Standard parts generally appear in modular fixtures, but there are too many standard parts. How much do you need to know? You can go to the bookstore to find books about modular jigs and see wenku.baidu/...4..
This is Baidu's modular fixture.
Question 2: The manufacturing and processing standard of fixture meets the stability and reliability of workpiece positioning during use;
2. There is enough bearing or clamping strength to ensure the construction process of the workpiece on the fixture;
3. The simple and quick operation in the clamping process is satisfied;
4. Wearable parts must be of a structure that can be quickly replaced, and it is best not to use other tools under sufficient conditions;
5. Meet the reliability of repeated positioning of fixture during adjustment or replacement;
6. Avoid complicated structure and high cost as much as possible;
7. Try to choose standard products with reliable quality on the market as spare parts;
8. Comply with the safety laws and regulations of the country or region where the fixture is used;
9. The design scheme follows the principles of manual, pneumatic, hydraulic and servo in turn.
10. Form the serialization and standardization of internal products of the company.
Question 3: Is the pressure plate in fixture design a standard part? 1. According to the fixture design manual of machine tools, the press plate in fixture design is a standard part.
2. Standard parts refer to commonly used parts (components), such as threaded parts, keys, pins, rolling bearings, etc. , has been completely standardized in structure, size, drawing and marking, and is produced by a professional factory. Broadly speaking, it includes standardized fasteners, connectors, transmission parts, seals, hydraulic components, pneumatic components, bearings, springs and other mechanical parts. Narrow sense only includes standardized fasteners. The commonly known standard part in China is the abbreviation of standard fastener, which is a narrow concept, but it does not rule out the existence of a broad concept. In addition, there are industry standard parts, such as automobile standard parts and mold standard parts, which also belong to generalized standard parts.
Question 4: 5 points for fixture assembly standard or assembly process. The question you asked is difficult for others to answer. To buy a book to study, it is only a few tens of dollars.
Question 5: What types of lamps are there? Usually, they are product parts, including thick steel plates, sheet metal parts, steel castings and a few plastic parts. Usually, special fixtures are used for machining and welding, and some of them are used as clamping mechanisms of inspection tools.
Question 6: What is a welding fixture? In the automobile welding assembly line, the workload really used for welding operation only accounts for 30% ~ 40%, while 60% ~ 70% is auxiliary and clamping work. Because the clamping is completed on the welding fixture, the fixture plays an important role in the whole welding process.
In the welding process, a reasonable fixture structure is conducive to reasonable arrangement of assembly line production, balance of station time and reduction of non-production time. For enterprises with many models, if we can scientifically consider using * * * or hybrid fixture, it will also help to build a hybrid assembly line and improve production efficiency.
First, the characteristics of automobile welding process
(a) materials and structure
Automobile welding materials are mainly low-carbon steel cold-rolled steel plates, galvanized steel plates and a small amount of hot-rolled steel plates. They have good weldability and are suitable for most welding methods, but because they are thin plates, they have poor rigidity and are easy to deform.
Structurally, the welded parts are mostly stamped parts with spatial curved surfaces, and their shapes and structures are complex. Some stamping parts with deep cavities not only have deformation caused by poor rigidity, but also have springback deformation.
(2) Welding method
Automobile welding methods mainly include CO2 gas shielded welding and resistance welding. CO2 gas shielded welding has a wide range of applications, and the requirements for fixture structure are not very strict. Resistance welding requires strict fixtures, especially multi-point welding, reactive welding and robot spot welding. Because automobile welding is mainly resistance welding, this paper will discuss the design of resistance welding fixture.
(III) Welding process flow
The basic feature of automobile welding is the combination and process from assembly to parts to assembly.
Every process from assembly to body welding assembly is independent of each other and is a link between the past and the future. Therefore, the welding accuracy of the assembly determines the welding accuracy of the assembly, and ultimately affects and determines the welding accuracy and quality of the automobile body welding assembly. This requires that the positioning datum of interrelated assemblies, parts and fixtures in body welding assembly should be unified and inherited. Only in this way can the final product quality be guaranteed, and even if there are quality problems, it is easy to analyze the reasons and correct and control them.
The welding process is mainly assembly line production, so the design of fixture should be conducive to the layout and design of assembly line, and also consider providing convenience for production management.
Second, the design method and steps of welding fixture
1. Before designing the welding fixture, we must first understand the production procedure, product structure characteristics, process essentials and production line layout, conduct sufficient process research, refer to the advanced fixture structure at home and abroad, and determine the overall scheme of the fixture in combination with the actual situation. Such as fixed fixture or movable fixture, the level of mechanization and automation, and whether several types of main fixtures are mixed.
2. Determine the positioning and clamping mode according to the structural characteristics of the weldment and the specifications of the required welding equipment; At the same time, according to the process characteristics of stamping parts and the needs of subsequent assembly process, the appropriate positioning points and key positioning points are selected.
3. After the main mechanism is determined, the auxiliary device can be determined. Such as water, electricity and gas circuits, gas and hydraulic components, and copper plates needed to protect external welding points of covering components.
4. Because of the huge overall structure and complex spatial structure and size of welding fixture, coordinate method and modular design method should be adopted in its design to improve design efficiency.
5. When designing the specific structure of fixture, standardized components should be adopted as far as possible, or the degree of generalization and serialization should be improved.
Three. Composition, structure and requirements of welding fixture
Automobile welding fixture usually consists of fixture base plate, positioning device, clamping mechanism, measuring system and auxiliary system.
(1) Fixture bottom plate
Fixture bottom plate is the basic component of welding fixture, and its accuracy directly affects the accuracy of positioning mechanism, so there are strict requirements for flatness and surface roughness of working plane.
The datum of the measuring device of the fixture itself is built on the fixture bottom plate, so when designing the fixture bottom plate, there should be enough places to set the datum groove of the measuring device to meet the needs of actual measurement. In addition, the frame structure is adopted as far as possible without affecting the assembly of the positioning mechanism and the setting of the positioning groove, which can save materials and reduce the weight of the fixture, which is especially important for the accompanying fixture on the assembly line.
(2) Positioning device
The parts in the positioning device usually include a fixed pin, a pin, a stopper, a V-shaped block and a positioning block determined according to the actual shape of the weldment (Figure 1 is a special positioning block).
1. Due to the frequent use of welding fixtures, the positioning elements should have sufficient rigidity and hardness to ensure the accuracy during replacement and trimming.
2. In order to facilitate the adjustment and replacement of main positioning elements and make the fixture have flexible stirring function, the positioning mechanism should be designed to be as adjustable as possible. As shown in figure 1, positioning element A- 1 >: >
Question 7: What does welding fixture mean? What are the requirements for welding clips? Welding fixture is used to ensure the size of weldment, improve assembly accuracy and efficiency, and prevent welding deformation. There are many kinds, most of which are used for specific occasions (products). For example, the position of the central axis of the bicycle frame in the picture below is welded by five pipes. If there is no special welding fixture, it is difficult to ensure the correct position of each other.
The picture below shows a universal welding fixture, which can ensure the right angle between weldments.
General requirements of welding fixture:
Quick action and convenient operation;
There is enough assembly and welding space, which will not affect the welding operation and observation, and will not hinder the loading and unloading of weldments;
Reliable clamping and proper rigidity. Can't destroy the positioning position and geometry of the weldment;
If necessary, protective devices should be set up;
Will not be damaged in the welding process;
The application point of the fixture should be located at or near the support of the weldment to prevent the supporting reaction force from forming a couple with the clamping force or gravity;
Pay attention to the special requirements of various welding methods for fixtures in terms of heat conduction, electricity conduction, magnetic isolation and insulation;
The positioner and clamping mechanism on the fixture should not have too many mechanical forms to facilitate manufacturing and maintenance;
Pneumatic and other driving modes can be adopted to improve production efficiency and reduce labor intensity of workers;
Give priority to the use of universal and standardized clamping mechanisms and standard parts;
As a part of the secondary circuit of welding power supply, a secondary circuit should be led out from the nearest end of the weldment to avoid welding current passing through the whole fixture;
Wearable parts are usually designed as replaceable structures;
Easy to manufacture, less investment, low manufacturing cost and short payback period. When in use, the energy consumption and management cost are low.
Question 8: What is an anchorage? What is a fixture? The statement upstairs is not correct, because I am a professional, and fixtures and anchorages are both tools for prestressed tensioning.
Fixture is a tensioning tool, which is used to clamp prestressed tendons during the production of prestressed components, and can be removed and reused after the production of components is completed.
Anchorage is a kind of prestressed production tool. After the prestressing tendon is tensioned, the rebar is permanently anchored at the end of the component to prevent the prestressing tendon from retracting (causing stress loss), and it bears the same force as the component * * * and cannot be unloaded and reused.
Are you clear?
Question 9: What types of welding fixtures are there? The main functions of welding fixture are as follows: (1) Accurate and reliable positioning and clamping can reduce or even cancel blanking and marking. Reduce the size deviation of products and improve the accuracy and interchangeability of parts. (2) Welding deformation is effectively prevented and alleviated. (3) The workpiece is in the best welding position, the weld formability is good, the process defects are obviously reduced, and the welding speed is improved. (4) Mechanical devices are used to replace the heavy work such as positioning, clamping and workpiece turning when assembling parts by hand, which improves the working conditions of workers. (5) It can expand the application range of advanced process methods and promote the all-round development of mechanization and automation of welding structure production. The basic requirement of fixture design (1) is that the fixture should have sufficient strength and rigidity. When the fixture is put into use in production, it must bear various forces, so the fixture should have sufficient strength and rigidity. (2) The reliability of clamping. The positioning position of the workpiece will not be destroyed during clamping, and the shape and size of the product meet the requirements of the drawing. It can neither make the workpiece loose or slip, nor make the workpiece too tightly constrained to produce large constraint stress. (3) Flexibility of welding operation. The use of fixtures should ensure enough welding space, so that operators have a good vision and operating environment, and the whole welding production process is in a stable working state (4), which is convenient for the loading and unloading of weldments. During operation, it should be considered that the product can be taken out of the fixture smoothly after assembly, tack welding or welding, and the product should be turned over or lifted to avoid damage. 5) Good manufacturability. The designed fixture should be easy to manufacture, install and operate, and easy to check, maintain and replace wearing parts. The existing clamping power source, hoisting capacity and installation site of the workshop should also be considered in the design to reduce the manufacturing cost of the fixture.