tag:blogger.com,1999:blog-12223283.post138770684032782270..comments2009-02-13T19:01:52.439ZAdrian Bowyerhttp://www.blogger.com/profile/17595509188999219420noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-12223283.post-85253767798824402932008-05-20T20:31:00.000+01:002008-05-20T20:31:00.000+01:00A static cooling value need changing with different print jobs and is also dependent on the machine layout (phenotype), it cannot be stored as metadata of the .stl (for the proposed multi-material format that contains .stl's)<BR/><BR/>Why is the cooling period not calculated (with an adjustable factor)? If the build time of a layer is short, the cooling should be longer. A function as such:<BR/><BR/>CoolingTime = abs(MinimumCooling-lastLayerBuildTime);<BR/><BR/>A thermal model would be better, but this may do the trick already. Leaving the fan on as Chris does may also be an option ;)Erik de Bruijnhttp://www.blogger.com/profile/09433438819279256757noreply@blogger.comtag:blogger.com,1999:blog-12223283.post-4882333479951923062008-05-15T17:04:00.000+01:002008-05-15T17:04:00.000+01:00Why wipe the nozzle, when you can plug it with piano wire?Joelhttp://www.blogger.com/profile/16755460714090772432noreply@blogger.comtag:blogger.com,1999:blog-12223283.post-57724403032411262592008-05-15T13:08:00.000+01:002008-05-15T13:08:00.000+01:00You definitely need cooling when the object gets below a certain size. Basically heat is being delivered to the object at a rate determined by temperature, flow rate and specific heat capacity.<BR/><BR/>It leaves it at rate proportional to its surface area. Once it gets small enough that it is arriving faster than it is leaving then the object gets hotter and hotter and becomes a molten blob stirred around by the nozzle.<BR/><BR/>I run a fan continually. It allows me to make smaller objects without pauses but there always comes a point where I have to slow down as well. Vik's wine glass is a good test of this as the stem gets smaller and smaller. Even with a fan on I had to slow from pi mm3/s to half that rate for the stem when making it from PCL.<BR/><BR/>I think a fan also improves the build quality because it hardens up the layers below quicker giving sharper corners etc.<BR/><BR/>You need good insulation on the nozzle and good airflow from the fan to the object without being shadowed too much by the extruder.nopheadhttp://www.blogger.com/profile/12801535866788103677noreply@blogger.comtag:blogger.com,1999:blog-12223283.post-68923501492909798462008-05-15T12:56:00.000+01:002008-05-15T12:56:00.000+01:00Couldn't this be done already by setting the cooling period to zero?<BR/><BR/>Vik :v)Vik Olliverhttp://www.blogger.com/profile/14574212494833831824noreply@blogger.com