Makerbot Replicator Print Quality Troubleshooting _ Gaps in Top Layer

[Adamantium Wolf]

Hello everyone,

I am responsible for operating and maintaining 3 Makerbot Replicator printers (named A, B, and C) at my local college, and recently I have been having some print quality issues when using B and C. I haven't used A much; B and C have historically produced better prints. I am trying to print what we call "kit blocks". The prints I ran prior to the ones I am currently trying to run came out nearly perfect, so I thought I had found my "Goldilocks" settings. I have not changed the settings much if at all, and the test cube prints that I did before starting the kit blocks came out really well.

Problem: There is some stringiness as well as layer separation/oozing, but most importantly, I have some very large gaps in the top layers. If you orient the part the same as it was on the print bed, you can see it is actually the same area that is being affected. I can't seem to attach pictures at this time.

My settings are as follows:
Infill: 5% hex
Extruder temp: 215F
Travel Speed: 150 mm/s
Speed on shells and first layer: 10 mm/s
Layer height: 0.2 mm
Fan: 45-50%
Shells: 3 with fixed start point
Roof/Floor Thickness: both 1mm
Retraction Distance: 1 mm
Filament diameter: 1.72 mm
No supports

Room temperature is 77F, and we have cardboard boxes over the printers as well. I am printing with a raft and use painter's tape as well. I am fairly new to 3D printing, so any advice would be most helpful.

[Adamantium Wolf]

Here are the pictures of the prints from printer C.

[Adamantium Wolf]

Here are the pictures from printer B.

[curious aardvark]

couple of things.
150 travel is REALLY fast.
I generally have the travel the same as the printspeed - or 70mm/s at most.
2 - fan should really be either off (first 1 or 2 layers) or 100% (all other layers). The faster you cool the plastic the better the print will be.

You haven't put the print speed.
For pla, you don't need the boxes, you want it to cool and set as fast as possible.

What slicer are you using ?

Oh yeah and it's most likely a bed levelling issue - 90% of print problems with replicators are down to printbed levelling.
Well all mine have been :-)

For infill pattern, use tringular if you have it - just as strong as hexagonal, but faster and easier for the printer to make.

and if you haven't tried flashprint slicer - try it :-)
http://www.flashforge.com/support-ce...print-support/
Select Creator Pro.
Knocks makerware into next week.