sticky raft / unsticky base

[taavet 0]

Hi all,

i am quite new in this forum all tough i have had ultimaker for a year now. Thankfully new cura works much better than previous (netfabb?) version on mac so i found courage to start printing again.

Few questions - when i print for example iphone case, i have to add raft, because while i try to print directly on printing surface, the pla plastic wont stick on it. But while using raft, its kinda difficult to remove it from the back of the case.

So is it possible to print directly on the platform - shall i adjust the base manually higher or is there a way to tell Cura to print first layer slower?

And by te way are there any user made presets or wiki-s how to use full settings in Cura?

Best,

Taavi

 

[gr5 2,173]

1) If you don't have blue painters tape on your print bed I recommend you get it. Preferably large, wide pieces of tape (>50mm wide) but try whatever you have. This is available at any paint store.

2) before printing clean the blue tape with isopropyl (rubbing) alcohol. Found at any store that sells bandages. Without cleaning with alcohol, the PLA won't stick to the tape. This is the most important step since you already said you are having problems sticking.

3) Don't use a raft. Raft's are for badly calibrated printers. So instead calibrate your Z height very carefully. Spend a good 10 minutes the first time. After practice you can do it in 1 minute. You have to re-level every day as the bed droops over time. Home z axis only. Grab the head and move it over the 4 corners of your bed. Try to slip a piece of paper between the (cold, clean) nozzle and the blue tape. The paper should slide easily with a small amount of resistance. Turn the nearest bed screw and make it loose so the paper sees zero resistance - then increase until you feel a tiny bit of resistance. Repeat for the other 3 screws. Then retest the 4 corners. If you had adjusted anything you will probably have to repeat the process several times. Ideally you want 0 distance between nozzle and bed so turn the screws and extra 1/8 turn after the paper is out.

When you print the first layer, default is .3mm which is fine. Just understand that Cura will move the head to z height .3mm if the first layer height is .3. Or .2mm if layer height is .2.

When the skirt is printed make sure it is sticking by trying to lift it gently with your finger nail. It should not be round like a string - it should be squished flat. If it is round like a string your nozzle is too high off the bed. If it is not smooth and flat and instead is bumpy then your nozzle is too close to the bed.

For iphone case I recommend:

layer height .2

first layer height .2

wall thickness .4 (same as nozzle width - always be 1X or 2X or 3X nozzle width)

top/bottom thickness .6 (3 layers of .2)

infill 20% (not a critical thing)

First layer speed 20mm/sec (be patient - I know it takes forever)

Also consider making the temp 240C and then after the first layer completes lower it (using cura or ulticontroller) to 220 or 210C.

 

[taavet 0]

hey thank you so much! i do have a blue tape. i did calibrate the bed and also made the skrit line up to 2 times, so the filament starts flowing properly before going to the model itself. using alcohol is great idea. gotta try this too.

now something unexpected happened, cura just pauses itself whuile printing. had happen several times for now, usually when it has been printing for an hour. my laptop where cura runs, has sleepmode unabled. so it cant be that i guess. when i hit resume, it continues, but there is a gap in slice. the nozzle still keeps temperature on 220, doesnt cool down while on pause, but still such automatic pause mode is weird. does anyone has an idea what might cause it?

[gr5 2,173]

Make sure you don't have any plugins installed. If you use the "pause at height" or "pause at z" plugins on a print, cura remembers and the plugin is still enabled for the next print.

 

[taavet 0]

aargh, you were so right! i got accidentally that plugin enabled. Thanks. It might have driven me crazy blaming god knows what.

 

[taavet 0]

Awesome printer. Still lot to learn, but so far very happy w results.