Cnc Basic principles of processing tooling fixture design

• 1. Meet the stability and reliability of workpiece positioning during use;
• 2. There is enough bearing or clamping force to ensure the processing of the workpiece on the tooling fixture;
• 3. Meet the simple and fast operation in the clamping process;
• 4. e vulnerable parts must be of a structure that can be replaced quickly. It is best not to use other tools when conditions are sufficient;
• 5. Meet the reliability of repeated positioning of the fixture during adjustment or replacement;
• 6. Avoid complex structures and expensive costs as much as possible;
• 7. Choose standard parts as component parts as much as possible;
• 8. Systematization and standardization of products within the company.

Tooling fixture design basic knowledge

An excellent machine tool fixture must meet the following basic requirements:

• 1. To ensure the machining accuracy (precision) of the workpiece The key to ensuring the machining accuracy (explanation: an important part of metaphor) is first of all to correctly select the positioning datum, positioning method and positioning components, and if necessary, positioning error analysis Also, pay attention to the influence of the structure of other components in the fixture on the machining accuracy to ensure that the fixture can meet the machining accuracy requirements of the workpiece.
• 2. The complexity of the special fixture to improve production efficiency should be adapted to the production capacity. Various fast and efficient clamping mechanisms should be used as far as possible to ensure easy operation, shorten auxiliary time, and improve production efficiency.
• 3. The structure of the special fixture with good process performance should be simple and reasonable, which is convenient for manufacturing, assembly, adjustment, inspection and maintenance. In numerical control processing, the control system sends out instructions to make the cutter perform various movements that meet the requirements, and expresses the processing of technical requirements and processing requirements such as the shape and size of the workpiece in the form of numbers and letters. It generally refers to the process of processing parts on CNC machine tools. In order to improve production automation, shorten programming time and reduce CNC machining costs, a series of advanced CNC machining technologies have also been developed and used in the aerospace industry.
• 4. Tooling fixtures with good performance should have sufficient strength and rigidity, and the operation should be simple, labor-saving, safe and reliable. CNC machining generally CNC machining usually refers to computer digitally controlled precision machining, CNC machining lathe, CNC machining milling machine, CNC machining boring and milling machine, etc. The feed route for finishing is basically carried out along the contour of its parts. Therefore, the work of determining the feed route is to determine the feed route for rough machining and empty stroke. Under the premise of objective conditions and economical application, mechanized clamping devices such as pneumatic and hydraulic should be used as much as possible to reduce the labor intensity of the operator. The tooling fixture should also facilitate chip removal. When necessary, a chip evacuation structure can be provided to prevent the chips from damaging the positioning of the workpiece and damaging the tool, and to prevent the accumulation of chips from causing a large amount of heat to cause deformation of the process system.
• 5. Special fixtures with good economy should use standard components and standard structures as much as possible, and strive to have a simple structure and easy manufacturing to reduce the manufacturing cost of the fixture. Therefore, the necessary technical and economic analysis of the fixture program should be carried out according to the order and production capacity during design to improve the economic benefit of the fixture in production.

 Issues considered in tooling fixture design

The design of the fixture is generally single, and it feels that the structure is not very complicated. Especially now that hydraulic fixtures are popular, their original mechanical structure is greatly simplified, but if they are not considered in detail during the design process, unnecessary trouble will inevitably occur:

• a) The blank allowance of the workpiece. The blank size is too large, causing interference. So be sure to prepare the rough drawing before designing. Leave enough space.
• b) The chip removal of the fixture is smooth. Due to the limited processing space of the machine tool during design, the fixture is often designed in a relatively compact space. At this time, the iron chips generated during the machining process are often stored in the dead corner of the fixture, including the outflow of chip fluid. Processing brings a lot of trouble. Therefore, at the beginning of the actual process, the problems in the processing process should be considered. After all, the fixture is based on improving efficiency and convenient operation.
• c) The overall openness of the fixture. Ignoring the openness, it is difficult for the operator to install the card, time-consuming and laborious, and the design is taboo.
• d) Basic theoretical principles of fixture design. Each set of clamps 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 (precision) retention, so do not design something contrary to the principle . Even if it is a fluke right now, there will not be a long-lasting continuity. A good design should be tempered by time.
• e) Replaceability of positioning elements. The positioning element is worn (a basic type of component failure) is serious, so replacement should be considered fast and convenient. It is best not to design into larger parts.

Accumulation of fixture design experience is important. Sometimes design is the same thing, and it is the same thing in actual application, so good design is a process of continuous accumulation and summary. CNC machining generally CNC machining usually refers to computer digitally controlled precision machining, CNC machining lathe, CNC machining milling machine, CNC machining boring and milling machine, etc. The feed route for finishing is basically carried out along the contour of its parts. Therefore, the work of determining the feed route is to determine the feed route for rough machining and empty stroke.