Question 1: What are the specific standard parts of the fixture? Clamps are divided into three types. Clamp types can be divided according to their usage characteristics: ①Universal universal clamps. Such as machine vises, chucks, suction cups, dividing heads and rotary worktables, etc., which have great versatility and can better adapt to the transformation of processing procedures and processing objects. Their structures have been finalized, and their sizes and specifications have been series. ization, most of them have become a standard accessory for machine tools. ②Specialized fixture. It is specially designed and manufactured for the clamping needs of certain product parts in a certain process. The service target is specific and highly targeted. It is generally designed by the product manufacturer itself. Commonly used ones include lathe fixtures, milling machine fixtures, ram molds (machine tool fixtures used to guide the tool to drill or ream holes on the workpiece), boring dies (machine tool fixtures used to guide the boring bar to drill holes on the workpiece) and traveling fixtures (used to guide the boring bar to drill holes on the workpiece). Mobile fixture on the automatic line of combined machine tools). ③Adjustable clamp. Special fixtures that allow components to be replaced or adjusted. ④Combined fixture. A fixture composed of standardized components of different shapes, specifications and uses, suitable for trial production of new products and single-piece, small-batch production and temporary tasks where products are frequently changed.
Standard parts generally appear in combination fixtures, but there are so many standard parts. How much do you need to know? You can go to the bookstore to find books about combination fixtures and read wenku.baidu/...4
This is Baidu’s combination fixture
Question 2: Manufacturing and processing standards for tooling fixtures. Meet the stability and reliability of workpiece positioning during use;
2. Have enough The load-bearing or clamping strength to ensure the construction process of the workpiece on the fixture;
3. Meet the simple and fast operation during the clamping process;
4. Vulnerable parts It must be a structure that can be quickly replaced, and it is best not to use other tools when conditions are sufficient;
5. The reliability of repeated positioning of the fixture during adjustment or replacement must be met;
6. Try to avoid complex structures and expensive costs;
7. Try to use standard products with reliable quality on the market as component parts;
8. Meet the requirements of the country or region where the fixture is used Safety laws and regulations;
9. The design follows the principle of priority in order of manual, pneumatic, hydraulic, and servo;
10. Form the serialization and standardization of the company's internal products.
Question 3: Is the pressure plate in fixture design a standard part? 1. According to the "Machine Tool Fixture Design Manual", the pressure plate in fixture design is a standard part.
2. Standard parts refer to commonly used parts (parts) that have been completely standardized in terms of structure, size, drawing method, marking, etc. and are produced by professional factories, such as threaded parts, keys, pins, etc. , rolling bearings, etc. Broadly speaking, it includes standardized fasteners, connections, transmission parts, seals, hydraulic components, pneumatic components, bearings, springs and other mechanical parts. The narrow sense only includes standardized fasteners. The commonly known standard parts in China are the abbreviation of standard fasteners. It is a narrow concept, but the existence of a broad concept cannot be ruled out. In addition, there are industry standard parts, such as automobile standard parts, mold standard parts, etc., which also belong to broad standard parts.
Question 4: Questions about fixture assembly standards or assembly processes. 5 points. It’s difficult for others to answer this question you asked. Go buy this book and learn about it. It costs dozens of dollars.
Question 5: What types of fixtures are there? They are usually product parts, including thick steel plates, sheet metal parts, steel castings, and a small number of plastic parts. Usually special fixtures are used for machining and welding, and some are used as inspection fixture clamping mechanisms
Question 6: What is a welding fixture? On the automobile welding line, only 30 to 40% of the work is actually used for welding operations, while 60 to 70% is auxiliary and clamping work. Because clamping is done on the welding fixture, the fixture plays an important role in the entire welding process.
During the welding process, a reasonable fixture structure is conducive to rational arrangement of assembly line production, easy to balance work station time, and reduce non-production time. For companies with multiple models, if they can scientifically consider single-use or mixed-type fixtures, it will also help build mixed-type assembly lines and improve production efficiency.
1. Characteristics of automobile welding process
(1) Materials and structure
Automobile welding materials are mainly cold-rolled steel plates of low carbon steel and galvanized steel plates. and a small amount of hot-rolled steel plates. They have good weldability and are suitable for most welding methods. However, because they are thin plate parts, they have poor rigidity and are easy to deform.
In terms of structure, most of the welded parts are stamped parts with spatial curved surfaces, with complex shapes and structures. Some stamping parts with deep cavities have rebound deformation in addition to deformation caused by poor rigidity.
(2) Welding methods
The main automotive welding methods include CO2 gas shielded welding and resistance welding. CO2 gas shielded welding has a wide range of applications, and the requirements for the fixture structure are not very strict. Resistance welding has strict requirements on fixtures, especially multi-spot welding, reaction welding and robot spot welding. Since automobile welding is mainly resistance welding, this article will discuss the design of resistance welding fixtures.
(3) Welding process flow
The basic feature of automotive welding is a combination and reassembly process from components to components and then to the assembly.
Each process from components to body welding assembly is independent of each other and connects the past and the future. Therefore, the welding accuracy of the components determines the welding accuracy of the component assembly, which ultimately affects and determines the quality of the body welding assembly. Welding accuracy and quality require that the positioning datum of interrelated components, parts and body welding assembly fixtures should be unified and inheritable. Only in this way can the quality of the final product be guaranteed. Even if quality problems occur, the causes can be easily analyzed and corrected. and control.
The welding process is mainly based on assembly line production, so the fixture design should be conducive to the layout and design of the assembly line, and also consider providing convenience for production management.
2. Design methods and steps of welding fixtures
1. Before designing a welding fixture, you should first understand the production program, product structural characteristics, process requirements and production line layout, conduct sufficient process research, refer to advanced fixture structures at home and abroad, and determine the overall fixture plan based on the actual situation. Such as whether it is a fixed fixture or a portable fixture, whether the level of mechanization and automation is high or low, whether the main fixtures of several vehicle models are mixed and used, etc.
2. Determine the positioning and clamping methods according to the structural characteristics of the weldment and the model and specifications of the required welding equipment; at the same time, select the appropriate positioning points and key positioning points according to the process characteristics of the stamping parts and the needs of the subsequent assembly process.
3. After the main mechanism is determined, the auxiliary device can be determined. Such as water, electricity, gas circuits, gas and hydraulic components and protective copper plates required for external solder joints of covering parts.
4. Because the overall structure of the welding fixture is very large and the spatial structure and size are complex, its design should adopt the coordinate method and modular design method to improve design efficiency.
5． When designing the specific structure of the fixture, as many standardized components as possible should be used, or the degree of generalization and serialization should be improved.
3. Composition, structure and requirements of welding fixtures
Automobile welding fixtures usually consist of five major parts: fixture floor, positioning device, clamping mechanism, measurement system and auxiliary system.
(1) Fixture floor
The fixture floor is the basic component of the welding fixture. Its accuracy directly affects the accuracy of the positioning mechanism, so it affects the flatness and surface roughness of the working plane. All have strict requirements.
The benchmark of the fixture's own measurement device is established on the fixture floor. Therefore, when designing the fixture floor, sufficient space should be left to set up the reference slot of the measurement device to meet the needs of actual measurement.
In addition, without affecting the assembly of the positioning mechanism and the establishment of the positioning slot, a frame structure should be used as much as possible, which can save materials and reduce the weight of the fixture. This is especially important for accompanying fixtures on the assembly line.
(2) Positioning device
The components in the positioning device usually include fixed pins, latches, stop irons, V-shaped blocks, and positioning blocks determined according to the actual shape of the weldment. {Figure 1 shows the dedicated positioning block}.
1. Because welding fixtures are used very frequently, the positioning components should have sufficient rigidity and hardness to ensure accuracy during the replacement and trimming period.
2. In order to facilitate the adjustment and replacement of the main positioning components and to enable the clamp to have a flexible hybrid function, the positioning mechanism should be designed to be combined and adjustable as much as possible. As shown in Figure 1, the positioning component A-1...gt;gt;
Question 7: What is a welding fixture? What are the requirements for the welding fixture? The welding fixture is to ensure the size of the weldment and improve the Assembly accuracy and efficiency, clamps used to prevent welding deformation. There are many varieties, most of which are used for targeted occasions (products). For example, the position of the central axis of the bicycle frame in the picture below is welded by 5 pipes. Without a special welding fixture, it is difficult to ensure the correct position of each other.
The picture below is a universal welding fixture that ensures right angles between welded parts.
General requirements for welding fixtures:
Quick action and easy operation;
There is enough space for assembly and welding, and it cannot affect the welding operation and welding observation. Does not hinder the loading and unloading of weldments;
Reliable clamping and appropriate rigidity. The positioning position and geometry of the welded parts cannot be damaged;
Protective devices should be installed when necessary;
They cannot be damaged during the welding process;
The fixture The force application point should be located at or near the support of the weldment to prevent the support reaction force from forming a force couple with the clamping force or gravity;
Note that various welding methods have different effects on thermal conductivity, electrical conductivity, magnetic isolation and insulation, etc. Special requirements put forward by the fixture;
The positioner and clamping mechanism on the fixture should not have too many mechanisms to facilitate manufacturing and maintenance;
Pneumatic and other driving methods can be used to Improve production efficiency and reduce labor intensity of workers;
Prioritize the use of universal, standardized clamping mechanisms and standard parts for production;
As a component of the secondary circuit of the welding power source When doing so, a section of the secondary circuit should be led out from the nearest end of the weldment to prevent the welding current from passing around the fixture;
The vulnerable parts are usually designed to be replaceable structures;
Easy Manufacturing, less investment, low manufacturing cost and short payback period. Energy consumption and management costs are low during use.
Question 8: What is an anchor? What is a clamp? The statement above is incorrect, because I am a professional, and both clamps and anchors are tools used for prestressed tensioning
The clamp is a tensioning tool that clamps the prestressed tendons for tensioning during the production of prestressed components. It can be removed and reused after the components are produced.
The anchor is to permanently anchor the steel bar at the end of the component after the prestressed tendons are tensioned to prevent the prestressed tendons from shrinking (causing stress loss). They bear the same force as the component and cannot be removed. A prestressed fabrication tool that can be used repeatedly.
Do you understand?
Question 9: What types of welding fixtures are divided into? The main functions of welding fixtures are as follows: (1) Accurate and reliable positioning and clamping, which can reduce or even eliminate blanking and marking. line work. Reduce the dimensional deviation of products and improve the accuracy and replaceability of parts. (2) Effectively prevent and reduce welding deformation. (3) The workpiece is placed in the best welding position, the formability of the weld is good, process defects are significantly reduced, and the welding speed is increased.
(4) Mechanical devices replace the arduous work of positioning, clamping, and workpiece turning when manually assembling parts, improving workers' working conditions. (5) It can expand the scope of use of advanced process methods and promote the comprehensive development of mechanization and automation in the production of welded structures. Basic requirements for fixture design (1). The tooling fixture should have sufficient strength and stiffness. When the fixture is put into use in production, it must withstand a variety of forces, so the tooling fixture should have sufficient strength and stiffness. (2) Clamping reliability. When clamping, the positioning position of the workpiece must not be damaged and the shape and size of the product must comply with the drawing requirements. It neither allows the workpiece to loosen or slip, nor makes the workpiece too constrained to produce large constraint stress. (3) Flexibility of welding operations. The use of fixtures for production should ensure sufficient space for assembly and welding, so that operators have a good vision and operating environment, so that the entire process of welding production is in a stable working condition (4), and it is convenient for loading and unloading of weldments. During operation, it should be considered that the product can be smoothly removed from the fixture after assembly, positioning welding or welding, and that the product is not damaged during flipping or lifting. 5), good workmanship. The designed fixture should be easy to manufacture, install and operate, and easy to inspect, repair and replace wearing parts. When designing, factors such as the existing clamping power source, hoisting capacity, and installation site of the workshop should also be considered to reduce the manufacturing cost of the fixture.