Finished Print

[Katieb 0]

Hey there,

Hoping you guys and girls can help me out again...

Ive printed quite a few cutters lately however I am getting really ugly finishes.

I dont use a raft or brim when printing as I dont find it necessary however a skirt is printed. I have scraggly pieces everywhere and the bottom layer looks messy.

Also, I honestly have no idea what the bottom layer is supposed to look like - ive had two results, which ive attached. The only difference in settings was the smoother result had a hotter bed when printing.

I prefer the smoother look but dont know how else to achieve it as if the bed is too hot, the filament curls and warps (I do have the fan on).

Any feedback would be greatly appreciated

[IRobertI 520]

Looks like your bed is simply a bit too far from the nozzle. Try running the bed leveling wizard again or manually adjust the three thumbscrews underneath the build platform while the printer is laying down the first layer.

That's assuming that the top layer and sides of the print look good.

[gr5 2,167]

Don't run bed leveling - just turn the 3 screws 1/4 turn counter clockwise as seen from below. You want the bottom layer squished slightly - not rope shaped. You want it more pancake shaped.

To get stunningly perfect bottom layers takes a lot of experimentation but basically you want to change the bottom layer thickness from .3mm to .1mm and you have to play with those 3 knobs whlie printing the first layer and you have to cancel the print and repeat maybe 10 times until you get it perfect. If you do the leveling procedure you will wreck it and have to start over. Basically with a .3mm bottom layer thickness getting the bottom layer accurate to .2mm is okay and accurate to within .1mm is great. But with a .1mm bottom layer you want to get the leveling accurate to about .03mm which is incredibly accurate for this machine and might not be achievable (tiny warps in the rods and glass).

Anyway stick to .3mm bottom layer for now and just move that glass up a 1/4 turn.

What temp was your glass? For PLA I recommend 60C - for ABS 100C.

[IRobertI 520]

If you do the leveling procedure you will wreck it and have to start over.

 

I'm sorry, what? I guess I've been lucky for the past couple of years and literally hundreds of machines I've done it on?

[Katieb 0]

Looks like your bed is simply a bit too far from the nozzle. Try running the bed leveling wizard again or manually adjust the three thumbscrews underneath the build platform while the printer is laying down the first layer.

That's assuming that the top layer and sides of the print look good.

 

Hmm, ok. the top layer and the sides are all good. I thought my nozzle was pretty close - doing the whole slide a piece of paper between the bed and nozzle trick - but ill give this a go, thanks

[Katieb 0]

Don't run bed leveling - just turn the 3 screws 1/4 turn counter clockwise as seen from below.  You want the bottom layer squished slightly - not rope shaped.  You want it more pancake shaped.

To get stunningly perfect bottom layers takes a lot of experimentation but basically you want to change the bottom layer thickness from .3mm to .1mm and you have to play with those 3 knobs whlie printing the first layer and you have to cancel the print and repeat maybe 10 times until you get it perfect.  If you do the leveling procedure you will wreck it and have to start over.  Basically with a .3mm bottom layer thickness getting the bottom layer accurate to .2mm is okay and accurate to within .1mm is great.  But with a .1mm bottom layer you want to get the leveling accurate to about .03mm which is incredibly accurate for this machine and might not be achievable (tiny warps in the rods and glass).

Anyway stick to .3mm bottom layer for now and just move that glass up a 1/4 turn.

What temp was your glass?  For PLA I recommend 60C - for ABS 100C.

 

Thank you! My bed was set at 63 (PLA) but ive reduced that to 60 and re adjusted the bed. So far so good

[gr5 2,167]

 

If you do the leveling procedure you will wreck it and have to start over.

 

I'm sorry, what? I guess I've been lucky for the past couple of years and literally hundreds of machines I've done it on?

 

If he did the leveling procedure the first time and ended up with the wrong distance I doubt doing it again will help. I also doubt that it's worth the time to run it again since the bed is probably already "level" it's just not the right distance from the nozzle.

The leveling procedure tends to end up with the .3mm layer being printed .3mm from the glass which is great for some parts but it won't stick as well as if you get the head a bit closer. Plus there is a large range of distances from when the head just barely touches the paper to where the paper has quite a bit of friction but not the max friction yet. I'm not sure that it's clear where the best leveling friction amout is.

Personally I have used the leveling procedure many times and I like to just have the head touching the glass (skip the paper - do it by eye). But once I level using the procedure once I fine tune it on the fly at the start of the next print. And again on a larger print that reaches closer to the screw locations (sometimes the center is good but not the edges).

[gerycruz 0]

gr5, thanks for your post I've been struggling with the correct amount of "friction" we're supposed to feel with the leveling procedure. Are you saying you adjust the level for every print? How can you tell if you have the right amount?

[gr5 2,167]

I just use the leveling procedure to get close.  Once per year or so.  Or when I rebuild the head.  Then on the very next print, when it first starts up I watch it print the skirt or brim.  That's the very first thing printed.  I push up and down on the bed a bit to see how it would look if bed is higher or lower and then I turn the 3 screws equal amounts to try to get it to that amount.  

I used to have photos of "perfect brim" and "bad brim".  I'll try to create a new set now.  Okay:

In the above photo I assumed the bottom layer is .3mm thick (cura default) and labelled how high I assume the head was *actually* off the glass.  .3mm would be normal/nominal and what UM's leveling technique is shooting for.  But I recommend closer to the bed.  The yellow cell phone case is too close.  In some places you can barely see the skirt.  The blue marvin is about perfect - that is close enough that Marvin won't fall off during printing.  the red is okay but getting a bit far such that your part might not stick as well.  The black filament is MUCH too high off the bed such that it's not sticking at all or barely causing a print failure on the bottom layer let alone higher up.  Note that these numbers are all guesses but the point is you want a skirt that looks about like the blue one if you want it to stick but more like the red one if you want the bottom most layer not to squish out a bit.  It's very rare that I print a part where the bottom layer can't squish out by .1mm more than my model.  Very rare. Therefore I aim for the blue marvin photo amount.

Edited June 16, 2016 by Guest

[JohnFox 25]

A quick sand using wet and dry paper will get them smooth. Start with 180 or 240 grit, then 320, ending with 400.