Some assembling process jigs design rules
In the industry of machinery and equipment, generally defined fixtures include Machine Fixture, Press Fixture, Heat Treatment Fixture, Welding Fixture, Assembling Fixture, etc. The specially defined fixture refers to the machine fixture, the device tool used to clamp the workpiece, it is mainly used for machine processing, but also the bridge between the machine and the workpiece and the cutting tool. The device tool used to hold the work piece and guide the cutter is called a fixture or drill die.
In the electronic industry, jigs are divided into three categories: process assembly jigs, project test jigs and circuit board test jigs. The process assembly fixture includes assembly fixture, welding fixture, dispensing fixture, irradiation fixture, adjustment fixture and shear fixture; Project test fixtures include life test fixtures, packaging test fixtures, environmental test fixtures, optical test fixtures, shielding fixtures, sound insulation test fixtures and so on; Circuit board test fixtures mainly include ICT test fixtures, FCT function fixtures, SMT through furnace fixtures, fixtures and CCD test fixtures.
Here, we mainly share the process assembly class fixture.
Usually the main production materials are metal, bakelite, PVC board, acrylic board, epoxy resin board and high temperature resistant synthetic stone and so on.
According to its power drive mode, the fixture can be divided into manual, pneumatic, hydraulic, pneumatic hydraulic, electric, magnetic, vacuum, etc. According to its application characteristics, it can be divided into general jigs, special jigs, adjustable jigs, combined jigs, random jigs and group jigs.
Jig design needs to follow some design criteria:
1.To understand the whole production, processing and manufacturing methods and processes; Don't totally rely on your own knowledge to judge, but also rely on the opinions of others.
2.Attention should be paid to the setting of datum level and datum point. Before and after the project should be unified, and there should be no inconsistency.
3.To take into account that the positioning support must match with the processing object and maintain sufficient rigidity.
4.To be as simple as possible, to stand in the user's position of design; To reduce operator waste, convenient operation.
5.You have to take into account the safety -- operation safety, safety prevention.
6.To use more standard products (widely sold in the market, standard specifications, etc.), try to avoid the use of special products.
7.Durability should be considered from the relationship between frequency of use and wear (such as parts quenching treatment).
8.Cost, accuracy, ease of installation and durability should be considered.
In general, the design of process assembly fixture mainly involves the positioning, clamping and stretching control and adjustment of moving parts forward and backward in a unilateral direction. Positioning mainly needs to consider positioning datum, positioning elements, positioning method, positioning error and how to control the six directions of freedom.
The clamping mainly needs to take into account:
1.When clamping the workpiece, the clamping device should not destroy the positioning of the workpiece, so it is necessary to correctly choose the direction and point of clamping force.
2.The size of the clamping force should be reasonable, to ensure that the deformation of the workpiece after clamping and the damage of the pressed surface does not exceed the allowable range.
3.The structure of the clamping device is simple and reasonable, the clamping action should be rapid, the operation side is labor-saving and safe.
4.The clamping force or clamping stroke can be adjusted and compensated within a certain range.
The main implementation method of clamping:
1.Spring clamping
2.Hinge clamp
3.Centering clamp
4.Eccentric clamping
5.Linkage
6.Helical clamping
7.Oblique wedge clamping
In a one-way forward and backward expansion control and adjustment method: manual, pneumatic, hydraulic, pneumatic hydraulic, electric, magnetic, vacuum, etc.
