US20090258577A1

US20090258577A1 - Method for Trimming Molds of Automotive Metal Sheets

Info

Publication number: US20090258577A1
Application number: US12/333,421
Authority: US
Inventors: Yuan-Kun TSENG
Original assignee: Coc Tooling & Stamping Co Ltd
Current assignee: Coc Tooling & Stamping Co Ltd
Priority date: 2008-04-10
Filing date: 2008-12-12
Publication date: 2009-10-15
Also published as: TWI344874B; TW200942340A

Abstract

The present invention provides a method for trimming molds of automotive metal sheets, which comprise a top mold and a bottom mold. The top mold has a concave mold surface, and the bottom mold has a corresponding convex mold surface. The method comprises: 1. Use the top mold as the base mold, and smear dye on the top mold; 2. Close the bottom mold to the top mold; and 3. Polish the mold surface of the bottom mold. Thereby, the processing method according to the prior art is broken through, and an ergonomic trimming operation is hence provided. Accordingly, the trimming process is simplified, and the labor hours are reduced. Beside, the accuracy of trimmed molds is improved and the subsequent mold-clamping process can be omitted. Thereby, the exterior quality of the metal sheets can be enhanced while reducing substantial labor hours, and economic benefits for manufacturing molds of metal sheets for an automotive body can be achieved.

Description

FIELD OF THE INVENTION

The present invention relates generally to a method for trimming molds of automotive metal sheets, and particularly to a method for trimming using a top mold as the base. Thereby, the exterior quality of the metal sheets can be enhanced while reducing substantial labor hours, and economic benefits for manufacturing molds of metal sheets for an automotive body can be achieved.

BACKGROUND OF THE INVENTION

The automotive industry is an important basic industry for modern people's livelihood. It is a common knowledge that an automobile comprises a great amount of components with various sizes. Most metal components are mass-produced via molds. For large-sized automotive metal sheets, according to the prior art, after an automotive metal sheet is shaped by stamping using a mold of large-sized automotive metal sheet, if flaws or deviations exist in size or appearance, they can be resolved by polishing. In addition, there is a certain tolerance in appearance. However, because modern automobile manufacturers' or consumers' demand on exterior quality is increasingly severe, more and more automobile manufacturers require no polishing for avoiding zinc-plating layer on metal sheets being polished, and thus reducing antirust capability, during the polishing operation. Furthermore, a polishing operation costs much in labor. Thereby, precise manufacturing and trimming of automotive metal sheets has become a crucial subject for enhancing exterior quality while maintaining economic benefits.
Please refer to FIGS. 1A, 1B, and 2. The stamping molds used for shaping metal sheets of an automotive body according to the prior art comprise a top mold 91 and a bottom mold 92. The top mold 91 has a proper form used for shaping, and exhibits roughly a concave mold surface 911. The bottom mold 92 has a proper shaping form corresponding to the top mold 91, and exhibits roughly a convex mold surface 921. As shown in FIG. 3, when stamping a metal sheet for an automotive body, a steel plate 93 is shaped by stamping by means of the top and bottom molds 91, 92 and thus the manufacturing of a metal sheet for an automotive body 94 is completed as shown in FIG. 4. Because the top mold 91 and bottom mold 92 are the principal parts when stamping a metal sheet for an automotive body 94, the manufacturing accuracy and efficiency have decisive influences on the quality, economic benefits, and competitiveness of stamping a metal sheet for an automotive body 94. The procedure of the manufacturing technology for stamping molds for metal sheets of an automotive body according to the prior art includes: acquirement of design drawings and CAD (Computer-Aided Design) data, design of manufacturing method, design of molds, manufacturing of Styrofoam, manufacturing of casts, NC (Numerical Control) programming, processing by large-sized machines, trimming (shiage), mold clamping, mold trial, and quality management (measurement and appearance judgment of metal sheets). The trimming process of the stamping molds (the top mold 91 and bottom mold 92) described above mainly performs polishing process on the stamping molds, referring to FIGS. 5 and 6, and includes the following procedure:

- 1. Take the bottom mold 92 as the base mold, and smear red lead (step 96 in FIG. 5) on the bottom mold 92. That is, use the bottom mold 92 with a convex mold surface 921 as the base mold, and smear red lead 961 on the convex mold surface 921.
- 2. Reverse the top mold 91 to make the surface of the top mold 91 face up (step 97 in FIG. 5). Because the surface to be polished and trimmed is on the top mold 91, reversing the top mold 91 helps the process of polishing and trimming.
- 3. Close the bottom mold to the top mold 91 (step 98 in FIG. 5). Namely, close the lifted and moving bottom mold 92 to the stationary top mold 91. Then, the concave mold surface 911, the surface to be trimmed, on the top mold 91 will be dyed with red lead.
- 4. Polish the mold surface of the top mold 91 (step 99 in FIG. 5). That is, trim the concave mold surface 911 dyed with red lead on the top mold 91. The polishing and trimming tools include: curved grinding wheels, coarse rubstones, grinding wheels with handles, pen-type grinding wheels, files, and wetstones.

The trimming process on molds for automotive metal sheets according to the prior art as described above can trim the molds for metal sheets of an automobile. However, there exist some significant drawbacks according to the method. For example, according to the prior art, the bottom mold is used as the base mold for polishing the top mold. Because of the concave mold surface of the top mold (including complicated mold shapes), the operation of polishing and trimming the concave mold surface does not comply with ergonomics. Thereby, the operation is difficult, costing long operation time, and hence is not economic. Beside, because the mold surface of the top mold is concave, it tends to deform or displace while polishing the shaped surface, and thus incurring other problems in trimming. Moreover, because the trimming processes are repeated operations of trimming and examinations, it takes months to perform the trimming processes, costing much in costs and time. Thereby, the shortcomings of high production costs, reduced efficiencies, and uneconomic problems according to the prior-art trimming process of molds for automotive metal sheets have to be overcome.
Owing to the shortcomings of the trimming process of molds for automotive metal sheets according to the prior art, the present invention provides a method for trimming molds of automotive metal sheets with economic benefits and product competitiveness.

SUMMARY

An objective of the present invention is to provide a method for trimming molds of automotive metal sheets. According to the present invention, exterior quality of metal sheets can be improved, substantial labor hours can be saved, costs can be reduced, and hence the overall production efficiency and economic benefit can be increased.
Another objective of the present invention is to provide a method for trimming molds of automotive metal sheets. According to the present invention, the processing method according to the prior art is broken through, and ergonomic trimming operations are provided. Thereby, the trimming process is simplified and the labor hours are shortened. In addition, the accuracy of trimmed molds is enhanced, and subsequent mold-clamping operation can be omitted.
The method for trimming molds of automotive metal sheets according to the present invention trims molds for metal sheets, which comprise a top mold and a bottom mold. The top mold has a concave mold surface, and the bottom mold has a corresponding convex mold surface. In order to achieve the objectives and benefits described above, the method includes:

1. Using the top mold as the base mold, and smearing dye on the top mold;
2. Closing the bottom mold to the top mold; and
3. Polishing the mold surface of the bottom mold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a schematic diagram of a top mold for a metal sheet according to the prior art;

FIG. 1B shows a schematic diagram of a bottom mold for a metal sheet according to the prior art;

FIG. 2 shows a schematic diagram of a top mold and a bottom mold for a metal sheet set up correspondingly according to the prior art;

FIG. 3 shows a schematic diagram of a metal sheet being stamped between a top mold and a bottom mold according to the prior art;

FIG. 4 shows a schematic diagram of a metal sheet according to the prior art;

FIG. 5 shows a flowchart of trimming stamping molds according to the prior art;

FIG. 6 shows an operation schematic diagram of stamping molds before closing up according to the prior art;

FIG. 7 shows a schematic diagram of a top mold and a bottom mold set up correspondingly according to the present invention;

FIG. 8 shows an operation schematic diagram of stamping molds before closing up according to the present invention; and

FIG. 9 shows a flowchart of trimming stamping molds according to the present invention.

DETAILED DESCRIPTION

In order to make the structure and characteristics as well as the effectiveness of the present invention to be further understood and recognized, the detailed description of the present invention is provided as follows along with preferred embodiments and accompanying figures.
Referring to FIG. 7, the method for trimming molds of automotive metal sheets according to the present invention trims molds for metal sheets 10, which comprise a top mold 20 and a bottom mold 30. The top mold 20 has proper shapes used for forming, and roughly has a concave mold surface 21. The bottom mold 30, likewise, has proper shapes corresponding to the shapes on the top mold 20, and roughly has a convex mold surface 31. Referring to FIGS. 8 and 9, the method for trimming molds of automotive metal sheets according to the present invention comprises:

- 1. Use the top mold 20 as the base mold, and smear dye on the top mold 20 (step 41 in FIG. 9). That is, use the top mold 20 as the base mold, use the concave mold surface 21 as the base surface, and smear dye 22 on the concave mold surface 21. The dye 22 can be red lead (added with some diesel oil) or other dying materials.
- 2. Close the bottom mold 30 to the top mold 20 (step 42 in FIG. 9). Namely, close the bottom mold 30 (moving) to the top mold 20 (stationary). By the closing operation, print the dye 22 (red lead) to the convex mold surface 31 to be trimmed on the bottom mold 30. Alternatively, in the present step, the top mold 20 (moving) can close to the bottom mold 30 (stationary).
- 3. Polish the mold surface of the bottom mold (step 43 in FIG. 9). That is, trim the convex mold surface 31 dyed with the dye 22 (red lead) on the bottom mold 30. Because the surface to be polished and trimmed is the convex mold surface 31 on the bottom mold 30, it is more ergonomic for polishing operations, drastically simplifies the polishing operations and shortens substantial labor hours.

In practical operations, because the trimming accuracy can be improved at the same time, the mold-clamping operation after trimming process can be omitted and mold trial process can be performed directly, shortening operation time by 2 to 3 months. Thereby, according to the present invention, the exterior quality of the metal sheets can be enhanced while reducing substantial labor hours, and economic benefits for manufacturing molds of metal sheets for an automotive body can be achieved.
The method for trimming molds of automotive metal sheets according to the present invention breaks through the selection of the base mold or base surface for trimming molds according to the prior art. According to the present invention, the top mold (the concave mold surface) is chosen as the base mold, and the surface to be polished is the bottom mold (convex mold surface). Because the trimming operation on a convex mold surface is far simpler and more convenient than on a concave mold surface, the labor hours for trimming processes are substantially reduced.
Accordingly, the present invention conforms to the legal requirements owing to its novelty, non-obviousness, and utility. However, the foregoing description is only a preferred embodiment of the present invention, not used to limit the scope and range of the present invention. Those equivalent changes or modifications made according to the shape, structure, feature, or spirit described in the claims of the present invention are included in the appended claims of the present invention.

Claims

1. A method for trimming molds of automotive metal sheets, which comprise a top mold with a concave mold surface and a bottom mold with a corresponding convex mold surface, comprising steps of:

using the top mold as the base mold and smearing dye on the top mold;

closing the bottom mold to the top mold; and

polishing the mold surface of the bottom mold.

2. The method for trimming molds of automotive metal sheets of claim 1, wherein the dye in the step of using the top mold as the base mold and smearing dye on the top mold is smeared on the concave mold surface.

3. The method for trimming molds of automotive metal sheets of claim 1, wherein the top mold and the bottom mold have corresponding shapes thereon.

4. The method for trimming molds of automotive metal sheets of claim 1, wherein the dye in the step of using the top mold as the base mold and smearing dye on the top mold includes red lead or other dying materials.

5. The method for trimming molds of automotive metal sheets of claim 1, wherein the step of polishing the mold surface of the bottom mold polishes the convex mold surface dyed with the dye on the bottom mold.