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LePaul

Analyze my print...Bowden Clamp

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Barnacules Nerdgasm posted a great video this week, a replacement to the Bowden tube feed connection. Here's the link on Thingiverse

http://www.thingiverse.com/thing:11864

http://www.thingiverse.com/make:48823

I printed with the following settings...

Layer Height .2mm

Shell Thickness .8

Bottom/Top thickness .6

Fill Density 20

Speed 50

Temp 220

Filament diameter 2.80

Flow 100%

I think I have the bed height almost perfect, however on the right front, it may need to go down a very small amount (blue PLA on blue tape is hard to see, but note the ring around the part)

gallery_536_202_4634.jpg

Here's the parts...I bet you guys will advise a bit lower temp...what do you think?

Things to note...the first layer is that desired SMOOSHED/FLATTENED of material so many of you have said to strive for!

The bottom layers seem darker...over extrusion (too hot?)

gallery_536_202_47523.jpg

I have been wiping the surface of the painter's tape with rubbing alcohol and I am ripping up a lot of tape trying to remove the parts when completed. While not a huge problem, I am having to lightly sand away the tape I can't peel away.

Thanks for your suggestions in advance

 

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Your prints are looking pretty good.

I rarely use alcohol for adhesion. Most of the time it makes the print stick too much, like you have experienced. I would use alcohol when printing something larger that would tend to warp and pull off the tape. For most parts, starting with the nozzle primed and adjusting the Z height on the fly while printing the first layer gets them sticking well. If this is hard to do, you could specify a thicker bottom layer in Curas Advanced tab under Quality. I usually reuse the tape for multiple prints before replacing. A good thing about narrower tape is that when a strips gets damaged, you an replace smaller areas.

I usually print the tops and bottoms at 4x or more of the layer thickness to get a nice finish on the top. The larger the flat areas, the more important this will be.

220 is a very safe temperature to print at for most any PLA. There are trade-offs between temp/speed/quality. At 220, you should be able to easily print these parts at 100mm/s without much loss of quality. Personally, I go for lower speeds and temps for better quality and less warping. I usually print around 200-210 and generally below 75mm/s. Every roll of filament seems to print differently.

 

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The print looks pretty good to me as well.

I suppose the bottom is darker because of the higher temperature during your first layer?

As I also wrote to Barnacules (he makes great videos!) personally i am hesitant about this upgrade, because by my understanding, what you are doing is applying force on the bowden tube so it can not move anymore.

But my concern is that it also effects the inner diameter of the bowden tube. It only is 3.16mm, If you have any heat traveling up causing the filament to expand or just some thicker filament i can imagine you get high friction very fast.

But i am curious to read how you are experiencing this upgrade, since my arguments are merely theoretical.

 

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I didn't make any temperature changes during the print

That's an interesting concern. I may wait on making any changes, I did print and install the improved zip-tie/clip for the bowden tube on the extuder. Maybe I should see how that affects print before I change anything else.

I slowed the video in the middle to show how it was applying the first layer. To my [untrained] eye, it looked a little heavy on the extrustion....thoughts?

 

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To my [untrained] eye, it looked a little heavy on the extrustion....thoughts?

 

I agree. It's minor though. Basically you are a tiny bit too close to the print bed. I would turn the screws tighter by 1/8 of a turn. Although that might be too much. Or maybe just the screw closest to this A shaped part.

 

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Here is a little something that I noticed about the first layer. Normally before a print starts the nozzle oozes quite a bit. I pull the strands away because when the head homes to 0 it would otherwise squash the already extruded filament and take the goo with it when it moves into printing position.

Illuminarti suggested to add the following to the start gcode section in Cura in order to extrude 6mm of filament before moving into position to print.

 


G1 F90 E6 ;extrude 6mm of feed stock

This has the advantage that it primes the nozzle and the already extruded filament beeing heavier, sticks to the bed at first and not to the nozzle.

This might help to get a nice and consistent first layer.

 

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That's an excellent idea, I haven't even looked at the gcode for the printer

I tweak the gcode in Mach 3 for the CNC mill I use when making aluminum parts for my R2-D2s. For some reason, the motor off doesn't translate over from vCarve Pro, so we have to add that in manually to each part we mill. Easy fix, just annoying if you forget ...

So on the second to last part (threaded screw), that doesn't look too heavy/over extruded at the begining?

Nice to hear I am honing in on getting this thing working well

The blue PLA is quite something, it shines so much, its hard to tell if its "wet" or not :)

 

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Your prints are looking pretty good.

I rarely use alcohol for adhesion. Most of the time it makes the print stick too much, like you have experienced. I would use alcohol when printing something larger that would tend to warp and pull off the tape. For most parts, starting with the nozzle primed and adjusting the Z height on the fly while printing the first layer gets them sticking well. If this is hard to do, you could specify a thicker bottom layer in Curas Advanced tab under Quality. I usually reuse the tape for multiple prints before replacing. A good thing about narrower tape is that when a strips gets damaged, you an replace smaller areas.

I usually print the tops and bottoms at 4x or more of the layer thickness to get a nice finish on the top. The larger the flat areas, the more important this will be.

220 is a very safe temperature to print at for most any PLA. There are trade-offs between temp/speed/quality. At 220, you should be able to easily print these parts at 100mm/s without much loss of quality. Personally, I go for lower speeds and temps for better quality and less warping. I usually print around 200-210 and generally below 75mm/s. Every roll of filament seems to print differently.

 

Mastory, we had a rough start but I wanted to thank you for this advice.

:)

 

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lower temps seem to do better with stringing - they reduce stringing. I don't know any other advantage of lower temps.

Higher temps reduces underextrusion (less pressure in the nozzle) and so that also allows you to print faster. But you get more stringing. I've heard that higher temps can improve bonding. I haven't experienced this. Also higher temps can sometimes get you a shinier look. I haven't noticed this either.

 

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Here is a little something that I noticed about the first layer. Normally before a print starts the nozzle oozes quite a bit. I pull the strands away because when the head homes to 0 it would otherwise squash the already extruded filament and take the goo with it when it moves into printing position.

Illuminarti suggested to add the following to the start gcode section in Cura in order to extrude 6mm of filament before moving into position to print.

 


G1 F90 E6 ;extrude 6mm of feed stock

This has the advantage that it primes the nozzle and the already extruded filament beeing heavier, sticks to the bed at first and not to the nozzle.

This might help to get a nice and consistent first layer.

 

Ok I looked at the start.gcode and wondering where to add that entry? Here's what mine looks like

;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}

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}

M117 Printing...

 

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You might just edit the fourth line from the bottom with your preferred priming distance. You can choose if want to keep the higher f200 speed or substitute f90 like your example. May not matter, but I think i would use the 90. The existing line extrudes 3mm at 200 speed. Idont know what the speed units are. May be just relative to max or something....

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