Warping on prints int he same place time after time. (Page 1 of 2)

have you leveled your bed? maybe that corner is a tiny bit lower so adhesion of the plastic isn't as good there.

http://wiki.solidoodle.com/leveling-the-print-bed

a brim would help alot for bigger prints.

Turn the skirt off in slicer, and add a 4+ brim instead.

Nice idea. Where would I find that option in Slicer? Will try it out and let you know how it goes

Thanks Hazer...

-Skyler101

But watch out. Just because you clicked "Configure" while you were set to print with "Solidoodle .3mm" doesn't mean that the configure page that comes up is actually for "Solidoodle .3mm". That one drove me crazy till I noticed that I had to use the pulldown (with the truncated configuration name) to find out which config I was actually editing :-).

Some general tips:

Calibrate ..... everything.

Use glass and hairspray for better stick with ABS. Make sure the bed is at target temperature for a good 2-10 minutes (aluminum = 2, glass = 10) as the sensor is right on the heater, but the print surface takes longer to get to that temperature. I had a few bad prints from impatience myself.

You have to adjust your steps/mm for the extrusion motor.

Then, you should perform your single perimeter 10mm cube extrusion calibration to adjust your flowrate for EACH spool of filament you use. Especially switching form ABS to PLA.

BTW, if you are using the aluminum bed, if you only level the bed in 3 points, you should check the entire bed for level as the bed is prone to be warped. So leveling it in the 3 places where the screws are does not mean it is level everywhere. Check all of the spots on the bed to see if it is warped. If it is, then go get a $4 mirror from Joanns. Or a $1 ceramic tile from Homedepot.

This is a small  aside, but I think it's more than reducing the thermal difference.

Case 1: 230 celsius into a 30 degree celsius chamber. dT = 200 C
Case 2: 230 celsius into a 55 degree celsius chamber. dT = 175 C     

Not a whole lot less.
I've been thinking that when you can get the temp up, you get the plastic to behave more like a fluid (closer to it's transition temp where it is considered fluid), and release strain over time.  I'm sorry, but I haven't found anyone talking about this and thought I'd jump into the moment and ask if there's a term for this and anywhere I can read up to further my understanding. An alternative phrasing would be for me to say that the plastics rapidly "creep" at higher temps, but I don't know if that's using the concept of creep properly.

I currently am experiencing the same warpage issues. I built a full enclosure out of aluminum foil that keeps A LOT of heat in. What i have not been doing is, as suggested waiting 10 minutes, after the bed sensor says ready. Can anyone else verify what temperature a IR gun is saying? Seems like the values reported to the software are pretty much bogus, not to mention strap a piece of plate glass on top of a warped aluminumin plate. Not the best way to transfer heat when an airgap is present. I will try the waiting trick and see if that helps. I used hairspray also, but it didn't help. Trying to print the dial indicator mod to actually tram my bed, in the mean time i have just been using a feeler gauge and have tried zeroing z @ .002" and .012" (.05mm and .030mm). Is it suppose to be @ zero or .03mm??

My dial indicator has my back right corner a little lower than the rest of my bed as well. Im using glass. The dial indicator is probably just pushing that corner down a bit since there is only one screw in back. But the back right side gets a lower reading than the left.

I usually get a top temp reading of 70 when im ready to print. Thats usually a few minutes after the RH reading says 99.

Adrian has done a full bed test using an IR camera imaging system to show what happens, with a good explanation of thermal dynamics.

But let me lay this in pretty generic and intuitive terms without the technobabble:

The heater is underneath the aluminum bed plate. The sensor is also there. The sensor will read 95 degrees Celsius (and the microchip will use that to maintain 95 degrees Celsius) long before the top of the aluminum reaches 95 degrees Celsius. Aluminum is a great conductor of temperature. This means it conducts heat and cold. Once the heater turns off, the edges of the bed help conduct cool to the center of the bed fast. Its why CPU heatsinks are made from Aluminum. And guess what, glass and ceramic are insulators. This means they resist changes in temperature. So if we soak these insulators with heat from our forced heating, they will keep this heat long after we turn the heater off. And therefore, resists curling while the print finishes.

Glass and tile help alot, but they hurt more than help if you try printing even one second before they are ready. Patience is needed, and rewarded.

Also the level of Infill will effect a models propensity to warp... the higher the infil, the more molten plastic, the faster it will contract while still being viscous elsewhere, which leads to warp.

If you wanted to be scientific about it, its volumes to contact surface area issue... the more volume of plastic with a lower contact surface area, the more likely that contact area will not be able to continue to overwhelm the effect of shrinkage of the much higher ratio of molten plastic...

This is why a Cube can even warp.. despite having a reasonable 'footprint', the ratio of its volume to that surface area, particularly once it gets past half-way, is quite high...

Adding brim greatly increases that contact surface area (since its an outer border - even a 2mm brim can alter that ratio substantially).

The alternative approach is, reduce the volume of 'stuff' pulling and pushing on the contact surface - i.e, drop your infill.
The difference between 20% infil (0.2) and 10% (0.1) can again be huge in altering that ratio....

Having a bed with greater thermal mass (ceramic et al) definately helps... but sometimes.. just dropping your infil 5%, 10% or 20% can be the difference between success and failure..

Likewise reducing the tempreature you are extruding at can help... 3-5° drop means its already that much closer to equilibrium with the bed, which means less time as a viscous substance that is prone to warping as it contracts...

And for models with a single wall, but a low contact surface area - you again suffer warpage for similar reasons - the ratio of molten plastic that is cooling and thus contracting to the contact surface area can be wildly skewed and its here the 'shape' makes a huge difference.... a cylinder will tend to contract evenly, where as vertices will have opposing forces and lead much more quickly to warpage....  This is why so called 'mouse ears' on the corners can be a god-send on models with low surface to high volume ratios...

Anyway... if its solid, try brim, then try reducing infil. If its not solid... keep enlarging the brim, or manually add over-the-top mouse ears to your model.

Its very model specific.. I tend to use 20% most of the time with 2 perimeters. That goes down to 5-10% on small models

Anything more than 65% appears to make no difference to strength, simply uses more plastic and increases warp potential.

It all depends on the model