UM1 settings for many "print all at once" objects

[peetersm 124]

Hi,

I am having trouble going from printing 2 objects at once to printing 60 objects at once. I did not change anything in CURA from printing 2 of these cylindrical beads, to then printing 60. The 60 bead print is getting a lot of ridges in the walls of these cylindrical beads. see photo and CURA 14.09 settings used.

any ideas what is happening? is it filament? is my Z axis sad?

I did not see any gringing on my filament and I am printing

layer = 0.1mm

speed = 50mm/s

temp = 240degC (I know that's a bit hot but this faberdashery Village Green likes to under extrude at lower temps)

[profile]

layer_height = 0.1

wall_thickness = 0.8

retraction_enable = True

solid_layer_thickness = 0.6

fill_density = 100

nozzle_size = 0.4

print_speed = 50

print_temperature = 240

print_temperature2 = 0

print_temperature3 = 0

print_temperature4 = 0

print_bed_temperature = 70

support = None

platform_adhesion = None

support_dual_extrusion = Both

wipe_tower = False

wipe_tower_volume = 15

ooze_shield = False

filament_diameter = 2.83

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 = 2

retraction_combing = False

retraction_minimal_extrusion = 0

retraction_hop = 0.0

bottom_thickness = 0.2

layer0_width_factor = 100

object_sink = 0

overlap_dual = 0.15

travel_speed = 150.0

bottom_layer_speed = 20

infill_speed = 0.0

inset0_speed = 0.0

insetx_speed = 0.0

cool_min_layer_time = 5

fan_enabled = True

skirt_line_count = 0

skirt_gap = 3

skirt_minimal_length = 150.0

fan_full_height = 0.5

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_type = Grid

support_angle = 60

support_fill_rate = 15

support_xy_distance = 0.7

support_z_distance = 0.15

spiralize = False

simple_mode = False

brim_line_count = 1

raft_margin = 5.0

raft_line_spacing = 3.0

raft_base_thickness = 0.3

raft_base_linewidth = 1.0

raft_interface_thickness = 0.27

raft_interface_linewidth = 0.4

raft_airgap = 0.22

raft_surface_layers = 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 =

object_center_x = -1

object_center_y = -1

 

 

[korneel 176]

it might have something to do with layer adhesion and cooling off.. the beads have cooled off so much that essentially you are starting a complete new layer, without "fusing" them together..

i would recommend placing them apart and using the print separately option in Cura.

 

[zoev89 73]

This is my line of thinking:

A little slag in the belts or a slight wobble in the pulleys can explain the differences. When you have 1 or 2 objects close

together then the probability of printing in a trouble zone is small. But if you fill the bed then there will be areas that are good and bad. Your photo also shows correctly printed parts not all of them have the same artifacts.

 

[gr5 2,178]

I think it's a temperature issue. But not certain. 240C should be plenty hot to fuse the layer onto a cold layer below so I don't think that's the problem.

Instead I'm thinking the nozzle is heating and cooling by as much as 10C (say 235C to 245C).

You can verify by watching the temp of the nozzle while it prints. It could be related to fan/air currents or the PID controller.

I recommend you add some kind of thermally conductive grease (silver grease?) that can withstand up to 300C to both the thermocouple *and* the heater. This will help the PID not get out of control. But before you do that either print with the cura window so you can see the temperature graph or just stare at the ulticontroler display for 10 minutes and take notes about the temperature while it prints.

 

[gr5 2,178]

Of course you can always do the "print one at a time" feature. But then you won't get nearly as many printed per session. For stretchlets I printed dozens at a time and had the test head push off the old one. Just do cut and paste the code with custom movements to move the head to the right spot to push it off at the end.

 

[mnis 11]

And yes, as gr5 already mentioned:

Thermal Compound can be very helpful to keep the temperature stable. After I installed a new Hotend in my almost one year old UM2, I noticed large temperature fluctuations of +/- 10 degrees and more. Previously similar I had not noticed. Anyway, after applying "Silver Grease" - Thermal Compound (I just had nothing else and it also contained only ten percent silver), although the currently displayed differences now are close to +/- 1 degree.

Markus

 

[peetersm 124]

Thanks! I did notice some wide temp swings (+-15deg) a month ago and tried testing the wires which all looked fine, reconnecting things may have helped since I think I am only seeing +-8degs swings now. I will use the cura screen to gather betting info.

So the grease idea is great. But the thermisor does not want to come out of the block, and I am worried about beaking it. I was able to add silver grease to the heater. I will keep an eye on this and also try printing one at a time.

I'll keep you posted.

 

[gr5 2,178]

The thermistor is easy to damage so be careful.

You can alternatively reduce P and I values a bit. Maybe set them to 75% of current values. This will make it take a little longer to heat up but should hopefully reduce temperature oscillations.

 

[gr5 2,178]

By the way my nozzle is always within 1 degree of goal temp.

 

[peetersm 124]

I love the idea of the custom gcode to push the object off and start over, but these beads require a little more pressure to remove than i would like to subject the print head to.

I did see some "jumping" in the temp (see image from CURA-pronterface-print window. but it would go long periods being stable. once when I was watching the ulticontroller I saw it drop to 230 the go back up to 240, or jump from 240 to 247 then come back down, but did not see this reflected in the print window graph?

anyway printing one at a time also helped, see pics.

Is the fix for jumping temps a replacement thermisor? autoadjust PID, - both?

I will continue to do one at a time prints since this is giving me better results. But would like to figure out how to be able to solve the jumping and maybe do more print all at once jobs.

 

[gr5 2,178]

Wow - your graph shows massive temp swings. That's definitely the problem (or you can call it the symptom).

What was the fastest the temperature jumped? Did it take less than 5 seconds? Less than 1 second? If less than one second that's impossible so it must be a wire. Most likely the wire from the top of the printer print head. It probably has more issues when the head is in the 4 corners where the wire has to bend more/less. You can push the head around at room temp and see if the temp jumps suddenly. Or poke the cables at the top of the print head while keeping your eye on the temp.

Consider switching to the auxiliary cable (meant for a second nozzle). Of course you need to swtich at both ends. And make sure you have good strain relief - the cable needs to go through the black plastic (delrin) F shaped strain relief thing.

 

[peetersm 124]

It was less than 1 second, like the blink of an eye. I am on my 2nd wires already. I will do more testing, but I did try seeing the short via the method you describe and was not able to see it. I will be more diligent with the poking and moving around.

I may need to look for replacement wire set. here a link to a short video I short showing the behavior at it's worst.

 

 

[peetersm 124]

UPDATE -

I did get better results after doing an auto-calibrate PID and printing one at a time. THANKS!!!

BUT still have the temp control issues. I am convinced my wires are fine, and now think my temp control issues are due to the fan running at speeds<100% and the PWM interference this can cause on the UMO.

This thread describes what I am seeing and talks about fan PWM and possible effects on temp sensors.

http://umforum.ultimaker.com/index.php?/topic/6327-weird-temperature-swings/

 

[zoev89 73]

At 100% the PWM can hardly interfere since it is on all the time...

The interference is also reduced buy using the fast pwm option which is to my knowledge default on. It is about 30Khz range PWM in fast mode if I remember correctly. I looked at the signals when I switched to 12V fans.