PLA printing problems

Hi guys,

I've just completed assembling and calibrating my ABS Prusa (RAMPS1.4, J-Head 0.4mm, no heat bed) and this is how my first PLA prints look like:
Album

I was trying to print this: pin chain and it gets mangled when it starts printing the finer details.

The only perfect prints were the z-holder and the calibration hollow "cube". All the others are distorted where the layers are thin.
I'm printing now at 195 degrees having experimented 185-200.

Another big problem is that the PLA doesn't stick extremely well to the kapton tape and prints larger than 3 cm are warped, most of them even get loose after the first 10 layers.

Any tips on what to check?

If your bed isn't heated I find Blue painters tape is better than Kapton.

Is there something special about the painter's tape being blue?
Mine is yellow. Can I use that?

If it's a rough paper based masking tape I would think it's fine, the stuff here is just generally blue.

It's a particular type of tape made by 3M that happens to be blue. It works a lot better than ordinary masking take that is beige.

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[www.hydraraptor.blogspot.com]

It seems one of the problems was the lack of ventilation. After adding a fan the small parts are printed almost perfect.
However, the warping problem still remains. Hopefully that will be fixed by the heated bed.

I printed with some hot melt adhesive layer on bed, it worked well on printing, stick to bed tightly, that can seen on my video :

Also i see someone add density medal mesh on the bed also printing PLA well.

I am plastic engineer of PLA, I know it well, I write a technical analysis about PLA natural propeties that lead to printing problem, and describe instructions to deal with the problems, if you interested ,you can download the file from here:
[skydrive.live.com]