First couple of layers not sticking/warping.

Does anyone know what would cause this? I'm extemely new to 3D printing and I just finished building one. I canceled the print half-way through for a different reason (idler was set to print at different Z height causing plastic to be extruded in mid air). It doesn't seperate like that at all sides so I'm thinking it's the bed height. I'm printing Ultimachine PLA with a bed temp of 70 degrees and an extruder temp of 185. I'm using Slic3r with marlin firmware and RAMPS hardware.

What layer heights and nozzle size?

Layer height is 0.4mm and nozzle is 0.5mm.

Try dropping to .3 or .25 on layer height. .4 with .5 nozzle is pretty tall.
You may also be able to lower the bed temp slightly.

I printed up a better x-carriage, so I'm going to install that tonight and probably re-do my hotend since I didn't use foil around the power resistor and I'm paranoid about the thermistor coming out. I'm measuring the bed temp from a thermistor underneath the PCB heatbed, so I assumed the temperature on the glass would be about 10 degrees cooler then at the thermistor which is why I'm using 70 degrees. I'll try your suggestions and see what happens.

I went back to basics. I recalibrated my extruder, recalibrated bed height (which was way off), re-tightened belts, cleaned my hobbed bolt, re-measured my filament in several places, etc. I also changed my print height to 0.3 and adjusted my in-fills, bed temp, and print speeds and the result was a much better print. Still not perfect though. I used cheap plywood for the bottom print bed and it warps like crazy so I am constantly adjusting the bed height. If you're new and happen to be reading this, please do yourself a favor and use MDF. Plywood sucks. You can compensate for it, but you'll be doing that for every print. Also, make sure your extruder's idler springs are tight as hell when extruding PLA. Every time your hobbed bolt skips, it picks up plastic from your filament that makes it skip even more. You don't want it to skip at all. I'm paranoid as hell when I hear a click. You can clean the plastic bits from your hobbed bolt but it's a PITA since you usually have to remove the X axis belt clamps (and the belt) before you can remove the gear/bolt assembly. Also, any time you work on the x-axis, you're putting stess on whatever z-axis coupler you're using, so be cafeful.

I'm not sure what extruder you are using, but I can usually clean the plastic out of the hobbed bolt just by:

Removing the filament,
removing/opening the idler,
Scraping the bolt with a knife point or small screwdriver.

Knocking all the plastic slivers out of the grooves while turning the bolt gear by hand.

You shouldn't need to disassemble all that much.

---

Komb'
Glankonian Protoforms

I tried that using a sharp metal pick, but found there were a few grooves that had plasic I just couldn't remove without putting too much pressure on the z rods. Once I removed the bolt, I could get that stubborn plastic out of the grooves. I know better now to make sure my idler is tight, so I hope I don't have to do that again. That said, this build is a week old so I expect to have to re-do a lot of things. For instance I just found out that my Z end-stop switch is in the wrong place (on X-idler side, should be on X-motor side). It's hit or miss the way it is now. I can print an object that is pretty close to perfect, only to follow with an object that is a complete failure. I've gotten a few replacement parts printed so well that you can't even see the layers unless you're looking for them and I've also gotten parts that the first layer wouldn't even stick properly.

1cm of sugar, dissolved in 3cm of water (use hot water so it dissolves quicker)

Wipe a thin layer on your bed (bed can be hot or cold)

Heat bed to 60-70

Watch as your prints adhere like you had glued them in place. Even a crappy first layer will stick.

To remove, allow bed to cool to room temp and the prints will pop off.

Does that actually work? It sounds like it would just make a big sticky mess, but if it works it's worth a try!

I use a solution of 1 part PVA (white) glue - such as elmers, and 4 parts water. I wipe it on with a paper towel while the bed is hot. It dries in a few seconds. Objects stick really well, and pop off after the bed cools. If I'm in a hurry, a flat bladed exactly knife can usually pry them off without too much trouble.

To prevent build-up, I clean the bed with nail polish remover - other solvents might work too. Sometimes I use the same coating for multiple prints, but if I ever have a print that doesn't stick, I clean the bed, re-apply the glue, and restart the print.

I've had great success with this method.

Yep JB, that's pretty much what I do too - I had parts sticking great (ABS) but had a bit of lifting after preparing a second batch of PVA which I guess meant I used too much water. I made the mix a bit stronger and the parts now stick like concrete which is too much. So, is your 4:1 mix the ideal ratio for sticking large parts as well?

I use the same solution for all place prints large and small. If I do have as issue with too much sticking, I just dilute the solution a bit, but 4:1 is always my start point.

I have not tried this solution with ABS, but might based on what you are saying.

Incidentally, when parts DO stick a lot, I just let things cool back to room temp and they usually pop right off.

Hairspray works better for bed. Cleans off with warm water, if using ABS can do several prints before having to clean of add more hairspray

I got some kapton samples from dupont, 5 mil which is nice and thick, i got a glass plate, then i used extremely thinned out rubber cement to attach the kapton film to the glass. for abs i just use some actone to clean the oils from my hands every once and a while, i have printed some pla on it, and it works fine without anything special. it did sort of rip in one spot, because i got a little frisky with a razor blade, other than that its perfect.

ive been doing some research and apperently just the backside of a one sided copper clad board is sticky enough once heated to do prints on, maybe better than kapton, so i just need to find an 18x18" single sided pcb, and then i can mill the other side into the heating element.

aduy Wrote:
-------------------------------------------------------
> I got some kapton samples from dupont, 5 mil which
> is nice and thick, i got a glass plate, then i
> used extremely thinned out rubber cement to attach
> the kapton film to the glass. for abs i just use
> some actone to clean the oils from my hands every
> once and a while, i have printed some pla on it,
> and it works fine without anything special. it did
> sort of rip in one spot, because i got a little
> frisky with a razor blade, other than that its
> perfect.
>
> ive been doing some research and apperently just
> the backside of a one sided copper clad board is
> sticky enough once heated to do prints on, maybe
> better than kapton, so i just need to find an
> 18x18" single sided pcb, and then i can mill the
> other side into the heating element.


I have stopped using any sort of tape on my bed and have had no problems with ABS or PLA. Just print straight onto the glass. Now I want some more glass to do quicker swaps.

what temp do you print at? i tried it at 100c and it sort of stuck, but not really it just clumped the abs into a ball, for pla i can see that working. perhaps some frosted glass would be a good surface to print on.

aduy Wrote:
-------------------------------------------------------
> what temp do you print at? i tried it at 100c and
> it sort of stuck, but not really it just clumped
> the abs into a ball, for pla i can see that
> working. perhaps some frosted glass would be a
> good surface to print on.


ABS will need 110-125c. For PLA, depending on what you are printing onto you can get away with no heated bed.

so i have a 12v switching supply, i can turn it up to 15v, would that be risky to run the bed at that high of a voltage?