Re: Preparing for large PET print
I did not use a box since the machine is a bit too high. I increased the nozzle temperature to 240 though.
The support layer at 4 mm was successful this time so I went to bed. When I woke up I checked the print and one support structure had fallen down so I stopped the print. I believe that the nozzle got stuck and pulled the support down.
The infill was not what I had expected. I had chosen 3D honeycomb, but the result was like the rectilinear grid I chose for support material.
The surface was pretty even, but with spots of uneven quality.
I could break the surface with my hands, it is a bit brittle.
I believe I run the nozzle att too high temperature.
Re: Preparing for large PET print
I have had some success, but I cannot use this print. I will have to buy some more filament.
A video of making the base: https://dl.dropboxusercontent.com/u/106944188/prusa-horn/2016-03-05%2016.55.51.mp4
A video of the end result: https://dl.dropboxusercontent.com/u/106944188/prusa-horn/VID_20160307_193056050.mp4
The first 5 mm of pet has melted and lost shape. There is support on about 90% of the base for about 4 mm. This support is impossible to remove.
I used honeycomb support. The two bigger supports on the sides came off very nicely because the surface is horizontal. The narrower supports on the rim made ugly marks on the horn. I didn't dare printing in full speed because of the tall wak supports. I printed 45-75% of full speed.
The construction is very stiff due to using 20% honeycomb infill adn solid infill every 30 layers. There is some ringing (bell sounds when knocking the horn), but I believe it is below the frequency range where I will be using it.
The nozzle is now almost black with burnt filament. Pieces of the burnt filament comes off the nozzle and makes black spots on the part.
My parameters:
The next print I will either turn of heatbed altogether, or print using rafts.
I will increase number of layers on horizontal shells to 8. I have 4 on vertical shells. The shells will be about 2 mm all over. I will increas infill to 30% to see if ringing frequency goes down. I will increase overhang threshold to 80 degrees or so in order to make more stable supports.
I need to clean the nozzle before printing more.
Any advice are welcome.
Mårten