Starting today we're launching the Ultimaker Schooling blog series, that will focus on topics such as 3D printer maintenance, printing how-to's and other helpful tips and tricks. For this special blog series we’ll combine our local Ultimaker experts with our online knowledge base and will regularly present a collection of tips. If you follow along with these blogs you'll become a specialist in no time at all! Read on to discover our tips on the topic of maintenance.
Even though we’re a 3D printing business, we still learn something new every day. And we should! It’s no wonder when you consider that it’s such a dynamic landscape where hardware evolves, software matures, companies grow and new applications rise all the time. No matter how much technology and expertise is put into 3D printing, it still feels like craftsmanship - with all the beauty and ingenuity that comes with it. A lot of our users have developed their own methods and workflows around 3D printing problems and have learned a great deal in the process. We’re passionate about sharing this knowledge with the world and we’re very lucky to have a thriving community who feels exactly the same. By doing so they not only help the makers of today, but also of tomorrow as our online knowledge base is always available. With such a great repository of expertise, we can all become 3D printing specialists.
The first tips on our list are a few points which should keep your Ultimaker 2 in the best possible shape. If you are eager to learn and want to know more, please continue to our community for even more expertise.
One of the most crucial and delicate parts of an Ultimaker is the print head. Therefore we thought this was the best place to start. What should you look for when doing maintenance? How can you potentially improve your print quality?
If you want to get the most out of your retractions, make sure there is no play in the Bowden tube. During assembly we secured it with the clip and the horseshoe, but what should you look for when it is printing or after you took it apart? The first thing you must do is remove the filament. On your Ultimaker 2's menu, select Material and Change. Next, before removing the Bowden tube from the head, or the feeder, you need to remove the horseshoe first.
Then press the clip down with your fingers – or a pair of pliers if it is really tight – and pull the Bowden tube out.
When you’ve completed your maintenance and you want to put everything back together, place the print head in the back right or left corner. By putting the head in the corner you have less chance of bending your rods when applying pressure. Now push in the Bowden tube in the print head all the way down into the PTFE teflon coupler. Make sure it can’t go any further. Pull on the Bowden tube gently, and insert the horseshoe underneath the clip. After the horseshoe is inserted and the Bowden tube is inserted, push it down again to ensure it is all the way down in the bottom.
It’s important to tighten the thumbscrews to the correct tension. If it is too strong, you can create a distortion in the alignment. If they are too loose, the print head won’t be tight enough and you can also create a distortion in the alignment. To set it to exactly the right tension, tighten the thumbscrews until they touch the surface of the print head. Then do another half rotation extra. That is the right tension. To finish up, tighten the thumbscrews in a diagonal order to divide the tension equally.
Make sure the fan bracket is not touching the heater block or the nozzle. This could result in a temperature error or very slow heating – a temperature error can be triggered when heating takes too long. The other thing to watch out for is that the fan bracket can also be bent. Also make sure there are no big seams in the bracket as they will hamper your printer’s ability to cool.
Skewed PTFE teflon coupler
Usually there are two reasons why your PTFE teflon coupler may be sitting skewed in the metal coupler. This is either because it’s deformed, or there’s dirt underneath it, for example the remains of some filament. Either way, there is a very high chance this will result in under extrusion or other troubles. When you’ve removed the PTFE teflon coupler and any dirt underneath it, put it back in the metal coupler. There should be a 2mm gap between the PTFE teflon coupler and the metal coupler.
Bearing print head
Double check that the three stacked black parts in the print head don’t have any seams. If they do then the bearing is not in its slot properly. Open up the print head and put the bearing in the right place. Before putting it back, if you look in the bearing you can see 4 rows of balls in it. Those 4 rows of balls should be in an ‘x’ shape instead of an ‘+’ shape. This will reduce the amount of stress applied on them and extend their life expectancy.
#2. Atomic Method.
When you only have one nozzle at your convenience but you want to print with different materials you have to clean the nozzle when you make the switch. If you don’t, residue of the previous material will most likely interfere with your new print material as each material has its own characteristics. Cleaning the hot end doesn’t have to be complicated. Follow this link to find out exactly how it is done. The Atomic Method is especially important if you switch from ABS to PLA.
When you inspect the rods, and in particular how they fit in the sliderblocks, there should be no gap between the rod and the sliderblock. If there is a gap, there’s a possibility the rod will work itself loose from the sliderblock. Hold the sliderblock in your hand and apply pressure to push the rod in. You should hear a click.
Approximately every 8 weeks, apply a few drops of sewing machine oil on these rods to keep everything smooth. Don’t use WD40, use sewing machine oil.
NOTE: The green magnalube tube supplied with your Ultimaker is for the threaded Z rod only. Mixing this up will severely influence the movement and function of your bearings.
#4. Bed clips & springs
When you want to take out the glass plate, open up the two front clips that hold it in place. If they’re too tight, use a tool to open it up a little, then just use your fingers. If you take out the bed, make sure that you do not lift it any higher than the clips, approximately 1cm. If you do lift the bed higher there is a good chance you will bend the clips and they will loose grip on the glass plate during a print job. If you think the clips are bent, remove the glass plate from the Z-stage and get a screwdriver. Hold the Z-stage at the front with one hand and use the tool to push down on the clip until it touches the Z-stage. Do this only once and the clip should be ok again.
When you are levelling your print bed, don’t add any height to compensate for the three springs under the heated bed. They are intended for fine-tuning the bed so it’s level, but not to create any actual distance. If there is not enough tension on these springs, there is not enough resistance and the movement of the print head and bed can be reflected in the quality of your print. Keep your springs tight.
#5. Print profiles
Even if your Ultimaker has been precisely calibrated, when you fire up a file with an unbalanced print profile, you’ll get nothing but trouble – or 3D printed spaghetti. So to finish off his first Ultimaker Schooling blog we’ve decided to give you a few rules of thumb in what to look for in a print profile. Firstly, it’s good to realise every material has its own ideal print temperature. For PLA this usually is around 210º, and for ABS and CPE it’s around 240ºC.
Next, there are a few basic values we need to take into the equation: speed, temperature, layer height and the general shape of the model. For example, even with all the settings perfectly right a fast profile probably won’t work for a very complex fragile model.
To keep it as clear as we can, we’ve created three key categories; slow print, normal print and fast print.
Usually printing slower will result in better surface quality, but this doesn’t mean that a normal or fast print won’t result in a good print, it’s just that the slower end of the spectrum is usually safer. We consider 30mm/s to 50mm/s as slow. Depending on the exact speed, you’ll need to tweak the temperature as well.
Keep in mind: a slow speed requires a low temperature. For 30mm/s start your print around 190ºC. Every resolution from 0.04 micron to 0.2 micron should work. But a thicker resolution requires a higher temperature as well. When dealing with a complex model, we recommend you dial down your speed to 20 or 30mm/s.
When your model is not particularly complex and you’re not in a hurry, you can print at normal speed. Normal speed is considered to range from 50mm/s to 75mm/s. The print temperature that works best for these speeds can range from 210ºC - 230ºC. We are nearing the speed where the resolution you choose starts to have an effect. Remember, if you choose 0.2mm, the volume you extrude per second is significantly higher compared to 0.06mm.
To make sure your hot-end can keep up with what your feeder is pushing forward, your temperature needs to be higher. Cura will tell you when you’re pushing the limits, but to give you some more insight you can calculate the extrusion volume per second with this simple bit of maths: speed x nozzle size x resolution in mm. The Ultimaker should easily handle 8mm3/s.
To give you an idea, here is a default print profile:
- 0.06mm / 60 micron - 220ºC - 65mm/s
- 0.1mm / 100 micron - 225ºC - 65mm/s
- 0.2mm / 200 micron - 235ºC - 65mm/s
When time is not on your side and you really want to get most out of rapid prototyping, or you’re dealing with a straight forward model, you can choose what is considered a fast print. A fast print runs from 75mm/s to 150mm/s. When doing 150mm/s with PLA you need a relatively high temperature to get a successful print, like 240ºC.
To stay within the boundaries of reliability you should not exceed 8mm3/s, in conjunction with a variety of settings. The Ultimaker can do more, but this requires tweaking of a variety of settings and therefore a higher degree of expertise is needed. When you think you are ready, feel free to play around. By sharing your experience and feedback, we can all learn.