By Mitch,
April 8th 2024
In a departure from our current series of articles, "3D Design, Visualization and Prototyping", we're going to take a look at a common issue that arises among home users of 3D printers. How do I calibrate my 3D printer?
Now, you may be thinking that, as a 3D printing and prototyping company, we wouldn't want to promote the use of home 3D printers. Well this isn't the case as we at Politech recognise that 3D printing is something that should be available to all. There will be times when you need the specialist services that we offer but then you may still want to 3D print as a hobby. You may also be inspired by the quality work that Politech does and decide to but your own 3D printer for smaller jobs. Either way, we're here to help and guide you in whichever way you need on your 3D printing journey.
So, let's recap on some things we may already know and the look at how to perfectly calibrate your 3D printer.
Overview
3D printing has taken great leaps forward in the last decade with one of the most significant being the ability to 3D print at home. Home users make up the majority of the sales of new 3D printers and the hobby continues to grow at an ever increasing rate.
One of the main issues though that faces 3D printing home users is how to correctly calibrate their 3D printer. This can lead to frustration, wasted time and materials and even complete abandonment of the hobby before it’s started.
It’s worth noting at this point that we will mainly be looking at FDM (Fused Deposition Modelling) printers as they need more set up and calibration. However, there will be a brief look at SLA (Stereolithography) or resin printers at the end of the piece.
Let’s then start off by looking at the main set up of an FDM 3D printer.
Printer Setup
As you can imagine, it would be virtually impossible to give a one-stop guide to setting up every different printer currently on the market. Therefore, the article will just give a broad overview of a standard FDM 3D printer such as the ever present Creality Ender 3.
Most FDM printers, like the Ender 3, these days come partly assembled but it’s usually just a case of constructing the x-axis gantry, positioning the control panel and adding on the filament spool holder.
It’s also necessary to connect up all the essential wiring to things like the drive and stepper motors and then it’s just a case of turning the printer on and making sure everything looks functional.
The firmware and operating system should be up to date but checking online will show if the printer has the latest software installed.
Calibration
Again, it’s impossible to give specifics for each printer in such a short space but there are key things that should be done and adjusted to get the printer working at its best.
Bed Levelling
You’ll hear this a lot as you go through the 3D printing journey but it is by far the most commonly occurring issue among FDM 3D printer users.
The bed in question is the print bed onto which the filament is deposited. If this isn’t level then it’s unlikely that the filament will stick properly and therefore the print will fail before it has started.
There are a couple of ways that this can be done but just a warning not to be fooled into thinking that if the printer has an Auto Bed Levelling (ABL) system that it’s all done for you. If the printer has an ABL such as a BL Touch then that’s great but all that will do is detect any unlevel areas of the bed while printing and adjust the nozzle to compensate. This of course is a good thing but doesn’t mean that the bed is level.
Therefore it’s always advisable to manually level the bed, particularly for first use but also on a fairly regular basis going forward. The way to do this might seem pretty low-tech but it works and there hasn’t been a better method yet to surpass it.
The bed should have a hand adjustable knob at each corner underneath. The way to level it manually is to first get a piece of normal paper like you’d find in an office printer. Then, auto-home the nozzle so that its in the bottom left corner of the bed. It may take it to the centre of the bed if the printer is set up that way but the nozzle can be manually moved using the control panel.
Place the piece of paper between the nozzle and the bed (both need to be heated to working temperature first) and then see of there is a slight resistance when moving the paper between the two heated parts. Use the knob at that corner to adjust the bed until resistance is felt and then move the nozzle (using the controller) to the bottom right, top right and top left corners in order. Repeat the process at each corner and then the bed should be nice and level.
You may find that when the nozzle is auto-homed again that there is a bit of a gap between the nozzle and the bed. This can be adjusted by changing the “Z-Offset” figure via the controls. This moves the nozzle either up or down in 0.01mm increments to make sure that the distance is as accurate as possible.
E-Steps
The E-Step determines the amount of filament that is fed through by the extruder to the nozzle. If this setting isn’t calibrated correctly then it will cause either over or under extrusion, both of which will result in major quality issues with the prints.
E-Step calibration is another manually performed task which again might seem a little low tech. With practice it becomes second nature but hopefully this won’t need to be a regular occurrence.
Again, it’s difficult to say where to find the E-Steps figure on every specific printer but it should be in the “Control > Motion” in the menu of the Ender 3. On an Ender 3, the default E-Step figure is 95.0mm but older models may have it at 93.0mm. This means that for every 100 mm of cold filament that goes into the extruder, 93.0mm is extruded through the hot end nozzle. That may seem odd but it relates to the heating of the filament and the fact that it stretches when extruded.
To see if the printer’s E-Steps are correctly calibrated, you need to extrude 100mm of filament and see how much is actually extruded. To do this, follow these steps.
1. Measure the filament from as close to where it disappears into the extruder as possible, to a point at 100mm. Then make a mark with a permanent marker and also marks at 10mm either side of the 100mm point.
2. Heat the nozzle to the correct working temperature for the filament being used. For ease, use PLA which therefore needs to be heated to 200ºC. Go to the settings on the controller and set the extruder to feed in 100 mm of filament.
3. Wait until this process has finished and then look at the marks on the filament. If the 100mm mark is just visible and you can still see the 90mm mark, then the E-Steps are fine. If not and there is either more or less of the 100mm extruded, then some calculations are needed.
4. Let’s say that the extruder only loaded 88mm of filament so is in fact under extruding. The formula needed to calculate the new E-Step figure is as follows:
The expected amount of extruded filament (100mm) X The current E-Steps (95.00mm)
The actual extruded amount (88.0mm)
This then gives the new E-Step figure of 107.95 which now needs to be entered into the printer settings. This can be done on the Ender 3 by going into the E-Steps setting by the same route as before but one thing to note is that if you turn off the printer, it might not save the setting. Therefore, check what the setting is the next time the printer is turned on.
The calculation is the same for over extrusion but will obviously give you a different figure.
So, that’s the main two elements of calibrating an FDM 3D printer but there are a few other things that need to be checked before printing.
Tighten all the screws
Go around the printer and make sure that everything is fixed where it should be and that all the screws and fixings are nice and tight.
Tighten the belts
Make sure that the timing belts on both the z-axis and the y-axis are tight but be careful not to over tighten them which will restrict smooth movement of the axis.
Adjust the eccentric nuts
The eccentric nuts are part of the wheels that move the z and y axis along their tracks. If these are loose then they will wobble when they move and the prints will be uneven.
That then is pretty much it for the initial calibration of an FDM 3D printer. Any other print settings will be adjusted in the slicer program that’s used to set up the prints but that’s for another day.
Let’s finally now take a brief look at the calibration needed to set up an SLA printer.
SLA Printer Setup and Calibration
With regards to set up of an SLA printer, there’s not much needed apart from finding a secure and level platform on which to place it. You may then need to attach the resin vat and ensure that the FEP film is tight and has no mark or tears.
The other thing is then to attach the print bed but as this will only be going up and down on the z-axis, there isn’t much to this. However, the bed will still need to be levelled and this again is done using a piece of paper.
Remove the resin vat and put a suitably sized piece of paper in its place. Rather than being the method of levelling this time, the paper is mainly there to protect the glass lens of the printer. Loosen the thumb turn knobs which hold the bed in place so that the bed is attached but can move. Slowly lower the build plate down so that it’s just touching the paper and then adjust the thumb turn knobs on each side so that it’s level with the lens. The build plate is now level and that’s all that’s needed to calibrate an SLA printer.
Conclusion
The set up and calibration of a 3D printer is fairly straightforward and relies quite a bit on common sense. As long as everything is properly connected and tightly fitted where appropriate, there shouldn’t be any issues with the general operation of the printer.
The calibration side of things is again fairly easy as long the steps that have been shown above are followed. Once the printer is fully calibrated, you should achieve good print results and hopefully enjoy your 3D printing experience.
Of course, if you need any assistance or advice on your 3D printing needs then you can always contact Politech and we'll be happy to help.
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