# Slow Motion



## Blogwitch (Apr 4, 2012)

A few of you may have read where I have bought a new camera to help me in the shop.

I have been waiting for a ring light to fit around the lens so I can get up close and personal with bits of metal with the macro, and allow me to do vids in slow motion.

So this is my very first outing with hi speed shooting, done hand held, just to see what it turns out like.

I still need to get the focusing sorted, as it is very complicated on that side of things when you have a long zoom lens and you are shooting from rather close, in this case, about 6".

So I will just explain what this horrid vid is about.

I was always fascinated because of the way I grind my flycutters, and really, within reason, even with a large depth of cut, I still get mirror finishes.

So this is my flycutter at about 400 RPM, on a fairly slow feed (under power) and a cut depth of approximately 0.100" (2.5mm).

I took it at two speeds, 448FPS and 1000FPS (frames per second), then it is automatically slowed down to 25FPS. The first minute is at the slower speed.

http://www.youtube.com/watch?v=FipAdIUr5OE&feature=youtu.be

This has shown me that instead of one piece of swarf being generated on each sweep, there are multiple cuts being done across the whole cutting face, all being formed into tightly curled pieces of swarf. So the way I understand it, maybe as though a half a dozen cutters, all acting at different depths, and because the lower one is so fine, it gives the mirror finish that you can see on the metal being cut (aluminium with no lubricant).

Can anyone see anything else?


I promise, it will get better.

John


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## Mike N (Apr 4, 2012)

Feed-rate must be pretty slow??

Not much of a chip load!

What does it look like with a much higher feed-rate?


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## lazylathe (Apr 4, 2012)

Now that is neat!
Usually when i fly cut i am jumping around brushing the hot chips off me! ;D

What would be a very cool video in slomo would be a good cut with a curling chip on the lathe!!!

I think it is an excellent start John!
Not much else to add!

How much space does a slow mo video take?

Andrew


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## b.lindsey (Apr 4, 2012)

That is really amazing video John. Had you posted info on the camera here on HMEM previously. I am thinking it could be quite a useful tool for making some videos for the machine shop class I teach. Concepts like milling cutter feed per tooth per revolution, single pointing threads, flycutting, etc. 

Bill


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## Blogwitch (Apr 4, 2012)

Give me a chance Mike, this is only the first time I have tried it in the shop. But I did do a slow feed on purpose, because if a faster feed was run, the chips would have maybe merged together and I wouldn't have seen the different cutting layers so easily. Next time I will do a fast feed, just for you.

Andrew,

The clip that was uploaded was about 11MB. But the originals were 35MB each on the photocard for 20 seconds worth each. The camera only takes 20 seconds at a time. When you consider that at 1000FPS, it is slowed down 40 times to 25FPS, so would give you 13mins 40 secs of rather boring video, about half that for 448FPS, so I knocked them back to 1min each. As I said, I am still playing at this time, I need to be a bit further away and use the zoom to get better focus, the limit is my ring light, only useful to about 1 metre. But that should do me just fine, I don't want to fill the shop with photo lighting etc

Bill,

Mine is a Fuji Finepix HS10, two times removed from the latest model (and less than half the price), but there are a few camera now that have slomo, Casio is one that jumps to mind, and is very reasonably priced, but is only a compact.

Be careful as to what format they generate, I have stuck with Fuji for many years now, purely because I know that I can cut and chop the videos very easily (about five minutes to chop 'em up and join together). In fact you can do most of the work in the camera itself.


John


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## miner49r (Apr 4, 2012)

Awesome John,
  This brings to mind something my father once said. (I'll probably get it wrong) Any cutting action is actually a burning action. I has something to do with heat created by friction which actually melts the material being cut. 
  I don't claim to know the science behind it but when my Olde Dad told you something, it was a fact.
Feel free to corect me.
Alan


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## petertha (Apr 4, 2012)

Very cool videography! If you ever feel ambitous, I'd like to see 
- a multi-cutter tool in action
- when a flycutter cutter is 're-surfacing' along the material segment already been cut. Typically, thats where my surface gets shiny surface, I guess knocking down the tops of the hills 
- 2 flute vs X flute end mills

hmm... this could go on & on ;D


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## Blogwitch (Apr 4, 2012)

Alan,

I won't argue with you at all, purely because many moons ago, that topic was discussed on here in detail, and is rather heavy for what this post is about.

But please raise another topic about it if you want to know more.

I can't remember who the culprits were, but I think Rick was involved somewhere in the discussion. 
My offerings were absolutely zilch on the subject, I knew about it, but not enough to get involved, so I kept my mouth shut (very rare).


Peter,

I wanted to see what a deep cut with my flycutter would show up to see how my radiused tool worked, but as I get better at it, I am sure other tooling will get involved.

If you noticed on the second minute, it only does a very narrow band shot at the high FPS. That is because of the camera limitations, trying to get as much detail into a very short space of time, it can't cope with a full screen, plus the resolution isn't very good, but good enough to see what I want to see.

I think what everyone has to realise, a few years ago, to get such video would have cost megabucks, but now it is coming into the realms of the masses to achieve, with relative ease and fairly low cost. 

I wish I had this camera in the early 80's, when doing a couple of years as a professional photographer between engineering jobs, I could have made a fortune.


John


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## tel (Apr 4, 2012)

Now that is very danged impressive! You'll find a lot of use for that set up I imagine!


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## Captain Jerry (Apr 4, 2012)

Very nice video, John. I spent most of the day yesterday with a fly cutter, which is ground to your example, on aluminum. I have been using this style of cutter for a while now and I am always impressed by how well it works and how easily it cuts. I love this tool and the results it gives.

 I was surfacing a piece of aluminum that was 1.5" wide with a cutting radius of about 2" and taking .100" DOC while coming to size with finer finish cuts. Feed was hand controlled but I kept the chip load full and I did not feel that my little X2 mill was stressed.

Jerry

My bench and shop floor is covered with chips but the chips are nearly flat with just a little curve but certainly not curled. I'll try to get some pics and measurements of the chips if you are interested.


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## Deanofid (Apr 5, 2012)

John, that's very interesting, not to mention fun to watch. Might even help people understand
how this tool grinding stuff works to their advantage.
Thanks for the videos!


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## jor2daje (Apr 5, 2012)

Great video very neat to watch, I have the one of the casios you mentioned, the fs10, and experimented a little when I had my southbend. The tool was probably incorrectly ground/ incorrectly used as it was just left over in the box of stuff I got with the lathe and my first time running a lathe, but still could be of interest.

 Thanks for taking the video I cant wait to see more machining operations done by a pro in slo motion. ;D

[ame]http://www.youtube.com/watch?v=9iE89Lx1oI0[/ame]


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## Ken I (Apr 5, 2012)

Bogstandard  said:
			
		

> Can anyone see anything else?



When cutting with such a generous radius the actual depth of cut per chip feathers away to zero directly under the tool - even on aluminium you can see the tool riding off the material occasionally - evidenced by the differing "widths" of the chip coming off (or am I delusional).

I think I can also see galling build up on the cutting tool just behind the edge which is normal cutting dry.

Brilliant video - I'm guessing that camera is going to be used for all sorts of diagnostics.

Look forward to seeing more discoveries related to the quirks of our hobby.

Regards,
      Ken


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## Blogwitch (Apr 5, 2012)

Jor2,

Very nice video shots there. One thing mine can't do is slow down and speed up during a take. Camera limitations on my part I expect, but I do know that the Casio does make a fair job of things.

I am far off being a pro, I'm just someone who looks at home machining from a different angle than the norm. Putting my many years of general experience to good use, trying all sorts of things and getting around problems in an easy way, rather than sticking to the 'written in stone' way of doing things. 
Many of the professional machinists on here would run circles around me when it comes to getting some jobs done, where I score is that I have experienced such a lot of different types of production, I can bring ideas into my workshop that have come from areas not normally associated with machining, but very relevant.


Ken,

I think it was a bit of an optical delusion, maybe caused by a little out of focus and the varying shadows. But I could be wrong, and that was why I asked, two (or hundreds) pairs of eyes are better than one.

I too had noticed the galling, but I didn't want to add any lube because it would have hidden my view of the cut.

Just this basic take has shown me what I wanted to know, how the chips form tight spirals rather than chunks. That is maybe because I have a fairly large top rake ground onto the cutter, and yes, when I get a little more proficient, it might answer a few more tantalising questions I have in my head.
One thing I really want to look at is parting off, even though I don't have a problem with it, others might benefit from seeing how chip forming etc can affect the way a tool and material reacts, or even how a touch of lube changes the whole process.


John


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## Blue_Rock (Apr 5, 2012)

Nice video John. Looking forward to seeing more.


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## Omnimill (Apr 5, 2012)

Great video John! Keep em coming!

Vic.


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## jor2daje (Apr 5, 2012)

John,

The shot was actually all taken at the same speed 420fps I think, but initially I doubled its speed about 3 or 4 times in windows movie maker to make it look close to the actual speed. Not really helpful to analyzing anything but does give you a rough idea of how fast its actually moving.

George


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## Blogwitch (Apr 5, 2012)

That explains a lot of things George.

I must have a look at some of the trick bits that comes with Windows, maybe I can do the same sort of thing.


John


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## gmac (Apr 5, 2012)

+1 on producing a parting off video John . Thanks for sharing the flycutting video - I'm off to grind up one of your cutters.

Cheers Garry


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## Captain Jerry (Apr 9, 2012)

John

I know the thread is about slow mo cameras but the flycutter chip is also worth talking about. Here is the cutter that I was using and the chips it produced;

















The depth of cut was about .060" across a 1.5" wide surface. The cutting radius is about 1" turning about 700RPM with a fairly aggressive feed rate. The chips are very uniform in size and shape. The convex side is bright and smooth while the convex side is dull and rough. The top edge (to the left in photos) is uniform and solid and the lower edge (to the right in photos) is very thin and ragged. In addition to these chips, The operation produced a lot of very fine slivers, almost fluff. The finished surface is very smooth but shows some tool path circles. A higher speed, fine finish pass eliminates that.

All of this seems to be just what I expected, EXCEPT for the uniform short length of the chips which I estimate to be about .25 inch. With the tool making a cut across a 1.5" surface, I would expect longer chips, or at least some longer but not the uniformly short chip. 

Any explanations?

Jerry


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## Blogwitch (Apr 9, 2012)

Jerry,

I can't explain where the extra lengths of chip has gone, but I might be able to explain why my chips were coming off spirally wound.

Looking at the cutting face on your tool, it has a lot less rake than mine. I use a lot of rake, about 10 to 15 degrees all round, and it is ground the same as I would a left hand cutting tool, with rake in three directions, top, front & back.

Also remember, I was taking a much shallower cut, so the metal being removed isn't as strong as the amount you are removing, yours would have a tendency not to twist as much.

When I get another chance, I will try to get some shots of mine taking larger cuts, and see if they match yours, and also see if I get the disappearing metal phenomenon.

BTW, with the way I grind mine, I always get a mirror finish, no matter what depth of cut I use (within reason), but I never go too fast a feed.

John


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## Ken I (Apr 9, 2012)

Captain,
      Material cuts in shear - imagine a deck of playing cards spread out to the length of the cut - then push the pack closed - its now thicker but narrower.

To some extent you can see this "stack of cards" effect on the dull side 0f the chip (the "up" side).

Measure the thickness of the chips - it will be much greater than your actual feed / cut rate.

Obviously chips can scroll closed and break at each closure or alternatively form long coils or ribbons. In your case the angular momentum of the chip is probably causing it to break at regular intervals along pre-existing shear lines.

Its also possible that is the entire chip - is "squashed down" by three or four times with a concommitant increase in thickness.

2c

Ken

P.S. The shaded area in the depth of cut zone goes into the shaded area in the chip volume.


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## Captain Jerry (Apr 9, 2012)

John

I'll check the angle again and try it with a little more. I like the way this cuts but if I can improve it, I'll like it more. In this case I was going for stock removal over finish. I had more than .25" thickness to remove so I made a lot of chips. Maybe this is not the right tool for the job. Is there a better way?

I suspect that the rigidity of your mill makes for a better finish. The gearing in the head of my X2 is sounding a little rough and has a lot of backlash so I have decided to change it to a belt drive system. The bearings may also be rough but I'll wait to see what the difference is with belt drive.

Ken

That is exactly what the chip looks like on the inside of the curl. It looks crunched. Maybe a little more angle or slower feed would reduce the crunch effect. Its hard to believe that the whole width of that cut is compressed into that short chip but that seems to be the whats happened. Anything else would produce more random results.

Thanks for the responses.

Jerry


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## Sshire (Apr 9, 2012)

John
Love the video. A few thoughts about focusing that may help.
Camera autofocus systems are based on contrast (passive autofocus) where higher contrast is assumed to be "in focus" or an IR beam reflecting off the subject (active autofocus). Most cameras use both. 
The problem is that the contrast based system may like something with greater contrast and decide that this should be the point of focus. I find that on my mill, the the passive autofocus loves the accordion bellows covering the column front. My solution is to place a piece of black or dark gray paper between the part to be photographed and the bellows. Since this has, in effect, no contrast, the part becomes much more interesting to the autofocus system. On the lathe, the offending contrast grabber is swarf. Same dark paper laid across the bed if I'm shooting down.
Check your camera's manual in the macro section. They may have some additional suggestions. 
One other issue with macro and high frame rates is that you need lots of light for two reasons. Depth of field at macro distances is tiny. The greater amount of light will result in the camera using a smaller diameter f/stop. Small aperture = greater depth of field. 
Second plus for more light is the noise issue. Most non-SLR sensors are tiny. Most likely your sensor is 5.76mm x 4.29mm. The only way to make the millions of individual photosites(the actual light gathering part of the sensor) fit on a chip that small is to make each one tiny. They can't gather a great deal of light at that size. So, the light is amplified and as the light level is lower, the amplification must be greater. This comes with a higher signal to noise ratio. Low light = higher noise. 
Hope this helps. When I was teaching, this usually caused lecture-induced sleep, so I'll skip the photon flux issue. ;D

Best
Stan


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