Here's a comment I got on Reddit with regards to this video. This guy shares some great insights about how the team on the other end (the manufacturing/shop team) might prefer to receive sheet metal designs, from CAD designers/engineers. These are some GREAT POINTS and the TLDR point here is: Always work with (or talk to) the manufacturing team and find out what works best for them - it can save you a TON of time, since you won't have to waste time coming up with a good flat pattern - just let them do it (if that's what they want) 🙂 ======================================================= REDDIT COMMENT from Joaquin2071 I think this is a very good explanation for beginners going into sheet metal, however, if you are engineering and not actually manufacturing, it’s important to know that you shouldn’t be messing with these as it is up to the engineers at the manufacturer to determine the bend deduction based on their machines and their dies, especially when air forming. As someone who is an engineer in manufacturing, my job is a lot easier when the customer does not give a flat pattern and even better when they don’t dimension off of a flat pattern because 99% of the time, whatever k-factor/bd they are using is going to be way different than what we use. As far as the way I see k-factor, as someone who works directly with the brake department and has a gigantic table of bend deductions for all sorts of material and thicknesses, I see k-factor as a dependent variable that is found after doing live bend tests, finding the bend deduction by solving for how much the material shrunk. then, when plugged into the formula for bend deduction, you solve for the k-factor. That k-factor can then be used for that material, thickness, and radius to solve for non 90deg angles. The only time I ever use k-factor built into solidworks is for hems, and from there we proof the flat to show a bend deduction and then that is given to the brake operator. Just my little 2 cents from working in mfg for almost 5 years now (learning from old heads lol). P.s. A tried and true k-factor that is used a lot though that will almost always work is .4469. Especially for aluminum when air forming. That’ll get you pretty dang close P.p.s always dimension to the virtual exterior tangents, thank you :)

Excellent explanation and much much better format in 12 mins, then in shorts. Not too long (20- mins), not too short (1- min).

This is probably the simplest and best explanation of the "K factor" I've seen so far! Thanks! Well done!

Finally, I understood the concept of K factor. Thanks for sharing.

Default K-Factor in most software is 0.440 If you use this number you are going to be very close. A larger K-factor increases material & a lower number reduces material. Example. Stainless Steel 1.5mm Standard Pressbrake Tooling V12-30 Bend Allowance = 3.10mm Internal Rad =2.50 External Rad=4.0 K-Factor=0.413 A great utility is available online called Bendworks V1.1 from 2003! but it works fine on Win11. You can reverse the k-factor by doing a bend test & measuring it. Cut a blank 100x100 bend it to 90 degrees & measure it accurately. Good tutorial Toby, I work in sheet metal & some of the customers need more training! Cheers

For someone don't have the knowledge in sheet metal just like me this is a great lesson, Thank you

Great explanation. What finally really helped me was to understand that the K-Factor is a percentage of the thickness of the material. In other words, the total thickness of the material is 100%. A K-Factor of .4 then is for all intent purposes 40% of the material thickness; your offset basically.

Visual explanation really helped to understand concepts.

Wow great video and shout out to the other commenters sharing their time tested wisdom!

Awesome , this is the best explanation I've ever heard for bend allowance, Thank you

That was new to me too! Home run!

Thank you for the lesson

This is well explained Toby!

Well explained, thank you!

Excellent, thanks!

great explanation

Hello, I have been looking for a video about unbend / flatness for determining blank size dies for a long time. I want to ask how to make blank sizes from neutral format parts such as STP, x.t, etc. Apart from using logopress and autoform If the solidwork format such as sldprt can still be unbend using the sheet metal feature,

They had us writing pages worth of reports on this shit. Im saying you spend 12+ hours grinding and they give you the report back at C- or D+ on a good day. Those engineers dont mess around.

it used to be a line of Wilson tennis racquets

Where did the 0.35 K-factor come from?

So the Q number in the table is bend deduction, isn’t it?

I completely understand what k factor is and I use it almost all the time. However I do not understand how to know what is the correct k factor or how to go about figuring out what the correct k factor should be. I just always use .5 since I almost never use metal thicker than 14 GA. I can't be that far off. But I would like to know how to figure out the right k factor for me.

so how is kfactor calculated for different thickness and radius?

Spot on but you didn't explain that K-Factor is just the percentage of the material thickness. The line/depth that doesn't change length throughout the bend. All the material on the inside of this line gets compressed and all the material on the outside of this line gets stretched. In the real world with steel and aluminum a K-Factor of .4 is a good baseline until you run samples or prototypes. And your shear size is smaller than the outside bend flanges combined.

If bend radius is greater than 3x material thickness, k-factor would usually be 0.5