tag:blogger.com,1999:blog-6290129843266976044.post4265643678386665580..comments2011-11-29T05:03:52.146-05:00Comments on Tasty Crepes: ElectronicsChris Purolahttp://www.blogger.com/profile/10889576164712613561noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-6290129843266976044.post-8526130595556230852010-04-28T10:47:26.661-04:002010-04-28T10:47:26.661-04:00I was also thinking of getting one of those newer ...I was also thinking of getting one of those newer hybrid PTFE/PEEK barriers that refsnyderb is selling, seems to have the best of both worlds. When i was doing my recent heating tests on the converted MakerBot, the PTFE did get really hot, so I might try and rig something up to help captivate the barrel, most likely similar to the plastruder setup.Chris Purolahttps://www.blogger.com/profile/10889576164712613561noreply@blogger.comtag:blogger.com,1999:blog-6290129843266976044.post-30309208074407645802010-03-30T20:19:39.705-04:002010-03-30T20:19:39.705-04:00I'm using a standard Makerbot Plastruder on my...I'm using a standard Makerbot Plastruder on my unit, but it shares the same brass barrel and PTFE thermal barrier as yours. On mine, the PTFE barrel is held in place by a retaining washer, which is then bolted to the main extruder body with long bolts.<br /><br />Two important issues:<br />1) The PTFE thermal barrier will get soft at the 220C temps needed by the extruder for ABS. This, with the pressure of the filament being forced in from above, will usually eventually push the brass barrel out the bottom, stripping the PTFE threads, and ruining the thermal barrier. To solve this, get a low profile 6mm jam nut and screw it onto the brass barrel. Now, put the brass barrel fully onto the PTFE barrier, and then snug the nut up against the PTFE barrier. The nut should now be between the PTFE barrier and the retainer washer. This transfers the force from the barrel to the retainer washer directly, and relieves the pressure on the PTFE threads.<br /><br />2) Having done the above, the PTFE barrier may still be soft enough to bulge out to the sides, letting the extrudant squeeze into the space between the brass barrel and the PTFE threads. This increases the force needed to push the filament through the barrel, and eventually stops extrusion. To fix this, get a 1/2" pipe/hose clamp and tighten it down halfway up the PTFE barrier, right where the brass barrel should end inside.<br /><br />I went through five PTFE barriers before I did these two mods.Anonymousnoreply@blogger.com