Problems with Top Layer.

Hello to all,

My name is Richard, I'm new to this forum and first, I like to say Thanks!! to all of you. I've been searching for answers in this forum since back in 2014, when I first get my 3D Printer, a Rigidbot Big by Invent-a-part, and all of you have been a valuable help to make my prints better and for troubleshooting my printer. And today is the first time I'm asking for direct help beacuse I ran out of ideas to solve this problem.

I have an issue with my printings, especifically the top layer and the supports.

Note: I have a RBB 1, and changed the original electronics for a Ramps 1.4 and Arduino Mega electronics.

The top layer prints with holes, as if there was no infill in the object. The outer shell prints just fine, but if there's an opening or hole in the object it's also stringy. I do have retraction enabled.
The support it's all stringy and it's not really a support structure, some time falls to the side, or sticks to the print.

In another note, but I guess it's related to the problem, this problems began only a couple of months ago. First, the heated bed stopped to heat, and then, the extruder had to heat all the way to 230° for it to print fine, it used to print with only 190° before the heated bed failed to heat.

-Things I've already tried-
-I change the Ramps 1.4 to a brand new, no change at all, heated bed not working.
-I change the PTFE Tube to a new one, also no change at all.
-Clean the nozzle and extruder, this is the original extruder that came with the printer.

I still not have a functional Heated Bed, and the Extruder has to reach to 230° to print "fine" because I still have the problem with the top layer. If I try to print with 190° it will print but with under extrusion.

If someone can help, or shine a light in the right direction, it will be greatly appreciated. Thanks a lot!!!

It seems your extruder is getting tired. How do your parts look, when you print slower?
Did you check the Vref of the extruder driver lately? Maybe the under extrusion is caused by skipped steps.
Can you raise pressure on the idler gear? Just in case the filament slips.

How about low current to the stepper due to an electrical fault in the hot bed?
You know it worked at 190C. In order to make it easier for the stepper you increased the temperature. Now it doesn't cool fast enough to bridge and is stringy.
So I would make sure the bed is turned off, disconnect the bed, remove the bed driver. Try again at 190C. Check for missed steps etc
Could still be a problem on the ramps but that's out of my range of experience.

I find that if my infill is to sparse then its basically bridging over the gaps, my work arroundis adding a couple more top layers

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Hello and thanks for all of your responses.

Unfortunately, I keep getting the same problem, and I really don't know what could it be at this point. I've already change the extruder for a brand new e3d Lite v6 that I bought from reprap.me (http://www.reprap.me/lite6-full-kit-1-75mm-universal-direct-12v.html). As I had to change the thermistor settings in the Marlin firmware, I change it and then reuploaded in to the Ramps 1.4. Still no change.

I removed from the Ramps the heat bed as suggested and then I saw that I had a melted (or burned) power terminal, the one next to the de D8 Pin. It was burned badly, so I check online and some users claim it would be better if I solder the wires to the board directly, so I did. But still no change.

Sometimes, when I print there was this brown-like filament that shows in the print. I guess it's burned plastic or something.

I've already tried everything I could think of from buying a new Ramps 1.4, to buying a brand new extruder. but the problem keeps getting worst. I used to print fine with a temperature of 190° and a decent speed, now I have to lower the speed almost 20% and heat the hotend all the way to 230° so I can get a semi decent print.

Below I have a comparasion between 2 bottle caps I print a year ago. The one on the left is the one I printed a year ago, It seems much better thant the one in the right wich was printed a month ago.

If anyone could help or give an opinion of what could be wrong, I would greatly appreciate it.

For me the right cap looks better. On the top it looks like a little underextrusion. And 230 deg is AFAIK way too hot for PLA. Did you adjust Vref on your drivers? Checked the current to the steppers, especially the extruder stepper? Are you printing with 3mm or 1.75mm filament? What's your nozzle size? 3mm filament and 0.3mm nozzle can be hard work for the extruder stepper. Do you have the chance to test a geared extruder, like Wade's?

looking at picture 4210 you have no hot end cooling fan for the fins!
YOU NEED a fan there!

As you were printing at 190c we assume your using PLA so 230 is way to hot and explains the brown marks and the stringing. So I would set it back to 190.
Then you check if you can push the filament through by hand. If so the issue is the extruder as O-lampe has pointed out.
From the picture it looks like the idler arm gets very close to the mounting block so check you have clearance and good spring pressure with filament installed.

Quote
Inhumierer
For me the right cap looks better. On the top it looks like a little underextrusion. And 230 deg is AFAIK way too hot for PLA. Did you adjust Vref on your drivers? Checked the current to the steppers, especially the extruder stepper? Are you printing with 3mm or 1.75mm filament? What's your nozzle size? 3mm filament and 0.3mm nozzle can be hard work for the extruder stepper. Do you have the chance to test a geared extruder, like Wade's?

Yes, sorry, the one on the right is the one I printed a year ago. 230° deg it's too hot, but is the only temperature that I can work with the PLA. I did adjust every once in a while the extruder driver, especially when I hear a clicking sound. I'm printing 1.75mm filament with a nozzle size of .4. And as for now, I haven't time to check a geared extruder

Quote
Floyd
looking at picture 4210 you have no hot end cooling fan for the fins!
YOU NEED a fan there!

I does have a fan, but is in the back, I printed this mount (https://www.thingiverse.com/thing:432000), so I can fix the e3d hotend to the Rigidbot.

Quote
MCcarman
As you were printing at 190c we assume your using PLA so 230 is way to hot and explains the brown marks and the stringing. So I would set it back to 190.
Then you check if you can push the filament through by hand. If so the issue is the extruder as O-lampe has pointed out.
From the picture it looks like the idler arm gets very close to the mounting block so check you have clearance and good spring pressure with filament installed.

Yes! Seems to be a problem with the extruder. More specifically, the tension on the feeder. Last night I tried to put more tension on the feeder, by adding a coin in the spring on the right (The pic is not mine, I found it online, but you can see where everything is), only then I could print again PLA at 190° temperature as before. I still get some under extrusion on some layers on the print but I will print this piece (https://www.thingiverse.com/thing:1516255) and see if I can get a better fix.

Thank you all for your input and advice!

Edited 1 time(s). Last edit at 06/29/2017 12:58PM by Bretta91.