If you have ever been watching your 3D Printer chug away and then heard a clicking noise from your drive gear, it could be because your printer hit its max flow rate, the point where it is pushing plastic out too fast. I have created a video on YouTube which explains the process (below), however for completeness I have also written the steps below.
Step 1. Decide on the values for your control variables (Nozzle Temperature, Nozzle Size and Printer Filament). In the video I opt for 210ºC, 0.5mm Nozzle and 3DTomorrow Pro PLA ~ Artic White.
Step 2. Download the Flow Rate Tower Below.
Step 3. Setup the Flow Rate Tower in your slicing software.
Firstly make sure you are printing in vase mode.
Secondly select a print speed which is not too fast, 30-40mm/s should work well.
Next choose your layer height, for 0.4/0.5mm nozzles, 200 microns is a good shout.
Finally, you then need to vary the extrusion width so that every 20mm increment is printed at a 10% higher extrusion width than the base nozzle diameter, i.e. the first layer extrusion width is the same as your nozzle diameter (for me this was 0.5mm) and then the next layer is 10% higher (0.55mm for me) and so on (0.6mm, 0.65mm, 0.7mm…). Simplify3D Makes this easy to do with multiple processes, but if you get stuck, just add a comment and I will help out.
Step 4. Print the tower!
Step 5. Examine the results and identify the layer where printing went well for the entire layer, this is the layer that will tell you a safe maximum flow rate for your printer setup (with the exact nozzle temperature, nozzle diameter and filament you previously selected). Make a note of the extrusion width this would have been, e.g. if 140% is the selected layer and you had a 0.5mm nozzle, the extrusion width should be 0.5*1.4 = 0.7mm.
Step 6. Use the calculator below to find out your safe maximum flow rate:
a = (extrusion width identified in Step 5)/2,
b = (layer height)/2,
c = print speed.
Step 7. Now that you have a safe maximum flow rate calculated you can convert this back into a safe max speed for your 3D Printer. To do this you need to calculate the surface area that represents the size of lines you normally print. One variable ‘a’ is the layer height in mm (so 200 microns is 0.2mm) and the other variable is the extrusion width in mm (e.g. 0.55mm). The formula is: π * a/2 * b/2
Step 8. Divide the maximum flow rate obtained in step 6, by the surface area of your normal print line obtained in step 7. This value is a safe max printing speed for your 3D printer with the nozzle diameter, temperature and filament you previously set.
- My temperature tower printed fine all the way, what do I do? This is a good thing, it means your setup has a nice high max flow rate, you will need to print the next tower which starts at 180% extrusion width. You can download this at the bottom of the page.