What is Bed Levelling?
In simple terms, it’s the consistency of distance between printer nozzle and the printer bed. The best way to achieve this consistency is to start with a perfectly level printer bed by levelling or ‘tramming’ it, but then you need to consider the z-height of your printer nozzle which is how far away the nozzle is away from the printer bed.
Why is having a level printer bed important?
An unlevel printer bed will result in a random z-height across the bed resulting in a number of quality issues including:
- The printed part could become detached during the print process causing a failure
- The bottom of your printed part may end up with an uneven bottom, or its top and bottom surfaces may not be parallel
- Where the printer head is too close to the bed you could see ugly defects such as bubbles in the print surface, it could cause your printer nozzle to become clogged, or cause ‘elephant’s foot’ – where the plastic has squished out sideways too much resulting in a wider print area at a cost of print layer height.
- If your print nozzle is too far away from the bed, the plastic may not stick because it doesn’t touch the bed whilst hot. The distance could also result in gaps between the lines of plastic in your printed part due to the plastic not ‘squishing’ enough.
This wonderful infographic from The Sprinkle Factory shows perfectly how important it is to get the right nozzle height.
How often do I need to level printer bed?
Unfortunately, this is a hard question to answer as it really depends upon your individual printer. Some printers may need it doing before every print, but those with greater rigidity may rarely need it. It’s just a matter of getting to know your printer and what it needs to get the best out of it.
But there are signs in the print, For example, if the plastic is inconsistent across the first layer, perhaps the plastic barely ‘squishes’ in one area but is translucent in another area – this is a clear sign that you need to level your printer bed. My best advice would be to get to know your printer!
So, how do I level my printer bed?
The easiest way to level your printer bed is to use the paper trick! Just follow these steps:
- Switch on your printer and select ‘auto-home’ in the menu. You’re basically telling it to go to its home (0, 0, 0 coordinates).
- Turn your printer off
- Slowly move your printer head (‘hotend’) to each of the corners of the printer bed. Adjust the bed height at each corner, until you can slide a piece of paper between the nozzle and printer bed. You are looking to be able to slide the paper in without too much resistance, you want the gap between nozzle and bed to just bite the paper.
- You may need to revisit the corners to ensure things haven’t moved as you’ve been adjusting, which can happen.
IMPORTANT NOTE: when manually moving the printer head, do it SLOWLY. If you do it too quickly it can to damage to the electronics, so take your time.
Get the Right Z-Height
Now that you’ve levelled your printer bed, the next step is to get the correct z-height for your printer nozzle. This is all about getting the right amount of squish for a high quality print. The paper is a great gauge as it is a good thickness to start at for z-height, but ultimately, the best way to get the right z-height is to adjust by eye as you print something live. I would advise a bed levelling calibration test print such as this one found on Thingiverse.
Most printers will have a ‘live z’ or ‘z height’ option in the menu which you’ll need to select before printing anything.
It’s then a simple matter of moving the nozzle up if you have too much squish, too little then move the nozzle down. The paper will give you a good starting point, this is fine-tuning things to get that perfect print.
What if I can’t get an even print?
There are things that will prevent you from getting that level printer bed. No amount of adjusting will get around a warped printer bed, but there is still a way to get an even print without too much added expense.
By investing in a bed levelling probe you can affix it to the printer hotend and measure the distance between the bed and the probe to produce a computerised mesh of how level your print bed is. Your printer then has the information it needs to automatically move the nozzle up and down to maintain a consistent z-height and produce a high quality print.
Essentially, a bed levelling probe removes the need to finely adjust your bed level as it will do it for you. We stock the Creality CR Touch Auto Bed Levelling Kit priced at £35.99, suitable for many common machines.
If your printer is needing regular calibration, then you could add some stiffening bed springs which should maintain your bed level adjustments for considerably longer.