12-19-2017, 04:43 PM
Hello Exchange Members!
About a week ago an industrial customer of ours called with, we won't say a complaint, but what we prefer to think of as a "question". The question was this; they'd been testing recently received and brand new cutting tools from their supplier and getting erratic readings on their multiple point edge sharpness tests. Anywhere from 260 to 480 on a single edge that was only 1.5" wide. First a little background though before we go further with this story:
We deal, typically, with process engineers at these companies. Process engineers have to wear many hats. They have to be able to diagnose problems in their 4-20ma current loops and select the right load sensor for a batch blending operation. If their manufacturing facility is also engaged in processes that cut, slice, shear or chop things then they have to contend with issues germane to edges as well. You can't be an expert at everything. That's why we get a lot of calls from those engineers who are experiencing problems relative to product quality, through-put, and/or cost of operation. In this case, the problem turned out to be one that applies to anyone who ever ground an edge so we thought that we would share it here.
So the company engineer agreed to send us a few samples of the new blades they had received from their supplier. The first thing we did was have a nice close look at the edges. Here is an optical microscope picture of the first edge we looked at:
It's easy to see why this edge would produce inconsistent readings. To the left, the edge is a mass of residual burr. To the right the burr is not quite so prevalent. Their edge test results were telling them exactly what the picture shows. This is what edge testing is really all about. Not just how sharp your edge is at the end of a sharpening session but using it as a diagnostic and learning tool. So OK we've all seen pictures of burr before but these edges weren't quite finished telling their story yet. Here's another picture of another blade that came from the same group of samples provided.
Believe it or not, this picture was taken after having been worked over with a leather belt mounted on a Kally. We tested it after deburring with the Kally and it still wasn't sharp so back to the microscope. The edge has been buffed up nicely but essentially, now, the burr side of the edge is a scraper. It looked, sounded and felt like a scraper as well when this side was drug across the surface of a leather hone. The top 75% of the burr has been removed leaving this stubby and substantial base. The shiny, almost weld-like look of the burr is rolled toward you in the picture. That's why it's shiny, it's reflective angle is different than the bevel portion of the edge. Our experience says that burrs like this occur when too much grinding force (or speed) has been used. Our experience also tells us that the only way to remove this burr is to grind it off. Hopefully with less applied force and speed the next time.
We're very open to other theories and interpretations regarding these pictures. We say the top 75% of the burr has been removed but, of course, we don't really know if that percentage is accurate. It's just a guess. We say the only way to remove this kind of burr is to grind it off, well that's our experience. If you see something here that we don't or if you just see it differently. Let's hear about it please.
In closing, industrial operations should represent a real opportunity for professional sharpeners because most industrial users (and very often their edge suppliers) simply do not have the knowledge base that can found right here on the BESS Exchange. How large is this market? Look around the room you happen to be sitting in. It's difficult to pick out an object that wasn't sawn, sheared, sliced or cut in a factory before it became the product you see. Look in the pantry or the cupboard. Those sliced peaches didn't grow that way. We promise, there's a whole world out there beyond just kitchen and carry knives.
About a week ago an industrial customer of ours called with, we won't say a complaint, but what we prefer to think of as a "question". The question was this; they'd been testing recently received and brand new cutting tools from their supplier and getting erratic readings on their multiple point edge sharpness tests. Anywhere from 260 to 480 on a single edge that was only 1.5" wide. First a little background though before we go further with this story:
We deal, typically, with process engineers at these companies. Process engineers have to wear many hats. They have to be able to diagnose problems in their 4-20ma current loops and select the right load sensor for a batch blending operation. If their manufacturing facility is also engaged in processes that cut, slice, shear or chop things then they have to contend with issues germane to edges as well. You can't be an expert at everything. That's why we get a lot of calls from those engineers who are experiencing problems relative to product quality, through-put, and/or cost of operation. In this case, the problem turned out to be one that applies to anyone who ever ground an edge so we thought that we would share it here.
So the company engineer agreed to send us a few samples of the new blades they had received from their supplier. The first thing we did was have a nice close look at the edges. Here is an optical microscope picture of the first edge we looked at:
It's easy to see why this edge would produce inconsistent readings. To the left, the edge is a mass of residual burr. To the right the burr is not quite so prevalent. Their edge test results were telling them exactly what the picture shows. This is what edge testing is really all about. Not just how sharp your edge is at the end of a sharpening session but using it as a diagnostic and learning tool. So OK we've all seen pictures of burr before but these edges weren't quite finished telling their story yet. Here's another picture of another blade that came from the same group of samples provided.
Believe it or not, this picture was taken after having been worked over with a leather belt mounted on a Kally. We tested it after deburring with the Kally and it still wasn't sharp so back to the microscope. The edge has been buffed up nicely but essentially, now, the burr side of the edge is a scraper. It looked, sounded and felt like a scraper as well when this side was drug across the surface of a leather hone. The top 75% of the burr has been removed leaving this stubby and substantial base. The shiny, almost weld-like look of the burr is rolled toward you in the picture. That's why it's shiny, it's reflective angle is different than the bevel portion of the edge. Our experience says that burrs like this occur when too much grinding force (or speed) has been used. Our experience also tells us that the only way to remove this burr is to grind it off. Hopefully with less applied force and speed the next time.
We're very open to other theories and interpretations regarding these pictures. We say the top 75% of the burr has been removed but, of course, we don't really know if that percentage is accurate. It's just a guess. We say the only way to remove this kind of burr is to grind it off, well that's our experience. If you see something here that we don't or if you just see it differently. Let's hear about it please.
In closing, industrial operations should represent a real opportunity for professional sharpeners because most industrial users (and very often their edge suppliers) simply do not have the knowledge base that can found right here on the BESS Exchange. How large is this market? Look around the room you happen to be sitting in. It's difficult to pick out an object that wasn't sawn, sheared, sliced or cut in a factory before it became the product you see. Look in the pantry or the cupboard. Those sliced peaches didn't grow that way. We promise, there's a whole world out there beyond just kitchen and carry knives.