I always prefer things to be more definitive than subjective. To that end, setting the Z-offset and getting the first layer squish just right has always seemed a little frustrating. That is until I designed this First Layer Squish Tool. Print it and you can see what is the smallest slot you can achieve with your current print settings. This tells you your squish in real terms. Then you can easily make adjustments.
It only takes a few minutes to print and gives you a quick definitive measure of squish. Using this tool, I have been able to quickly and easily return my printer to the same squish after changing the nozzle and making print adjustments. Equally as gratifying I have been able to quickly and easily set all my printers to the same squish.
It has a series of 10 slots ranging from 0.1mm to 1.0mm (in 0.1mm increments). The idea is that the slots will close up based on how much squish there is. The size of the largest slot that is closed tells you how much first-layer flare you have. In theory, the squish is half the slot width (because it is flaring for both sides). And, depending on the material you are printing you can adjust the squish as appropriate.
In my example pictured below, the first print shows 0.6mm slot is open. So the largest closed slot is 0.5mm. This tells me that I have about 0.5/2=0.25mm of elephant’s foot or first layer flare out. That is with my Z-Offset at -0.300mm. So I want to reduce the squish by increasing my Z-Offset. I have found that each increment in Z-Offset of 0.01mm equates to about one slot change on this tool. So to move from 0.6mm slot to 0.2mm slot (my goal in this case) I adjust my Z-Offset by 4×0.010=0.040mm. Therefore, my Z-Offset in this case changes -0.300-0.040=-0.340 and I reduce the squish to 0.2mm slot being open and the 0.1mm slot being closed. As you can see that got me to the 0.3mm slot, so I need to make one more adjustment. After making an adjustment re-print the tool and check it again. Of course, like always it is very important to heat soak your machine first to ensure it is stable.
I also included a series of 10 tabs ranging from 0.1mm to 1.0mm in thickness. These can provide additional information when measured with digital callipers. By measuring the tab thicknesses at various heights you can determine how your Z offset relates to the first layer flare out. For example, if the 0.40mm tab measures 0.44mm you also get further confirmation of the need to adjust your Z-Offset. The thickness of each tab can provide some clues into your Z-Offset accuracy.
Lastly, there is a large blank area (on the underside) to write down your results for future reference. Once you have adjusted your printer to the Z-Offset that you like the best. Print and save the First Layer Squish Tool. Then, if you need to re-adjust your printer in the future you can easily return to the same squish.
In my case, I really like (at the moment) a squish that lets me see the 0.2 to 0.3mm slot as the smallest printable gap on the first layer. If I later change my setup and then get a 0.6 slot, I need to reduce my Z-Offset by 0.3mm. And… bam! I am back to the exact same squish. And getting all my printers to have the exact same squish is now a breeze!
The rounded end of the tool has a chamfer on the bottom side to help in removing the print from the print surface.
2024-01-15 Update: I am now using the first slot (0.1mm slot) as my goal for PETG and it is working brilliantly. It has improved my overall print quality (even at higher levels) quite noticeably.
Printing
Material: Print this with any material that you are printing with and save it so you can return to those settings whenever switching materials.
My Setup:
Nozzle = 0.4mm
My Settings:
Layer height = 0.2mm
Line width = 0.45mm
Print Orientation – As shown in the screenshots.
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