Ultimaker 2 / 2+ One Modification That Addresses Several Issues!
If you have a Olsson Block already on your Ultimaker 2 or 2+ all you need is a new nozzle!
I stumbled on this modification for the Ultimaker 2 / 2+ by chance that proved to reduce many issues! This modification will require that your printer is using an Olsson Block. On the Ultimaker 2 this was an upgrade kit, the Ultimaker 2+ on the other hand comes standard with the Olsson Block upgrade.
If you are unsure what the Olsson Block is or if you have it in your Ultimaker 2 / 2+, you can look at the nozzle and see if it has a hexagonal pattern around the nozzle. This would mean the nozzle is removable and thus you likely have an Olsson Block installed. With the original design of the Ultimaker 2, the heater block and nozzle were both one so you were not able to “unscrew” just the nozzle.
Replace your nozzle in the Olsson Block with the one found below or you can find one from your local distributor. The main thing is to notice how much bigger the replacement nozzle is than the stock Olsson Nozzles.
You can find the nozzles I used on Amazon[AMAZONPRODUCTS asin=”B00PLBKS8M”]
During my tests I was able to drop my average printing temperatures by 5-20C depending on filament brands and print speeds. An example result with PLA, I was able to print at 186C @ 90mms vs. my normal settings of 215C @ 90mms for the same roll of filament before this modification.
This reduction in print temperature allows you to stay that much lower than the thermal limits of the PTFE insulator which directly increases the overall life of the PTFE.
Another unexpected outcome that was very much welcomed. I was able to continue using the last 5-20% of the filament left on cheap spools of filament. Most people who have used cheap filaments will likely encounter feed issues with the last portion of the spool because it is usually too tightly wound and will not feed thru the Ultimaker 2’s bowden tube very well. This results in misfeed and under extrusion. When I used this modification I was now able to use this before unusable portion of these spools because the added thermal heat storage allowed for less back pressure on the extruder drive allowing it to put more effort into feeding the filament vs. forcing it.
Technical Stuff (AKA Very Boring Explanation):
The Ultimaker 2 / 2+ is a great “out of the box” 3D Printer. But for some reason some of us have had issues with the PTFE insulator due to the design of the hotend. The PTFE appears to wear out or fails prematurely under 250hrs of use but for others it works fine for nearly 800hrs. Ultimaker and the Ultimaker Community does not have a clear answer why this happens for random people and not at all for others.
The Ultimaker 2 running either the stock heater block or an Olsson Block + Nozzle appears to have issues maintaining set temperatures on some printers. This can partly be blamed on the design of the heater block. While it is made of brass which conducts heat very well the mass of the heater block is very small and mostly hollow thus severely limiting its thermal retention capacity. Meaning in short, the block can cool down very quickly due to lack of heat “storage”.
With the Olsson Block upgrade you gain the advantage of an easy to replace or swap nozzle. But you also gain slightly more mass for heat retention because there is slightly more brass being added to the overall hotend region. The filament that is being pushed into the heater block and the nozzle is much cooler than these said parts which cause them to cool down slightly. As the Ultimaker 2 / 2+ uses 2.85mm filament the filament is retaining a cooler temperature slightly longer than 1.75mm filament would. This cooling of the hotend is countered by the heater cartridge continually reheating or attempting to reheat the hotend to desired temperatures. Depending your desired print speed this means you might have to run higher temperatures on your hotend to keep material flowing consistently to account for the more rapid temperature drops at higher print speeds.
What does all of this have anything to do with the PTFE which I initially started with and stopped talking about? Well the higher your set the print temperatures the closer you get to the PTFE’s thermal limit range, which is the point that it can start breaking down and deform. The PTFE will of course do this over time with use, but you can slow down the process by staying as far below the thermal limits as you can. Over time the breakdown and deformation results in under extrusion issues, jams and filament leaking. So if the single best way to extend the life of your PTFE is to print at the lowest temperature possible, how do we accomplish this? It is quite simple really. Increase the thermal storage capacity of the hotend, in the case of this example we increase the mass of the hotend. How do we increase the mass of the hotend without replacing the Olsson Block? Well we increase the mass of the removable nozzle of course.