{"action":"created","issue":{"url":"https://api.github.com/repos/Smoothieware/Smoothieware/issues/841","repository_url":"https://api.github.com/repos/Smoothieware/Smoothieware","labels_url":"https://api.github.com/repos/Smoothieware/Smoothieware/issues/841/labels{/name}","comments_url":"https://api.github.com/repos/Smoothieware/Smoothieware/issues/841/comments","events_url":"https://api.github.com/repos/Smoothieware/Smoothieware/issues/841/events","html_url":"https://github.com/Smoothieware/Smoothieware/issues/841","id":132049636,"number":841,"title":"Enhancement: plasma Pierce and Arc OK + delay","user":{"login":"openhardwarecoza","id":7695323,"avatar_url":"https://avatars.githubusercontent.com/u/7695323?v=3","gravatar_id":"","url":"https://api.github.com/users/openhardwarecoza","html_url":"https://github.com/openhardwarecoza","followers_url":"https://api.github.com/users/openhardwarecoza/followers","following_url":"https://api.github.com/users/openhardwarecoza/following{/other_user}","gists_url":"https://api.github.com/users/openhardwarecoza/gists{/gist_id}","starred_url":"https://api.github.com/users/openhardwarecoza/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/openhardwarecoza/subscriptions","organizations_url":"https://api.github.com/users/openhardwarecoza/orgs","repos_url":"https://api.github.com/users/openhardwarecoza/repos","events_url":"https://api.github.com/users/openhardwarecoza/events{/privacy}","received_events_url":"https://api.github.com/users/openhardwarecoza/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2016-02-08T04:31:16Z","updated_at":"2016-02-08T04:52:05Z","closed_at":null,"body":"Hi guys.  I have my Smoothieboard based plasma Cnc up and running,  but I could use an enhancement:   a plasma mode to M3:\r\n\r\nIn a plasma the start of each cut goes like this:\r\n\r\n**IHS phase: **\r\nInitial height sense:   uses a z endstop to touch off on the material to be cut,  homing z between moves (steel warps all the while while cutting) \r\n\r\n**Pierce Phase:** \r\nAfter touching off you do a G0 move to lift off a known distance (from you machines manual)  called the Pierce Height.  (differs between machines and materials - CAM step - no need for firmware enhancement)\r\n\r\nAt the pierce height you send M3 to enable the tool (plasma) \r\n\r\n**Wait for arc ok + pierce delay:  **\r\nAfter this comes the difference from other machines.  Any other machine can then start moving. But with plasma we have an external input to wait for: Arc OK\r\nAfter receiving an Arc OK we know the arc has started, then we delay a few ms to allow the torch to Pierce the material.  Then drop down to Cut height and start the toolpath\r\n\r\n(Arc OK gets triggered from the plasma inverter or THC to signal that an arc has succesfully established between the nozzle and the work piece, by measuring the current in work ground clamp.  The time it takes between closing the relay on the Trigger wires, and when an arc starts, is very random (clean vs rusty material, airflow rate, consumable condition, etc all impact this and it differs from one spot on the job to the next. Sometimes the arc starts almost immediately, sometimes the HF pilot arc sits there for a second or two before the cut Arc gets going...)\r\n\r\nI tried dwell delays in the absense of such functionality, but its not predictable enough.  Sometimes the arc takes 0.1sec to establish,  if the material is rusty in a spot it can take >1 sec.  And that changes along the position of the material.  (start moving before you have a pierce and the workpiece is ruined.  Wait too long before the move down and your consumable life drops to minutes instead of days (you need some height during piece to keep the orifice clear of any splashback molten metal, but once pierced the material has somewhere to go (out the bottom) and thus you can lower down.  The closer you are to the material, the lower the arc voltage (constant current arc) and thus the heat concentrates on the metal being cut, not the nozzle of the torch\r\n\r\nSo basically:\r\n\r\nG28 Z0 ; _touch off_\r\nG0 Z2.8 ; _pierce height_\r\nM3 D2000 ; _start plasma,  max delay 2 second (if no arc ok in 2 second,  pause and wait for user interaction (torch knocled off,  not on plate, machine has reached duty cycle and you need to pause for 5 min to let it cool down etc_) \r\n_Pause further execution until we get a signal on Arc OK pin or strike the timeout_\r\nG4 P300; _ from arc ok,  to allow torch to pierce through -  longer for thicker materials. Arc ok signals start iof successful arc,  not 'pierced'  - so delay to let torch melt through _\r\nG1 Z0.8 ; _move to cut height_\r\nG1 X... Y....  ;_ toolpath_\r\n\r\nCan we add a plasma module that handles the arc ok / pause after m3 until arc ok happens (if yes, continue,  if no after delay,  pause and turn off tool (m5) and alert user?"},"comment":{"url":"https://api.github.com/repos/Smoothieware/Smoothieware/issues/comments/181195812","html_url":"https://github.com/Smoothieware/Smoothieware/issues/841#issuecomment-181195812","issue_url":"https://api.github.com/repos/Smoothieware/Smoothieware/issues/841","id":181195812,"user":{"login":"openhardwarecoza","id":7695323,"avatar_url":"https://avatars.githubusercontent.com/u/7695323?v=3","gravatar_id":"","url":"https://api.github.com/users/openhardwarecoza","html_url":"https://github.com/openhardwarecoza","followers_url":"https://api.github.com/users/openhardwarecoza/followers","following_url":"https://api.github.com/users/openhardwarecoza/following{/other_user}","gists_url":"https://api.github.com/users/openhardwarecoza/gists{/gist_id}","starred_url":"https://api.github.com/users/openhardwarecoza/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/openhardwarecoza/subscriptions","organizations_url":"https://api.github.com/users/openhardwarecoza/orgs","repos_url":"https://api.github.com/users/openhardwarecoza/repos","events_url":"https://api.github.com/users/openhardwarecoza/events{/privacy}","received_events_url":"https://api.github.com/users/openhardwarecoza/received_events","type":"User","site_admin":false},"created_at":"2016-02-08T04:52:05Z","updated_at":"2016-02-08T04:52:05Z","body":"I like the G4 with a wait for pin! That would be an ideal generic use case!"}}