{"action":"created","issue":{"url":"https://api.github.com/repos/daid/Cura/issues/771","labels_url":"https://api.github.com/repos/daid/Cura/issues/771/labels{/name}","comments_url":"https://api.github.com/repos/daid/Cura/issues/771/comments","events_url":"https://api.github.com/repos/daid/Cura/issues/771/events","html_url":"https://github.com/daid/Cura/issues/771","id":28942106,"number":771,"title":"Holes on top surface (pillowing)","user":{"login":"luotinen","id":6695329,"avatar_url":"https://avatars.githubusercontent.com/u/6695329?v=3","gravatar_id":"","url":"https://api.github.com/users/luotinen","html_url":"https://github.com/luotinen","followers_url":"https://api.github.com/users/luotinen/followers","following_url":"https://api.github.com/users/luotinen/following{/other_user}","gists_url":"https://api.github.com/users/luotinen/gists{/gist_id}","starred_url":"https://api.github.com/users/luotinen/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/luotinen/subscriptions","organizations_url":"https://api.github.com/users/luotinen/orgs","repos_url":"https://api.github.com/users/luotinen/repos","events_url":"https://api.github.com/users/luotinen/events{/privacy}","received_events_url":"https://api.github.com/users/luotinen/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/daid/Cura/labels/Bug","name":"Bug","color":"e10c02"},{"url":"https://api.github.com/repos/daid/Cura/labels/SlicingEngine","name":"SlicingEngine","color":"fbca04"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":27,"created_at":"2014-03-07T07:04:26Z","updated_at":"2015-06-10T10:49:08Z","closed_at":null,"body":"On default settings Cura makes pretty sparse infill. On topmost layers the bridging of these large gaps is difficult. Observing the process the following appears to happen: part of the material sticks to the edges of the holes and forms cantilevers. Due to fan cooling the top and heat radiating, conducting and convecting from below part, the cantilevers bend upwards. After a few passes they act as wipers and result in gaping holes in the model or weakened and thinned centers of the holes.\r\n\r\nIn other software, the bottom and top infill can be set separately and the problem may be avoided in the slicer. The hardware solution is a stronger fan. For Cura I have some suggestions:\r\n- enable infill settings for top and bottom regions\r\n- automatic pillowing prevention (automatically start making more denser infill when approacing top layers and set fan on high)\r\n- enable fan boost for top layers\r\n- warn users about the consequences of using sparse infill\r\n\r\n![wp_20140306_004](https://f.cloud.github.com/assets/6695329/2354643/9d88830a-a5c6-11e3-9064-a6f752c21d5e.jpg)\r\nPillowing in top column (worse) and bottom flat regions (uneven quality) using default settings and layer height of 100 um.\r\n"},"comment":{"url":"https://api.github.com/repos/daid/Cura/issues/comments/110697764","html_url":"https://github.com/daid/Cura/issues/771#issuecomment-110697764","issue_url":"https://api.github.com/repos/daid/Cura/issues/771","id":110697764,"user":{"login":"nophead","id":566149,"avatar_url":"https://avatars.githubusercontent.com/u/566149?v=3","gravatar_id":"","url":"https://api.github.com/users/nophead","html_url":"https://github.com/nophead","followers_url":"https://api.github.com/users/nophead/followers","following_url":"https://api.github.com/users/nophead/following{/other_user}","gists_url":"https://api.github.com/users/nophead/gists{/gist_id}","starred_url":"https://api.github.com/users/nophead/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nophead/subscriptions","organizations_url":"https://api.github.com/users/nophead/orgs","repos_url":"https://api.github.com/users/nophead/repos","events_url":"https://api.github.com/users/nophead/events{/privacy}","received_events_url":"https://api.github.com/users/nophead/received_events","type":"User","site_admin":false},"created_at":"2015-06-10T10:49:08Z","updated_at":"2015-06-10T10:49:08Z","body":"It looks to me like the filament is being stretched too thin while crossing the gap and so it snaps. When you extrude onto a solid layer below you can smear the filament arbitrarily thin but when spanning a gap there is a lower limit on the filament cross sectional area relative to the nozzle size."}}