{"action":"created","issue":{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/2486","labels_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/2486/labels{/name}","comments_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/2486/comments","events_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/2486/events","html_url":"https://github.com/MarlinFirmware/Marlin/issues/2486","id":96484809,"number":2486,"title":"Auto Bed Leveling Innaccurate. Probing Z speed possible culprit?","user":{"login":"Natealus","id":10627706,"avatar_url":"https://avatars.githubusercontent.com/u/10627706?v=3","gravatar_id":"","url":"https://api.github.com/users/Natealus","html_url":"https://github.com/Natealus","followers_url":"https://api.github.com/users/Natealus/followers","following_url":"https://api.github.com/users/Natealus/following{/other_user}","gists_url":"https://api.github.com/users/Natealus/gists{/gist_id}","starred_url":"https://api.github.com/users/Natealus/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Natealus/subscriptions","organizations_url":"https://api.github.com/users/Natealus/orgs","repos_url":"https://api.github.com/users/Natealus/repos","events_url":"https://api.github.com/users/Natealus/events{/privacy}","received_events_url":"https://api.github.com/users/Natealus/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-07-22T06:26:04Z","updated_at":"2015-07-22T07:28:00Z","closed_at":null,"body":"Well I know I'm getting to pretty fine detail once I start printing at 100 microns. But the quality of finer layers is just undeniably better than the 200-800 micron layers (0.2mm-0.8mm). It also highlights any calibration and movement inconsistencies which may not even be noticeable at larger layer sizes. But I've been noticing my right side and other random spots seem to get closer than the rest of the part especially over at the left. I've moved the offsets to see if that would change the balance but it didn't seem to make a significant difference.\r\n\r\nWhat I do think though as I was testing #define XY_TRAVEL_SPEED 4000, which governs Traveling X, Y, and Z during none probing movement. I turned it down to 2000 then 500. Its good to have a value to affect that for different setups.\r\n\r\nBut it did not affect the downward Z probing speed. I'm starting to wonder if it's moving too fast to achieve the 0.01mm or 10 micron probing resolution that I need to bring the plane even enough to squash a 100 micron layer down to 70 micron bed to nozzle height.\r\n\r\nI was wondering since it seems to already be a separate speed value for that downward probing movement, if we couldn't add a #define right below #define XY_TRAVEL_SPEED 4000 for Z_PROBING_SPEED. It's currently going like 1000 or more cause it probed down faster than all the other XY and up Z moves at 500 mm/min.\r\n\r\nI believe if we let it move down significantly slower we would have far more accurate readings from the trigger to stepper position planner. And being able to set that really slow might help us to diagnose if there's other issues."},"comment":{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/comments/123589799","html_url":"https://github.com/MarlinFirmware/Marlin/issues/2486#issuecomment-123589799","issue_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/2486","id":123589799,"user":{"login":"AnHardt","id":211931,"avatar_url":"https://avatars.githubusercontent.com/u/211931?v=3","gravatar_id":"","url":"https://api.github.com/users/AnHardt","html_url":"https://github.com/AnHardt","followers_url":"https://api.github.com/users/AnHardt/followers","following_url":"https://api.github.com/users/AnHardt/following{/other_user}","gists_url":"https://api.github.com/users/AnHardt/gists{/gist_id}","starred_url":"https://api.github.com/users/AnHardt/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/AnHardt/subscriptions","organizations_url":"https://api.github.com/users/AnHardt/orgs","repos_url":"https://api.github.com/users/AnHardt/repos","events_url":"https://api.github.com/users/AnHardt/events{/privacy}","received_events_url":"https://api.github.com/users/AnHardt/received_events","type":"User","site_admin":false},"created_at":"2015-07-22T07:28:00Z","updated_at":"2015-07-22T07:28:00Z","body":"@Natealus \r\nAs the name says XY_TRAVEL_SPEED has no Z component. The Z_RAISE_*_PROBING? moves are done with DEFAULT_MAX_FEEDRATE. The first approach to an endstop is done with HOMING_FEEDRATE. The second and only precision relevant approach to the endstop is done with HOMING_FEEDRATE / HOMING_BUMP_DIVISOR. HOMING_BUMP_DIVISOR can be found in Configuration_adv.h."}}