Solving 3D Printing Problems

3D printing problems are frustrating!  It all worked out beautifully yesterday, but today it is not sticking to the bed, there is a big crack down one side and then it failed 3 rows before the end.

Understanding why things go wrong is the first step to understanding how to prevent them from happening in the first place.  In this article, we give you some examples of our own 3D printing problems along with the solution.

All of this refers to FDM / FFF 3D printers where we get to use real world materials, hands on.

Heat and 3D Printers

The number 1 cause of 3D printing problems is heat. The material expands when it is heated and contracts when it cools.

What can we do about it?

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Try to improve the stickiness of the bed to prevent the object from lifting. Using blue painters tape with PLA can help as well as heating the bed to 50 degrees.  Some people have used tape to stick down the object.

You could try changing the orientation of the print. Decreasing the surface on the bed will help. There may be reasons why this is not possible, so we might need another solution.

Having a consistent temperature will help to cool the plastic down at a more even rate.  Some people have installed fans but there is an even better solution provided by some 3D printers – have a heated build chamber.  The Robox overcomes many 3D printing problems by good design – it has a heated build chamber which helps to keep the plastic an a consistent temperature and prevents warping.

We can change the material – ABS operates at a higher temperature so the difference between hot and cool is greater, potentially leading to more warping. Don’t rule out ABS because of this – it is a great material and more suitable than PLA for some object.

A word about settings

So what temperature should your 3D printer be set at? What settings or materials should you use. The answer is – it depends!

There are many variables involved, here are just a few:

  • Temperature – outside,  inside, material
  • Speed of print
  • Quality
  • The object itself
  • The build plate
  • The material
  • Design of  3D printer

If things go wrong, you will have to adjust one variable at a time to solve the problem.  Here are some of our 3D printing problems:

The Bunnies

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The problem here was heat and material.  The big bunny printed quite well using PLA run at 220 deg. The small bunny started out the same way and we gradually tried decreasing the temperature.  The small bunny improved but the best result came from changing to ABS.

The small bunny meant the print head was always around the same part of the object so it did not cool as it should.  The bottom layer was still too hot when the next layer went on, so it squashed down. On the big bunny, the head moved away to print elsewhere, so some cooling was possible.

The Lovers – 2 Problems

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We used a dual head printer and printed both objects together.  When you do this, switching on the support also means a wall is built which tries to separate the 2 materials to prevent cross contamination.  What happens is that one head nudges the part the other head printed, a small amount of material smudges onto the “wrong” side. In this case, we end up with black spots on the white object. Despite using the walls, this still happens. Dual head printers need to get better or only be used for printing in 2 materials. 

There was a second problem with one of the lovers – you can see a line across its head.  This is an easy fix – it was caused by having to change the materials half way through printing. So the lesson is – make sure you have enough filament to finish the job!

The Hot Dog Effect

When we don’t get a good finish on the platform side of the bed, the cause can be that the head is too far away from the bed. This will also cause the object to lift from the bed instead of sticking.

I call this the hot dog effect.  If the head is too far away from the bed, the material does not spread on properly, it comes out like mustard on a hot dog.  But we need it to be spread on to the hot dog.

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You will need to re-level the platform if this happens.  You can see if this is going to happen by looking at the material when it lays down the first row.  There should be a smooth line, not a wiggly line.  Sometimes, it is smooth at one side but becomes wiggly at the other. This means the bed is not level.  With some 3D printers, you can adjust the screws whilst the job is printing, if you catch it early enough.

Sudden Stop

In these 2 examples, the symptoms were the same but the cause was not!

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This is why 3D printing problems can be so frustrating!  In both cases, the printer stopped at exactly the same point.

Stopping at the same point is usually indicative of a problem in the software – perhaps the .stl file has been corrupted or the rendering software has not read it right.  You need to fix the original file before printing will be successful.

In the second instance, we had printed this object many times so we knew the file was ok. We changed the filament and it worked fine.  We had been using a cheap imported filament but when we changed to our Elefilament, it worked fine.

So the lesson is, use quality filament.

These are just a few of the 3D printing problems we have encountered. To become good at it, you will need to print many objects and try making different adjustments to see what works for your object, printer and material.