Introduction
Your filament will come with a suggested temperature range for printing. For example, Spoolworks EDGE (PETG) has a suggested temperature range of 230-250°C. 20°C is a large difference in temperature when it comes to 3d printing and whilst you will get away with just picking the middle value of 240°C calibrating the print temperature will help improve the surface finish quality and the interlayer adhesion.
You will also find that the print speed has an impact on the print temperature required, for faster print speeds you will have to increase the temperature and for lower print speeds you will need to lower the
One of the easiest ways to calibrate your printing temperature is to use a temperature calibration tower, there are many of these available on Thingiverse all with different features, but the main aspect you are looking for is the chunks, and ideally, try not to choose a model with temperature embossed for PLA when you will be calibrating PETG, as this will just cause confusion. We have a simple temperature calibration tower that we recommend that can be found here: https://www.thingiverse.com/thing:335811...
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Upload the model to your slicer, for this example Cura is being used.
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Click on custom mode to open up the additional options.
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Select the material you will be using as a base to work from.
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For this example CPE is selected because it's the closest profile to EDGE (PETG)
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We will be triggering the change in temperature using the layer heights, to view this you need to 'prepare' the model
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With a 0.2mm layer height we would be looking for the print temperature to be lowest at layer 0, In this example we are looking at a spool of EDGE, so will start at 220°C
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We can then see the second chunk begins at layer 48, so this is where the first trigger will be. The third chunk will begin at layer 98, the rest of the layers follow this same pattern.
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In order to change the temperature at the different chunks you will need to enter some custom Gcode, luckily cura makes this realy simple.
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Click Extensions > Post Processing > Modify Gcode
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This should open up a window called post processing scripts.
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Change the trigger parameter to layer height and enter 48.
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Set the behaviour to keep value.
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Number of layers to 1, this means it will change the temperature over 1 layer, this should give a crisper visual gradient between temperatures.
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Select change extruder 1 temp to 225°C (or 5°C above the previous temperature.)
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So how do you judge the best temperature?
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You are looking for a balance of the best visually smooth a neat surface finish and a good inter layer adhesion.
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Obviously if you are more concerned about the look of the print choose the best looking temperature, and if you are looking for the best inter-layer adhesion pick the strongest part.
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it isn't the most accurate way of determining inter layer adhesion but because of the induced weakness of the cut away on the front the weaker inter layer adhesion will pull apart more easily than the chunks with stronger inter layer adhesion.
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The roughness of the higher print temperatures is most likely caused by slight over extrusion, you will be able to improve the surface finish by calibrating the flow rate.
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