Multiple Problems - One Solution  

RE: Multiple Problems - One Solution

One addition to the above.  I never could get a good print at any layer height below 0.2mm.  I usually got spaghetti.  Could be that the slipping gear responded worst to the smaller feed increments.  Haven't tested this yet.

(Correction above - got the MK3 in July/18)

RE: Multiple Problems - One Solution

Not sure how or why, but people miss the detail that the set screw must be screwed down to the FLAT on the motor shaft.  If you miss that step, all bets are off one how long it will stay tight. Minutes? Hours? days?  But it will come loose if screwed on to the shaft round.

RE: Multiple Problems - One Solution

Well, the honeymoon is over. Back to prints not sticking for maybe 15 tries/several days.  I have tried all the usual.  Multiple isopropyl cleanings, hairspray, and finally PVA (Elmer’s Washable School glue).  Even different PLA filaments and several Z calibrations.  I haven't done an acetone cleaning yet.

The glue did the best, but there is one corner that refuses to stick on all tries, no matter what.  Could this be related to the gcode file??

Will try moving the object around on the print bed to see if that matters.  I note a similar forum session below "Part breaks free at same place every time”, so I will defer to that.

Looks like acetone cleaning is not recommended for the textured sheet.  What about the regular sheet?

RE: Multiple Problems - One Solution

After moving the part forward and changing the density to 20% from 100% (used on other parts), the front left corner improved.  So, I waited until the print covered the original front corner position.  The print became very thin, with gaps between the lines. It looked like it wanted to lift, so I pushed it down with a spatula.  This implies a bad metal bed.  My prints have always had significant variations in the uniformity of lines on the first layer.

Calibrations, cleaings, etc. don’t seem to fix the problem. Wonder if Prusa has a QC problem.

It seems like some people have significant, ongoing adhesion problems and others have few if any.  I have read in these forums comments implicating 

Cleaning, (many different versions)

Density of print,

Feed rates,

Temperatures, etc…...

The only common denominator is the plate itself.

Has anyone changed plates and gotten rid of the problem?

RE: Multiple Problems - One Solution

Posted by: ben.g16

Well, the honeymoon is over. Back to prints not sticking for maybe 15 tries/several days.  I have tried all the usual.  Multiple isopropyl cleanings, hairspray, and finally PVA (Elmer’s Washable School glue).  Even different PLA filaments and several Z calibrations.  I haven't done an acetone cleaning yet.

Soap and water work best for cleaning spring steel sheets. Keep hands and fingers away from the print surface; use fresh paper towels for scrubbing and drying; do NOT use alcohol after a soap wash.  When adhesion wanes, go back to the sink with soap and water.  

RE: Multiple Problems - One Solution

and gaps sound like you need to adjust the Live Z

RE: Multiple Problems - One Solution

Next chapter.  I washed the sheet thoroughly in soapy water with one of those nylon wool scrubbers (not too hard). Wiped dry with paper towel.  Put it on the machine and left it overnight.  This morning I began a print.

The brim showed a poor adhesion in one spot, so I did a live Z adjust.  The first layer print shows multiple defects (see pic), but is a bottom surface I can live with, since I have deadlines and no successful prints for a week.

Area 1: Good adhesion and line width.

Area 2: Poor adhesion and lifting

Area 3: narrow line width, not filling to boundary.

At this point I am at a loss.  I have tried all the remedies listed in this thread with no success.

RE: Multiple Problems - One Solution

it looks like you are not using a prusa flex sheet to print on. maybe the sheet you are using is not a uniform thickness

RE: Multiple Problems - One Solution

Yep, official Prusa sheet supplied with the kit.  Still wondering if it is defective from the beginning.

RE: Multiple Problems - One Solution

I re-read  this thread looking for one thing and if it is there I missed it. How many measure points do you have configured for mesh leveling? 3x3 or 7x7? If only 3x3, try upping it to 7x7. While the beds of the printers look flat, on the scale of 0.1mm (this is significant for the first layer) there can be a lot of variation across the bed that a 3x3 mesh will miss.

RE: Multiple Problems - One Solution

I have been using the anti-ooze startup gcode that warms the PINDA to 35ºC, but the default G80 code for 3x3 mesh.  I just changed it to G80 N7, for  a 7x7 mesh,  but have several hours to go before I can try it.

RE: Multiple Problems - One Solution

 nylon wool scrubbers  ... The brim showed a poor adhesion in one spot,

Yep - more contamination added to an already dirty bed.

Use a FRESH paper towel to clean with.

RE: Multiple Problems - One Solution

OK, two more tries.  Washed plate with soap and water, holding under spigot to avoid submersion in other (dirty?) water.  Used new paper towel.  Dried with another new paper towel.  Cleaned off heater bed to eliminate any dirt on it.

Printed with G80 N7.  It did not do 7x7, but did 3x3.  I watched bondtech roll over.  Looked smooth.  On this part, the first layer is the visible top, so I cancelled both prints.

Result is shown in picture.  What next?

RE: Multiple Problems - One Solution

What brand steel sheet are you using?   Your's doesn't look like a Prusa sheet I am familiar with.

Also, you might try figuring out how to use the 7x7 mesh level; it's worth the effort.  

RE: Multiple Problems - One Solution

The sheet is standard Prusa that came with the kit. Looks like the pale version in the pic. Will send better photo.

I decided to smear the glue stick from Prusa on the bed for one more try. It is a mess and don’t know how to smooth it out, but it seems to be working. Will report later with more data. If true, then this may verify that printing directly on the sheet is no good, but printing on a layer over the sheet may work.  

After turning turning the power on & off the 9x9 mesh worked. 

RE: Multiple Problems - One Solution

As an FYI - way back wheren - when I was starting out, I was having severe adhesion problems, and was trying everything to get PLA to stick.  I was just about to sand my sheet with 80 grit.  But someone suggested I try soap and water.  I was very dubious but out of desperation I tried a hot water wash with flowing, not standing water.  I used a paper towel as awash cloth since it was handy.  Dried the bed with another towel. Placed the sheet on the bed and was absolutely surprised with how good PLA stuck.  So much better than with the glustik I had been using.

So I did some more experiment. I tried my microfiber towels for drying: large fail there. I tried my scrubber sponge, anther super fail.  

What I have found is one finger print will spread over time and if you use alcohol will thin out and become an invisible barrier to PLA.   I've also found that for whatever reason guys simply don't want to believe a single finger print is this bad.  Beds must be handled by the edge while washing, touching the surface in any way will foul it so PLA won't stick.  If I even suspect I've bumped my bed with my hand it goes back to the sink.  It just isn't worth the hassle of a part lifting while printing.

If you have soft water, it takes a while longer to rinse the soap off - I use Dawn, others say it's the best.  But I use Dawn fo rmy dishes and always have, so can't say.  But I do have soft water, and it takes a while to rinse off soap.  So I start with just a drop or two on a paper towel. Scrub, rinse, then rinse again until water is beading on the sheet. If the rinse water isn't beading, the bed is still dirty or soapy.

The 7x7 mesh level is settable in the menus.  I had tried the gcode N7 command with 3.7 and that never worked for me - even though it was working with the custom 3.6 gcode I had been using.  But the 7x7 selection in the menus is working, sort of.

RE: Multiple Problems - One Solution

I had all sorts of bed adhesion, and solid infill issues. The extruder idler tension screws ended up fixing me. Also slowing the first layer.

RE: Multiple Problems - One Solution

RE: Multiple Problems - One Solution

My OG smooth PEI sheet came with the grid markings, but the 2nd purchased in mid-2018 came with the fine markings.