Suddenly bad prints

[kd7eir]

My 10" i3v has been working great for over a month.

I printed a case to hold four relays that came out absolutely perfect. The next day I tried to print some ornaments that I have successfully printed before, and they failed. The skirts (6) are adhering to the bed quite well, but after a few layers the ornament itself is coming loose and moving around on the bed. I leveled the bed, and made sure that all screws/bolts/nuts were tight. Belts are not slipping or binding, pulleys are all securely attached. I have adjusted my e steps several times as well.

I tried to print the Marvin keychain as a test, and again the skirt is perfectly fine, the feet start out great, but then suddenly come loose and start moving around. The bed is at 70C, the print head (Hexagon .40 with 3mm PLA) is at 225C. These are the defaults in the MakerFarm Slic3r config file.

I have tried the printhead at between .1mm and .5mm from the bed, and I get the same results. Filament is not binding in the spool, and I have tried several different spools of filament, all with the same result.

Any suggestions?

[JimG]

I use a thin coat of Elmers All Purpose Glue Stick on the bed. Wet a paper towel and apply some of the stick to the wet towel. Then apply some glue directly to the glass. Swish the wet towel around on the bed to give an even, very thin coat.

When applied this way, I very rarely get lift off with either PLA or ABS. They pop right off when the bed cools. Don't put on too thick a layer because you will have a very hard time getting your prints off.

Jim

[eghm]

....
The bed is at 70C, the print head (Hexagon .40 with 3mm PLA) is at 225C
...
Any suggestions?

Those sound like ABS temps to me. I use 65-60 for the bed and 185-181 for the head. I've been printing on a layer of blue painters tape. The only times I've had problems with not sticking there was too much of a gap between the hot end and the bed.

[kd7eir]

You can see how the piece has twisted once it came loose.
IMG_2036.jpg

Here you can see how the bottom is curving
IMG_2037.jpg

[kd7eir]

The only change I have recently made was to install clough42's improved hexagon cooling shroud so that I could use his ABL servo mount. The first print I did after this was the relay case that out perfect. Since that print, nothing but trouble. I added a 40mm fan to the front of the extruder where I had planned on adding a print cooling fan, and it seems to be working better, but still not perfect. I am printing the 24mm test cube, and at about 50% complete the back of the cube is lifting off the bed, but the front is still attached so far. It's not loose enough to allow the cube to move around so far.

[printbus]

Explain how you prep the print surface. Do you make sure it is finger-oil free by swabbing it with alcohol? Any hairspray or anything applied? I haven't tried the glue stick approach yet, but I found blue painters tape swabbed with alcohol forms a very strong bond with PLA - dang near permanent if I print with the bed heated.

You could reduce the skirt and print with a brim so that the part has a larger holding area on the bed.

Are you checking the gap between the nozzle and glass with everything cold or with everything hot? Measuring hot is more accurate.

[kd7eir]

Explain how you prep the print surface. Do you make sure it is finger-oil free by swabbing it with alcohol? Any hairspray or anything applied? I haven't tried the glue stick approach yet, but I found blue painters tape swabbed with alcohol forms a very strong bond with PLA - dang near permanent if I print with the bed heated.

You could reduce the skirt and print with a brim so that the part has a larger holding area on the bed.

Are you checking the gap between the nozzle and glass with everything cold or with everything hot? Measuring hot is more accurate.

I clean the surface before each print with alcohol. No hairspray or anything else.

I set the gap with everything hot.

I reduced the bed temp to 60C and the printhead to 200C, removed the extra fan I had placed on the extruder for testing, and so far everything is printing fine.

What I find so odd is that I have been printing at 70/225C for over a month and getting great prints, and yesterday right after I installed clough42's improved Hexagon cooling shroud, I printed a case for four relays that was one of my best prints so far.

Not sure what could have changed between the relay case yesterday, and today, but I am printing just fine now, so I'll probably not try to dig too far into it for now.

I really appreciate everyone's advice!

[gmay3]

kd7eir, as printbus mentioned try using a brim instead of a skirt (I use typically one loop of the skirt). The brim is essentially the same as the skirt you printed except it is attached to the first layer of your part.

A little more description on the uses of both:

A skirt is used to purge any air in your hotend before the print is drawn to make sure that there is filament coming out of the nozzle and that the complete first layer of your print is drawn. I have also seen some people use a skirt printed 10 to 15 layers high to shield the print from cool air drafts, although I haven't ever needed to do this. The more loops you specify, the thicker this skirt will be.

A brim is used to increase the surface area of the part on the first layer which will increase the part's adhesion to the bed. It's super effective (pokemon) at getting the part to stick and reducing corner lifting. I use a 5mm brim on parts that I can't quite get stuck down by using normal bed treatments.

[printbus]

I'll add that I've been experimenting with the glue stick idea. So far I'm very impressed with how it's working out.

[AbuMaia]

It's hard to go wrong with a gluestick and a brim.