FAQ – General questions on 3D Printers

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Can 3D printer print without any computer connected:

3D printers that have a LCD display with a SD card reader are able to print without any attached computer
In this case you can only print without a computer if you have any SD card module attached to the printer.

How much time takes to print a 3D plastic part?

The printing time can be estimated by the 3D softwares called « Slicers » such as CURA, Slic3r, Kissslicer, etc…
The estimation mainly depends on several parameters:

  • The size of the object to print
  • The size of the hot end nozzle
  • The height of each printed layers
  • The thickness of the shell
  • The infill percentage
  • The different spees used : infill, inside shell, outside shell, movement speed etc…

The print estimation is also taking into account some hidden parameters such as accelerations on the 3 axes X, Y and Z. THose parameters are often hard coded and cannot be changed on slicers.
Often you can  take between  10 and 20% of error margin for the slicer estimation. The real print time is more likely to be slower than the estimation.
During a print you can also help yourself with the process percentage on the LCD scree and in this way better estimate the remaining printing time..

What to do the the plastic filament is stuck inside the hot-end.

This case can happen for different reasons:

  • The retraction value is too high and the PLA can expand inside the hot-end
  • The filament diameter tolerance is too low, which can cause jamming inside the bowden plastic tube or even on the hot end itself
  • Extruder screws are tighten and deteriorates the plastic filament causing a jamming inside the hot end
  • Some dust or other similar particles are blocking the hot-end nozzle causing the plastic to be stuck inside it.
  • The fan blowing on the full metal hot end heat sink is stuck or stopped causing the PLA filament to inflate inside it.

First, it’s strongly advised to first remove the filament from the hot end while it’s still hot.

If you cannot remove it  by retracting the filament using the big wheel of the extruder, you will have to remove the PTFE bowden tube so that you have direct access to the filament at the base of the hot end.
Do to this, you need to unplug the pneumatic connector at the base of the hot end and attempt to remove manually the filament by hand or using the flat pliers if you struggle too much.
You might require to extrude the filament a little bit to that it makes it possible to remove the PTFE tubing from the pneumatic connector.
In the case where there are some impurities inside the nozzle you will have to cleanup your nozzle.

How to cleanup the hot end nozzle.

The procedure is mainly the following:

  1. You need to do this operation while the hot end nozzle is hot. It needs to be hot enough so that the plastic inside it can melt (at least 180°C for PLA and 230°C for ABS)
  2. First, you can try to heat more than needed and push on the filament to see if the plastic start to get out of the nozzle freely.
  3. If not, you will need to unscrew the nozzle and clean it up as described in the following steps:
  4. Slightly unscrew the nozzle with very little force, be very careful to take the appropriate precautions to avoid to burn yourself with the hot nozzle!
  5. Once the nozzle is out, remove as much plastic as possible from inside the nozzle while it’s still hot.
  6. If the plastic is cooling down and hardening, the first thing to try is to place it into a glass full of Acetone, this should clean and soften a little bit the plastic.If you are using ABS, this should dissolve totally the plastic from inside the nozzle. Once the plastic is totally dissolved, check that the nozzle is clean, you should be able to look through the nozzle hole. If not, help yourself with a small pin or thin needle to cleanup the hole.
  7. If you are using PLA, the easier and cheaper solution is to use a candle and a very thin needle:
  • Light up the candle and use a pliers tool to hold the hot end nozzle and place it just over the candle flame .
  • Keep the nozzle over the flame a little while , the remaining plastic inside the nozzle will start to melt.
  • Take a needle and remove the plastic from inside the hot nozzle, this can take 10 to 15 minutes to make sure no more plastic or residue remains inside the nozzle.
  • Once cleaned you should be able to see through the nozzle hole.
  • Place the cleaned nozzle into a glass of Acetone, it will remove the black carbon traces from the candle, After a few minutes you can take a paper tissue to clean it up.
  • You can now replace the nozzle into the hot end. Make sure the hot end is hot before doing to avoid any possible future leaking.

Can i adjust parameters during a print .

The LCD display allows you to make a few changes in real time such as:

  • Change the overall print speed (feed rate)
  • Tune the printing temperatures (both bed and hot end)
  • Tune the acceleration on each axis
  • Adjust the max print speed per axis

However changing parameters while printing can cause the current print to fail.
Changing parameters during print is to be used at your own risks.
Those are very useful features when you calibrate your printer.

How to check that the printer is working properly ?

Printing calibration parts at the beginning allows to quickly check that the printer is properly tuned.
Calibration parts can be freely downloaded on websites like www.thingiverse.com
3D modular systems freely provides a set of calibration parts on github, check it up:

What can i do if the plastic filament doesn’t get out of the printing nozzle ?

You have several possible cases:

  • The hot-end is too low on the heat bed preventing the plastic from exiting the nozzle. You need to reduce the parameter « Z offset » of your printer. reduce it by 0.2mm step at the beginning and once you feel you are very close to the proper value, you can use 0.1mm steps . The plastic should start to get out of the nozzle.
  • The print temperature is too low, preventing the plastic to properly melt and exit freely from the nozzle. Check that the print temperature is compatible with the material you are using.
  • The plastic can be jammed inside the hot end. In that case, remove the plastic from the hot end, sharp cut the end of the plastic and try to reinsert it inside the hot-end. Make sure afterward that the plastic exit the nozzle properly.

The printer is making a click noise during printing .

  1.  The filament is not correctly inserted into the hot end and cannot be pushed properly by the extruder. Remove the filament, make a sharp cut on the end of the filament and insert it again into the hot end.
  2. The filament diameter is not compatible with the diameter of your hot end and cannot fit inside the body of the hot end.
  3. The cooling of the plastic from the previous print might have inflated the plastic inside the hot end preventing the extruder to properly feed the hot end nozzle. You will need to extract the filament from the hot-end, cut the end of it and push it back to the hot end.
  4. The hobbed bolt used to pushe the filement inside the extruder might be full of plastic and so is sweeping instead of pushing the plastic filament. This can happen if the extruder screws are too tight and so the hobbed bolt is just smashing the plastic filament. At this moment the plastic dust will fill up the teeth of the hobbed bolt. You will need to clean it up by either blowing air into it, or unmount it and clean it with some brush or needle and clean the teeth one by one.

The filament is stuck inside the hot end, what to do ?

  1.  Check that the real temperature of the hot end has properly reached it’s designated temperature.
  2. When the hot end has reached it’s working temperature, push the filament inside the hot end and retract it rapidly .

The printed object doesn’t stick to the heatbed, what to do ?

  1.  Check that the height of the nozzle has the proper level when starting the print. To check up the height, take a sheet of paper and it should just slide freely between the nozzle and the bed.
  2. Check that the print temperature is correct (often between 185 to 210°C for PLA  and 220-235°C for ABS). Also check the heat bed temperature (60°C for le PLA and 110°C for ABS.
  3. Clean up the heat bed with acetone (preferred) or window cleaning liquid to remove any traces of grease.
  4. Change the polyamid tape to renew the print surface . This type of tape is very robust and can be kept for tens of prints. You can keep it until you damage it when removing the part from the print surface.
  5. Apply some hair spray (very strong) on the polyamid tape. This should greatly improve the stickiness of the plate. You may want to try different brands/quality (we tried a lot of different brands/quality already) of hair spray as some sprays wont work and some will work great.  The price has often nothing to do with the fact that the hair spray will more likely work, so feel free to experiment and when you feel one brand/quality is good for you just stick to it.

The part to print stay firmly stuck on the print surface. A few tricks to remove it .

  1. Wait until the print surface is cold and try again.
  2. Take a painter spatula and sharply hit the base of the printed part taking care to keep your print surface intact and avoiding to scrap your polyamid tape.

The printer cannot read the files on my SD card .

  1. Restart your printer and try again.
  2. Check that the filename you want to print ends by .gcode. Only this file extensions are compatible with the printer.
  3. Check the filesystem of your SD card, it needs to be FAT16. other filesystems are most likely not supported (FAT32, NTFS, EXT2, EXT3 etc…) .
  4. Some types or size of SD cards might not be compatible with the SD card reader. Often SD card of 1 or 2GB are far enough for your overall use.

I need to stop the printer during a print .

  1. With the LCD screen, just push the LCD knob to reach the main menu.
  2. Depending on the language your are using select « Arreter impr. » or « Stop print« 
  3. IMPORTANT: Wait a few seconds until the hot end temperature is below  70°C. If you stop the power supply when your hot end is still hot, the plastic inside the hot-end will expand and will cause your next prints to fail.
  4. If a dangerous event happens, shut down the power supply, wait a few seconds and power it on again so that the fan attached to the heat sink of the hot end start cooling it again to prevent the plastic from expanding.
  5. IMPORTANT: Before restarting your printer, make sure that the height of the hot end nozzle is at least 3 or 4mm above the heat-bed!. Indeed, at the next print, the homing procedure will move the hot-end on X and Y axis and then Z axis. If the nozzle is too low, it’s likely to scrap your polyamid tape or even your print surface.

The finish of my printed part is poor .

  • The finish of printed par can vary depending on the material you are using.  It can also vary depending on the color of your filament, as dies used to color the plastic is changing the plastic characteristics, you may encounter some differences when switching colors. If you cannot print your part in ABS, try with PLA. The printing behavior is completely different as well as the finish.
  • The shape of your object must be compatible with the FFF printing technology.Your object must have the less possible surface in the void and the climbing angles must be higher than 45°. The machine will be able to print some parts in the void up to 2 to 3mm max without support. After that, for PLA the cooling capacity and it’s orientation will greatly impact the capacity to print overhangs.
  • Check that the size of your object is compatible with the size of your nozzle. For example a 0.8mm nozzle will be limited when printed very small detailed parts. It will be more effective when printing very big parts!
  • In the opposite a 0.4mm nozzle will be more likely to give you nice detailed object, but will be very slow at printing very big objects, so choose your nozzle carefully.