Reliably measuring small internal features (+/_.0002") IN MACHINE (cost efficient)
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    Default Reliably measuring small internal features (+/_.0002") IN MACHINE (cost efficient)

    Ok, posting here as it seems the most appropriate, but hoping it doesn't get "lost" as this doesn't seem to be a popular sub-forum.

    I am looking for ideas to check small internal features (per the title) in the machine. They are small, but easily accessible. Needing to measure within about +/-.0002-.0003". Feature size would mostly range .03"-.07" (or there-abouts..) with depths of .050-.100" deep. We have a vision system (so verifying numbers isn't really the issue), however we need to get as close as possible in machine measurements, as parts take some time to machine, and finding out it is out of spec after removing from machine is getting time consuming...

    A couple ideas floated ----

    Tenth set pins (deltronic, target size, etc) _ would be great, and accurate for our needs, but spendy considering we have a relatively large range of sizes and these only cover +/-.0012"

    Molding compound _ just thought of this while posting, but not sure a vision system would be reliable with this depending on voids and "flash"... could you actually use a mic on this stuff after it sets? is there shrinkage? is it expensive/take a long time to set?

    What have I missed?? ID mics I have seen start at .2"... Bore gages (would be a PITA imo having to rock them for and aft and left to right and up and down) ..maybe, but smallest I have seen again starts around .2-.25" In machine probing, maybe (?) but the stylus would need to be around .5mm/.020" and not sure how accuracy is affected at these numbers (Haas machines*). Small hole gages -too finicky, see bore gages, plus not direct reading.

    I tried a search for small gage blocks, like .020-.030 etc, but would need these in multiples AND need tenths (.0201, .0202, .0203 etc), did not find anything... Shop made gages are pretty much out of the picture as we have one really crappy surface grinder (and only maybe 2 guys that 'might' be able to do it, including myself). We do have Sodick wedm, but not sure if they could hold +/-.0001 to make "gage block" like blocks, plus surface finish issues...

    *Just want to address the Haas issue before the peanut gallery gets here (LoL!). We can make these things fine, once we dial in comp, it is just trying to get there with a reliable in machine inspection we are trying to improve...

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    for .0003 - .0005 (for check to +- .0002) I could quickly make fit gauges with having a surface grinder, with the gauges to .00005 for widths..depths are harder to gauge.

    A crappy surface grinder can often still do great work for a short grind.

    Some times you grind to the high size and with not using the dials just one/two finger push the holding fixture and count sparks. Yes the part held out where you can measure with not taking it out of set-up.

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    Quote Originally Posted by michiganbuck View Post
    for .0003 - .0005 I could quickly make fit gauges with having a surface grinder, with the gauge to .00005 for widths..depths are harder to gauge.

    A crappy surface grinder can often still do great work for a short grind.

    Some times you grind to the high size and with not using the dials just one/two finger push the holding fixture and count sparks. yes the part out where you can measure with not taking it out of set-up.
    Appreciate the feedback. Making a fit gage is not practical as each part we make varies*. It is not a product line 'per se', they are made to order so to speak.

    *one part could be .0305" and the next one .0332", next one .0415" etc. Also, within these variances are different sizes (but we are happy to measure a few and ass-u-me the rest are good)., and might only span .03-.06" long, kinda hard to explain without a pic, but I can't post one, sorry.

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    Air gaging works great for this sort of thing, as it can do the precision and is self cleaning. The range of the plugs or fixtures can be large enough, but the basic plug or fixture might cost a bit up front.

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    Quote Originally Posted by Conrad Hoffman View Post
    Air gaging works great for this sort of thing, as it can do the precision and is self cleaning. The range of the plugs or fixtures can be large enough, but the basic plug or fixture might cost a bit up front.
    Great idea, I wonder if one could use a super micrometer to make and test in house made off jo blocks sizing made air gauge probes.

    I know this looks like missing parts ,so not this one.
    PRATT & WHITNEY G-2100 SUPERMICROMETER | eBay

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    Quote Originally Posted by Conrad Hoffman View Post
    Air gaging works great for this sort of thing, as it can do the precision and is self cleaning. The range of the plugs or fixtures can be large enough, but the basic plug or fixture might cost a bit up front.
    Can you use air gauging for flat/parallel surfaces? Also, back to having the need for very large ranges... appreciate the feedback.

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    Price good, shipping not so much! You can certainly make the needed fixtures to calibrate air plugs, though I've never attempted to make the plugs themselves. I used to use Edmund air gauges and they're quite knowledgeable.

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    Quote Originally Posted by Mike1974 View Post
    Can you use air gauging for flat/parallel surfaces? Yes.

    Also, back to having the need for very large ranges... appreciate the feedback.
    likely have to make a probe for each size or design an adjust able probe that could use clamped to a jo block.

    Sheffield Precisionaire Column Air Gage Meter - Model #607-SM | eBay

    SHEFFIELD PRECISIONAIRE MEASUREMENT COLUMN AIR GAGE METER MODEL # 1501-10 | eBay

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    Yes they are a little pricey, but tenth increment pins give you so much confidence in what you're doing, you'll forget about the price in short order.

    Also, air gaging only goes down to Ø.040" to .047" depending on who you talk to. Nobody will even make custom probes smaller than that, or else we'd be all over it.

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    Air gauges are for production runs not small one offs.
    They need a master which you will not have and are hard to work with outside of nice round things and not so good handheld.
    Features are pure holes or other?
    Assume the machine does not have linear scales bit I'd still be going touch probe but you are 50/50 crossing the line if the machine and screw comps are good.
    I suspect you have already found that problem.
    Batch size big enough to make a sacrificial part or first has to be right?
    If first out must be good machine on a piece of scrap and let your offline measuring talk to you?

    You say feature which makes me think not just a hole.
    Bob

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    Quote Originally Posted by Mike1974 View Post
    I am looking for ideas to check small internal features (per the title) in the machine. They are small, but easily accessible. Needing to measure within about +/-.0002-.0003". Feature size would mostly range .03"-.07" (or there-abouts..) with depths of .050-.100" deep. We have a vision system (so verifying numbers isn't really the issue), however we need to get as close as possible in machine measurements, as parts take some time to machine, and finding out it is out of spec after removing from machine is getting time consuming...
    It would help (me at least ) if you posted a picture or drawing so I could see what you wanted to do.

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    We literally ordered go/no go sized tenth pins for each job that had any internal features requiring sub +-.0005 tolerances at the time of order confirmation, they just got worked into the tooling costs. I don't actually know what happened to them after each job, some of them stayed with the drawings for future use. There were considered consumable, and not fit for final inspection, so they were not in the certification chain.

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    Quote Originally Posted by CarbideBob View Post
    Air gauges are for production runs not small one offs.
    They need a master which you will not have and are hard to work with outside of nice round things and not so good handheld.
    Features are pure holes or other?
    Assume the machine does not have linear scales bit I'd still be going touch probe but you are 50/50 crossing the line if the machine and screw comps are good.
    I suspect you have already found that problem.
    Batch size big enough to make a sacrificial part or first has to be right?
    If first out must be good machine on a piece of scrap and let your offline measuring talk to you?

    You say feature which makes me think not just a hole.
    Bob
    Correct, not holes. What we are trying to check is basically a dimension between two 'walls'.. the catch is they are so small conventional measuring tools aren't practical. Right now we are bascially cutting one, taking it out and inspecting, scrapping it, making comp adjustments and running another, we are trying to move away from that.

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    Quote Originally Posted by Winterfalke View Post
    We literally ordered go/no go sized tenth pins for each job that had any internal features requiring sub +-.0005 tolerances at the time of order confirmation, they just got worked into the tooling costs. I don't actually know what happened to them after each job, some of them stayed with the drawings for future use. There were considered consumable, and not fit for final inspection, so they were not in the certification chain.
    I know tenth pins would solve it. End of story. However, since these are all 'customs' we would end up with literally hundreds of sets!

    Imagine this - first part has two features we want to inspect, (from a real print) .0684 and .0615 so there are two sets of tenth pins at roughly $230 each. We make 4 of these part. Next part has dims of (from a real print again) .0750 and .0841, two more sets of pins at $230 each. Make 4-6 of those and so on. Eventually we would have enough pins to cover them all, but still...

    I understand sometimes that is the cost of business... I am just trying to figure out a better/easier/cheaper (I know what I am asking btw haha) way.

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    All these walls parallel? I wonder if you could order a set of gage balls and use those?

    A call to balltec may yield some results?

    Sent from my SM-G973U using Tapatalk

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    That kind of need would pay for a decent surface grinder pretty quick.
    One might use a radius dresser to arc a wheel to an inside radius so not to worry about beveling the corners.

    Run the flat fit gauges in a vice held horizontally and measure with an indicator micrometer, using a JoBlock to reference/set the micrometer. Perhaps 10 minuets to make a gauge.

    Faster would be a radius diamond, perhaps a .030 and a .060 for dressing wheel (perhaps a 60 I to L ), both set and left on the chuck with the diamond center (s) / cross feed dial number also noted so to go to it quickly. along with the vise position noted to go to vise quickly.

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    SO each custom gauge is for a very short run?

    Then they don't have to be hard, so theoretically you could turn your own pins. Just depends how round your lathe will turn and how well you can measure them on that machine. Same with grinding a block. When only making one, repeatability is just not a big deal, sneak up on the number until you get one right.

    Personally I am pretty happy with the make the first one junk and fix it from there. It tends to be cheaper than the alternatives. I mean if the part is less than 200 bucks......cost

    We have 2 dual vises on pallets, and offsets stored in the machine for all 8 stops. When the vises come off they don't go back perfectly, but they are close enough that 80 percent of the time it is a good part first time. WE run a part and tweek the stored offsets by the error and then run the parts. In my case stock is cheaper than time and the machine is wicked fast. Even if the stock were expensive we would probably run a stub piece or something.



    If you can use pairs of blocks/pins to measure, the number of blocks/pins is not infinite for a given range of dimensions

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    toolmakers microscope. I've got a mit and its graduated in tenths, it should do the job. put the cross hairs where you want and crank away.

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    From the answers here, there isn't anything readily available with the exception of tenth pins I guess?

    Maybe we need to put on our thinking caps and get to inventing it then!

    @Mcgyver- any recommendations? Google shows a few items that appear to be too cumbersome to put into the machine...

    I am beginning to agree with a few others here that just making one and scrapping it might be the most cost effective thing to do...

    @Gustafson- yes they are all customs and mostly short runs. Recently we made a run of about 20 and that was the largest "volume" I have seen here so far for those type of parts.

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    The tool makers microscope got me thinking of a friend of mine who would reverse engineer parts on a prototrak by putting a 300X camera with crosshairs in the spindle connected to a laptop that sat on the table. Maybe something like that would work for you?

    https://www.amazon.com/s?k=microscop...f=nb_sb_noss_1


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