It’s all about the first layer isn’t it?
If you have a 3D printer you know how frustrating it can be to see that hotend circling round and round your build plate, either pulling off bits of plastic that are not adhered strongly enough to the table or dribbling and dripping, blobbing across the machine because your Z axis is set just a portion of a millimeter too high.
No matter what make or model of 3D printer you have, it will need to be dialed in for the best results. Fractions of a millimeter make all the difference when you are dealing with the height of your Z axis and it is well worth your time to make sure that your first layer is properly adhering to the bed before you even consider moving on to large and complex projects.
A few things to consider:
1.) Be careful not to set the Z axis too low. The hot end can be set too close to the bed and it can scrape along the bed of your printer, leaving a gouge behind it. If it is too low, be prepared to run an emergency stop on your machine or simply unplug it from the power as quickly as you can before it does any damage.
2.) Another sign your Z axis is set too low is if there is not enough room between the hotend and the build plate for the plastic to be extruded. If the plastic doesn’t seem like it’s able to come out, or if it is building up in blobs around your hotend, your Z axis might be a fraction too low. The best way to describe the ultimate height for printing is that a sheet of paper should be able to slip between your hot end and the print bed.
On the other hand, if your machine is set too high, there are a few other things that you might be seeing:
1.) The plastic may be extruding, but not truly adhering to the bed of your printer. It may appear to be a round bead of plastic, but if you can simply pull it off easily, your axis is too high. The plastic should be just slightly “smushed” on to the bed of your printer by the hotend. If this is the case, adjust your z axis just slightly lower. Fractions of a millimeter can make a large difference. Work slowly.
2.) If your plastic is being extruded but is not laying down in a complete line but is instead falling on your bed in a chain of beads, the height of your z axis may be a problem. Once again, adjust it downwards.
If you have a Printrbot product you are working with, most of the newer machines come with the autoloveller. Here is a good video of Brook Drumm, CEO of Printrbot setting up a machine and adjusting the z axis height that might be worth your time to watch.
If you have an autolevel probe on your machine, you can work in the Repetier Host software to adjust your Z axis. In your print panel there is a G – Code box. If you type in the command M501 into this dialogue box, your 3D printer will output all of the current settings for your machine. This will include a line which shows the settings for M212 which will give you your X, Y and Z settings. These can be adjusted by simply typing in the G – Code dialogue box.
For example, if I type M501 into the G – Code box and get an M212 return of X0 Y0 and Z0 but I am having trouble with my Z axis being too high, I can adjust this setting. I could type M212 Z-0.5 and press enter. I would then type M500 to save the change I made to these settings. The next time I run the printer, the Z axis will be 0.5 mm lower, closer to the bed than it was previously. If this is too much I could change the M212 setting to something less. If this adjustment of 0.5 is not enough, I could continue the process again, changing the M212 setting bit by bit until I am happy with the result.
Setting up the perfect height and speed for your first layer can be a tricky and sometimes time consuming process. But it’s worth it when it comes to your ultimate print quality.