The more we know the harder it is to defeat us!

Some time ago I have decided to switch from the ABS filament to the PLA filament. This is how it starts 🙂 …

The advantages of the PLA over the ABS are far more immportand for me. The PLA does not need hot bed which is less cumbersome. Also the temperature of extrusion is lower than of the ABS. The last but not the least, the printing does not deform. When layer by layer the printing is rising the higher the object is the cooler the highest layers are when considering the ABS. The print out is deforming which is my primary concern. You can of course avoid that by building a heating chamber so the warmth will not escape so easily.

By switching to PLA you keep things simple. It does not need the heating bed but it can benefit from it and therefore you can get nice printouts.

This post is not however about the technology whether to choose the ABS or the PLA. It is about the effect of switching from the ABS to the PLA.

While printing a lot with the ABS I have decided to make the switch. I had known that the nozzle needs cleaning. The easiest way to do this was to manually push a PLA wire through the nozzle. Applying high pressure I have cleaned the nozzle so there was no ABS left. This went very smooth if not mentioning disassembling the extruder.

Everything was prepared, the spool was changed to the PLA and this is where the problems started to arise.

Painting with the PLA is not so simple if you use MK8 extruder. It is great for the ABS. However if you consider the PLA as a material of your choice it is not so great at all. The reason is the heating chamber. Basically it is very short and not cooled actively. When you try to extrude some PLA you will momentarily notice the difference. The filament is heating up before entering the nozzle and this is probably the cause. Heating PLA a bit makes it elastic and this leads to extruder jams. Below you can find a few pictures which will shed some light on the matter.

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This is a printout of a flower vase. As you can see the it is not finished and shows only the base. After a few layers the extruder gradually stopped to extrude the filament.

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Above you can see how the filament looks like when the nozzle jams. If you look closer you will notice that the head of the rod is a bit thicker than the rod itself. The change in the diameter is the most probable reason why the filament jams.

How to solve the problem?

The most likely it is because of the extruder. As I have written at the very beginning I am using MK8 extruder. It does not deliver the best while concerning printing with the PLA. I have decided to make a small experiment by switching the extruder. The J-head was chosen. When everything will be ready I will describe the results when using the PLA material.

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