When it comes to machining,
there are lots of factors that can throw off the accuracy of any machine. Now,
there's also lots of technology that can help correct those accuracy problems.
But in this video, I'm
going to show you how this little device right here that we created
helps you achieve what us machinists call dead nuts accurate.
Let's get started.
Okay, so let's take a look at this.
Now, this is not anything you can buy, at least in its complete form.
But the majority of this is this glass rod.
It's actually quartz glass.
Now, quartz glass has a very important property.
It is almost impervious or has a very low thermal expansion.
There's a coefficient of thermal expansion when things get hot, they grow.
When they get cold, they shrink.
So quartz glass.
In this form, a rod has a very low thermal expansion.
Now, we bought this on McMaster Carr for I want to say
like ten, 20 bucks, something like that.
I'll put some McMaster Carr links in the description below.
And then what we did these two orange pieces, we simply 3D printed these,
and they're just a method to hold the quartz class
and they also have embedded magnets that we just printed during
a pause feature on our Prusa printer, prints a portion of the way up,
dropping the magnet hit continue and it prints the rest.
So if you shake it,
you can hear that there's magnets here.
So how does this work if you haven't already guessed?
Well, what we do is in the machine behind us Haas VM3,
which is typically the most accurate machine that has makes
it has thermal compensation, but it doesn't have chilled ball screws.
If you've seen some of our other videos, especially our delivery video
of our Doosan MX2100, multitasking
mill turned machine, it is actively cooled,
actively cools the ball screw using a chiller.
Now chiller is kind of a misnomer.
It doesn't make things cold.
It samples the ambient air temperature.
And if the temperature of the fluid or the ball
screw is higher than it, it actively cools it.
If it's cooler.
I don't think that ours does this, but some can actually warm the
the fluid, the thick, essentially.
It's still like a coolant, but as machine as we know,
coolant is something different than what's in an engine.
But we'll just call it cooling oil.
How about that?
So the cooling oil gets chilled.
That's active response.
With this, it's a way to measure the accuracy of the machine
and apply corrections.
So let's take a closer look in the machine
and I'll show you how we implement this device.
Okay. A quick overview.
Now, the quartz glass rod came in
about a 12 inch size on McMaster car.
We got it. We took it to our digital height gauge.
We measured it with several different devices and we took readings off both ends
and we got a known value with known calibrated equipment.
The problem was when we probe different areas of the ends,
we got different readings.
Then we realized that from McMaster Carr they were not cut flush to each other.
So the first thing we had to do is prepare the quartz glass rod.
We essentially held it in a V block in a vice and using a diamond grinding tool.
Also from McMaster with about an eight inch diameter shank, we went
we stepped down with lots of little passes with the step over of about just 5000.
Now we mark the ends with a Sharpie just to make sure we are fully cleaning up.
Once we did that, then we knew we had a good square flush
and we flipped it around, did the same thing, retook
the measurement using our calibrated digital height, gauge
and probe different positions, flip it around and we got a known
value of 12 inch 23002/10.
That's key 12 inch 23002/10.
That is something that we recorded in the machine.
I'll get to that later.
But now that we have that known value,
now this is ready to be deployed into the machine.
At that point, we take it actually, we call up our program.
It calls up the probe, the probe rapids over and goes to a set position.
Then the display tells us that we need to position the glass rod in place
just within a quarter inch off the right side of the probe.
And then we reach in the machine. We do so
close the doors.
It's cycle start.
It probes the left side, the right side and gives us a value.
Then what we do is we take that known value and we compare it
to the actual value of the quartz rod.
That way we can apply any type of correction in a couple of different ways.
We use two strategies.
I'll show you those strategies in a minute.
But for now, let me tell you about how accurate these quartz
glass rods are now compared to aluminum.
Aluminum has a coefficient of thermal expansion
of 13 micro inches per inch per degree.
This works out in something we all can understand.
Five inches of aluminum, increasing temperature
by five degrees will grow about 3/10 of an inch.
So five inches five degrees
increase or decrease changes it by 3/10.
Quartz glass has
a coefficient of thermal expansion of point
three micro inches per degree per inch.
So 0.3 versus 13 micro inches.
It's really thermally stable.
Nothing's perfect.
Quartz glass is at the top of the list for thermal stability.
The only other element that really outshines quartz glass is diamonds.
And I'm not going to buy a diamond rod.
Okay.
So with that being said, why don't we hop into my office,
will sit down on my computer, and I'll go through some of the code
that talks about probing and we're just going to nerd out.
I'm going to show you all the variables that we plug in.
And like I said, two different strategies that we use to make any machine,
including our VM three, the most accurate machine it can be a.k.a dead nuts.
Okay. So here we are at the top of the program.
Now, let me give you a quick overview.
It's only about 40 lines of code.
That's even with.
Lots. Of notes and spaces in between.
So it's actually pretty simple, but starting at the top.
So we have some preparatory codes here and more importantly, this one here,
this G one on three, turn off, look ahead.
I don't quite understand this fully, but just know that look ahead
needs to be turned off.
Next we have our four macros that we're going to be writing to now.
The first one is 901.
That is where you input your measured probe.
That's where you measure it outside of the machine
and you want to get that with a calibrated piece of equipment.
Digital height gauge, you could send that out to an inspection company, whatever.
You just need that. No.
Number 902, three and four
are macros that we are going to fill out as we progress.
Now, right here on line 14, this begins the table movement
to get the probe in position so that we can put the quartz
glass rod positioned appropriately.
Now in line 19 and 130.
That is a hors m code so that we can play a little quick video
showing the operator where to position the quartz glass rod.
Line 22.
Again, preparatory moves, getting it to the center of the quartz glass rod.
And finally, right down here on line 35, we have 902903 and 904.
Now, 902 is simply our way of simplifying the output of what the machine measures.
So it's going to write it to macro 188 we want it in a better format.
When we look at the macro screen.
So we just write it to 902, that's a straight copy paste essentially.
Now 903 starts to do a little bit of math.
902 is what it measured.
901 is what we know it is.
So you take 902 and you subtract 9 to 1.
That's either a positive or negative number.
And that's fine because in the next line, nine of four takes that positive
or negative number, divides it by the glass rod known dimension and adds one.
Now I know that's a lot, but trust me, it works, whether it's negative or positive.
And then the cheat sheet here is if that macro 904 is a one,
then we have a perfectly thermally stable machine.
Now, if 904 is greater than one and a lot of times
you might get 1.0008, that means that your machine is cold.
And if it's less if it's point nine, nine, nine eight than it's warm.
Now from there, line 39 is simply g100 three.
That turns on look ahead
so that no other future programs get affected by us turning off.
Look ahead.
And then our M 30 now scrolling down here, here's some examples.
Now keep in mind
the control will never see these examples because they're below the m30.
So we have a very, very simple program starting on line 50 x zero, y zero.
Let's pretend that you're drilling at 0y0
and then your next hole needs to be at X ten.
Okay. So that's the program now in line 54.
Here is a true position example.
Let's say you are boring holes at 0y0, then you need to move over to x ten.
Here's how you do that.
We create a new macro variable.
905 and the math in there multiplies ten remember
on line 51 that is our second boring target.
We take that, so we take that ten inch number and we multiply it by 904.
Remember, 904 is a scaling factor.
It's going to be close to one.
Then on line 58, we have X in pounds 905 which simply plugs
in the result of that calculation on 57 and then our M 30.
Now the next programing example uses G 51.
That is a G code that uses scaling in the has control,
which is a paid option but comes standard if you have a probe.
So for G 51, we want to specify the point from which we scale from.
So in this point we're just going to call our origin,
which is X zero, y00 as a point where we scale from
and then the P asks for a number as a percentage to scale up.
So if you wanted to make something double
the size, you would have to if you wanted it ten times the size.
P10 If you wanted it half the size P point five.
So this is a beauty of that macro nine oh for the scaling factor,
it plugs right in.
And then as you can see, it's pretty simple.
It looks just like our original program x0y0 line 65 x ten.
It's going to scale all those positions.
And then at the end G50 turns off that scaling and then R and 30.
Now I also have a third example here on line 68 saying that we can display
macro 903 and 904, meaning the Delta
or the difference between the measured value and the known value.
That's 903 or nine oh for the scale factor,
we can put that on display in the timer's encounter section in the lower right
hand corner of our memo screen in the has control.
Now that's nice because it gives the operator an opportunity to know if the.
Machine is running a little hot or a little cold.
This would be something where in your shop,
if you're trying to control very tight tolerances.
Across.
Large parts, you might want to run your machine
when that scaling factor is as close to one as possible.
Okay.
So with all that being said, I know this is not anything that you really see.
I mean, am I wrong?
Did we invent it?
Did we not?
Is it buried in Machinery's handbook from the 1800s?
I don't know, but it works like a charm.
Now, in the previous code that you saw, I showed you two ways that we apply it.
Are there other ways that you can apply it?
Is there code snippets that you can share?
Let's have some positive stuff that can help the machining community
down in the comments section.
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go innovate your production.