Archive for the ‘Tips and Tricks’ Category

replicator-2-teflon-filament-guide-tube-problem

Last week we were having a weird issue with our MakerBot 2 Replicator 3D printer that was stopping to extrude filament properly ater 5 to 10 millimeters from the height of a print is normally printed, resulting in a failed attempt to print the object. The filament was just stopping to extrude properly or completely and we’ve had to unload and load it again to resume normal operation. It was not like a standard filament jam that requires the disassembly of the extruder to clean a filament jam. We have started to check the usual suspects that might be a cause of filament jams such as improper leveling of the build plate, problems with the heating temperature of the extruder, worn off nozzle, the filament guide mechanism and motor and so on. None of this however made any difference and we were still having failed prints regardless if it was a simple or more complex model, we have even tried using various filaments to exclude a possible issue with the PLA filament we’ve been using from MakerBot.

Changing the filament did not help at first as we were changing complete spools, but once we’ve tried a few short samples of various filaments that were 10-15 meters and not on spool we got a hint of another unexpected possible issue. Using a shorter filament wrap for a test print we did not get it through the teflon filament guide tube that we use normally with the filament spools and surprisingly we’ve had no trouble with the filament stopping to extrude properly anymore and no failed prints. But bringing back a spool with filament that goes through the filament tube and the prints started failing again, so apparently the Polytetrafluoroethylene (PTFE) guide tube was causing the problems with the print. We did not expect that to be the cause as there were no visual or any other kind of signs that something is wrong with the filament guide tube. After all the idea of this filament guide tube is to make the feeding of filament easier and more problem free, but apparently it also can wear off over the course of few months of usage and starting to cause issues. Since we did not expect the tube to be the cause of the problem we were having it took us some time to rule out every other possibility that we considered first, but if you are having a similar issue you might want to temporary remove the teflon filament guide tube to see if it might turn out to be the culprit in your case.

Next time we’ll have another new thing to consider when we start having issues with failing prints, and we are already waiting to get a replacement PTFE filament guide tube to see how long will the new one work without starting to cause troubles like the original tube. We are also going to be looking out for some alternative ways for improving the filament guide on the MakerBot Replicator 2 3D printer to make printing less problem free.

replicator-extruder-replace-insulation

One of the most annoying issues with 3D printers that extrude thermoplastic materials is when the filament jams inside the extruder causing a failed print and if the problem persists you need to figure out what is causing it. The problem is that there could be numerous thing that are causing the filament to jam and stop extruding from the nozzle and you need to check them one by one until you resolve the issue and are able to continue printing again. One of the most common causes, the one you should start with, is to check the build plate and try to level it again as often after a few prints the position of the build plate may change a bit along the Z axis and this may cause trouble for the filament to either stick properly or to come out normally from the nozzle.

If it the filament happens again after a bit of normal operation after you have realigned the build plate and you are sure that it is not the cause, then you might want to check the thermal insulation of the heated block of the extruder. Usually, as is the case with MakerBot Replicator 2, the heated block to which the nozzle is attached is insulated with special kind of insulation material that is taped with Kapton tape. If the insulation needs to be replaced as it is not functioning properly anymore you may need to replace it or it can cause the filament material to jam inside the nozzle. If you are having trouble with the insulation the actual temperature of the block that melts the filament may be lower than it is needed for normal operation with the specific type of filament used and this may lead to the filament jamming as it is not hot enough to come out at the desired speed from the nozzle. An easy thig you can usually do to check if this is the cause for the filament jam is to increase the extrusion temperature with 10-15 degrees Celsius over the normal one you use and if the jams do not happen anymore then it could be the insulation.

Based on our experience we have found out that anther cause for filament jams could be the nozzle that the extruded thermoplastic material goes through, even though it might seem just fine it can still be the cause. So you should always have a few nozzles as spare to replace them over time as they do wear out and the process is faster if you use composite filaments such as ones that contain chopped carbon fiber or other materials as a part of the filament.

Another different kind of issue that can appear over time that can cause jams or problems with proper extrusion of thermoplastic is the feeding mechanism of the extruder of the printer. If the extruder uses a spring to provide tension to the filament feeding mechanism after a while the spring may soften up and the tension may get inconsistent or too little for proper feeding of the thermoplastic material into the nozzle and as a result cause a jam.

Sometimes the 3D printer jams can be caused by various other things such as low quality filament, the use of exotic material that is not designed to be used with your specific 3D printer and so on, so it is not always easy to figure out what is causing the issues and you need to start checking and eliminating them one by one until you find the culprit.

alfa-romeo-dual-color-keychain-3d-print

Dual or multi-color printing on 3D printers that do have just one extruder can be a tricky thing to do, but it is still possible, though with dual-extruder printers it is much easier. We have been playing with our MakerBot Replicator 2 3D printer in order to make dual-color 3D prints, though the methodology is the same as if you want to be able to print with more than two colors. Essentially what you need to do is pause the printing process with one color, replace the filament, then resume printing and you should get a dual or multi-color printed parts as a result. Normally, if you are using a 3D printer that uses GCODE you are able to script the commands to pause the printer to change the filament directly from the 3D model that you are printing, but with Replicator 2 this is unfortunately not possible. The reason for that is the MakerBot Replicator 2 uses the binary X3G format for the model you are printing and scripting a pause in GCODE file and then converting it to X3G does not help resolve the issue either.

makerbot-replicator-2-z-pause-height-option

There are essentially two ways that you can print with dual or multiple colors on MakerBot Replicator 2 3D printer and they are both limiting and not very useful if you want to print a really complex colorful 3D model. You need to essentially pause the printing process from the device itself, either manually, or by specifying the model height at witch the printer to execute an automatic pause then replace the filament type or color and resume printing. This is just fine if you have a 3D model that has a base with one color and then something on top of it in another color, but if the used colors are being mixed in a single layer, then it is not possible to use this pause/resume solution. So a nicer and smarter solution for multi-color printing on the MakerBot Replicator 2 and other single extruder 3D printers like it would be the upcoming Mosaic accessory, but until then you should do with what you have available. There is also another option that does require you to replace the firmware on your MakerBot Replicator 2 3D printer with one that does support GCODE like the Sailfish Firmware, but we haven’t tried that yet.

Dual-color printing with manual pause:
– Start the 3D printing with the first filament color
– Monitor the printing process carefully and when you are close to the point when you need the second color manually pause the printing
– To manually pause the printing press the left arrow from the Replicator 2 keypad and choose Pause
– Go to Change Filament and Unload the old filament and Load the new color
– Manually Resume Build to continue printing and select Back to Monitor to get to the print status screen again

The drawback of manual pausing and resuming is that you cannot easily get to the same point if you need to make multiple prints of the same model, though it might still be fine if you manage to pause while the infill is being printed.

Dual-color printing with automatic pause:
– Start the 3D printing with the first filament color
– Press the left arrow on the keypad and select Z Pause Height
– Enter the value in millimeters for the height of the printed 3D object when you need the printer to automatically pause
– Set Pause Active to On in order to tell the 3D printer to activate the pause at the set position
– Go to Done and Back to Monitor and wait for the printing process to reach to the set point when it will automatically pause and activate the Change Filament menu
– You need to Unload the old filament and then Load the new color and then just Resume Build

The drawback of the automatic pause is that you can only use values that fractional such as 1.2 mm or 2.3 mm etc, you can use only 1, 2, 3 mm and so on ad object height on the Z axis. If you take this limitation into account when designing the 3D model of the object you are going to be printing it might be fine, but this could be a problem if you want to print an already designed model.

While both the methods described above do have their limitations and are far from perfect, you can still get pretty good results printing with dual colors or even more colors if you have the patience. Do note however that the more the colors the higher the chance of issues , our dual color test prints ended up quite well, though not perfect. Again a reminder that the the above options you have for the MakerBot Replicator 2 for pausing and resuming the print will work good if you don’t want to have multiple colors in a single layer of the object you are printing.


top