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What Was Your Mentally Exhausting Program??

cheesiechanman
The reason I ask is because of the program I am working on right now. I have 3 fixtures with 4 parts that I have been working on. All of them have complicated Datums / Poor design. The fixture that holds two parts is the most complex of course. The gage is the only one built to hold the part vertically. It has a hole in the back of the gage to probe the bottom of the part through. So the part sits with the rear surface in the CMM's +x direction. The part sits on the net pads for datum A about 120mm from the back surface of the gage (where the hole is) There are 18 small clips spaced around the outside edge of the part that I need to touch in the -x direction. This means I need to articulate my probe to, at times, an angle of A-115B35. This shortens the distance from the end of the probe to the Z axis column. Most of the time I am less than 2mm from crashing into the gage.

The part also only has one tiny slot to control rotation on one side of the part. So when placing the part on the gage it can rock, roll and slide everywhere. So that means I need to create local alignments on each clip to ensure that they hit correctly which means dancing around that almost crashing point the entire time. And I need to create alignment after alignment to ensure that I am hitting it correctly and then be sure that I recall a fixture alignment before proceeding because if I forget to revert back to the fixture and the next part changes in size/ location/ rotation by a mm or 2 I am guaranteed to crash. And this doesn't include the complexity of some of the dimensions and the callouts. For example a profile without datums with a unequal tolerance called out..... or a position on a single plane.....

So with all that being said I have been programming these parts for a couple weeks now and my head at the end of the day is just mush. That's where the Forum comes in. So I want to thank all of you for giving me a source of relief from my mental torture chamber over here.

Also, What are you more exhausting program memories. What is that one job that really kicked your butt?


  • My 1st ITERATIVE alignment program. It was a C-ARM that used for a small MRI machine. Used for hands / feet / limbs and such. We had to explain to the customer that we needed 2 DATUM points on the "RAD" so we could locate the machined features correctly as we couldn't use the center point of the Streatched Formed Rad as it had to much variation. We fixtured the part on those 2 points and milled both ends. Not overly complicated. Really, program was easy , it was more trying to explain to customer what we were doing and the internal people as well. So I prove out the program, give the DATA back to CNC setup guys, they proceed to 2nd guess everything and use the MANUAL CMM , beep the RAD to find center because they dont understand the 2 DATUM POINTS on RAD and make adjustments..... even though I specifically told them NOT TO CHECK IT AS A RAD and reasons why.... and then repeat.....and then repeat.....and then repeat ...... and then when ALL the parts are scrapped proceed to tell me the CMM program I made isnt working right..... So in a nut shell......the CMM program is always the easy part no matter how hard it hurts your brain, all the other " obstacles " are always worse...
  • in reply to Schlag
    Man if that isn't the truth. One of the hardest things to do is evaluate someone else to determine at what level of stupid I need to dumb it down to. So I don't get blamed for them not understanding.

    Me: "CMM go beep. Part no good. Circle too small"

    Engineer: *dragging knuckles across the ground "I don't understand. Ship as is?" (followed by various caveman grunts)
  • in reply to Schlag
    Years ago I had a tooling/CNC operator manager that didn't understand after I dumbed things down for him multiple times. He was adamant that he was right and the CMM was broken and that was why it was saying the parts were coming off the machine bad. I finally told him I would explain it in a language he would understand and started grunting and pointing like an old Tim Allen comedy bit. He was furious but the rest of his department was laughing hysterically. I got a talking to by my boss... but it was worth it.
  • in reply to Schlag
    I am actually certified to ASME Y14.5. This was supposed to help them to listen to what I am saying but when you give leadership and you walk away and everything goes all lord of the flies its out of my hands...... CMM programmers were such garbage here for 10 years before I took over that the whole culture here was the #'s on the B&S were BS. It took yearrrrrs to slowly overcome that....
  • an Aileron with two station changes (in Metrolog)
  • A partial knee (left and right). Nothing more than a part (plastic and 17-4 trials) that looked like a potato chip (size and shape and about 2.5-3mm thick) with nothing to hold and no datum structure on the original customer drawing. We played with the prototype for a couple of weeks trying to determine the best way to hold it and sent the drawing back with datum target points ID'd and a CMM program to run it. Getting a fixture put together to hold 8 sizes was a PITA to say the least
  • A partial knee (left and right). Nothing more than a part (plastic and 17-4 trials) that looked like a potato chip (size and shape and about 2.5-3mm thick) with nothing to hold and no datum structure on the original customer drawing. We played with the prototype for a couple of weeks trying to determine the best way to hold it and sent the drawing back with datum target points ID'd and a CMM program to run it. Getting a fixture put together to hold 8 sizes was a PITA to say the least

    I have experience with similar sounding situation....

    I used to work for a company that made funky shaped medical implants. Parts were made in a mill-turn & supplied to the CMM still on the dovetail/not "cut off" yet. We'd put the dovetail in a vice & measure the exposed part using an iterative alignment (op10). Made it really easy to hold and work with. Op20 was usually the cutoff and we'd inspect the profile of the "cutoff" area with an inspection mylar on an optical comparator. Hopefully this helps in some way.

    Here is a pic of some of the parts I am referring to..except for the screws and PEAK bone spacers all of these parts are at a weird huge broad sweeping radius and are controlled by iterative alignments:



    ​​​​​​


  • I have experience with similar sounding situation....

    I used to work for a company that made funky shaped medical implants. Parts were made in a mill-turn & supplied to the CMM still on the dovetail/not "cut off" yet. We'd put the dovetail in a vice & measure the exposed part using an iterative alignment (op10). Made it really easy to hole and work with. Op20 was usually the cutoff and we'd inspect the profile of the "cutoff" area with an inspection mylar on an optical comparator. Hopefully this helps in some way.

    Here is a pic of some of the parts I am referring to..except for the screws and PEAK bone spacers all of these parts are at a weird huge broad sweeping radius and are controlled by iterative alignments:

    {"data-align":"none","data-size":"large","data-attachmentid":498347}

    ​​​​​​

    Those kind of parts are the parts I currently work on! I actually thought you may have taken the pic from my works website.


  • Those kind of parts are the parts I currently work on! I actually thought you may have taken the pic from my works website.

    maybe we worked with the same customers? k2m, smith's medical, st jude, jarvis artificial heart, all top tier FDA work. i had a blast and was honored to work with some of this stuff but honestly i like aircraft a lot more
  • in reply to A-machine-insp
    Looks like you worked at RMS in Coon Rapids MN. I made 100's of the green screws 20 years ago there.
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