Submicron Measurements!
ฝัง
- เผยแพร่เมื่อ 8 มิ.ย. 2024
- We took some of our norseman blades to Miltera to measure on their CMM machines and we found some interesting stuff.
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John Grimsmo Knives Instagram: / johngrimsmoknives
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Thanks for visiting John! It was a pleasure to have you as our guest!
Starting to wonder if John knows he's just making knives or thinks he's making rocket parts lol!
A lot of rocket parts are not even to these tolerances.
@@fpoastro lol yes actually worked at a place that made them. Actually did a lot of facing of flanges
If I pay $1200 for a knife... I want this obsessiveness involved in its making
@David Lewis Actually right.. of course numerous components made to extreme tolerance but there a thousands of others that are made a to a spec' far above sub-micron accuracy. Why? Because its unnecessary. This all just pointless banter because the entire conversation is like having one with your wife where if you mention acceptance of a reasonable spec' its interpreted as shipping "bad parts" when the real issue is what is your return rate? What is your customer complaint ratio? No one following this channel is suggesting making a convenience store knife but even at $1200 there is a point of diminishing return. But if that path with zero flexibility is the only one allowed and the funds to support it are there so be it. There are numerous outspoken individuals waiting for product which is a good thing. The question just becomes when is an insanely extreme level of accuracy enough. The customers will decide. Good for him. I have a hard time believing there isnt an off the cuff/back channel conversation between the CMM shop, Saunders, and Grimso that while its admirable... this may be something to talk with your therapist about lol.
@David Lewis sounds like we agree on saunders. Nuff said
This was interesting. I spent 8 years working in R&D at the Custom Metrology division of Brown & Sharpe (now Hexagon Metrology), designing new CMMs and sensors.
A CMM should be part of your production process, and you need an air-conditioned "Metrology Room" in your factory to use it in. (air temp changes the size of the parts)
The purpose of metrology in production is twofold.
1) It allows you to fine-tune your process to make reliable and consistent parts.
2) It allows you to track the gradual effects of tool wear and CNC machine calibration drift on your production parts, so you can take corrective action BEFORE they make a single out of spec part. The CNC machine itself is just the measurement tool, it is the "Statistical Process Control" (SPC) Software which is what adds value and keeps your parts in-spec.
A CMM+SPC should pay for itself by eliminating part-scrappage and down-time, and through the increased sales you will get from having a brand with a reputation for quality and reliability.
He's not only going to end up with his own metrology lab, he's going to be a factory-authorized replacement parts manufacturer for Zeiss. Give it another seven years, they'll contact him and say "hey, the stuff coming out of your shop is equivalent to our quality control standards. Would you be interested in a contract for some small-batch parts?"
Next week: John buys a CMM.
Aside from an EDM, its the only thing left
Haha that got a laugh. John would put it to good use Im sure.
Hey guys, welcome back to grimsmo metrology...
No cmm, edm, nada will cure it lol
@@ovd33 You forgot the AFM and REM
I just recently ordered my first Norseman #5085. Can’t wait to get it in hand. I’ve been an avid follower & subscriber of your channel for years. Thank you for the many hours of entertainment and knowledge.
Here is an idea I had. If you machine a blade but leave a little section of the blade without being machined (preferably far away from the screw acting as a pivoting point) then you can probe that section in the Kern before and after machining and see how much it moved. That will let you know if your gripping pads are doing the job.
That’s the difference between proper engineers who have served a proper Apprenticeship…..And entrepreneurs who have just learnt on the job on the fly…who have not had the years of knowledge passed down….this is basic and an easy fix and already been mentioned in the comments why you fixture up the way you have is ridiculous in the 1st place if your chasing any kind of repeatability…
@Zachary Shumaker And your point is I lost interest after the 1st few words ?
@Zachary Shumaker what’s a soldger ?
@Zachary Shumaker for a start soldiers is plural I’m 1 person so the word you wanted was soldier.Complicated stuff I know..But please feel free to carry on your obviously deeply offended which I find entertaining massively if I’m being totally honest and yes your right I’m bored shitless @ this minute in time so what little stimulation you offer with your sharp whit and below average intelligence is for me,well one of those little daily wins what gets me through the day.So please feel free to enlighten and humour me some more 😀 please give it your best shot in fact pretty please with a cherry on top push the boat out I promise I’ll try my best to come across all upset and offended scouts honour…And let’s not forget the fact 13 people who actually know what their talking about have agreed with me so…
@Zachary Shumaker ahh I see now I’ve just went back and read the comment in full..your a theoretical physicist…so your a virgin and all this is just you expressing sexual frustration..don’t worry I’m sure you will meet that right person 1 day who accepts you for what you are then all,this anger and bitterness will all just drift away and then you and your new boyfriend can skip off into the sunlight and leave all this behind..
@Zachary Shumaker behave yourself girl 👧 lab next door yeah of course she is…you should be on a stage please keep going this is best thing I’ve heard all week..
Hey John, have been following you ever since the Garage days, when I was just giving my first course in sharpening during my education as product development and production engineer. Its been such a joy to be able to join you on your journey, while riding my own having worked for a major knife manufacturer in the past, and now working for an engineering consultancy company as a specialist in sharpening and edge technology seeing this type of content makes me beyond happy and interested. Would love to get to meet you one day, you are an amazing inspiration and who knows, we might make a knife together one day!
Have an excellent progression of your production optimization and might you ever want to have a free chat with a production engineer to bounce ideas of off, just let me know!
Awesome Job brother!
I had to finish the video and read comments before I comment. I saw the problem at the beginning. The present fixture is inadequate for sustained repeatability. I'm personally a BIG fan of Mitee byte fixturing. Having the grippers on the bottom will produce an unpredictable part height throughout the production, produce a whistle effect when cleaned with compressed air and trap chips. The clamp should have the grippers instead. Still, this will only go so far. Changing to a small EM to do the slots will help, but you're introducing a new problem. Axis compensation. What happens is that both axis have a setting that allows them to initiate translation a set distance before the programed point. (HAAS is default .025") This setting will make the end radii smaller and out of form. This can be seen with a gage pin. The pin will not bottom out. I tune this compensation setting in the program for roughing and finishing. The smaller the compensation, the longer the cut time, but better precision.
Having the Norseman blade mounted to a single point with a cap screw in the tombstone turns the blade into a hinge.
Grabbers are an aid, not a solution. The part needs a physical stop point touching it from 4 sides like a part in a vise. I'd suggest tapping three more holes in the fixture. You've got the pivot area covered, call that one West. Add East, North, and South. The part is moving during milling.✌
I think that's called 'over-constrained'.
The fixturing is really non-ideal, as is, as you point out, it's hinged in the fixture, not properly constrained in rotation. I guess that it's 'flat', so the clamp maintains that dimension, but it would be well worthwhile to develop a sacrificial feature at the tip of the blade, to prevent rotation, while allowing unconstrained motion along the blade axis, for any expansion/contraction caused by temperature changes(since i have no idea of the blade temperature coming in, or leaving, this set of operations)
Damned tablet keyboards! It appears that all of the dimensions critical to the lock and open are at the one end, so that the blade 'length' is not critical, and that tip feature needs only to be precise in rotation, with a tiny amount of 'slot' in the blade axis direction...if feasible, quite simple, adds only one feature, which can be cut away as the last operation, after all of the critical operations. Just a thought.
The blade essentially needs to be constrained at datum features. Primary datum would be the flat side of the blade, second is the point he’s already using, and then a third stop to prevent rotation. The fixture he’s currently using doesn’t fully constrain the workpiece which allows position and profile error.
Ideally they would add another datum feature simulator to the fixture and then build a fixed functional gage for pass/fail acceptable of the critical features.
I love watching you and your content, it's excellent as always.
GG dude and good luck with solving those issues.
Oh really cool channel. At 3:00. My solution would be, to watercut the blades as a pair (Like they are sitting in the fixture) and leave a small bridge in between (where this top plate is holding them down). So both blades are physically connected and cant move, untill you mill away the joint between the screws.
Thanks for sharing, like most learning, you went to get answers and ended up with more questions. Charles
It looks like the error is the same so my initial thought is get an end mill cut for reverse rotation and reverse the tool path or maybe mirror your whole setup so you can machine the slot from the other side.
My second thought is that precision is great but making your knife design tolerant of that level of error would be even better.
If I remember correctly, the ends of that slot are critical but the middle shouldn't be. I would enlarge the whole thing including the radii at both ends because I think your stops use point or line contact, they don't need an exact fit.
That was extremely interesting, thanks !
Guessing you guys are already saving up for a CMM? :)
Have you looked into wire EDM. Anymore ? That would give you more repeatability. Along with awesome surface finishes after you knock off the wire residue.
There weren't really any operations on the knife that would lend itself to wire EDM.
Sinker EDM maybe...
Thank you for your time
Great video 👍 The Arc interpolation is not cutting but ram and swarfe shifting, maybe drill undersize then run end mill cut to finish.
Those gripper pads are an excellent idea!
Hey John. I have very positive experience with Shunk Tendo tool holders combined with carbide reamers. These will make consistant size holes.
Instead of drilling and reaming those corners, consider drilling undersized and backed off the finished wall by 0.02 or so. Then let the endmill finish the slot as normal, there will be less load in the corner hopefully alleviating the problem without losing dimensional control over the slot.
Good stuff Bud... Big ThumbS Up 😃👍
Next time on JohnGrimsmo "We got a CMM!"
Its going to be very interesting to see what Johns Next product is after this journey of bringing the rask back, and moving the norseman to the kern. I am sure hes got something new and interesting in his head, that all this learning and experience is going to bring to the table.
I thought those little grip points was going in the clamp. In order to have access to the points so that they do something, the part now has to be lifted off the entire flat surface. This will only cause more problems, sorry to say.
John , A way to fix this would be harden the blades and than grind them to tolerance.
Might be time to look into a Grinder and EDM
As a retired engineer I found this video extremely interesting. And as a Rask owner all I can think to say is…..When are you going to ramp up Rask Production!
Wonder if it would be a better strategy to drill and burnish the end radii for the stop pins then put in the curved slot without re machining the rads
Would a change to the cutout of the blade leaving another tab on the other side to be screwed down not work? Then to be removed after
Have you considered analyzing the mechanism across a tolerance range? You might be able to adjust the design such that it can give a more consistent feel across the typical range of variance, rather than relying on the diminishing returns of higher-precision machining.
Really tricky with corners , specially with small end mills , what I do is slow or even stop the end mill in the corner , but I don't let it dwell to much cuz it's gonna make it bigger , made a few stamping dies that are HRC 58-62 with radius tolerances like r4+-0.02 mm. We all know how doing a second pass with same end mill will still take off material , if it got no run-out still takes off 5-6 microns
do you still have your old diy cnc? if you do I would love to see a video with it
Great video!
Maybe the current clamp is part of the problem. The current contact area may be too little and only one point per blade which can lead to the shift. Of you split the one clamp in two and make two defined clamping points on the clamps it will support the blade even better I think.
You may blue the blade and clamp down to see how you are gripping it at the moment and see how you can improve.
Also bigger screws will help a lot in clamping and are a easy fix
John would it be better to put the grippers on the tomb stone under the knife blank and in the top clamp to eliminate and slippage?????
I would be worried about warping the blade. That sounds silly, but when your accuracy resolution is 0.00001" or better, any kind of point load can throw a wrench into the gears.
@@Coffreek I agree, but the way John has the tomb stone set up seems there will always be an issue with slippage.
He might be able to change tool paths so that the operation is always pushing the blade in against the clamp. It would add more time, and wouldn't answer if some of the problem is during heat treat, but with all the time he's put into those fixtures, he's into a "sunk cost" situation.
Wouldn't be a bad idea to probe the piece a couple times during the operation, either. Yes, it adds time, but if the blades are getting moved, a re-probe could allow the mill to call a subroutine that adjusts all the X and Y moves by whatever fraction the piece has moved. Hell of complicated, though.
Is that necessary or just doing it because it’s possible? It’s even the less overkill way the laser one would have been crazier.
If you ream a hole you can try to put a drill spining thru that hole and if it leaves marks you know that the hole is oversized (now) :)
Using a screw through the blade’s pivot hole to locate the blade in the X & Y directions may produce the variations you are describing. Perhaps using a precision dowel with a “tight” locational fit will give you better results. Also, using a dowel against the spine of the blade will prevent the blade from rotating around the Z axis. Once the blade is located in the fixture by the dowels, that is when the blade should be clamped down.
John, have you considered looking into your own CMM and something like Q-DAS to allow you to analyse every single part of your process? It seems like it'd be perfect for a shop like yours
What kind of knife needs CMM accuracy? And how would that fix his fixture issues? lol
@@modris2980 A Grimsmo knife, maybe you haven't watched this channel before? It's not just any old knife, John wants them to be absolutely perfect. Q-das can help you track down the cause of an issue over thousands of parts. It can also automatically adjust offsets on the machine etc.
The moment it swept the lock pin stop pocket was the moment I knew john is buying a CMM
Microns! We want angstrom repeatability! ;-)
For flat parts like that you should get a keyence IM
Trying to make a knife blade perfect, is a bit odd. But hey now!
love the E-Stop on the CMM....yikes! ,don't want to know how much a crash cost on that thing. Imagine what the watchmakers go through on tolerance on those ultra small parts compared to what your trying to achieve on a big ol knife blade
I think you should cmn the fixtures
Drilling and reaming will get you a fairly nice round hole but will not help you to hit positional tolerances. To hit position machine with an endmill, bore with an end mill, bore with a boring bar, or jig grind, more or less in order of achievable accuracy. I forget if you are hardmilling these features already but hardmilling with a smaller endmill seems like the most reasonable approach. Jig grinding would be cool but seems like overkill considering the availability of modern hardmilling processes.
I don't believe it . Point 3 micron, maybe electronically / software, not physically .
16:27 that's exactly why Grimsmo deserves a CMM. also finish machining AFTER heat treat could be your magic solution. its not fun but 16:27
Finish machining after heat treat would solve that issue but also create new pains with having to machine such a small area that's super hard. There would be a lot more tooling cost, and machining cost, ect.
@@Cheezzyizill, I know the light bulb went on over my head: "oh yeah! HT is a complete wildcard at these tolerances!" Seemed obvious once somebody said it. Let's see how many other ways John tries to solve the problem before "giving up" and spending the time and money.
Zeiss Duramax. US$60k. Not a .3 micron machine like the "real" Zeiss CMMs, but definitely a 1 micron machine which will let you control everything way better than any manual gauging process. Scanning head, comes with the software, doesn't need a climate controlled room.
It's not a Duramax. It's a Micura.
@@littlejackalo5326 I know it's not, I'm saying John should look at a Duramax for his own shop. A Micura is about 2x the price, an while it is an order of magnitude more accurate, going sub-micron is probably unnecessary (also, he would need to build a climate controlled room for a Micura, the Duramax can live right next to the Kern and be just fine).
@@LumaLabs I thought you were saying that the one in the video was a Duramax. My bad.
On the one Printout the flatness of the blade is 0,012 mm. Seems a little much coming straight from the surface grinder. That might be a problem too
Ya new video
I'm surprised that with the holes in the blade you wouldn't pre-drill one and use it for a location pin on that tombstone. I know it is an additional op - but yield is yield right?
Actually that's a really good idea would also add another point of contact
I think your screw pivot is not enough accurate, try to make a custom screw which has a stage centers the water jet cut hole perfectly.
My old Master says: its ALL about fixture...
EDM!!!
Let me guess, its not the machine 😂
Wish i had a kern :( id be making mechanical watches lol
Started making em by hand, abandoned not enough time lol
Sell to me the soft details blade little damage
You can use your cnc for that too .. its not gonna be that accurate as cmm but still it will be quite close to perfection
Call Reate haha
I know it
1/2 way into the video.
I'm going to say the tombstones have something wrong with them.
So when do you let "good" be good enough and put all this skill and dedication into developing new products?
2nd!!!
"Identically same" is an oxymoron.
*Tautology
@@anemac9 , good point!
FAOK YOe 🙄
63 microns or 6 hundred of a mm or 0.063mm For anybody using imperial that's 2,5thou
My guy you are making knives lol wtf? what a waste of recourses and energy it wouldn't even matter if they were out 10 thou lmao
too bad they had a jet engine running in the cmm room so i cant hear much.
Our inspection laboratory has 8 blowers boosting the dedicated HVAC system through 8 HEPA filters, so unfortunately it's quite loud. This is required to maintain the airflow necessary for particulate filtration, temperature and humidity control.
You are letting extreme engineering bravado and a total lack of experience overwhelm common sense. Perfect and ultra tight tolerances are NOT desirable for field products like folding knives. Why was the AK-47 rifle so successful? LOOSE TOLERANCES ALLOWED FOR WEAR AND DIRT!
You need to make your design such that it accommodates loose tolerances, dirt, abuse and future wear, but maintains tight and smooth operation. What you have, is a knife design that could literally lock up and be unusable due to normal rough usage and dirt invasion. Take a Rolex, put a tiny bit of dust inside it...it stops. You have the same thing with your knife design but without the sealed and protected watch environment. In effect, you have a highly over engineered bad design for real world use. The only place on a folding knife that needs tight tolerances is the pivot pin and blade pivot bearing surface. Make that tight, extra tough, maybe a bit bigger, and self lubricating and you'll have a really solid knife. Lastly, bring in a old time manual machinist to fix your setup and design issues. It's obvious you and your engineers have no idea what you are doing.
You shouldn't be so insulting, he obviously knows plenty and is able to achieve tolerances that only a fancy CMM can measure. I think he has just been seduced by those tolerances and is trying to use them to get consistent feel from each knife.
You don't need tolerances like an AK, or places for dirt to get in to, you just need a slot that's a tight fit when you're on the stops but not between them.
For feel, I think he needs to give himself some adjustment flats that can be hand stoned to tune the feel as an assembly.
As for the watch analogy, you seem like a Casio guy. Other people like Rolex. A Casio keeps better time but that's not the point for the person who chooses Rolex...