Ender 3 pro TPU profile for simplify3d attached below:
As you probably already know that Thermoplastic Polyurethane known as TPU filament material in a 3d printing world is a flexible, abrasion resistant thermoplastic.
3D Printing TPU has become widely available but getting your first successful flexible print may be harder than you think.
Below I will go over some of the most frustrating issues that I have encountered and bring you the solution so you don’t waste your filament on trials and can go straight to the project.
Here is a list of issues I have encountered when printing TPU:
- Filament would curl up into a spaghetti at the drive gear motor.
- Filament is too much or too little (under extrude or over extrude)
- Top cover layer is not “covered” appears like a mesh
- Layers not sticking together.
- Part not sticking to the bed and curls up.
- Finished product looks rough and dull.
Solutions for the issue described above.
Filament would curl up into a spaghetti at the drive gear motor.
So, if you have only experienced 3d printing with hard plastic materials like PLA then you may never have encountered the issue of filament curling at the drive gearmotor. TPU however is very different from any hard materials.
The reason for the loop curl at the drive gear motor is – the extruder head not being hot enough. The typical temperature setting for for the extruder head when printing TPU is 230*C.
You can also find the recommended temperature setting on the spool of filament for that specific brand that you are working with.
From my experience, when switching brands of filament additional tuning may be required for that specific 3d printer.
When the extruder head temperature is too low then the filament does not melt fast enough while the drive gear motor is pushing the soft filament into the tube resulting in a jam at the gear motor looking like a spaghetti loop.
This is similar to if you were to take a rope and try to guide it through the pipe upwards by pushing on the back end of the rope from below.
What to do if the temperature setting is set at the recommended extruder head temperature and still get the jam on the filament drive gear motor?
The common result of this may be a clog in the extruder head or as often referred to a hot end nozzle.
3 ways to clean out the extruder hot end nozzle:
- Method 1: (Clean nozzle with a needle)
- Use extreme caution when performing this operation as the nozzle will remain hot.
- Preheat extruder hot end nozzle to 240 degrees, cooling fans to remain off during this process.
- After temperature reached 200 degrees, pull out filament.
- Then use the silver needle that came equipped with your 3d printer and insert the needle up into the nozzle from the dispensing side.
- Repeat until all the impurity are cleaned our of the nozzle.
- Reload the filament until it come out normally from the nozzle.
- If method 1 did not fix the issue proceed to method 2 below
- Method 2: (Change nozzle)
- Use extreme caution when performing this operation as the nozzle will remain hot.
- Preheat extruder hot end nozzle to 240 degrees, cooling fans to remain off during this process.
- After temperature reached 200 degrees, pull out filament.
- Unscrew two screw that hold the fan cover and move fan cover out of the way.
- Use the small open end wrench that came equipped with your 3d printer to unscrew the nozzle.
- Load the filament thru the feeding tube and push to clean out any impurities out of the tube and the heat block.
- Install new nozzle or reinstall old nozzle after insuring that it is cleaned out and tighten it with the wrench. Please use caution as the extruder head is hot.
- Reinstall the fan cover and tighten the screws.
- Reload the filament until it come out normally from the nozzle.
- If method 2 did not fix the issue proceed to method 3 below.
- Method 3: (clean out nozzle pipe)
- Use extreme caution when performing this operation as the nozzle will remain hot.
- Preheat extruder hot end nozzle to 240 degrees, cooling fans to remain off during this process.
- After temperature reached 200 degrees, pull out filament.
- Cut loose zip-tie or tape that hold the Teflon feeding tube to the wire.
- Unscrew two screw that hold the fan cover and move fan cover out of the way.
- Use the small open end wrench that came equipped with your 3d printer to unscrew the nozzle.
- Unscrew the large quick connect fitting on top of the extruder head and pull out the Teflon tube.
- Disconnect the Teflon tube from the quick connect at the filament drive motor.
- Use the Teflon tube to insert into the nozzle head with the fitting removed to clean out any impurities.
- If the ends of the Teflon tube are clogged or damaged. Replace with new one or salvage the old one by cutting the damaged ends off.
- Reassemble everything back and reload the filament until it come out normally from the nozzle.
If the above steps do not apply to your case and you are experiencing this same issue the solution may be down below:
The first thing to look at is the flow rate of the filament. TPU filament is very soft and flexible therefore it is extremely difficult to push through the feeding or Teflon tube although not impossible.
Reduce the flow rate of the filament. This can be done on the printer itself while the machine is running by overriding the g-code setting with the printer tune in setting or in the slicer software by adjusting the flow or extrusion multiplier setting.
Filament is too much or too little (under extrude or over extrude)
When printing a test model or a calibration cube for example you may notice the cube does not look like a cube but more like a mesh or the opposite, corners would be bulky and rounded. This is a common result of under or over extrusion.
In simple terms too much or too little filament. The fix for this is the same for all types of filaments, simply adjust the flow of the filament as described in the paragraph above.
Top cover layer is not “covered” appears like a mesh
In this instance is a little bit different from the issue described above. Here we see that the extrusion is perfect for the bottom layer and the walls but the top layer is not covered.
We solved this issue by increasing the number of “top” layers to 5 in the layer settings tab in the simplify3d slicer software.
Layers not sticking together.
One of the most frustrating things to live through is waiting for hours on the project to complete printing just to find out that the layer did not stick together and the superhero you just printed is sliced up into hundreds of layers like a stack of pringles.
Most common reason for this is the print temperature is too low. It is just enough to melt the material to dispense it but not not enough to bond it to be layer below. The material cools and solidify too quickly before it actually reaches the layer it is being extruded on.
The solution for 3d printing layer separation is as simple as increasing the nozzle temperature. The typical temperature setting for for the extruder head when printing TPU is 230 degrees Celsius. This may also depend on the size of your nozzle. If you are using larger nozzle try increasing the nozzle by ten degrees at a time and see if this helps you achieve better results.
Part not sticking to the bed and curls up.
When your 3d print is not sticking to the bed one of the simplest things to try is to add a brim to your part. A brim is much like a support material that is printed on the first layer extending out of the part that can be broken away after the part is finished printing.
This will allow more surface area on the bed and help with the adhesion. Here I found a helpful video on this topic that may bring you some value.
Finished product looks rough and dull.
When your finished 3d print looks rough and dull one of the reasons may be the material flow. To fix the flow issue you can follow the steps we have laid out above. The other reason for the parts to be rough is the TPU filament is not dry.
If your TPU filament makes little popping and sizzling noises from hot end when it is extruded, the reason is that it has absorbed too much water.
This can be remedied by drying the filament in the conventional oven, a food dehydrator, or a dedicated filament dryer.
TPU filament absorbs moisture and if it has been sitting out for some time and absorbed moisture then when printing this will result in an unfavorable results.
Struggling with stubborn stringing when printing TPU?
When 3d printing TPU filament it is extremely important to DRY out filament thoroughly. TPU filament that has been sitting out absorbs moisture and will cause stringing regardless of settings and effort to prevent it.
There are few ways you can dry out the TPU filament before using it.
- One is to use conventional oven 160 degrees Fahrenheit for 1 hour.
- Two is to use food dehydrator
- Three is to use a filament dryer.
If you have the food dehydrator you can utilize it for drying out filament. Better yet is the filament dryer you can get online. The best yet is most budget friendly is the conventional oven.
To dry TPU filament using conventional oven. First preset your oven temperature to 160 degrees Fahrenheit. Then place a full 1kg spool in the oven for about an hour. After an hour, remove the spool from the oven and it’s ready for printing. The results will astonish you.
You can download fff simplify3d profile for that we used on our Ender 3 pro to print with Amazon Basics White TPU that we got on Amazon.
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