德语
1. Basic methods and steps for designing tool fixtures
The original information for preparing tool fixture design before design includes the following contents:
a) Design notice, finished parts drawing, blank drawing and process route and other technical information, understand the processing technical requirements of each process, positioning and clamping plan, processing content of the previous process, blanking situation, machine tools, tools, inspection and measuring tools used in processing, processing allowance and cutting usage, etc.;
b) Understand the production batch and the demand for fixtures;
c) Understand the main technical parameters, performance, specifications, accuracy of the machine tool used, and the connection dimensions of the structure of the fixture connecting part, etc.;
d) Standard material inventory of fixtures.
2. Issues in the design of tooling fixtures
The fixture design generally has a single structure, which gives people the feeling that the structure is not very complicated. Especially now, the popularity of hydraulic fixtures has greatly simplified its original mechanical structure. However, if the design process is not considered in detail, unnecessary trouble will inevitably occur:
a) The margin of the processed part. This causes the blank size to be too large and interfere. Therefore, you must prepare a blank drawing before designing. Leave enough space.
b) Chip removal smoothness of fixtures. During design, due to the limited processing space of the machine tool, the fixture is often designed with a relatively compact space. At this time, the iron chips generated during the processing process are often ignored in the storage of the fixture dead corners, including the poor flow of chip liquid, which brings a lot of trouble to future processing. Therefore, problems that arise during the processing process should be considered at the beginning of actual practice. After all, fixtures are based on improving efficiency and convenient operation.
c) Overall openness of the fixture. Ignoring openness makes it difficult for operators to install cards, time-consuming and labor-intensive, and a design taboo.
d) Basic theoretical principles of fixture design. Each set of fixtures has to undergo countless clamping and loosening actions, so it may meet the user's requirements at the beginning, but the addition should have its accuracy retention, so don't design something that is contrary to the principles. Even if you can be lucky enough to be able to do it now, there will be no long-term sustainability. A good design should be tempered by time.
e) Replaceability of positioning elements. The positioning elements are seriously worn, so quick and convenient replacement should be considered. It is best not to design into larger parts.
Accumulating experience in fixture design is very important. Sometimes design is one thing, and in practical applications, it is another thing. Therefore, good design is a process of continuous accumulation and summary.
Commonly used tool fixtures are mainly divided into the following types according to their functionality:
01. Clip mold
Definition: Tools for positioning and clamping using product appearance
Design points:
1. This type of clamping mold is mainly used on vis, and its length can be intercepted as needed;
2. Other auxiliary positioning devices can be designed on the clamping mold, and the clamping mold is generally connected by welding;
3. The above picture is a simplified picture, and the size of the mold cavity structure is determined by the specific situation;
4. Fix the positioning pin of diameter 12 at the appropriate position on the moving die, and slide the positioning holes at the corresponding positioning mold to fit the positioning pin;
5. The assembly cavity needs to be offset and enlarged by 0.1mm based on the outline surface of the non-shrunk blank drawing when designing.
02. Drilling and milling tooling
Design points:
1. If necessary, some auxiliary positioning devices can be designed on the fixed core and its fixed plate;
2. The above picture is a simplified structural diagram. The actual situation requires corresponding design according to the product structure;
3. The cylinder depends on the size of the product and the stress during processing. SDA50X50 is commonly used;
03. CNC, instrument chuck
A CNC chuck
Toe-in chuck
Design points:
1. The dimensions not marked in the above picture are based on the inner hole size structure of the actual product;
2. The outer circle that is in positioning contact with the inner hole of the product needs to leave a margin of 0.5mm on one side during production, and is finally installed on the CNC machine tool and finely turned to size to prevent deformation and eccentricity caused by the quenching process;
3. It is recommended to use spring steel as the material for the assembly part, and 45# for the tie rod part;
4. The thread M20 on the tie rod part is a commonly used thread, which can be adjusted according to the actual situation.
Instrument toe-in chuck (1)
Design points:
1. The above picture is a reference diagram, and the assembly size and structure are based on the actual product’s overall dimensions and structure;
2. The material is 45# and quenched.
Instrument external beam chuck (2)
Design points:
1. The above picture is a reference diagram, and the actual size depends on the inner hole size structure of the product;
2. The outer circle that is in positioning contact with the inner hole of the product needs to leave a margin of 0.5mm on one side during production, and is finally installed on the instrument lathe and finely turned to size to prevent deformation and eccentricity caused by the quenching process;
3. The material is 45# and quenched.
04. Gas testing tooling
Design points:
1. The picture above is a reference picture of the gas testing tooling. The specific structure needs to be designed based on the actual structure of the product. The idea is to seal the product in the simplest way possible and fill the part that needs to be sealed with gas to confirm its tightness;
2. The size of the cylinder can be adjusted according to the actual size of the product, and it is also necessary to consider whether the stroke of the cylinder can meet the convenience of picking up and placing the product;
3. The sealing surface in contact with the product generally uses materials with good compression capacity such as Uni glue and NBR rubber rings. At the same time, please note that if there are positioning blocks in contact with the appearance surface of the product, try to use white glue plastic blocks and cover them with cotton cloth during use to prevent damage to the appearance of the product;
4. The positioning direction of the product must be considered during design to prevent leakage of gas from being trapped inside the product cavity and causing false detection.
05. Punching tooling
Design points: The picture above shows the common structure of punching tooling. The bottom plate functions to facilitate fixation to the workbench of the punch machine; the positioning block functions to fix the product. The specific structure is designed according to the actual situation of the product. The center point is surrounded by the center point for convenient and safe picking and placing of the product; the baffle functions to facilitate the separation of the product from the punching knife; and the pillar functions to fix the baffle. The assembly positions and sizes of the above parts can be designed according to the actual conditions of the product.
06. Welding tooling
Welding tooling mainly fixes the position of each component in the welding assembly and controls the relative size of each component in the welding assembly. Its structure is mainly a positioning block, which needs to be designed according to the actual structure of the product. It is worth noting that when the product is placed on the welding tooling, a sealed space must not be created between the tooling to prevent excessive pressure in the sealed space from affecting the size of the parts after welding during the welding and heating process.
07. Polishing jig
08. Assembly tooling
Assembly tooling is mainly used as a device to assist in positioning during the assembly process of components. The design idea is that the product can be easily picked up and placed according to the assembly structure of the components. The appearance of the product cannot be damaged during the assembly process, and the product can be covered with cotton cloth to protect the product during use. In the selection of materials, try to use non-metallic materials such as white glue.
09. Pad printing, laser engraving tooling
Design points: Design the positioning structure of the tooling according to the engraving requirements of the actual product. Pay attention to the convenience of picking and placing the product, and the protection of the product appearance. The positioning block and the auxiliary positioning device in contact with the product should be made of white glue and other non-metallic materials as much as possible.
Note: All pictures in the article are reprinted online, and will be deleted if infringed!
