Doesn’t it suck when the person on 1st shift encounters a problem yet continues to run the machine without informing someone more experienced or getting the problem fixed before their shift ends leaving you to solve the problem? Well it happened to me today I got to work someone was running the machine without a hole being chamfered why this was happening was beyond my knowledge but was my problem to fix so I manually got to adjust the offsets running the program all the way until it did that operation eventually I fixed it. but then something else comes up! the machine decides to do whatever it wants! I did everything the way I was supposed to but before I knew it the machine is try to drill out a hole in a bar in the wrong coordinates. Today was FUCKED right from the start luckily it leveled out after about 3-4 hours almost half my shift while really screwing my productivity.
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Restarts can be easy to make a mistake depends how program was written. when reset pressed defaults like G54 G90 G1 or G0 G49 G40 often go into effect. some programs do not recall or repeat modal settings. i had checked a machines grid shift calibration and the horizontal rotary table was B180 and had assumed program would restate B0 (98% of programs restate table position often) and it did not so crash happened. if program uses G92 then the zero point is shifted from the normal zero return homing position, i usually go to zero return position and see if i got zero or if G55 in effect it should be G55 numbers just opposite sign. if G52 was used many cnc if reset pressed the G52 shift is no longer in effect. same with tool comp length and dia. same with if using G55 or other work offset.
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had job following work sheet which says G55, G57, G58 is used so i adjust G57 for error comp on a set of bores and it does nothing cause program used G58. it was a similar part that was not done exactly the same. program print out was out of date so it was confusing too as well as work sheet was confusing.
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i like to follow a work log as i do program. i record what i did and measurement trends like finish cut is often .0004 smaller than test cut. this is also useful to record problems like broken tooling. and next shift can see what was happening on earlier shift
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about worse thing is when previous shift adjusts tool offsets to make a tolerance but does not put it back to original offset. like somebody adjusting a boring bar that suppose to be 10.0000 and its 10.2000. it comes out at tool change and does a test cut .2000 oversize. i end up checking all critical tooling on a tool presetter to confirm its where its suppose to be.
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i also use a white board like a chalk board to write notes. i also just write notes on a pad of paper which i feel is better as it does not get erased so you can read what was written days earlier.
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sure worst thing is following somebody who writes nothing down and does everything from his head or memory. my most common program edits are adding M1 stops and warnings to watch or check stuff. same with work log it mostly full of warnings to watch for stuff or check confirm stuff.
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had a boss who said anybody can make a mistake but what are you going to do to make sure the mistake never happens again. boss gets really upset with repeated mistakes. boss also wanted logs with who did what when where and how. he would ask a week later on a part did you check something on this day ? i would need to be able to answer.
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i also check the tool preseeter calibration everyday. had somebody crash it and it was way off and nobody said anything. i learned to take a minute every day to not assume but verify it is ok. sure takes longer confirming or verifying stuff.
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i had a big part i torqued 10 ft/lbs but it was not enough to push it against the fixture stops. normally i confirm it. next operator caught it. best operators learn to verify and can catch each others mistakes. also single block mode and looking at distance to go screen is your best tool at reduced rapids and feeds.
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i also if i run another part reload program sometimes operator edited program to take a deeper test cut or to make a tolerance and did not change program back to original. i learn never assume program has not been changed. sure can make life difficult always worried about stuff
