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lennart-bruggink

warping / support material issue aid wanted

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Hello World,

I have already printed some models on my recently obtained Ultimaker2 ( with PLA, check my other posts),

But I have come across some issues regarding to support and warping, and ask for some advise.

What I mean:

https://www.dropbox.com/s/nvtyhm3xevfv89s/2013-12-27%2018.20.46.jpg

Where the part from the yellow arrow should be as the white arrow, however is nocked off of the support material, presumably through warping and the extruder hitting it (literally, no pun intended).

I see that the prints that I have made already also have the issue that when printing, the outer edges seems to bend upwards, and when the extruder goes over it, it nocks it over.

Either the support is not very "supportive" and it should be encasing the structure more, but then i have the issue that the next picture shows:

Breakage when removing/ difficulty when removing.

https://www.dropbox.com/s/y2v93cp8ucvyw5s/2013-12-27%2018.50.00.jpg

adjusting support cannot (yet) be done properly, as neither Cura nor Kissslicer are that customisable by me.

Or

The heat settings should be optimized regarding to warping. What are my options:

Cooler extrusion temperature for a more rigid PLA layer?

Slower printing does not seem to be very effective ( tried it at UM2's onboard settings, 100% to 50%, still too fast?).

Create another suppert structure: will rafts/brim be better than the current support?

Minimum speed (under Cool settings in expert settings) : 10 mm/s. Higher?Lower?

Any more?

I will also try GR5's settings ( for original UM that was IIRC) from his post at

http://umforum.ultimaker.com/index.php?/topic/3038-can-your-ultimakerultimaker2-print-such-quality/

2) To minimize stringing (I had none. No cleanup!) I set temp to 190C (and enabled retraction and set retraction expert minimums to 0mm)

3) To get good quality at such a low temp I did 20mm/sec (I normally print at 100mm/sec) or at least at lower speed

4) I did 3 shells (1.2mm shell) to keep infill or other stuff from making the outer edge ugly. instead of 0.8

 

 

settings of Cura:13.11.2 ( if it should help)

 

[profile]

layer_height = 0.1

wall_thickness = 1.2

retraction_enable = True

solid_layer_thickness = 0.6

fill_density = 20

nozzle_size = 0.4

print_speed = 50

print_temperature = 220

print_temperature2 = 0

print_temperature3 = 0

print_temperature4 = 0

print_bed_temperature = 70

support = Everywhere

platform_adhesion = Brim

support_dual_extrusion = Both

wipe_tower = False

ooze_shield = False

filament_diameter = 2.85

filament_diameter2 = 0

filament_diameter3 = 0

filament_diameter4 = 0

filament_flow = 100.0

retraction_speed = 40.0

retraction_amount = 4.5

retraction_dual_amount = 16.5

retraction_min_travel = 0

retraction_combing = True

retraction_minimal_extrusion = 0.0

bottom_thickness = 0.3

object_sink = 0.0

overlap_dual = 0.2

travel_speed = 100.0

bottom_layer_speed = 20

infill_speed = 0.0

cool_min_layer_time = 5

fan_enabled = True

skirt_line_count = 1

skirt_gap = 3.0

skirt_minimal_length = 150.0

fan_full_height = 5.0

fan_speed = 100

fan_speed_max = 100

cool_min_feedrate = 10

cool_head_lift = False

solid_top = True

solid_bottom = True

fill_overlap = 15

support_fill_rate = 15

support_xy_distance = 0.9

support_z_distance = 0.19

spiralize = False

brim_line_count = 20

raft_margin = 5

raft_line_spacing = 1.0

raft_base_thickness = 0.3

raft_base_linewidth = 0.7

raft_interface_thickness = 0.2

raft_interface_linewidth = 0.2

fix_horrible_union_all_type_a = False

fix_horrible_union_all_type_b = False

fix_horrible_use_open_bits = False

fix_horrible_extensive_stitching = False

plugin_config = (lp1

.

object_center_x = -1

object_center_y = -1

 

[alterations]

start.gcode = ;Sliced at: {day} {date} {time}

;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}

;Print time: {print_time}

;Filament used: {filament_amount}m {filament_weight}g

;Filament cost: {filament_cost}

;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line

;M109 S{print_temperature} ;Uncomment to add your own temperature line

G21 ;metric values

G90 ;absolute positioning

M107 ;start with the fan off

G28 X0 Y0 ;move X/Y to min endstops

G28 Z0 ;move Z to min endstops

G1 Z15.0 F{travel_speed} ;move the platform down 15mm

G92 E0 ;zero the extruded length

G1 F200 E3 ;extrude 3mm of feed stock

G92 E0 ;zero the extruded length again

G1 F{travel_speed}

;Put printing message on LCD screen

M117 Printing...

end.gcode = ;End GCode

M104 S0 ;extruder heater off

M140 S0 ;heated bed heater off (if you have it)

G91 ;relative positioning

G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure

G1 Z+0.5 E-5 X-20 Y-20 F{travel_speed} ;move Z up a bit and retract filament even more

G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way

M84 ;steppers off

G90 ;absolute positioning

start2.gcode = ;Sliced at: {day} {date} {time}

;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}

;Print time: {print_time}

;Filament used: {filament_amount}m {filament_weight}g

;Filament cost: {filament_cost}

;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line

;M104 S{print_temperature} ;Uncomment to add your own temperature line

;M109 T1 S{print_temperature2} ;Uncomment to add your own temperature line

;M109 T0 S{print_temperature} ;Uncomment to add your own temperature line

G21 ;metric values

G90 ;absolute positioning

M107 ;start with the fan off

G28 X0 Y0 ;move X/Y to min endstops

G28 Z0 ;move Z to min endstops

G1 Z15.0 F{travel_speed} ;move the platform down 15mm

T1 ;Switch to the 2nd extruder

G92 E0 ;zero the extruded length

G1 F200 E10 ;extrude 10mm of feed stock

G92 E0 ;zero the extruded length again

G1 F200 E-{retraction_dual_amount}

T0 ;Switch to the first extruder

G92 E0 ;zero the extruded length

G1 F200 E10 ;extrude 10mm of feed stock

G92 E0 ;zero the extruded length again

G1 F{travel_speed}

;Put printing message on LCD screen

M117 Printing...

end2.gcode = ;End GCode

M104 T0 S0 ;extruder heater off

M104 T1 S0 ;extruder heater off

M140 S0 ;heated bed heater off (if you have it)

G91 ;relative positioning

G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure

G1 Z+0.5 E-5 X-20 Y-20 F{travel_speed} ;move Z up a bit and retract filament even more

G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way

M84 ;steppers off

G90 ;absolute positioning

support_start.gcode =

support_end.gcode =

cool_start.gcode =

cool_end.gcode =

replace.csv =

switchextruder.gcode = ;Switch between the current extruder and the next extruder, when printing with multiple extruders.

G92 E0

G1 E-36 F5000

G92 E0

T{extruder}

G1 X{new_x} Y{new_y} Z{new_z} F{travel_speed}

G1 E36 F5000

G92 E0

 

 

As always,

Thanks for the help!

 

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I found this in an older post:

http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

 

The first layer of solid infill is unlikely to print well, because of the gaps involved. The extrusion only sticks for a few mm as it crosses the infill lines. With cooling, those short stretches of infill either side of the infill lines form a flat-topped platform that reduce the gap slightly, so it becomes easier and easier to close up the gaps on each pass. Without the cooling, when the first layer of extrusion hits the infill lines, the bottom of the extrusion sticks, while the top keeps moving for a few mm. This has the effect of pulling on the trailing blob of plastic, curling it upwards so it sticks up above the print level. This provides a rough, springy, sticking-up base for the subsequent layers to try to print over, resulting in an incomplete, bubbled up top surface, that even ten layers of solid infill can't cover over.

Moral of the story: if you see an uneven or incomplete, bubbled-up surface on horizontal top surface, make sure that your fan is working properly, and delivering enough cooling air to the print head.

 

Do you think my problem could be a heating problem? I can relate to the cruling upwards of the print.

Howeeevar: my fan is always on at 100%. Sometimes I do this at less than the first five layers.

 

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To get good adhesion, I put a thin layer of gluestick on the bed, and then take a wet cloth and spread it around the bed until all the glue has dissolved into the water. Then let it dry as the bed heats up. I print PLA with a bed temp of 60º.

Rather than using Cura's mass support for this print, why not look at Meshmixer, and add some custom supports to the print. It's a lot more versatile, and far easier to remove:

Dragon with MeshMixer

 

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The meshmixer support is very good advice.

I often have the "warping upward hit by nozzle" issue. It doesn't happen on vertical sided portions - only when things get wider - such as on the Y part of your support at the intersection of the Y. Once you are done with the intersection the two upper arms of the Y will be fine.

It is caused because upper layers are shrinking and pulling hard on the lower layers. Because there is overhang the hinge point makes the edges lift upwards. When printing a cube there is no problem because the hinging means that instead the bottom edge will lift off the print bed (fixable with glue).

So what is the solution?

Well adding glue helps so that it is harder for the print head to knock it over. If you are watching the print, you can use a putty knife to push down on problem areas while printing.

Temperature of PLA does not matter. The affect mostly occurs when cooling from around 80C to air temp. The best fix is a heated chamber. If you graph shrinkage (density versus temperature) PLA is very linear (not perfect but close enough). But PLA is still in glass phase down to about 50C so it is the last bit of cooling where it causes a problem (from around 80C to room temp).

So the easiest thing to do on a UM2 is crank the bed temp to 70C. No hotter because PLA will start to melt any hotter than that. Even at 70C PLA is in a glass state.

The next thing you can do is cover the front and top of the machine. And/or turn off the fan. Fan helps with some things (stringing, cooling small details faster, bridging) but hurts with other things.

If you can get the ambient air temp from 20C up to 40C that will help quite a bit. If you can get it up to 70C you will have zero issues with shrinkage but you may overheat your stepper motors. 40C is a good compromise air temp with 70C on the platform.

OR you can design everything so that it won't matter - make all support be the same cross section as you move up the layers.

 

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To get good adhesion, I put a thin layer of gluestick on the bed, and then take a wet cloth and spread it around the bed until all the glue has dissolved into the water. Then let it dry as the bed heats up. I print PLA with a bed temp of 60º.

Rather than using Cura's mass support for this print, why not look at Meshmixer, and add some custom supports to the print. It's a lot more versatile, and far easier to remove:

 

The glue idea is really good. I have tried it ever since and for the lower levels it just.. works! I also use the brim, with which I can tune my height just a little if needed.

Another question comes to mind: the bed temperature is a standard setting each time (75°C), and I cant seem to change it on my UM2 for every print, only for the individual( already forgot it a few times). Is this solvable with hooking the UM2 up to Cura ( usb?) And perhaps where to find it on the forums?

Meshmixer is great, but I have seen it go through a model, not being sliced correctly and not being removed correctly.

I will try it in future prints to verify my prejudices!

 

The meshmixer support is very good advice.

I often have the "warping upward hit by nozzle" issue. It doesn't happen on vertical sided portions - only when things get wider - such as on the Y part of your support at the intersection of the Y. Once you are done with the intersection the two upper arms of the Y will be fine.

It is caused because upper layers are shrinking and pulling hard on the lower layers. Because there is overhang the hinge point makes the edges lift upwards. When printing a cube there is no problem because the hinging means that instead the bottom edge will lift off the print bed (fixable with glue).

So what is the solution?

Well adding glue helps so that it is harder for the print head to knock it over. If you are watching the print, you can use a putty knife to push down on problem areas while printing.

Temperature of PLA does not matter. The affect mostly occurs when cooling from around 80C to air temp. The best fix is a heated chamber. If you graph shrinkage (density versus temperature) PLA is very linear (not perfect but close enough). But PLA is still in glass phase down to about 50C so it is the last bit of cooling where it causes a problem (from around 80C to room temp).

So the easiest thing to do on a UM2 is crank the bed temp to 70C. No hotter because PLA will start to melt any hotter than that. Even at 70C PLA is in a glass state.

The next thing you can do is cover the front and top of the machine. And/or turn off the fan. Fan helps with some things (stringing, cooling small details faster, bridging) but hurts with other things.

If you can get the ambient air temp from 20C up to 40C that will help quite a bit. If you can get it up to 70C you will have zero issues with shrinkage but you may overheat your stepper motors. 40C is a good compromise air temp with 70C on the platform.

OR you can design everything so that it won't matter - make all support be the same cross section as you move up the layers.

 

 

  • Glue is good ;) . Manual putting it down, not so good

  • I have designed a simple front end cover that I want to Lasercut from (perspex?) at Fablab Eindhoven. I'm planning on releasing it here with some pictures, if it comes out nicely. The top however is more difficult to close. Moving parts, duh. Two or four roller window shader-ish things woulld do, but they will put some force on the axis.

  • For the temperature of the bed , see my reply on Illuminarti reply above

  • Fan can do: so off when "cupping" on when straight. That is not too hard to remember ( however to do it after you remember it is a different thing)

  • 40°C, if I can find a thermometer anywhere I will check what the temperatuer becomes when I have the cover installed.

 

At last, as always, Thanks for the replies

It is good that these advices are documented/written down.

Perhaps It is good to make a sticky post with Known issues and how to prevent/solve them.

Sounds like a good idea?

Cheers!

Lennart

& Happy Old Year!

PS: Remember to make (Read: design and print) an "awesome jar for 2014, in which you put a note of every event that was awesome! My (regular boring) glass jar for 2013 is to be emptied soon!

 

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Another question comes to mind: the bed temperature is a standard setting each time (75°C), and I cant seem to change it on my UM2 for every print, only for the individual( already forgot it a few times). Is this solvable with hooking the UM2 up to Cura ( usb?) And perhaps where to find it on the forums?

 

You have two choices. The UM2 comes with 2 materials in the menu system: PLA and ABS. You can either:

1) Create a new material called "CUSTOM1" that has the bed temperature and other settings that you want or

2) Modify the existing material called "PLA" to have the bed temp you want.

Doing this is very confusing. I was able to do it but I don't know how I did it and it wasn't obvious what I was doing. You just have to play with it until you get it right.

 

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