How to Easily Calibrate Retraction in 3D Printers

Retraction Calibration 3D Printers

Hey, Karl here with a short article on retraction tuning. I really enjoy reviewing 3D printers and all things 3D printing with one exception…. when I have to calibrate retraction (aka retraction tuning). It takes so much time.

What is Retraction?

While 3D printing on a standard FDM printer, the filament is pushed with an extruder motor that has a gear attached. It pushes the filament, either directly into the hotend assembly or through a Bowden tube to the hotend. Molten plastic is then layered to produce a model. When it is printing nearly all prints require non-extruding movements. During the extruding moves pressure builds up and in order to stop stringing and blobbing during non-printing moves, a retraction happens.

There are 2 main variables that affect this: the speed it moves and the distance. In the past, I would take a calibration model and adjust these 2 variables and test. This can take a long time. First, I had to slice the model into G-code the printer can read and take a stab in the dark with variables. Then print. I had to wait for build plate to heat up…, then hotend to heat…, then the print time. It takes about 10-15 minutes for 1 test. Time adds up quickly.

I am currently reviewing a printer – the Sovol SV01 – and I finally took the time and created a spreadsheet that generates G-code to programmatically test a lot of different combinations in 1 print. I think this is very useful and that is why I am sharing this here now.

Retraction Calibration Method & Spreadsheet

Retraction Spreadsheet
Click to Enlarge

I setup the code in a Google Sheets doc here. This is a work in progress. I have only tested on the printers that I have on hand. If you have any suggestions feel free to email me. My email is in the sheets doc.

To start you will need to download and open in excel or open in your sheets instance. The link is for read-only.

Let’s start with the G-code sheet. This is where you setup the G-code for your specific printer.

  • X and Y dimension – Pretty self-explanatory. With the exception of a delta…set both to 0. Or any printer that homes to the center
  • Start Retract – Shortest retraction distance it tests
  • Increment Retraction – How much it increments for each test. There are a total of 16 tests
  • Starting Ret Speed – First speed it test. From 0 to 5mm height (it will make more sense later)
  • Ret Speed Inc – Every 5 mm in height it will increase the speed this amount
  • Move Speed – The speed for non-extruding moves
  • Starting Temp – Hotend starting temperature
  • Increment Temp – Temp will increase this amount every 5mm in height I haven’t used this for testing.
  • Bed Temp – Temp of the heated bed.
  • Fan Speed – Fan speed at layer 2. 0 is off: 255 is 100%, 127 is 50%, 191 is 75%

Once you set all your parameters copy column M into a G-code file all 30000+ lines. Before you print go into your settings and find out what the max extruder speed is. In Marlin 1.1.6 Control>Motion>Velocity>Vmax E and note the fastest movement. You can stop the print early once it reaches max speed. Before removing from the bed mark your origin corner. It should be obvious, but just in case it isn’t.

calibrate retraction box
You will end up with a box like this.

 

3D Printer Retraction Calibration
Click to Enlarge

Here it is from the top. You can see as it moves around stringing blobbing gets better as the retraction increases. Origin is bottom left.

How it Prints

retraction box diagram

The print starts at the origin moves right …retracts at the circle then a non-extrude movement for the green arrows then un-retracts at the circle then starts over and moves all the way around.

retraction-table

As the print progresses every 5mm in height the speed increments.

Interpreting the Print

3d printer retraction results

Now that the print is complete we have to interpret the print. As you change the variables on the other sheet it will update the instructions sheet for easy interpretation. I mark the spot that looks the best. I then reference this page and measure to find settings. On some printers, I had to look very close and be very critical. You might even skip over the best one if the increments are too much. If you think that is the case print a second one with lower increments and increase your starting point based on the first print.

tenth millimeter comparison
There is a .1 difference between these

I have found that in general if it is hard to tell opt for the shortest fastest. It will lower your print time.

If you test this please leave some feedback on your experience. I can also start logging retraction settings on a separate sheet if you think it is a good idea. You can send me an email with your settings. If you want to see this in action I did a Livestream on YouTube where I tuned ABS live for the SV01.

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fse
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fse

thanks for this!

Jack_77
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Jack_77

There is a mistake at B24584. “Layer 176” should be “Layer 277”. The mistake runs to the end.

Vasily
Guest
Vasily

Hi Karl,
It seems to me that there is a mistake in gcode – E value is not change and is constant on every string. So filament has not extruded during printing.
Regards.

Vasily
Guest
Vasily

Sorry, i’ve found a reason – relative extrusion mode.
Regards.

carlo
Guest
carlo

Hi thanks for sharing. I tried using this file to test a Tenlog D3 Pro, but it doesn’t print anything.
The filament is continuously pushed up and down by the retraction commands but is not extruded by the printing commands.
I put a pen mark on the filament and after 10 minutes of printing it is right where it was at the beginning. It keeps going up and down but it never enter the Hot-End.
I even noticed that in my printer the Z axis is never increased: after 10 minutes of printing the head of my printer is always at the same height.
I have also seen that in the header of the gcode file, a command is given to move Z to 0.2, before the G91 command to set relative; then in the first line of the first level a G91Z 0.2 command is given again to move up again. This makes the first layer to be printed at 0.4 mm from the bed. It’s right? I think it’s a bit too high and pla won’t stick … Thanks for your attention. I am a newbie and could have written a lot of crap. Please be patient…

Volodymyr Poltavchenko
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Volodymyr Poltavchenko

I’ve got same problem during first print.
Check regional settings in your OS. Look like you have decimal separator “,” instead of “.”

Kiraly Kornel
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Kiraly Kornel

Is this for 0.4mm nozzle?

Kiraly Kornel
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Kiraly Kornel

What formula did you use for the flow?

Taus
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Taus

Me again. The file helps me a lot, but in my tests I notice a big difference with Cura Z hop “on” or “off”. I wonder if there is the possibility to include something like 0.2 Z hop in the file. Thanks.

fscx
Guest
fscx

So the file you currently have posted, does not print like the one in the photo’s on the site. It does not print the box and lines on the inside. So could you update the pictures or check the file for this? Because after printing it it all looked the same and no way to tell stringing.

garag
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garag

hello.many thanks for you job!
pls make do model with brim ?
thx

Jeremy Chavers
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Jeremy Chavers

I had problems with adhesion also, so I made an 80mm x 80mm x .5mm rectangle to print first, and then adjusted the start layer of the test to .7mm and printed it over top.

Member
Marco Tonoli

Hi, thanks for you work.
I’m tryng for my delta (wit a looooong bowden) and seem to work.
My test are “reversed” , the extrusion are on external direction, not to internal direction… is normal ?

If i understand i must find the wall/point/high with most reduced blob as possible ?
thanks
Marco

Member
Marco Tonoli

i find a bug (think), fan is not powered off at the endo…. (and a bit of brim maybe useful)

Angus Kerr
Guest
Angus Kerr

Hi Karl … FINALLY! A proper tool to get the proper retraction settings instead of printing numerous tests with stab in the dark settings.

I am using a modified Anet A6 with a bowden E3D V6 clone hotend. I did find however, that the print is printing way over to the Xmax, Ymax, and had to reduce the bed size, and then it printed and stayed on the bed. My printer has X0, Y0 in the bottom left hand corner, but nowhere in the gcode do I see a move to a sort of middle of the bed?

This is nit-picking though. Retraction is really tricky, since it involved 3 variables: distance, speed and temperature. It’s really great to have a tool where you can tune all 3.

Angus Kerr
Guest
Angus Kerr

Hi Karl…I did some work on the spreadsheet – I tried the stock gcode on both my Anet and Ender-5 printers and it did the same thing – printed in the far upper corner, never went to the centre of the bed. Also, I noticed the fan setting wasn’t taken to the gcode either….. I’m happy to share my modified spreadsheet with you… Now both my printers work properly…..and I have my Anet dialled in…the Creality …hmmmm looks like we have a faulty Bowden tube coupler…!

Matt
Guest
Matt

I see from your diagram that the nozzle is supposed to retract, move inside the cube, then move back out. Mine for some reason is doing the opposite – it’s retracting, moving out of the cube, then back in. Overall the lines on the cube seem to be identical after over an hour of printing
I’m using an Ender 3 pro w/ Bigtreetech mini 1.2 board installed and flashed to default 2.0.5.3 marlin release (no bltouch or led)

Wassingue
Guest

Hi Karl. Thank you for this wonderfull tool. I use it on a Dagoma Neva/Magis (Delta) and it work perfectly.
I must just to replace start and end code and adjust the retract amount and speed values for good test.
May be you can update the software with a optional user start and end code.
But this tool is fabulous as this !
Thank you again.

Wassingue, France

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