Thanks for everyone being here and willing to share their experiences and knowledge. I bought a (please don’t laugh) a CTC Printer (Dual extruder). Pulled it out of the box a week ago. Could NOT get the software to work for anything (all in Chinese). A friend said to use MakerBot free software. So, I downloaded it and it seems to be working pretty well. Printed a couple small things pretty nice. They had some issues, but thought it was me and just learning. Then all of a sudden the prints were going crazy. Sticking to the extruder, moving off the bed, globbing, stringy and a bunch of other NOOB things. Did some searching and apparently I was running things too hot. Had the extruder running around 250 and around 110 for the bed. Reading and reading it seems I should be dropping things down a little. So, I have the bed around 50 and the extruder around 205. Things seem to print MUCH nicer, cleaner and regulated.
Okay… Great. Now when I print it seems I can not print anything unless I print a RAFT first. So, to even try I printed a flat print about .5" high and about 4" by about 3". Printed about three or four layers and then it started shifting and moving around on the bed so the print messed up. Okay, same print with a raft - perfect! The raft is only about 1/8" bigger than the actual print. So, my question is what would cause this effect. I see videos of a lot of people printing smaller objects with the same printer without a raft. Is the bed still too hot? is the extruder still to hot or too cold?
I haven’t tried to lower the settings much more than they are. Is it advisable?
Tram the bed - The most likely reason is the bed is not level properly not the plastic arms on the CTC move to you have to check your level often (I have one as well) the Raft will cover some of this up as the first “layer” of the raft is really thick and will more likely stick to the bed.
I haven’t used a raft since figuring out the bed traming (it is a bit of an art will a bit of feeling to it).
ABS can be tricky to get to stick to a bed 110° bed temp for ABS, and it will probably need a Kapton tape surface.
PLA is a little easier, 60ish °c bed temp, and get yourself some PVA glue sticks! give the bed a wipe over with the PVA glue stick, let it dry and try that.
-There are settings in the latest Makerbot software in which you can change the speed of the first layer. I’ve found slowing the print of the first layer down gives it time to stick nicely to the bed.
-The ideal temperature for ABS and PLA filament varies with the quality, manufacturer and even colour! Start a print from one of the demo pieces in Makerware (I like to use the Octupus!) PLay around with the settings a bit and check which comes out nicely :). Then jot down or screenshot all the settings you used for that print.
I would check what temp readings you are getting from your sensors when it is cold. At room temp (around 16C) my extruder temps read 18C and my platform temp reads 35C !!! Therefore I adjust accordingly when printing.
I normally print in PLA on a glass sheet clipped to my build plate with a bit of purple glue stick on it. I find that 205C extruder temp and 85C (which is really around 65C) works pretty well for most PLA I have tried.
So, I printed the 20 x 20 cube out last night. Right extruder was at 205. Bed was at 60 for layer 1. 1st layer was at 90% height and a speed of 45 %. Did a fast honeycomb infill 10% Cube actually stayed put and completed! 1 win! The first layer was a little a little bumpy, meaning I could feel the lines in it. Setting was Medium so kind of expect it. One of the and a partial side seems to curve in slightly. and the entire 1st row just, doesn’t look right. Maybe that is because it was only 90% height, but it does look different than the rest. The sides look totally fine and 100% acceptable. The top, looks like it might the PLA might have been too warm and it started to sag between the honeycombs. Not horrible, but you can tell it sagged.
Great reference and thank you. I have leveled the bed several times. Actually, once I found that my entire extruder head was loose? WTH? How did that happen??? Tightened it up and it seemed to go good.
Printing PLA right now. Figured I would get the easy stuff down first. I’ll have to try that Glue Stick trick. heard it a few times now in various places.
Here are the pictures of the 20mm cube. If you look at the bottom, the PLA seems to be far apart in places. On the corner of one, there seems to be a separation, but it really isn’t a separation. Then on the top there seems to be a little bit of waviness going on where it looks like the plastic was pretty warm and it started to sink into the infill. The infill was only 10 % fast honeycomb.
I use a cooling fan which helps with sagging a lot. There are various designs out there - I use thing:537918 (requires a bit of extra cabling for an additional fan).
