First layer keeps getting gunked up

[Karyn Traphagen]

I have a Rep2, just installed my Drive Block Replacement. I've been traveling for a bit, so haven't printed in a while, but printer has not been moved.

Trying to print small items (Sea Creatures: http://www.thingiverse.com/thing:25276), which I think should be pretty standard. Using MakerWare on a Mac.

The first pass keeps tangling up and I have to keep canceling the job. The PLA adheres at the front corner ok, but once it starts to lay down the first layer of the build, the edges just clump together and gunk up. I've tried it on the Standard setting and on the High setting. 

Suggestions? I need to figure this out bc I need to print out dozens and dozens of these little guys!

Thanks,

Karyn

[Jetguy]

Most likely, an issue of improper print surface preparation.

 

The MOST important thing in 3D printing is first layer. The only way first layer sticks is the surface must be prepped and the nozzle must be the correct height for first layer.

You didn't say what bed surface you are using but the following is true regardless of bed surface.

It must be clean and free of any dust or even invisible fingerprints. The oil from just touching it one time is enough to keep a print from sticking

Being you are using a Replicator 2, I assume either you are printing on blue painters tape or the build surface itself?

Either way, wipe down with pure 90% or better rubbing alcohol and a paper towel. This greatly improves adhesion of first layer and removes any fingerprints.

 

The next problem is the build surface must be level to the nozzle path or plane. We call this leveling or tramming the bed. At the same time, this also sets the height of the build surface compared to the nozzle. One noted problem on many Replicator 2s is the build surface can warp and therefore cannot ever be properly trammed or leveled to the nozzle plane. This means the nozzle will typically bee too close in the center of the plate and maybe even touch or block off the nozzle and cause the extruder to click since it cannot build pressure and on the outer edges of the plate the nozzle will be too high.

A quick fix is to take the plate down to the local hardware store and get a cheap pane of glass cut the same outer dimentions of the plate or maybe just less so it fits past the clips. You then place this glass on top of the acrylic and put blue tape on top and wrap it around the front and back edges (the long edges) so the glass cannot slide or move relative to the original acrylic plate. Window glass is far flatter than the original acrylic. You are still printing on blue tape, but now have a flat surface. You must then re-level the bed obviously turning the nuts in so the bed is lower to compensate for the new glass thickness.

[Karyn Traphagen]

Thanks for the tips.

I am still using the acrylic base and I've had success (at various times/seasons/air temps) with just the plain plate, with blue tape on the acrylic plate, with hairspray on the blue tape. I've found that ambient temperature has had an affect on my success too.

I think I'm at the point where I'll take the suggestion (that others have had success with too) and get the glass. 

Thanks for taking the time to answer in such detail!

Karyn