Issues with removing raft, and trying to print without raft

I'm currently working on doing some large prints with my Flashforge Creator Pro, and am having great difficulty with both printing with and without a raft. Currently I'm slicing files with the Makerbot software.

Whenever I try a raft, the print is seriously stuck to the raft. It doesn't want to break away at all. I've tried carefully prying it off with various tools like an xacto knife, but it just isn't enough. I can't get between the model and support at all. I've tried multiple prints all at different raft settings, but it all ends up being the same, the raft is stuck and if it does come off it leaves marks along the bottom of the print.

When trying to print without a raft, the first layer won't go down well. The outer edges of the print usually stay in place, but the inner parts won't adhere to the bed. Or if they do, they'll quickly get caught by the nozzle and attach to it as it moves around. The result is often a shell with broken and stringy lines in the middle of the print. Because the filament often starts to stick to the nozzle as it moves around, I abort the print and clean it off. Don't like the idea of filament possibly pooling around the nozzle for any length of time.

Does anyone have suggestions? Right now I'm using PLA at 230 degrees, and the print bed heated to 60 degrees.

Rafts are generally not recommended, unless you're printing items with a very small footprint. Alternatives to using a raft:

1) use hairspray on a glass build plate
2) use a brim (not available in MW)
3) use a soluble material for your raft (PVA for PLA, HIPS for ABS)
4) slow down the first layer. The more complex, the slow it should be. Try 10 -20.

Proper bed levelling may be a solution to your problem. I have also experienced parts of a first layer print curling up (stringy) when the bed is not levelled correctly. Mostly that will be to one side of a large print, not the middle.

So, based on outer parts bonding but inner not for first layer, it sounds like your heatbed is not flat but buckles in the middle. I would advise a glass build plate + hairspray as well. Apart from being the most easy (and endurable!) bed type (my experience), it may also help with the buckling issue (if it is depressed in the middle as your experiences seem to suggest).

I never use rafts with PLA or PETG on glass/hairspray, only ABS and only when needed.

With a glue stick you may also solve your problem by slathering it on more thick in the middle, again to fill up the assumed depression there, but you will see the marks after lifting the print. Glass+hairspray gives a mirror-smooth surface when applied correctly.

Finally, 230 is too hot for PLA in my experience, but that depends on the accuray of your thermistor more than on the experience of other people.

Thanks for the tips. I've been working on getting the bed levelling exactly right, which seems to be helping a lot. It's still not perfect, but I haven't had time to sit down and get it exact. I've gotten half the first layer down well, but the other needs work. I will look at a glass build plate in the future as it seems a popular choice here, but without access to one I went with the old standby of blue painters tape and switching off the heated bed.

Quote:

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Originally Posted by Alibert

Proper bed levelling may be a solution to your problem. I have also experienced parts of a first layer print curling up (stringy) when the bed is not levelled correctly. Mostly that will be to one side of a large print, not the middle.

So, based on outer parts bonding but inner not for first layer, it sounds like your heatbed is not flat but buckles in the middle. I would advise a glass build plate + hairspray as well. Apart from being the most easy (and endurable!) bed type (my experience), it may also help with the buckling issue (if it is depressed in the middle as your experiences seem to suggest).

I never use rafts with PLA or PETG on glass/hairspray, only ABS and only when needed.

With a glue stick you may also solve your problem by slathering it on more thick in the middle, again to fill up the assumed depression there, but you will see the marks after lifting the print. Glass+hairspray gives a mirror-smooth surface when applied correctly.

Finally, 230 is too hot for PLA in my experience, but that depends on the accuray of your thermistor more than on the experience of other people.

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@terrydactyl89 : Sorry I dont mean to steal your thread but I am on the same boat with you. Using the stock blue sticker and Simplify3D printing PLA with the default setting 230/60. I am think about trying glass and hairspray and I would love it if someone could give me some tips and guidance about the glass type/dimension and how to apply hairspray. I think I can print the clip for the glass along with the thing to prevent the extruder from going down too deep onto the surface.
The current sticker is not bad at all it's just that in the long run I will run out of them and they're not cheap from Amazon. Glass seems very cheap and durable in the long run.
Thank you guys.

Maybe i read this thread too fast,
maybe i don't understand your problem,
maybe i got it wrong,


but it's 2016. I thought PLA not sticking to the bed was a problem from the past.

I've been printing on this sheet for the past year and never used any raft, sometimes a little brim, that's it:
http://www.amazon.com/gp/product/B00..._detailpages01

I even remember seeing it discussed on this forum, i thought everybody knew about this material,....

i don't even clean it up, same sheet, never changed it, printing at PLA 210C/bed 65C, then you let it cool down and the part pops right off. Don't even bother to level the bed.

And you stick the sheet to your alu print bed, or glass, with this tape:
http://www.amazon.com/gp/product/B00..._detailpages00

If you don't mind spending a bit on a new bed, you might try this: http://www.geckotek3d.com/ I've had awesome results with it.