From the shape of the bottom of the package, there are rectangular, arc-shaped package bottom, the two ends of the bend in the side of the package, other package bottom, etc.; from the bottom of the structure of the ordinary package bottom, embedded package bottom, double package bottom, etc.. In the fan design, the main performance is symmetrical and asymmetrical fan two types. As the fan is sewn around the bottom, so the bottom length of the fan and the circumference of the bottom must be equal, and the fan needs to be accurately aligned with the bottom, otherwise the whole body will appear skewed phenomenon.
1. The bag body composed of rectangular bag bottom
Rectangular package bottom including ordinary rectangle, rectangle with slightly rounded corners, rectangle of various deformations, etc., of which the first two are more commonly used, ordinary rectangle according to the size of the bottom of the package view can be drawn. Sometimes due to the need for design, the bottom piece of the package will be decorated with tooth strips to meet the needs of the shape and aesthetics.
In the production, if the bottom part of the package is inlaid with teeth, it is necessary to sew the teeth to the bottom of the package first, pay attention to the production of the teeth in the corner part of the bottom of the package, the margin of the four corners of the teeth should be uniform, the teeth should not be too loose or too tight, so as not to cause the unevenness of the parts. The bottom of the right-angle package is seldom inlaid with pressure strips, if it must be used, the corner part of the right angle should be cut in the pressure strips to ensure that the length of the pressure strips and the size of the bottom edge of the package. In addition, two fan parts should be sewn together at the side first, and then, finally, the bottom of the bag and the sewn fan should be sewn together - when sewing, strict attention should be paid to the correct alignment of each mark alignment point, and the symmetrical parts should be absolutely symmetrical, otherwise it will cause the skew of the bag body shape.
2. Body made of oval and round bottom
The bag body made of oval bottom, in the actual sewing process, the sewing order is the same as the bag body made of rectangular bottom, except that the corner curve of the oval bottom is longer and the production difficulty is lower than the smaller radius corner, which can be handled in accordance with the approximate straight line. The package body composed of a round package bottom, more rectangular or trapezoidal sector to form a barrel-shaped package. This kind of bag form variation is expressed in the upper mouth of the bag body through different ways of rope belt through the knot and produce different visual effects, or in the side of the bag body with another patch of leather to increase the sense of roughness, etc.. Some bags are made of tapered scallops, and their production methods are similar to those of barrel-shaped bags.
By the semi-elliptical bag bottom composition of the bag, the front and back of the sector is generally asymmetric. Asymmetric fan surface form changes freely and richly, mainly in the following aspects: to add rigid parts of the rear fan surface as the basis, the front fan surface to do various forms of change, such as the front fan surface of the plane, curved changes, etc.; rear fan surface to the bag cover and front fan surface extension of the modeling changes; the bottom of the bag to the front fan surface extension of the modeling changes. In the sewing, sewing procedures and the rectangular bag bottom composed of the bag body is basically the same, but need to pay attention to the straight line and arc connection parts of the alignment problem.
3. The bottom of the bag extended to the bag body drawing
In modern bag design, the bottom of the bag often has two variations: one is the bottom of the two ends to the side, the end of the different changes in shape to increase the change in the form of the bag body; the other is the bottom of the bag or both sides of the same time to the fan extension, so that the bag body shape is new, chic. This structure requires two projections, namely, the main view and side view to more clearly understand the extension of the bottom of the package, through the side view can determine the shape and height of the bottom of the package bent into the side part, as the basis for the production of the bottom sample. The shape of the end of the bottom of the package is generally triangular, arc, rectangular, etc. The following is an example of the bottom of the package with the shape of the end of the arc to introduce the production method.
The bottom of the package is made by bending the part of the person's side and rectangular package bottom combination, in the sector mapping to subtract the bottom of the extended person package side of the arc part, so bending the person's side of the arc-shaped package bottom in the sewing or will be regarded as the bottom of the package, not the side of the package. When sewing, pay special attention to the stitching of the part bent into the side, because this part is mostly shaped and has - a certain production difficulty, when sewing, pay special attention to the corners and arc parts and the connection of the fan, try to ensure that the connection is smooth and round, the curve is smooth, never due to sewing problems caused by the failure of the decoration. When making, according to the reverse stitching method, the front and back fan is sewn together, and then the bottom of the bag is sewn together with the fan, and finally the fabric and lining are sewn together at the top of the bag to complete the body of the bag.
Although the bottom of the bag is the basic part of the bag body, the changes in the form of the front and back sectors are also very rich, such as changes in the thickness and quantity of the bottom, which can increase the thickness of the bottom and express the modern sense of leather goods, or form a multifunctional bag through the division of the vertical space; the displacement of the structure line between the front and back sectors and the bottom and changes in form, the principle of change is to make the "change" of the parts on the basis of the basic structure. The principle of change is to "expand" or "reduce" the components on the basis of the basic structure, while other components are adjusted accordingly, and when the reduction is insufficient, other components are added to make the overall structure change qualitatively and carry out structural innovation.
