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  1. #41
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    Quote Originally Posted by trevj View Post
    Called as seen from this side.
    Listen, there simply is no need to get personal with people. We have too much disrespect in society. If this is a forum for professionals, then I expect to be addressed in a corresponding manner, and, of course, others should demand I do the same.

    So far, your suggestions as to what may seem to fit your needs, seem to me to be way out of line with your stated needs.
    I have no way to calculate or even guess as to what the machine specifications for my simple requirement should be. I have done lots of sheet metal design, with the manufacturing always being done at dedicated sheet metal production shops with the appropriate big dollar CNC equipment.

    This is me asking a simple question really: What can I get a way with if I want to be able to prototype simply bracket-type stuff? If we can do this in house it would save a ton of time. Right now we have to wait for every single little part to come back from the sheet metal house. When you have to wait a couple of weeks for a few simple brackets, the motivation is there to try to get the simple stuff in house. That's how I ended-up buying my first VF3-SS many years ago. After going through some $150K in prototypes for a tough thermal management heat sink design I decided we could iterate faster and for less money if we setup our own CNC shop. That was about fifteen years ago. Good decision. The case was similar with surface mount electronics assembly. We eventually got our own pick-and-place line and never looked back.

    If you don't need the tonnage for the work you do, why are you shopping for a press and add-ons that will do grossly heavier bends than you expect to see? Honest question.
    Everything I have read here has told me I need a higher tonnage machine. The little CertiFlat seems like a nice tool. I don't need to cut, we can do that on the VMC. Again, for prototype quantities, that's fine. Frankly, for $500 I'll probably get one to try. I can't imagine a tool like that not being useful.

    Also, I called various tool manufacturers and spoke to their applications engineers --including the famed 3-in-1 machine. The consensus seems to be that my 1/8 in mild steel requirement is the deal-breaker, even though I don't really need to bend anything wider than about 2 inches. The consensus seems to be that 12 to 20 tons is the right range.


    As I see it, what you could or should be using seems to be a DiAcro Bender with a extended set of dies for the wider material you plan on using.
    Sounds like an interesting idea. Thanks. I think the issue here might be that this is only good for what I am going to call in-plane bends. In other words, if I take a straight rectangular piece and need a couple of 90 degree bends perpendicular to the part, no problem. What if I need to make bends that are at, say, 30 or 45 degrees? Like this:

    14-07-2021-17-35-50.jpg

    Clamping in your flat stock and swinging the lever once per bend, seems a lot less hassle than spending the day pumping a jack
    Definitely. You reminded me of the beefy rebar bender I got three years ago when I had to fabricate rebar cages for the column footings of our solar array installation. Also got an electric powered rebar cutter, which was just slick as can be.


    The press brake on a 3-in-1 is craptacular, but the way it works is adequate
    It is obvious this won't work for me. Yet it could be a great little tool for the kids at the robotics club I mentor. It doesn't have to be perfect...and they certainly don't need to deal with anything super thick. If they do, I'll bend it for them on whatever we buy. I am always CNC machining stuff for them anyway.

    As for your "Try This"... Maybe you could try responding, in any way at all, to all the different suggestions made, that were not made like you were too dumb to understand them.
    I will, once I get a good sense of what this all means. Some of the responses are perplexing. I have been very clear that I don't need to bend anything wider than about two inches. I don't know how to read a suggestion to buy a 36 inch wide machine. Are they reading what I said or are they saying this is the smallest machine I should consider if I want to bend a 2 inch wide 1/8 in thick bracket?
    Last edited by martin_05; 07-14-2021 at 10:34 PM.

  2. #42
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    Quote Originally Posted by martin_05 View Post
    I will, once I get a good sense of what this all means. Some of the responses are perplexing. I have been very clear that I don't need to bend anything wider than about two inches. I don't know how to read a suggestion to buy a 36 inch wide machine. Are they reading what I said or are they saying this is the smallest machine I should consider if I want to bend a 2 inch wide 1/8 in thick bracket?
    Perplexing, eh?

    Maybe that should be one of your earlier cues, that you know less than you think you do!

    In all seriousness.

    To use a press brake of any sort, you really need to know what does and does not work, as well as what dies will get you 'past', a lot of the things that don't work with a straight vee male and female dies. Whether that is doglegged dies or offset top dies to allow clearance for odd overhangs.
    Odd angles, really depend, among other things, on your experiences, your imagination, and sometimes, your sense of humor! Then you have to be able to imagine your way from one end of the project to the other. And to keep track of where you are in the set of steps you need to follow.

    In other words, you really have to understand how you are getting from here to there, and if the tool you chose, is the correct one!

    Case in point. DiAcro makes some very nice, 12 inch wide machines, as far as shears and brakes. But their benders still will bend what you need, better.

  3. #43
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    Quote Originally Posted by trevj View Post
    Maybe that should be one of your earlier cues, that you know less than you think you do!
    I haver claimed to know it all or think I know more than I do. The universe of what I do not know (about all subjects) is vast and wide when compared to what I know.
    Show me where I claim to know it all and I will apologize without reservations. I can't be faulted if people make this assumption because I might question what they are telling me. I am not an unthinking blob of cells sitting in front of a keyboard. Right or wrong, I will question what I am told and not just accept it unless it makes sense.

    How does anyone learn? Most people come into any domain of knowledge not understanding what they don't know. You don't know what a road looks like until your travel that road. That's just normal. Clobbering someone over the head for something that EVERYONE goes through in life multiple times isn't constructive.

    You and I are having a professional conversation right now, so the above comment isn't aimed at you at all. It's more of a general statement of something I see all too frequently on this forum and other places online. The "you must be an idiot" kind of response has to be fought against because it leads to nobody learning a thing. And, no, that's not shop talk. Show me a shop were people spend the day insulting each other and I'll show you a bankruptcy case.


    To use a press brake of any sort, you really need to know what does and does not work, as well as what dies will get you 'past', a lot of the things that don't work with a straight vee male and female dies. Whether that is doglegged dies or offset top dies to allow clearance for odd overhangs.
    Odd angles, really depend, among other things, on your experiences, your imagination, and sometimes, your sense of humor! Then you have to be able to imagine your way from one end of the project to the other. And to keep track of where you are in the set of steps you need to follow.

    In other words, you really have to understand how you are getting from here to there, and if the tool you chose, is the correct one!
    I'd like to think I understand this. I've done enough sheet metal work over the last, say, 20 years to have learned a thing or two. I usually work closely with engineers and technicians at the sheet metal house to look at manufacturability issues. In fact, my very first question when I farm out a design for manufacturing is always the same: Before you spend too much time quoting this, let's discuss what changes we might need to make in order to improve manufacturability, reduce cycle times, cost, etc.

    In the early days I'd go to the plant and see the entire process through in order to learn what I did not understand. So, yes, I understand ideas such as which bends to make first and with what kind of tooling in order to be able to make the other bends. I am no expert, but, yes, I think I do get it.

    Case in point. DiAcro makes some very nice, 12 inch wide machines, as far as shears and brakes. But their benders still will bend what you need, better.
    I can see how this would be possible. Sure. Make a fixture to gold the strap at the appropriate angle and off you go. I get it. I also reviewed their "The Art of Bending" (per your suggestion), which opened my eyes to the possibilities. I am going to call them today to gain a further understanding.

    What I don't want to do is buy something that becomes a chore to use. From my perspective, a simple manual 20 ton press is quite a useful tool to have (we don't own a press at all). From there the question is about whether or not it can be tricked out to have it serve as a convenient bracket maker.

    The manual pump aspect is a royal pain in the behind if you have to make, say, 25 to 100 brackets --which isn't out of the question for a test run. Which is where the air actuation, or, what I seem to prefer, electric actuation, seems to be of benefit. It isn't going to move very fast (you wouldn't want to because there are no safeties) but at least you are pushing a button rather than pumping a lever. The manual pump with turning a knob to release doesn't sound like a formula for something anyone would look forward to doing except on rare occasions.

    The DiAcro approach is also very interesting if it works. Pulling on a lever 25 to 100 times? Sure, sign me up. That's better than pumping a jack. The machine, while incredibly versatile, is limited to just bending stuff.

    OK, now it becomes a comparison between something like an electric powered hydraulic press --with it's many uses-- to a lever-actuated dedicated bending machine which can bend just-about anything you want but that's all it does. I get the sense that the cost of the equipment would be comparable. So, if you have a 4x4 foot spot on the shop to install one machine, which way do you go? My gut feeling right now, without applying much thought to the matter, is that the electric-actuated hydraulic press could be a far more useful tool. This changes if we want to bend a bunch of other stuff, the press cannot do the amazing range of things the DiAcro does without effort.

    That's where I am right now. For the kids, a the CertiFlat press for $500 sounds like the ticket. It's a good deal and it works at their time scale (bend a handful of pieces per year). For our shop, I think we are spending $5K to $10K on something. Not sure what that is yet. I am leaning towards a hydraulic press mainly due to the perceived general utility of the machine.

    Thanks.

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    Man, I can't say this enough. That Enerpac bench mounted Hydraulic press in out last shop, got used a LOT, and was a really handy tool, with a value well above the very limited space it took up.

    Build your own version of the Easton press brake, to fit your own needs.

    I would suggest a look around the web for books that deal with press brake stuff. It's not a new tech, and there are a lot of ways that guys have worked out quick and dirty but accurate enough estimates of the tonnage required.calculating required tonnage for press brake - Google Search

    My method is simpler than most. Easton says in their video that their brake will bend 3/8 steel brackets on 20 tons. That pretty much tells me that a 20t press is way more than you need.

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    Quote Originally Posted by trevj View Post
    My method is simpler than most. Easton says in their video that their brake will bend 3/8 steel brackets on 20 tons. That pretty much tells me that a 20t press is way more than you need.
    I can appreciate that. My thinking is: Other than bending, which might only require, say, 10 to 12 tons, what else are we going to want to do with this thing that might require more force. I don't have an answer for that yet.

    I am also going to guess that if you have a tool that can bend 3/8 in material you could easily start to get greedy and, well, bend thicker stuff. In other words, having the capability for prototyping would change design considerations. I can't think of anything in the last, say, twenty years, were we've had to design a bracket much thicker than 1/8 in, so this might be completely irrelevant.


    Build your own version of the Easton press brake, to fit your own needs
    Interestingly enough, in my research I came across a bunch of videos from people who have done some pretty interesting things exactly along these lines. These guys seem to have made a business out of it:

    SWAG Press Brake Kits

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    Quote Originally Posted by martin_05 View Post

    Interestingly enough, in my research I came across a bunch of videos from people who have done some pretty interesting things exactly along these lines. These guys seem to have made a business out of it:

    SWAG Press Brake Kits
    Right. Those guys make kits marketed to guys that are heavy enough into offroading, that they want to make roll cages and in some cases, complete frames for their vehicles.

    Steal the idea, scale it to what you need, rather than just buying and building the kit they are selling.

    As a suggestion,I would put it to you that a brake like that with a single 4 inch wide straight, and a single 4 inch wide goosneck die in it, would likely cover your needs for a very long time, based on what you say your needs are. Hell like as not, a single 4 inch gooseneck die would do all you wanted.

    If you want to make brackets in the flat, and have the holes etc., all drilled or milled out, prior to bending, you also need to learn how to calculate your bends using the "K" Factor for each bend. This factor is essentially the distance of extra metal you add to the bend to account for the amount needed to form the radius.

    This site has a trove of sheet metal info. Creo Parametric Help Center

  7. #47
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    Quote Originally Posted by trevj View Post
    I would put it to you that a brake like that with a single 4 inch wide straight, and a single 4 inch wide goosneck die in it, would likely cover your needs for a very long time, based on what you say your needs are. Hell like as not, a single 4 inch gooseneck die would do all you wanted.
    I think you are right.

    If you want to make brackets in the flat, and have the holes etc., all drilled or milled out, prior to bending, you also need to learn how to calculate your bends using the "K" Factor for each bend. This factor is essentially the distance of extra metal you add to the bend to account for the amount needed to form the radius.
    I have K factor tables in Solidworks Sheet Metal that were provided to us by the sheet metal vendors we use (so parts come out perfect). The stock SW K factor tables were OK, but we got better results with vendor-provided tables. I'll start there and hope the same K factor will produce usable results for manual prototyping. If not, we'll create a new set of bend tables for whatever manual approach we use.


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