The calculation of sheet metal expansion is an important skill because the sheet metal unfolding size directly affects the precision of the sheet metal workpiece. The sheet metal unfolding size is an important data that affects the accuracy of sheet metal bending. The accuracy of the sheet metal expansion calculation is determined by the bending deduction factor. Today is not to talk about the calculation of sheet metal, mainly if the sheet metal is not allowed to open, or other factors, the size of the sheet metal bending is not allowed to do? The calculation of the sheet metal subtraction factor can be seen in the article shared earlier.

When we make a sheet metal bend, we need to calculate the sheet metal unfolding size first. The actual sheet metal unfolding size is measured, and the calculation is performed without any problem. Some of our bending operators have a bad habit of bending directly according to the size of the paper. After bending and forming, the final bending size is measured, which is a few millimeters worse than the drawing, and the sheet metal parts are directly scrapped. Some of the final molded dimensions are dimensionally fit and have tolerance fits.

How do you bend a part that is unfolded and has actual errors?

1. Look at the drawings to see if there are any tolerances. The tolerances are generally matched with other parts. If the dimensions are too bad, the parts will be scrapped and the quality inspectors will not be qualified. For tolerances, bend according to the actual size of the drawing. To ensure that the drawings have tolerances, other non-significant dimensions can be increased or decreased according to the actual situation.

2. What should I do if the drawings do not have tolerances? This requires bending according to actual experience, assembling it yourself or having an assembled drawing, consulting and viewing those important dimensions, and bending according to the above method. For sheet metal parts that are not assembled in your own company and cannot be communicated to the technical information, you can refer to the following methods to bend:

a. Door plate type sheet metal parts, the embedded door is the largest size of the shape has a matching relationship. The external dimensions of the external door are also important, and the thickness direction is also important. Therefore, only the first bend of the door panel is not an important size and can be adjusted accordingly.

Door plate type sheet metal bending diagram

b. Sheet metal parts with waist holes (long round holes), the waist hole is used to adjust the machining error, and the bending size of the waist hole can be adjusted accordingly.

c. Parts with positive and negative bends, the first bend is less than 10 mm. Generally, it is a frame part that cooperates with the door panel. The first bend can also be adjusted according to the actual situation.

d. If you can't tell the actual use, you can only divide the bending error for each bend. The bending dimension is within the free tolerance.

The method of making the sheet metal unfolding and not conforming to the actual situation is written in this way. Xiao Bian suggestion: The above method is just a way to do it. When working, it is necessary to ensure that the unfolding size is calculated accurately. It is more in communication with the sheet metal process, and more communication with the CNC punching or laser cutting operator. The final sheet metal size is strict. Strive to be the best sheet metal. Be the best sheet metal mechanic.