User:Rsol

2/7/2014

Changes to Extruder

To assure heat does travel through convection and begin morphing the ABS motor support one needs to separate the nozzle from the extruder. Cut the MDF piece about 5mm along its long axis and position it under the x-carraige of the MDF printed block to separate the Prusa nozzle from the MakerGear Motor support.

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Changes in Marlin

Max Temp of Extruder Must be set to 350 It was found that halfing power dosen't allow the extruder to reach the set temperature. Even at max power, nozzle temperature reaches 10 degrees less than desired.Therefore:

#define PID_MAX 256 // limits current to nozzle; 256=full current

For the inability to reach set temperature change the temperature as to which the printer feels it should start printing. 10- 15 degrees is sufficient. Therefore:

#definte TEMP_HYSTERSIS 15

#definte TEMP_WINDOW 15

Further, get the printer printing once the polycarbante is in the head to make sure glass transition temperatures are not reached at the top of the extruder. Although no fan is needed, the polycarbonate will not flow if it sits to long in the extruder. It is hypothesized that the small fan correctly place will solve this problem. Therefore, to begin printing immediately:

#definte TEMP_RESDENCY_TIME 1

Printing Temperature

Set your pronterface and slicer to 310 knowing that the nozzle can't reach the set temperature and will be 10 degrees less than desired.

Printing Temperature(C): 310

Bed Temperature

One desire warm enough that the plastic sticks to the ABS glue. However, note one does not want to over warm the bed to the point where the your ABS/PLA support pieces reach glass transition temperature. Some site will recommend a bed temp of 100C or 120C. At this temperature though support pieces, if ABS or PLA, started morphing.

Bed Temperature(C): 85

Print Speed

What is very important with print speed is to make sure that your printer is not skipping. Once it skips plastic will agrregate at the nozzle and this aggregation will prefer to stick to the extruder rather the previous layer as the print continues.

Print Speed: 45 (Both inital layer and normal print), but ultimately speeds depend on your printer** Layer Height The usual is 0.3. I find however, that the PC is a fairly thick material and that one of the necessities is to avoid the previous layer from sticking to the nozzle. Therefore increase the layer height by alittle help assure you get smooth layers. Layer Heigh(mm): 0.4 Filament Diameter Getting the filament to continously flow to assure that glass transition temperature is not reach is one of the particulars of PC as stated before. Therefore, increase flow to assure that the plastic continues smoothly is a plus. Flow(%): 130

Polycarbonate Bed Material

Two layers of Kapton tape are required. One of the things of polycarbonate is as it cool it likes to bendd in on itself and since it is such a strong material it takes the ground tape with it as well. Therefore, by double layer the Kapton you can assure a more even print over time. The other necessity is ABS Glue. I don't know why but it works like magic. Pour the ABS glue, spread with a brush and finally, sand it down with a sander. By sanding you will be assuring that there is much more even surface, especially when bubble are created from acetome evaporation. NOTE: By letting the polycarbonate cool after a print you will not have to reapply the ABS glue. If you get too impatient and try ripping off the PC part before the bed temperature reaches a cool enough temperature you will take the ABS glue with it and have to reapply. 50C is usually a good temperature to start trying. Therefore: 2 Layers of Kapton Tape ABS Glue - ABS Pieces + Acetone in a nail polish container.

Starting Z Height

Want your initial Z zero to be about .2 mm high. You don't want it touch the bed but a bit of height helps the plastic flow.

No Brim

I removed the Brim setting because the Brim line would not stick well in the print and interfere with the main part intial line. Once interefered it destroys the inital layer.

Large Prints (150x150x150 particularly boxes)

One of the challenges of large prints especially when creating square designs is that corners tend to cool faster then walls. Therefore, it is best to design things with oval structure and round edges than with sharp edges. I also believe that over a certain period of time like 3-4 hours although you might have plastic flowing the nozzle temperature at the top will reach a sufficient temperature that polycarbonate glass transition temperature will be reached. This will eventually stop your flow. To avoid this problem I hypothesize that by placing a fan one can continously print with out worry for longer periods of time. On larege prints I also hypothesize that a hotter bed temperature would be recommended and increase print speeds. The cooling between layer happens more easily since the nozzle has to go all the way aorund from its original point. The plastic will not be as hot as it should be if your nozzle is not travelling fast enough because polycarbonate does solidify quickly. More experimentation is required to create ideal settings for large prints.