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Integrated BIM tools, including Revit, AutoCAD, and Civil 3D
Professional CAD/CAM tools built on Inventor and AutoCAD
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Transcript
00:00
Inspect operation one.
00:03
After completing this video, you will have a better understanding
00:07
of common measuring tools,
00:09
the Go no go measuring concept
00:11
and most importantly
00:13
how to correct an out of tolerance feature.
00:16
When measuring our previous part, our aluminum piston,
00:19
we relied mainly on a set of calipers to measure inside and outside features.
00:24
Now for our caliper operation here, this first
00:28
inspection, we have a lot more tools available to us that we can make use of.
00:32
Now,
00:32
we will work our way through this simple inspection sheet using
00:36
it as a road map to explore a few more inspection tools
00:39
and some important metrology concepts.
00:42
Metrology is just a science of inspection.
00:46
And while that is a part of this video,
00:48
what we're really concerned about is how those inspection results
00:52
affect our machining processes.
00:54
We are inspecting this part in order to better understand how we as machinists
00:59
can make adjustments to make better parts.
01:02
That is this video
01:04
feature. Number one on our inspection sheet is this 0.6 inch step.
01:09
Now we'll use depth micrometer to check this distance.
01:12
Before we measure the step,
01:14
we've set our depth mic on a granite table and verified the tool reads zero when flat.
01:20
If it didn't read zero, we'd get some help and recalibrate the tool.
01:24
Now, this is a digital depth mic.
01:27
So all we need to do to zero, it is press and hold the zero button.
01:30
The set button,
01:33
we are right on the money with this dimension,
01:35
which makes sense because the same tool T seven created both this face
01:41
and this pocket.
01:43
If this value were off, if it didn't measure 0.6 inches,
01:46
we could not fix it with a simple offset adjustment because bringing the tool
01:51
up or down would bring both of those surfaces up and down together.
01:55
It wouldn't change the distance between those surfaces.
01:59
Now,
01:59
the first thing I would check is to make
02:01
sure that our top surfaces cleaned up completely.
02:05
If it was still raw stock,
02:07
then our stock might have been undersized or
02:09
we could have set an offset incorrectly.
02:11
And we would need to look at that.
02:13
If all of these surfaces had cleaned up, we would need to go back into fusion 360
02:19
check things there.
02:20
That's what this video is about to help get us thinking about what we need to adjust
02:25
if things don't measure up
02:28
and we don't have to understand everything all at once.
02:30
We're gonna gain experience with
02:32
each new part that we run.
02:34
One features, 004 is the 0.255 hole near the center of our part.
02:40
Now, for this hole, we are choosing to use gauge pins as our inspection tool.
02:45
Now with a tolerance of plus or minus 0.004 inches, four
02:50
th
02:51
and a nominal diameter of 0.255 inches.
02:54
Any size hole between 0.251
02:58
and 0.259 would be within spec
03:02
and that's how we judge our features. They're either within spec or not
03:07
good or bad pass or fail go
03:11
or no go.
03:13
If we were running production, we could set up a go no go gauge for this size hole.
03:18
Now, in this scenario,
03:19
the 251 is our go pin. We want it to fit
03:24
the 259 pin is our no go pin. We do not want this to fit.
03:29
Now, if the go pin fits and the no go does not fit,
03:34
then we know that our hole is somewhere within our
03:36
tolerance window of 0.251 to 0.259 a good feature.
03:42
If the 251 pin, the goin did not fit in the hole, then that hole is too small.
03:49
It is out of tolerance.
03:51
And if our 259 pin,
03:53
the no go pin
03:55
fits easily into the hole, then that hole is oversized and out of tolerance.
04:01
Ok.
04:02
If this feature measured good,
04:04
then we would just move down to the next item on our inspection sheet.
04:08
But what if this feature measured bad? What if that hole were oversized.
04:13
If that were the case, we would need to check our tool.
04:16
We can measure the drill bit with calipers to make sure we load the correct one.
04:20
We could move our drill into a more precise style of holder
04:24
like an er, call it holder.
04:27
We could check our drill for run out in the machine by
04:30
inspecting it with an indicator to make sure that the tool wasn't bent
04:34
either way.
04:35
Our go no go inspection lets us know if we are
04:38
all set or if we need to do some more investigating.
04:41
Our next feature to measure is our 2.75 inch bolt hole spacing. And this is a fun one
04:46
because I get to show off the coolest feature of a set of digital calipers,
04:51
the ability to rezero them on any specific bolt hole diameter.
04:56
We can hold the inside blades of our calipers against
04:58
the inside of one of our holes or counter boards.
05:01
And while holding them there, we can press and hold the zero button, the set button
05:06
when fully closed the calipers now display our whole diameter.
05:11
When we use these calipers to measure the distance between these two holes,
05:15
they will automatically subtract our whole diameter for us
05:18
and give us the whole center to center distance.
05:21
We are looking for magic.
05:24
Our bolt hole spacing is perfect. So we'll write that down.
05:27
But what if it wasn't perfect? What if it was off
05:30
if our bolt hole spacing were off. The first thing I would look at is our spot drill.
05:34
Did we use a spot drill
05:36
a lot of times with a, with a high speed steel drill? Especially a long one,
05:40
the tool could have walked on entry and that
05:42
could cause us problems with our bolt hole spacing.
05:45
But we did use a spot drill. Our holes are perfect. So we're moving on
05:51
feature six, a
05:53
three inch bolt hole spacing.
05:55
We'll use our calipers again for this one.
05:58
We'll write that value down
06:05
for these 255 holes. We can use gauge pins again to measure things.
06:10
Now, these 255 holes have a different tolerance
06:14
than the 255 hole that we measured earlier.
06:17
These are plus or minus five thousands of an inch
06:20
while the earlier hole was plus or minus four thousands of an inch.
06:24
These use a different go no go set up.
06:28
This is why we often balloon a print giving each feature its own character
06:33
number to help us avoid confusion between
06:35
similar features on our inspection paperwork.
06:39
Our piston board diameter has a tolerance of plus or minus 5/1000 of
06:44
an inch five thou while we could use calipers to measure it.
06:48
I'm choosing to use a more accurate board gauge.
06:51
Now, this board was created with our tool seven
06:54
a half inch end mill.
06:55
Now, if the board measured oversize over nominal by 2000 of an inch
07:00
we can adjust our tool wear for T seven
07:04
by positive two thou
07:06
making the hold smaller.
07:08
If the board measured undersize by say
07:11
one thou,
07:12
then we could adjust our T seven wear by negative one thou
07:17
making the hole bigger on the next part.
07:21
By making these small tool diameter wear adjustments,
07:25
we can walk in this board diameter
07:27
as close to nominal as we'd like
07:30
measuring a feature and finding out what changes we can make
07:33
to bring us closer to the center of our tolerance,
07:36
closer to nominal is what this video was all about.
07:39
Now, sometimes that involved a small change to a tool or a work offset.
07:44
Other times it involves a change to an actual tool like a drill bit.
07:48
And we might also make a change an adjustment in our C AM system in Fusion 360
07:54
knowing which change to make and when is what makes a good machinist.
Video transcript
00:00
Inspect operation one.
00:03
After completing this video, you will have a better understanding
00:07
of common measuring tools,
00:09
the Go no go measuring concept
00:11
and most importantly
00:13
how to correct an out of tolerance feature.
00:16
When measuring our previous part, our aluminum piston,
00:19
we relied mainly on a set of calipers to measure inside and outside features.
00:24
Now for our caliper operation here, this first
00:28
inspection, we have a lot more tools available to us that we can make use of.
00:32
Now,
00:32
we will work our way through this simple inspection sheet using
00:36
it as a road map to explore a few more inspection tools
00:39
and some important metrology concepts.
00:42
Metrology is just a science of inspection.
00:46
And while that is a part of this video,
00:48
what we're really concerned about is how those inspection results
00:52
affect our machining processes.
00:54
We are inspecting this part in order to better understand how we as machinists
00:59
can make adjustments to make better parts.
01:02
That is this video
01:04
feature. Number one on our inspection sheet is this 0.6 inch step.
01:09
Now we'll use depth micrometer to check this distance.
01:12
Before we measure the step,
01:14
we've set our depth mic on a granite table and verified the tool reads zero when flat.
01:20
If it didn't read zero, we'd get some help and recalibrate the tool.
01:24
Now, this is a digital depth mic.
01:27
So all we need to do to zero, it is press and hold the zero button.
01:30
The set button,
01:33
we are right on the money with this dimension,
01:35
which makes sense because the same tool T seven created both this face
01:41
and this pocket.
01:43
If this value were off, if it didn't measure 0.6 inches,
01:46
we could not fix it with a simple offset adjustment because bringing the tool
01:51
up or down would bring both of those surfaces up and down together.
01:55
It wouldn't change the distance between those surfaces.
01:59
Now,
01:59
the first thing I would check is to make
02:01
sure that our top surfaces cleaned up completely.
02:05
If it was still raw stock,
02:07
then our stock might have been undersized or
02:09
we could have set an offset incorrectly.
02:11
And we would need to look at that.
02:13
If all of these surfaces had cleaned up, we would need to go back into fusion 360
02:19
check things there.
02:20
That's what this video is about to help get us thinking about what we need to adjust
02:25
if things don't measure up
02:28
and we don't have to understand everything all at once.
02:30
We're gonna gain experience with
02:32
each new part that we run.
02:34
One features, 004 is the 0.255 hole near the center of our part.
02:40
Now, for this hole, we are choosing to use gauge pins as our inspection tool.
02:45
Now with a tolerance of plus or minus 0.004 inches, four
02:50
th
02:51
and a nominal diameter of 0.255 inches.
02:54
Any size hole between 0.251
02:58
and 0.259 would be within spec
03:02
and that's how we judge our features. They're either within spec or not
03:07
good or bad pass or fail go
03:11
or no go.
03:13
If we were running production, we could set up a go no go gauge for this size hole.
03:18
Now, in this scenario,
03:19
the 251 is our go pin. We want it to fit
03:24
the 259 pin is our no go pin. We do not want this to fit.
03:29
Now, if the go pin fits and the no go does not fit,
03:34
then we know that our hole is somewhere within our
03:36
tolerance window of 0.251 to 0.259 a good feature.
03:42
If the 251 pin, the goin did not fit in the hole, then that hole is too small.
03:49
It is out of tolerance.
03:51
And if our 259 pin,
03:53
the no go pin
03:55
fits easily into the hole, then that hole is oversized and out of tolerance.
04:01
Ok.
04:02
If this feature measured good,
04:04
then we would just move down to the next item on our inspection sheet.
04:08
But what if this feature measured bad? What if that hole were oversized.
04:13
If that were the case, we would need to check our tool.
04:16
We can measure the drill bit with calipers to make sure we load the correct one.
04:20
We could move our drill into a more precise style of holder
04:24
like an er, call it holder.
04:27
We could check our drill for run out in the machine by
04:30
inspecting it with an indicator to make sure that the tool wasn't bent
04:34
either way.
04:35
Our go no go inspection lets us know if we are
04:38
all set or if we need to do some more investigating.
04:41
Our next feature to measure is our 2.75 inch bolt hole spacing. And this is a fun one
04:46
because I get to show off the coolest feature of a set of digital calipers,
04:51
the ability to rezero them on any specific bolt hole diameter.
04:56
We can hold the inside blades of our calipers against
04:58
the inside of one of our holes or counter boards.
05:01
And while holding them there, we can press and hold the zero button, the set button
05:06
when fully closed the calipers now display our whole diameter.
05:11
When we use these calipers to measure the distance between these two holes,
05:15
they will automatically subtract our whole diameter for us
05:18
and give us the whole center to center distance.
05:21
We are looking for magic.
05:24
Our bolt hole spacing is perfect. So we'll write that down.
05:27
But what if it wasn't perfect? What if it was off
05:30
if our bolt hole spacing were off. The first thing I would look at is our spot drill.
05:34
Did we use a spot drill
05:36
a lot of times with a, with a high speed steel drill? Especially a long one,
05:40
the tool could have walked on entry and that
05:42
could cause us problems with our bolt hole spacing.
05:45
But we did use a spot drill. Our holes are perfect. So we're moving on
05:51
feature six, a
05:53
three inch bolt hole spacing.
05:55
We'll use our calipers again for this one.
05:58
We'll write that value down
06:05
for these 255 holes. We can use gauge pins again to measure things.
06:10
Now, these 255 holes have a different tolerance
06:14
than the 255 hole that we measured earlier.
06:17
These are plus or minus five thousands of an inch
06:20
while the earlier hole was plus or minus four thousands of an inch.
06:24
These use a different go no go set up.
06:28
This is why we often balloon a print giving each feature its own character
06:33
number to help us avoid confusion between
06:35
similar features on our inspection paperwork.
06:39
Our piston board diameter has a tolerance of plus or minus 5/1000 of
06:44
an inch five thou while we could use calipers to measure it.
06:48
I'm choosing to use a more accurate board gauge.
06:51
Now, this board was created with our tool seven
06:54
a half inch end mill.
06:55
Now, if the board measured oversize over nominal by 2000 of an inch
07:00
we can adjust our tool wear for T seven
07:04
by positive two thou
07:06
making the hold smaller.
07:08
If the board measured undersize by say
07:11
one thou,
07:12
then we could adjust our T seven wear by negative one thou
07:17
making the hole bigger on the next part.
07:21
By making these small tool diameter wear adjustments,
07:25
we can walk in this board diameter
07:27
as close to nominal as we'd like
07:30
measuring a feature and finding out what changes we can make
07:33
to bring us closer to the center of our tolerance,
07:36
closer to nominal is what this video was all about.
07:39
Now, sometimes that involved a small change to a tool or a work offset.
07:44
Other times it involves a change to an actual tool like a drill bit.
07:48
And we might also make a change an adjustment in our C AM system in Fusion 360
07:54
knowing which change to make and when is what makes a good machinist.
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