Trinus comes with a 0.4mm nozzle installed. With a nozzle kit, 0.2mm, 0.4mm and 0.6mm nozzles are available together with a box wrench (10mm) and an open wrench (17mm).
This is the throat tube that sticks out of the heat block. It is the most fragile mechanical part of the extruder assembly and as such, can be considered a consumable because every time you remove the nozzle for cleaning, you subject this tube to a lot of mechanical stress. The PTFE tube inside is also subject to deform when subjected to extra high temperature for very long periods.
The nozzle and throat tube are held in place by the heat block.
The heat block is made of aluminum and it has many holes for attaching to it the nozzle, the throat tube, the heater cartridge and the thermistor (temperature sensor). This shows different angles of the heat block so you can understand what hole is for what.
For just removing the nozzle to replace it, one can do it by unscrewing the nozzle while the heat block is hot. BUT when removing the nozzle, one thing you should never ever do is to try to unscrew or screw the nozzle without a counter force to hold the heat block. This is a definite No-No… because you risk damaging and breaking the throat tube at the neck.
At the very least, you need to hold on the heat block to provide the counter force to the turning of the nozzle. This is how you should do it if and when you remove the nozzle while hot (recommended because the filament inside acts like a very hard glue when cold.) The open wrench can slip off position and you can get injured in such an incident. The use of thick cotton gloves is recommended for this sort of operation if you are new to this kind of work.
Be sure to loosen the set screw that holds in place the throat tube in the heat block (not shown… see position of this set screw in the photo previously shown above). Also make the heat block hot to the temperature recommended for the last filament used to prevent the hard filament inside from acting like tough glue.
But you can also remove the nozzle and throat tube while cold, but you first need to disassemble the hotend assembly. Begin by loosening the thermistor set screw in the heat block. Remember that you don’t have to completely unscrew the set screws. They are very small and easy to misplace, so keeping them inside their threaded holes is the best way to keep track of them.
The hex wrench you need to turn the set screws is 1.5mm .
Then pull out the thermistor cartridge
Then loosen the heat cartridge set screw
And pull out the heat cartridge
With all the wire clutter removed, we can proceed to loosen the throat tube set screws at the cold block… there are two, so the first one…
And the second cold block throat tube set screw…
You can then try to pull out the throat tube. If the set screws are not unscrewed enough, they can still catch on the throat tube so you may have to unscrew the set screws a little more if you cannot pull out the throat tube.
Now, we have the throat tube, heat block and nozzle detached so we can work on them without the heavy weight of the rest of the extruder assembly… We need to loosen the set screw in the heat block holding on to the throat tube. Take note of the fact that when you can see the throat tube set screw, the throat tube’s cold end set screw notch is facing down. You need to keep that in mind when you re-assemble the parts together again.
Once the throat tube can wobble more freely from the heat block, we can proceed to unscrew the nozzle itself. Notice the use of the open wrench and box wrench which are supplied with the nozzle kit. You can use your own set of wrenches. For holding the heat block, a table mounted vise works best because open wrench can slip out and you can injure yourself with hands hitting other objects. Using a pair of gloves is recommended for this operation to avoid injury should the wrench slip out of place.
You can probably manually unscrew the nozzle near the end.
And slowly pull out the nozzle away from the heat block.
The whole Throat Tube can go out together with the nozzle, or only the PTFE tube can get pulled out together with the nozzle. There is also the chance that the nozzle disengages but the Throat Tube (and PTFE tube inside) remains in the heat block. If necessary, you can push-pull the throat tube to the right (never try to pull the throat tube to the left as it won’t budge… you will just damage the throat tube trying to do that.)
There is a bigger chance that the throat tube stays in its original position, but it can also disengage freely like in this photo.
When you completely pull out the nozzle, the PTFE tube inside the throat tube may come off together with the nozzle if there is some hard filament in the PTFE tube.
Using a cigarette lighter, you can heat the nozzle to allow the PTFE tube to disengage from the nozzle after the left over filament softens.
You can pull off the PTFE from the nozzle after the nozzle has been heated with a cigarette lighter. Because the nozzle had been heated, you will need a pair of pliers to hold on to the hot nozzle. Notice the left over filament still sticking in the nozzle. If the filament came off with the PTFE tube, you will need to insert a wire into the PTFE tube to push out the filament. PTFE will not hold on to the filament so it should readily be pushed out of the tube.
You can pull away the stuck filament from the nozzle while the nozzle is still warm.
Success… you have removed the nozzle, cleared the old filament, and removed the throat tube.
If the condition of the throat tube and the PTFE tube is still good, you can just reassemble the whole extruder assembly by taking the steps backwards. Otherwise, you can replace the throat tube with a new one (with a brand new PTFE tube inside). When assembling, take note of the orientation of the throat tube’s cold end set screw notch relative to the heat block. See the photo above when the throat tube was being pulled out of the heat block.
If you look inside the nozzle, you should be able to see light through the tiny hole. If not, you may need to manually turn a tiny 0.4 drill bit into the hole to clear anything clogging the hole.