Calibration cube

[dunginhawk]

So I dont really know where to put this thread... perhaps troubleshooting? just not sure..
So with mhacks new thread in the Tips and Tricks, it got me thinking about doing calibration cubes etc....

So here is my first run at it.

At the end ill post a few pictures..

215 c temp (abs) , seems cold, but my temps may be off (thermocouple coming tomorrow).
95 degree bed.

So i have to say i think this turned out fantastic... But always room for improvement. I do notice clearly that the bottom of the cube, the first 8-9 layers (the ones where the inside is also filled) have the bottom pushed out a little bit more than the above layers (nothing inside/hollow).
It is very noticeable. Im not sure why/how that happens, or if its normal.

Measurements of the cube are 25x25x25 and here are my measurements

24.92 x 24.97x24.89
So not perfect, but when you are talking about 125 layers, i support a tolerance of less than .1mm is not all that bad..

The width of the walls of the cube are.

3.02mm 2.97 3.04 3.0
so again not perfect, but pretty close.


Now for the pictures.

I would LOVE to get some thoughts, advice, criticism etc... I am REALLY going to start dialing this thing in for PRECISION. I have a very important job coming up and need it to be dialed in. My next line of work after this is going to be to try to figure out my extraction settings so i dont get blobbing. I had blobbing with this cube in the past due to over extrusion/temps etc.

[img]http://i1132.photobucket.com/albums/m562/dunginhawk/1CAE92B5-F2FB-43DB-936D-59F2D1BAA388_zpstmdoikf5.jpg[/img]

[img]http://i1132.photobucket.com/albums/m562/dunginhawk/5CE0DB22-88C2-41BF-A6B7-A65F69E48BBB_zpssyicibll.jpg[/img]

[img]http://i1132.photobucket.com/albums/m562/dunginhawk/723217CC-2125-4465-9279-843B62D42A08_zpsunsikjzm.jpg[/img]

[mhackney]

Well done and I'm glad my post is helping you out. It takes a consistent level of practice up front. Spend a little time now and it will pay dividends later. It's like a musician - practice, practice, practice - then later, pick up some new music and play it the first time through. Its that way with any art, you have to internalize it, let the media (printer, filament, thing) talk to you.

I am not sure what you mean with the bottom 9 layer pushed out. I don't see it in the photos. The cube looks quite good. Print 9 more of them and strive for consistency. Then start tweaking slicer settings (one at a time) and observe the effect. I like to use the extreme-division (I think I coined this but maybe not) approach - print at one extreme (say .5mm retract) then print at the other extreme (say 5mm retract) and see what you get. Do the next one 1/2 and compare, the next 1/2 way between the two best. Keep dong that until you get the best result consistently. If the first two extremes didn't have a noticeable effect, put that parameter off and pick a different one, your settings/printer/filament/part are not very sensitive to that parameter so don't optimize it until you have those with more effect optimized.

It is important to note that the world is not perfect, you can't really optimize each parameter in isolation, they are dependent on each other, some more than others. But, 1 at a time will 1) get you in the ball park and 2) start to educate you on how changes affect the print. You'll eventually internally how a particular parameter (say retract length) and be able to manipulate it to get the results you want.

[dunginhawk]

So now im working on my retraction settings using the fine_positive_features test... Would it be strange to say 8 mm retraction at 30mm/s is working better than at like 5mm retraction?

What are folks using for good ABS retraction settings? I like to raise my nozzle up 5-8mm during retractions that helps break that connection (thanks other board members).

any other settings people really like?

EDIT: so just changing how high the nozzle rises but leaving the retraction speed at 30mm/s and the amount to 8mm produced better results than the 8mm height movement.. I am running a 2mm z hop, so a big change. Ill keep posting as I go along... if only 1 person finds any of this info useful, ill feel its worth it.

[Khalid Khattak]

Marvelous ... Great work... soon i will print my 1st calibration cube... thanks for sharing your work

[dunginhawk]

So, the cube prints great, which means the 25mm around the center of the bed are great... Woohoo.. who cares
when i actually go to print something larger, i get 90% of the first layer looking good, then about 10 % is rough, with little nicks and burrs here and there... is that caused simply by a spot in the bed being unlevel?
Now it doesnt ultimately affect the print as the second layer goes over it and makes it look amazing...
just curious.

Im also seeing zero globbing on the test cube, but much more on a larger print.. this is a 10 hour print, so here and there im seeing some globs form and come off on the print.

[dunginhawk]

So i got my thermocouple in, but if i just touch the tip to the tip of the extruder it reads like 175c when its set to 210....is there a specific way i should be using it? thanks

[jdurand]

You may have a ground loop, I don't know if there's any isolation in the adapter board.

[dunginhawk]

Ive been printing fine for months now.. so i cant imagine thats the actual temperature