My Second Print! Still needs some work...

Hi Everyone,

I've been lurking here for a while as I was saving up for my 12" i3v. i got it a few weeks back and took my time putting it together over a few weekends. I printed off a 24mm cube last weekend and I could tell my printer needed some work. I tightened my belts and adjusted my rollers so they would be tight but able to roll. A little grease and a bunch of failed tries and I got my second cube printed last night. The first layer is much better after adjusting my Z height but I never thought to level my X to my Y axis so Ill check that out tonight.

Let me know what you guys think? I believe I am over extruding material so I'll need to look into how to fix that as well. Using Slicr 0.9.9 with the stock config from Colin. Makerfarm silver 1.75mm PLA used.

Attachment 5642Attachment 5643Attachment 5644

what layer resolution is that printed at ?

Printed at .2mm @225C (Hotend) and 70C (Bed)

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Originally Posted by curious aardvark

what layer resolution is that printed at ?

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Bottom seems nicely filled. Top may be passably filled where it is supported by the infill, but droopy everywhere else. The sagging may be why the lines don't touch. Or else it may actually be underextruding a bit. Main problem to me is the perimeters are not perfectly lined up. I would drop the extruder temp a bit (190º-200º?) which may help with both the top sagging and the perimeters staying put.

Do you have a fan for cooling the part? Probably not necessary for the cube, but if you are going to do a lot of PLA it could be very useful.

Edit: BTW, nice self diagnosing/fixing so far.

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Originally Posted by jasay

Bottom seems nicely filled. Top may be passably filled where it is supported by the infill, but droopy everywhere else. The sagging may be why the lines don't touch. Or else it may actually be underextruding a bit. Main problem to me is the perimeters are not perfectly lined up. I would drop the extruder temp a bit (190º-200º?) which may help with both the top sagging and the perimeters staying put.

Do you have a fan for cooling the part? Probably not necessary for the cube, but if you are going to do a lot of PLA it could be very useful.

Edit: BTW, nice self diagnosing/fixing so far.

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Thanks, I'm trying learn as much as a I can on my own before I ask. I plan to print Clough42's Print Cooling Fan System (http://www.thingiverse.com/thing:351280) in the near future as well as his Improved Hexagon Cooling System (http://www.thingiverse.com/thing:335613) to help cool the part and keep stray air away from the bed.

I'll try the temperature adjustments tonight after checking that my X axis is level when compared to the Y axis. Is 70c still good for the bed?

70°C should be fine.

Tried printing at 200c and the results are below. The knob end up being too large at the base so I can't push it in to go through the options on the LCD display. I also found that my extruder gears have been getting chewed up because somehow it tightened itself. I loosened the bolt and it turns much easier now so I'll have to see how/if it affects the edges in my prints since the bottom and top are not filled in like I would like.

Am I experiencing Z wobble?

Attachment 5656Attachment 5657Attachment 5658

what do you have your first layer height and extrusion set to?
the only reason the knob would be too large at the base is extrusion is too much, or you are smushing your first layer to the point where it is enlarging the print.
so i would try to do first layer height at 100% and extrusion at 90% for pla or 100% for ABS and see what happens.
the layer issues you are seeing (the fact that they arent in line) could be a number of factors, but most likely slop somewhere in the system.
I had those issues as well. now im getting prints that look like this. after only a few test prints.

First pic is before i had all my stuff slop free
http://i1132.photobucket.com/albums/...psmrazlbck.jpg

this is after i tightened and tuned everything. stick with it.
http://i1132.photobucket.com/albums/...psgtrxfepa.jpg

picture doesnt do it justice.

Layer height was set to .2 and extrusion was set to .3 so i'll drop it down to .18 so hit that 90% of height mark you mentioned. Also the knob is too big due to design of the part, it's not made for the graphical LCD on my 12" i3v it seems.

I've tightened my belts and can't get them any tighter since I'm all the way over in the adjustment slots for the motor bolts. But the belts seem fine to me, I can pluck them like guitar strings. I leveled my X rails to the Y rails last night and leveled the bed nicely.

Outside of tightening belts what else can i adjust (tighten) to remove any slop?


Thanks for all the help, your prints look great!

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Originally Posted by dunginhawk

what do you have your first layer height and extrusion set to?
the only reason the knob would be too large at the base is extrusion is too much, or you are smushing your first layer to the point where it is enlarging the print.
so i would try to do first layer height at 100% and extrusion at 90% for pla or 100% for ABS and see what happens.
the layer issues you are seeing (the fact that they arent in line) could be a number of factors, but most likely slop somewhere in the system.
I had those issues as well. now im getting prints that look like this. after only a few test prints.

First pic is before i had all my stuff slop free
http://i1132.photobucket.com/albums/...psmrazlbck.jpg

this is after i tightened and tuned everything. stick with it.
http://i1132.photobucket.com/albums/...psgtrxfepa.jpg

picture doesnt do it justice.

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This may be a dumb question but is your extruder tight to the X cradle? If it is loose at all, that can cause a little play in the X/Y direction.

Good idea, ill check that out tonight.

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Originally Posted by BLKKROW

This may be a dumb question but is your extruder tight to the X cradle? If it is loose at all, that can cause a little play in the X/Y direction.

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thats what i meant by slop. the belts can be perfecly tight, and still cause issues.
x carriage issues - just grab the x carriage and move it around, and see if there is any play at all. do the same with the y bed. i found most of my slop was on the X axis motor area where it went up and down. those bearing wheels were not tight to the bars.

By the way I printed the same knop and it was also to big.

I tightened up my X carriage and the Y bed though I still think the Y bed has some play in it that I can't get out with the eccentric spacers alone. Currently printing this knob for the printer and the layers are better defined but i'm still having issues with them not lining up along the Z axis on the lower portion especially.

I think i'll try to tighten my idlers some more to see if i can get rid of more slop. Is there anything else I should be trying to improve my prints?

Attachment 5666

EDIT - Print just finished. The top looks considerably better than the bottom. I think i'll try a thin wall cube next to see how the printer does.

Attachment 5667

its coming along. there is still a lot of room for improvement. dont settle for less than great. this printer is capable.
best advice i ever got was change 1 thing at a time.
dont monkey with a ton of things, because you will never know what/if its resolved. it will take a LOT longer but change 1 thing (in slicers etc) print a test. change another, test, change another, test etc.

Got rid of all the slop in the Y bed and tighted down all the other idles while I was at it last night. Re-leveled my bed and ran a few thin wall cube prints. They are better but i'm not sure what else I can do to improve them any more. Should I check out the calibration thread and start going through the software? Or is there more than i should be doing on the hardware side first?

Attachment 5698

Quote:

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Originally Posted by dunginhawk

its coming along. there is still a lot of room for improvement. dont settle for less than great. this printer is capable.
best advice i ever got was change 1 thing at a time.
dont monkey with a ton of things, because you will never know what/if its resolved. it will take a LOT longer but change 1 thing (in slicers etc) print a test. change another, test, change another, test etc.

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is that ABS or PLA? are you using a cooling fan?

PLA (1.75) no cooling fan yet. I wanted to get my prints into better shape (which I feel i've reached now) before I started printing fan shrouds, new end stops, brackets, etc..

Only fan I have is the extruder fan

Quote:

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Originally Posted by dunginhawk

is that ABS or PLA? are you using a cooling fan?

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It's hard to tell from the pictures, but on the layers where the plastic sticks out farther on the outside of the part, does it also stick out farther on the inside? If so there is there is either too much plastic on those layers or the layer height is shorter causing the plastic to squish out in all directions more. If not, there still may be some mechanical misalignment.

Variable amounts of plastic might be due to the filament you are using (varying diameter along length, voids/air bubbles inside, etc.) or if say the extruder gears are oval they might move different linear amounts per degree of rotation.

Choice of layer height can be important in getting consistent movements. You don't want to stop in a microstep since the motor can't hold that position as well as it can a full step. 0.2mm works well for out 5mm threaded axis. 0.25mm does not.

A really interesting article that covers this better: Taxonomy of z-axis artifacts

From looking at my prints it seems that the layers will both expand and contract equally around the object. What I have noticed is that when I'm leveling the bed while it is heated that when the relay clicks on (begins heating) the glass will dip in the middle quite a bit (over 1mm), and when the relay clicks off (stops heating) the glass will come back up towards the nozzle. My nozzle is right at 0 in each of the 4 corners, its the middle that gives me issues.

Since this dip and retraction happens many times during a print I think that may be causing my issues with the layers "poking out". I've been heating my bed to 65-70C when printing in PLA so someone recommended trying a lower temp (around 40-45) to see if I can reduce the movement of the glass in the middle.

If the lower temp doesn't fix my issue is there another type of glass I should try or maybe use a spacer in the middle of the bed?

Quote:

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Originally Posted by jasay

It's hard to tell from the pictures, but on the layers where the plastic sticks out farther on the outside of the part, does it also stick out farther on the inside? If so there is there is either too much plastic on those layers or the layer height is shorter causing the plastic to squish out in all directions more. If not, there still may be some mechanical misalignment.

Variable amounts of plastic might be due to the filament you are using (varying diameter along length, voids/air bubbles inside, etc.) or if say the extruder gears are oval they might move different linear amounts per degree of rotation.

Choice of layer height can be important in getting consistent movements. You don't want to stop in a microstep since the motor can't hold that position as well as it can a full step. 0.2mm works well for out 5mm threaded axis. 0.25mm does not.

A really interesting article that covers this better: Taxonomy of z-axis artifacts

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Get some blue painters tape. Lay it across the bed as flat as you can with minimal gaps between strips (or just use the 2"+ wide stuff for the small parts). Then you can print PLA with a cold (room temp) bed.

What thickness of glass do you guys use? I'm using some 3/32" glass from Lowes which is just shy of 2.5mm

I'm thinking of picking up something thicker. Home Depot has 3.175mm glass (.125") which is a difference of .794mm so that may help along with setting my temp lower.

I'll give it a shot and see if the issue goes away when printing on cold glass. Thanks for the help

Quote:

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Originally Posted by jasay

Get some blue painters tape. Lay it across the bed as flat as you can with minimal gaps between strips (or just use the 2"+ wide stuff for the small parts). Then you can print PLA with a cold (room temp) bed.

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Quote:

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Originally Posted by Carrot_or_Stick

From looking at my prints it seems that the layers will both expand and contract equally around the object. What I have noticed is that when I'm leveling the bed while it is heated that when the relay clicks on (begins heating) the glass will dip in the middle quite a bit (over 1mm), and when the relay clicks off (stops heating) the glass will come back up towards the nozzle. My nozzle is right at 0 in each of the 4 corners, its the middle that gives me issues.

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A change in height of the bed could definitely cause layers to squish more or less depending on the direction of the height change. It's surprising that the glass would flex that much though. What is the temperature swing reported? Is the glass confined (perhaps by the screw heads) in such a way that it cannot expand in length/width and so has to bow instead when it reaches a certain temp?

I didn't watch the temp reading very closely but what I recall is the swing would be + - 2C. The glass is clipped on the left and right sides towards the top and bottom corners with binder clips. The glass is also only 2.5mm thick window pane glass so it's quite thin.

I've actually watched the glass move almost a full millimeter when the relay is switching on and off. I should take a video sometime.

Quote:

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Originally Posted by jasay

A change in height of the bed could definitely cause layers to squish more or less depending on the direction of the height change. It's surprising that the glass would flex that much though. What is the temperature swing reported? Is the glass confined (perhaps by the screw heads) in such a way that it cannot expand in length/width and so has to bow instead when it reaches a certain temp?

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Tightening up the temperature swing might help. You can autotune the PID settings: http://reprap.org/wiki/PID_Tuning

Also make sure the sides of the glass are not touching anything so that it can expand. I'd still try the tape/cold bed first though just to make sure this is the root cause.

Thanks for the info. I got some 1/4" glass from a glass supplier and that fixed all my issues. Turns out it WAS my glass flexing while being heated.

Quote:

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Originally Posted by jasay

Tightening up the temperature swing might help. You can autotune the PID settings: http://reprap.org/wiki/PID_Tuning

Also make sure the sides of the glass are not touching anything so that it can expand. I'd still try the tape/cold bed first though just to make sure this is the root cause.

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