How To: Calibrate the Z-Offset
Posted: Mon Nov 30, 2015 10:21 pm
Note: If you got a new machine after 03/01/16 you likely have the Rev.E version of the machine and you do not need to perform this calibration. Read the Rev. E Beginner's Guide here: viewtopic.php?f=3&t=3542
For users with an earlier version of the M2.....Before you Calibrate the Extrusion Width (viewtopic.php?f=3&t=1964) it's very important to begin your calibrations by making a small adjustment to the starting point for the bed, when beginning a print.
Unless you plan to spend a lot of time getting your Z-Stop set perfectly, (and I'm not knocking it, because a lot of the experts do it that way), the odds are that you are not going to have it set correctly. And when you switch to a different kind of filament, it will definitely be wrong. (Lot of reasons for this - but the main one is going to be due to the heat expansion of the bed and nozzle at the different temperatures.)
We are talking about a difference in starting point that is no thicker than a strand of hair, meaning the difference between a perfect print and total failure.
To make the adjustments that you need:
In the G-Code section of the printing parameters in S3D, there is a Global Z-Offset slot. (There is also a Z-offset in Slic3r that should work the same way.)
1. Step one is to print Ed's calibration square below. (Print with 0.20 mm layer height, 0.40 mm layer width, at 100% layer height.)
2. Measure the height of the printed square with calipers, (as accurately as possible), subtract the measurement from 2.0 mm and then enter that resultant number into the Z-Offset slot in your profile. (If the square is not tall enough, you'd enter a positive number, if it's too tall, you'll add a negative adjustment.) A positive number in the Global Z-Offset slot moves the bed farther away from the starting point for the first layer, so that the thread gets laid down evenly instead of getting squished out. A negative Z-Offset adjustment number brings the bed in closer before printing, so that the thread can stick to the plate with the correct bonding ratio.
I generally run a second and maybe third square, just to fine-tune it, until I get a square exactly 2.0 mm tall.
That's it, and it's pretty easy - but you'd be amazed at how many problems not doing this will cause. At a minimum, you'll want to determine the Z-Offset for each type of filament (PLA, ABS, PETG, Wood, Flex, etc.). I used to calibrate each spool of filament, but you will still get very good results if you just calibrate for the type.
Note: You want to perform this Z-Offset adjustment after you have correctly set the Z-Stop, which is a separate procedure.
Second Note: Don't forget to save this Z-Offset value into your profiles for this particular type of filament. You will want to test for this value at least once for each type of filament that you plan to print. (PLA, PETG, ABS, Wood, Flex, PC, Nylon)
*******************************************************************************************************************************************
BIG NOTE: If you have a Dual setup, you will be forced to set one gap that has to work perfectly for both nozzles. Since those might be extruding at different temperatures, you will have to adjust how you set the gap by changing how far down you seat each nozzle first.
Write-up on that procedure here:
viewtopic.php?f=13&t=2917
Have fun!
For users with an earlier version of the M2.....Before you Calibrate the Extrusion Width (viewtopic.php?f=3&t=1964) it's very important to begin your calibrations by making a small adjustment to the starting point for the bed, when beginning a print.
Unless you plan to spend a lot of time getting your Z-Stop set perfectly, (and I'm not knocking it, because a lot of the experts do it that way), the odds are that you are not going to have it set correctly. And when you switch to a different kind of filament, it will definitely be wrong. (Lot of reasons for this - but the main one is going to be due to the heat expansion of the bed and nozzle at the different temperatures.)
We are talking about a difference in starting point that is no thicker than a strand of hair, meaning the difference between a perfect print and total failure.
To make the adjustments that you need:
In the G-Code section of the printing parameters in S3D, there is a Global Z-Offset slot. (There is also a Z-offset in Slic3r that should work the same way.)
1. Step one is to print Ed's calibration square below. (Print with 0.20 mm layer height, 0.40 mm layer width, at 100% layer height.)
2. Measure the height of the printed square with calipers, (as accurately as possible), subtract the measurement from 2.0 mm and then enter that resultant number into the Z-Offset slot in your profile. (If the square is not tall enough, you'd enter a positive number, if it's too tall, you'll add a negative adjustment.) A positive number in the Global Z-Offset slot moves the bed farther away from the starting point for the first layer, so that the thread gets laid down evenly instead of getting squished out. A negative Z-Offset adjustment number brings the bed in closer before printing, so that the thread can stick to the plate with the correct bonding ratio.
I generally run a second and maybe third square, just to fine-tune it, until I get a square exactly 2.0 mm tall.
That's it, and it's pretty easy - but you'd be amazed at how many problems not doing this will cause. At a minimum, you'll want to determine the Z-Offset for each type of filament (PLA, ABS, PETG, Wood, Flex, etc.). I used to calibrate each spool of filament, but you will still get very good results if you just calibrate for the type.
Note: You want to perform this Z-Offset adjustment after you have correctly set the Z-Stop, which is a separate procedure.
Second Note: Don't forget to save this Z-Offset value into your profiles for this particular type of filament. You will want to test for this value at least once for each type of filament that you plan to print. (PLA, PETG, ABS, Wood, Flex, PC, Nylon)
*******************************************************************************************************************************************
BIG NOTE: If you have a Dual setup, you will be forced to set one gap that has to work perfectly for both nozzles. Since those might be extruding at different temperatures, you will have to adjust how you set the gap by changing how far down you seat each nozzle first.
Write-up on that procedure here:
viewtopic.php?f=13&t=2917
Have fun!