved. 

Best solution is to create filament profiles with the correct max volumetric flow rate.  This will make sure it doesn't print too fast regardless of the speeds in the print configuration. 

RE: MK4 IS profiles defaulting to grid infill is a mistake

Interesting thread, I'm new MK4 owner (and new Prusa printer owner) and so far am in love with this printer.  I just had my first print failure, turned on the lights to find the base of my part off to the side of the print bed and a big ball of spaghetti in it's place.

I cleaned things up and re-started the print and as it started making the infill I could hear the nozzle hitting the lines - kind of like a car hitting the warning rumble strips on the interstate.  The infill was messy looking, like something was raking through it and tearing it up.  The perimeters were great, the walls were perfect.  

I have solved the problem for now using the Gyroid infill, it's happily printing away.

I'm curious how the rocket engine sample model included on the USB drive was sliced, that printed fine for me with no issues.  The print that failed on me was the first large part I tried to print outside the rocket engine.  I did have a minor issue printing a full bed worth of rocket launcher ammo ( https://www.printables.com/model/432773-rocket-launcher-toy-print-in-place).  I was printing 60 or 70 of them in one go and a couple of them were knocked over, I'm assuming it was from the nozzle hitting the infill as well.  When I used gyroid on a second run of them I didn't have any issues.