Has your 3d printer got you down? Not sure if you are over or under extruding? 1st layer woes? Most printers can turn out excellent quality prints if the time to calibrate them is taken.
Getting the bed level (or “trammed” actually) is step #1. I use the sheet of paper method. I adjust the bed until I can feel the nozzle just start to touch the paper. Measure all 4 corners of the bed and the center. That should get you close enough to get started. Usually to check, I print a decent size square in the middle of the bed (70×70) and see how the first layer goes down. If it’s decent, then on to the next step.
Calibrate E-Steps/ steps/mm
When your slicer says “send 100mm of filament” that’s what you should get. Chances are, you’re not, but you’re close. Getting this right is critical to being able to set your extrusion multiplier.
- Load your chosen filament into your printer.
- Mark out 120mm from where your filament enters your extruder with a marker (I use a Sharpie)
- Hook up to your printer so you can send individual G code commands to it
- Heat up your hotend to your usual printing temperature. Make sure there’s plenty space between the nozzle and the bed because we’re going to make a pile of plastic
- Send M83, this puts your printer into relative mode
- Send G1 F50, this sets extrusion feedrate to 50mm/minute
- Send G1 E100, this will send 100mm of plastic. It’ll take 120 seconds, but this is done on purpose to make sure that internal friction/pressure isn’t causing any problems.
- Shut off your hotend
- Measure from your mark on the filament to where you measured from before. If you get 20mm, awesome, your printer is set up perfectly. If not, you need to adjust the E Steps.
So to make the adjustment, you need to know what you’re currently set to. That easy to get by sending M503. These are all the settings currently stored. I suggest saving those (just like doing a DIFF ALL when you first fire up a quad) in case you need them later. You’ll see something like this
Recv: echo:Steps per unit:
Recv: echo: M92 X80.00 Y80.00 Z400.00 E96.01
Recv: echo:Maximum feedrates (units/s):
Recv: echo: M203 X500.00 Y500.00 Z15.00 E50.00
Recv: echo:Maximum Acceleration (units/s2):
Recv: echo: M201 X1000 Y1000 Z100 E5000
Look for the E value after “Steps per unit” in this case it’s 96.01. Now to calculate the new number. All you have to do is take your original measured length (120mm) and subtract the amount that is still sticking out. I had 22 sticking out so 120-22=98. To find the new number you want to divide your desired distance by the actual distance. So that’s 100/98=1.02. Muliply that number times your existing e steps number to get to the new value: 1.02×96.01=97.9302, but 97.93 will be just fine. Now you just ahve to send that to the printer and save it.
To do that, send M92 97.93 to set the new Esteps, and then send M500 to save them to memory.
Congrats! You’ve got your esteps calibrated and saved!
Extrusion Multiplier
So many times I’ve heard “set your extrusion multiplier to 0.9, that’s about right.” and never really heard the reasoning why. I thought that if I was getting underextrusion, I needed to bump that up, overextrusion, bump it down. However there wasn’t an accurate way to do this. I figured there had to be one but just never ran across it. Well (no surprise) turns out there’s a methodical approach to determining your extrusion multiplier and it’s quick and easy.
Getting the Esteps right is the first part, which we did previously. To get accurate prints, you have to make sure that the extrusion width you’re getting when you print is what you actually asked for in the slicer. This is also really simple, but of course, involves more math.
First step is to find out what your filament actually measures. It’s supposed to be 1.75, but I’ve found filament ranging from 1.70 to 1.85. Oversize filament can be the cause of many a sleepless night as it jams the hotend. Undersized isn’t as bad as it’s just ends up underextruding, but also not good. Measure in several spots with calipers (micrometer if you’ve got one) over about a 3 foot (1 meter) distance. Take the average and enter that into your slicer. While you’re there, make sure your extrusion multiplier is set to 1. Also look for your extrusion width, as that is the number we’ll be comparing to.
You need a calibration cube for the next step. You can get one here, I use the 25mm size. I wouldn’t go smaller, but you can go bigger if you like, it’ll just take more time. Print the cube in vase mode. Measure all the walls and find the average. This number should equal the extrusion width in your slicer, if not, you need to adjust your extrusion multiplier. To do that, take the current multiplier times your extrusion width divided by the measured wall thickness. For me (I’m using a 0.6mm nozzle) my extrusion width is 0.675, my multiplier was 1 and I measured the walls at 0.72. That looks like (1×0.675)/0.72=0.9375. Print the cube again to see how it comes out. Mine came out just a bit fat still, so I went to a multiplier of 0.93…I just dropped off the last two places. This time it came out perfect at 0.67.
In the process above, you may notice that your layer height may be off as you get the esteps/multiplier calibrated. I had to move my bed up. Apparently I was really overextruding and I had compensated for this by moving the bed down. Now that everything is set like it’s supposed to be, I’m getting killer prints out, really the best I’ve ever made.
