Ten Years in Sheet Metal Industry: Exclusive Secrets of Laser Cutting and Bending+ View more
Ten Years in Sheet Metal Industry: Exclusive Secrets of Laser Cutting and Bending
+ View more
Date：2024-12-13 09:24
Being in the sheet metal business for ten years has given me a great deal of experience. It has truly been both an unexpected and yet natural journey; I have been part of diverse projects and seemingly endless teamwork along the way. Today, I want to share what I have learned about the design of sheet metal parts, especially when it comes to the two processes I think are most often used and misunderstood by our best customers—those who design parts for us to make. With laser cutting and bending, I think you can sometimes overlook some very basic yet very important rules that are key to our mutual success. My knowledge comes from a mix of what my very smart colleagues have taught me and what I have delved into and sorted out over the years.
The project I worked on dealing with server storage enclosures required a number of special parts. The most important one, obviously, was the enclosure itself. We made that with a laser cutter. But before we could get to the point of using the laser cutter to manufacture the enclosure, I was first responsible for making sure my team could use the laser cutter properly. This was important for two reasons: we wanted everything to fit together (a minimum of human error in the cutting operation would help ensure that), and we absolutely, positively did not want anything catching on the enclosure. That's part of what required the enclosure to be a smooth, uninterrupted surface; otherwise, we could end up with the kind of conditions that wouldn't get the enclosure past the necessary approval stages on the way to being a legal thing.
Surface smoothness was critical. If the surface was even slightly uneven, the edge I was grinding would have a burr or just wouldn't be smooth. Most crucial was that there be no rust on the surface. The focus of the laser cutting had to be right on, too. If the laser isn't focused properly, then no matter what else you do, the cut won't be clean. When I first started working with a laser cutter, I quickly found out that the problem with the machine was with me. After a few unfortunate tests, I realized that focusing was the issue. Generally, the best place to focus the laser is just above the surface of the material; every material has its own optimum focus point, and the thicker the material, the more below the surface you should focus.
Bending also contains a lot of knowledge. Beginners often focus solely on the thickness of the sheet and neglect more basic issues, like whether the edge at the bend is sufficiently radiused to prevent cracking. It's hard to believe, but it seems we never learn those things until we pay for them in cracked parts. The thing is, they really are basics. Everything we bend is in some way connected to or contingent on those fundamental concepts. And of course, we also learn that if we don't understand the basics well enough, bending dies will cost us cracked parts, too.
Moreover, the arrangement of bends in a complicated sheet metal component necessitates very careful consideration. It is really essential to make an appropriate and sensible choice of the order in which to make the bends so that the part ends up with the kind of precision—and also the kind of strength—that a finished component is supposed to have. In most instances, when the order of bends has already been decided, the part is bent first at smaller angles and then at larger ones, which, in most cases, works quite well and avoids a fair number of headaches that could arise from interference and excessive deformation.
Sheet materials are known to spring back from bends. But how much they spring back affects how close they come to being dimensionally accurate. One time, I worked on a project that required such a high level of precision that I found myself trying to produce parts that came out with a slight amount of springback (which I was hoping would turn out to be "not quite as much as we expected"). When I realized my mistake, I did some homework to understand the issue better, and then I ran some trials. From my work, I came up with two methods I think might help reduce springback: one is to increase the bend angle somewhat, and the other is to use several bending operations instead of just one.
The project I worked on dealing with server storage enclosures required a number of special parts. The most important one, obviously, was the enclosure itself. We made that with a laser cutter. But before we could get to the point of using the laser cutter to manufacture the enclosure, I was first responsible for making sure my team could use the laser cutter properly. This was important for two reasons: we wanted everything to fit together (a minimum of human error in the cutting operation would help ensure that), and we absolutely, positively did not want anything catching on the enclosure. That's part of what required the enclosure to be a smooth, uninterrupted surface; otherwise, we could end up with the kind of conditions that wouldn't get the enclosure past the necessary approval stages on the way to being a legal thing.
Surface smoothness was critical. If the surface was even slightly uneven, the edge I was grinding would have a burr or just wouldn't be smooth. Most crucial was that there be no rust on the surface. The focus of the laser cutting had to be right on, too. If the laser isn't focused properly, then no matter what else you do, the cut won't be clean. When I first started working with a laser cutter, I quickly found out that the problem with the machine was with me. After a few unfortunate tests, I realized that focusing was the issue. Generally, the best place to focus the laser is just above the surface of the material; every material has its own optimum focus point, and the thicker the material, the more below the surface you should focus.
Bending also contains a lot of knowledge. Beginners often focus solely on the thickness of the sheet and neglect more basic issues, like whether the edge at the bend is sufficiently radiused to prevent cracking. It's hard to believe, but it seems we never learn those things until we pay for them in cracked parts. The thing is, they really are basics. Everything we bend is in some way connected to or contingent on those fundamental concepts. And of course, we also learn that if we don't understand the basics well enough, bending dies will cost us cracked parts, too.
Moreover, the arrangement of bends in a complicated sheet metal component necessitates very careful consideration. It is really essential to make an appropriate and sensible choice of the order in which to make the bends so that the part ends up with the kind of precision—and also the kind of strength—that a finished component is supposed to have. In most instances, when the order of bends has already been decided, the part is bent first at smaller angles and then at larger ones, which, in most cases, works quite well and avoids a fair number of headaches that could arise from interference and excessive deformation.
Sheet materials are known to spring back from bends. But how much they spring back affects how close they come to being dimensionally accurate. One time, I worked on a project that required such a high level of precision that I found myself trying to produce parts that came out with a slight amount of springback (which I was hoping would turn out to be "not quite as much as we expected"). When I realized my mistake, I did some homework to understand the issue better, and then I ran some trials. From my work, I came up with two methods I think might help reduce springback: one is to increase the bend angle somewhat, and the other is to use several bending operations instead of just one.
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