Print The Porto

A collection of tips about 3d printing.
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Printing Ninjaflex TPU filament on the E3D titan extruder

I recently upgraded my eclips3d printer to use an E3D Titan extruder, which has been printing out pretty great once I dialed in all the settings. I needed to print a bunch of rubbery feet for a wire shelf. In the past I've used my printrbot simple to print with ninjflex, so I was curious to try the titan since it is seriously grippy when handling other filaments.

TLDR;

All the normal rules on how to print with ninjaflex still stand. But on the Titan extruder, you need to lessen the tensioner bolt to 1 bar. Looser is better anything higher and it jams.

Try and try again

Following the guide I wrote to myself on how to print with ninjaflex I started up a new print and it constantly kept failing. The filament would actually get squeezed past the geared teeth and bunch up causing it to bind within the netheregions of the titan extruder.

Pile of failed ninjaflex prints
Pile of failed ninjaflex prints

Pile of failed ninjaflex prints with a bad infill
Still looks bad from the top

Printing super slow at 10mm/sec seemed to help, but eventually it would still happen. Scouring the internet I did find a little gem of information on the solidoodle forum with a user who installed the titan on his machine. The most pertinent info came from Sanjay who works for e3d.

We've been printing TPUs of various types on Titan without much drama. The usual flexible material caveats apply in terms of making things go a bit slower (Start @10mm/s or so and work up, depending on the stiffness/softness you should be able to do 20-30 with most), having a bit more retract than usual (1.5mm works for us). Temperatures for TPU are extremely sensitive and I usually find there is a tight 3 degree window in which they work best. For Ninjaflex this seems to be around 227C on a standard E3D-v6.

The most important bit of info is how soft the specific TPU you're using is. Our softest TPU that we've used is Ninjaflex which is Shore 85A (or around Shore 40D). Which TPU are you using, and do you know the hardness?

Sanjay

Using this new information I changed my settings, but still wasn't quite successful. By chance I saw a great review for the new flexion extruder by Maker's Muse. Seems like a great extruder, but didn't understand why the titan would be much different. Until he mentioned how he lowered the tension in order to print with ninjaflex/tpu on the flexion. The light bulb went on in my head and I checked how tight the tensioner was on the titan; It was pretty tight.

Starting up a new print, printing at 15mm/sec and with the tensioner set to 1 bar and it printed beautifully.

Good prints

Some zits on the side due to using the volcano hot end and large nozzle diameter
Some zits on the wall due to retraction not being dialed in for ninjaflex
Good smooth prints
Smooth layer lines. 0.44mm layer height.

Test updates and findings

After spending some time printing up a couple of test pieces seems I found a good tension for ninja flex on the titan as you can see below, setting the tension to 1 bar, had the best success rate. Results shown from left to right all printed with saphire blue ninjaflex at 20% linear infill.

  1. Layer height .44mm at 20mm/sec speed at tension bar 2. win
  2. Layer height .44mm at 30mm/sec speed at tension bar 2. fail
  3. Layer height .44mm at 30mm/sec speed at tension bar 1. win
  4. Layer height .32mm at 40mm/sec speed at tension bar 1. win
  5. Layer height .32mm at 45mm/sec speed at tension bar 1. outer wall which printed at half speed win, infill was sloppy and under extruded fail
  6. Layer height .32mm at 45mm/sec speed at tension bar 2. fail
  7. Layer height .32mm at 50mm/sec speed at tension bar 1. fail

The larger version was made to test printing faster, when it was smaller the slicer would always slow it down due to it not having to cross so much distance. Making it larger did work and would have been a successful print had I completed the infill at 30% and printed more solid top layers.

Categories: Ninjaflex, tips, Filament

Tags: Ninjaflex, Filament, tips

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How to calibrate extrusion width

First make sure you've calibrated your e-steps.

Using a digital caliper, measure the thickness of your filament at 5 different points and get the average. You'll find most filament is not actually 1.75mm in width, but usually less. Enter the measured filament diameter in your slicer.

Download a 20mm calibration cube from http://www.thingiverse.com/thing:271736

Using the cube load it into the slicer and set the following:

  • One, single perimeter (1 wall)
  • No infill
  • No top and bottom layer

You should get a print that looks like this:

Use your caliper and measure the top layers of the wall at several points to get an` average thickness. I got measurements around 1.07mm with my current extrusion multiplier of 1 and extrusion width set automatically to .96mm (120% of nozzle width) for my .8mm nozzle. Using the formula below, lets calibrate the extrusion.

Extrusion Formula
(desired thickness / measured thickness) * old extrusion multiplier = new extrusion multiplier

.96/1.07 * 1 = .89

I changed my extrusion multiplier to 0.89 and printed the model again. I still didn't get the correct thickness, so I repeated the process until, the magic number appeared.

Having the proper extrusion thickness should help with printing out correctly sized and properly extruded models. This is a process that might be needed on a per filament basis. Otherwise, just make sure to always measure your filament, prior to printing, otherwise it throws off all your hard work.

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e3d volcano hot end tips

Getting good prints with a e3d volcano hot end can be very tricky. But I've figured out a couple of base rules to follow that can help with printing. For my example, we'll be using a 0.8mm nozzle/width.

Step right or step off

First thing first, this guide is totally useless if you haven't properly calibrated your extruder steps. I explain how to easily do that in a previous post. Go a head and read how to calibrate your e-steps guide. After that, you can check that you are extruding the proper width. Once that's done, continue below.

It's all about the size

First thing to know don't try to print layer heights larger then 80% of the nozzle width. It's a general rule to follow for any nozzle type not just even a volcano. For our example of 0.8mm width 0.6mm layer height would be your max.

Printing speed is dictated by layer height

If you want to print fast, (ie.: 60mm/sec), you want to use a smaller layer height in comparison to the width of the nozzle. The height should not exceed more then 50% of the width of the nozzle. For this example, you can print at .4mm layer height with the 0.8mm nozzle and get a reasonable looking print with speeds of 60mm/sec. If you go faster make sure to set a smaller layer height. Your millage will vary, but seems to hold true on my system and of course the type of filament you print will also have an effect.

Go large, go slow

When printing at 80% height of the nozzle width you want to print slow around 30mm/sec. What I have personally found is printing at layer heights of .5 and .6mm at anything faster then 30mm/sec, would not get good layer adhesion and would stretch out and begin a ball of spaghetti. There just isn't enough time to squash down the filament to the previous layer.

Heating and cooling

Lastly, sometimes it might help to either reduce the temperature you normally melt filament or increase it if you are going fast. This is something that is totally dependent on your printer. But be aware to make sure you use active cooling, since the filament retains more heat due to the thicker lines it lays down, overhangs can be an issue. Good active cooling can help with this, even on filament such as ABS etc...

Throw everything out the window when messing with flow rate

Just when you thought things were clear, there is one exception to all of this. The flow rate better known as, the extrusion multiplier. Can be used to help print quicker at larger layer heights. So lets take the example of printing at 0.6mm layer height. For my printer, in order to get a decent print I have to run it at 25mm/sec speed. At 0.86 extrusion multiplier, I get a perfect .96 diameter line when printing. But at .6mm layer height I can't print any faster then 25mm/sec. If I increase that multiplier to 1.5 I can print at higher then 25mm/sec, but I lose a bit dimensional accuracy. The reason for this, is that you are pushing out much more plastic then before. There is a simple formula to figure out how much more plastic you are pushing out:

Print speed * extrusion width * your layer height = flow rate mm^3/s

My example would net: 25 * .86 * .6 = 12.9mm^3/s.

So what can we do with this number? I'm not really sure to be honest, other then you have some sort way to keep track of things numerically.

I think it's easier to just write down and track at what speeds you can print with and play with the extrusion multiplier to increase speeds on larger layer heights. No need to work with a formula. For example I have the following saved and I refer back to it when I need to print things:

0.32mm layer height
best quality, printing speed at 35mm/s
good quality, printing speed at 40 and 45mm/s
ok; sloppy infill quality, printing speed at 65mm/s
sloppy infill quality, printing speed at 75mm/s

Just use a calibration cube with an infill of 20% and run a bunch of tests at different speeds and layer heights. Keep a log of how things print out. And you have a handy chart to follow.

Retraction and stringing

One thing you will start to notice is a ton of stringing, especially if you use PLA. So far I've been using a retraction distance of 4mm and an Extra Restart Distance of -0.4mm. The last part completely removes blobs and zits caused from the retraction starting points. This is something you will need to experiment with and can change with different filament.

I'll make sure to add on more info as I discover more. Good luck and I hope this can help another 3D printing soul.

Categories: tips

Tags: tips, 3d printing, e3d, e3d volcano

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