The Flat Out Truth
Over the years (and several times recently) we have manufactured many sheet metal projects in which we have received only the flat pattern of the parts to use for the build. Sometimes only vague final formed part information or dimensions were given, if at all.
If all you have is a flat pattern, we can certainly work with you. However, it usually takes more time, energy, and sometimes there are additional costs for everyone involved. This is because it is often very difficult to determine what the final part dimensions should be based on just a flat pattern, especially if the bend deductions used to create it are unknown (which is usually the case).
Our suggestion is to spend your time and design dollars on what the final formed part should be, and let us worry about creating a flat pattern for it. That way we can apply the bend deductions that we know our tooling and processes will require, producing an accurate flat that is directly related to the formed part requirements. Two caveats are worth noting however. First is that when you are designing the part, be sure that generally speaking a viable flat can be produced (the part does not overlap on itself when flattened out). The second, is that it is not a bad idea to put a flat on your drawings for reference only (the dimensioned formed views being the critical information). This way you can indicate the direction of the bends, and it can help us “see” the part better if it is complicated.
These points aside, the main point is that it is much better for us (the manufacturer) to receive from you the formed configuration and dimensions of your part, rather than the flat pattern. Let us handle the flat pattern so you can spend your time on other more pressing things. Happy designing everyone!