Why isn't the filament sticking to the printer bed?

Check that your printer bed is leveled correctly (see the User Manual for bed leveling procedure). Next check the Blue Painter's Tape. The two most common issues with the tape are the brand of tape being used (TKI recommends Scotch Blue Painters Tape) or that the tape has been used for too many prints and may have lost adhesion to the filament. If that is the case, try replacing the painters tape under your print area. Finally, if you are still having trouble, apply an Elmer’s Glue Stick to the tape around the print area. Let the glue dry and you should have no issues getting the print to stick.

How do I remove filament?

First you must remove the current filament by heating up the hot end of the nozzle to a minimum of 185C. Once the hot end has reached temperature, push up on the extruder tensioning lever to release the filament from the drive gear. Push a small amount of the filament into the hotend (about 1 inch) so that it comes out of the nozzle. This will shape the filament so that it can fit through the tube to be removed. With the extruder tensioning level still pressed, pull on the filament until it is completely removed. (See User Manual for more detailed instructions with images.)

How do I insert new filament?

Remove previous filament (see FAQ, How do I remove filament?). Once the old filament is removed, prep the new filament by clipping the end at a 45 degree angle and straightening out about 1-2 inches of the filament. Feed the new filament into the extruder and keep feeding it until the filament reaches the hotend of the nozzle. Continue to push the filament through the feeder tube to flush out the nozzle until none of the old filament color is left. (See User Manual for more detailed instructions with images.)

Why isn't the top layer of my print filled in?

Your filament flow percentage is too low, which can lead to gaps between the filament. Adjust your flow percentage in your slicing software (we recommend using Cura). Increase the flow percentage value by 5% and try printing again. Continue to increase the flow in 5% increments until the print is filled in correctly.

What are the benefits of different nozzle sizes?

The standard nozzle size included with a TKI printer is .4 mm, which will give you a minimum layer height of 0.1 mm and a maximum layer height of 0.2 mm. Smaller nozzle sizes allow for higher resolution, but require more time to print. Whereas larger nozzle sizes have the opposite effect, lower resolution but less time to print. If you need to print detailed parts try a 0.3 mm nozzle or for faster, less detailed prints try a 0.5 mm nozzle.

How do I change the nozzle?

Remove the filament from the hot end of the nozzle (see FAQ, How do I remove filament?). Allow it to cool to room temperature, which will take about 10 minutes. Next, loosen the three set screws on the heated block to remove the heater core and the temperature probe. The hotend of the nozzle should unscrew from the heat sink. Now you can screw in the desired hot end with the correct nozzle size. Reinstall the heater core and temperature probe back into the hot end and tighten the set screws. Before printing, monitor the heating of the new hot end to ensure that everything is working properly.

Why is my LCD screen displaying random symbols?

This is caused when the ribbon cables underneath the printer are not seated correctly and cannot properly send and receive signals. Try restarting the printer to see if normal operation returns.

Note: if this issue occurs during a print, do not stop the machine, because the screen display does not affect the printing process. Once the print is complete, check the ribbon cables to see if it will resolve the problem.

How do I print multiple parts at the same time?

Setting up Cura to enable multiple parts printing is quick and easy. The first step is to setup the printer head size under Machine>Machine settings… This tells the program the size of the printer head (nozzle, heater core, etc) to verify it will not hit other parts while printing. Input the follow settings for the Kossel Model A printer head size.

The final setup step is to select “Print one at a time” under Tools. Now you can load multiple files onto the available area on the printer bed. The printer will fully print one object before moving to the next object without any user input interaction.

During printing the layers shifted slightly. How do I correct this problem?

There are two main sources that cause layer shifts as a part is being printed. The first source is a belt has slipped on the pulley. To correct this problem tighten the belt according to the User Manual instructions. The second source is the printer travel speed is set too high. The inertia of the gantry at higher speeds may cause the nozzle to overshoot the desired position as it travels around the printer bed. Under the Advanced tab adjust the Travel speed to 80 mm/s and try the print again. A lower travel speed will result in better accuracy but requires longer print times.