Hole combination fixture and its application
Because the hole series modular fixture is positioned by pins and holes, its advantages are high precision, good rigidity, and good reliability, and it is suitable for parts with high machining accuracy. As the assembly of hole series modular fixtures mainly relies on the computer to calculate the assembly size, its disadvantage is that it requires high technical level of modular fixture assembly personnel and modular fixture designers' calculation ability, difficult adjustment, and lower assembly efficiency compared to slot series modular fixtures.
Classification and design principle of hole series modular fixture
(M16), medium (M12), small (MS) three series; basic parts, support parts, positioning parts, compression parts, fasteners, guide parts, assembly parts, and other parts, a total of eight types of components. The three series are all positioned with positioning pins; the positioning holes and threaded holes are regularly distributed, and the hole distances are different; the positioning holes of the hole system fixture components adopt an insert sleeve structure. Its design principle is to use any hole as a dot to make a straight line adjustment with a 0.01mm difference on a base plate with a uniformly distributed positioning pitch of 40mm x 40mm. Its assembly accuracy can meet the accumulation error of the fixture to not more than 1/3 of the part size tolerance -1/5. The rigid positioning structure of the two pins and one side of the hole series modular fixture, the stability is comparable to that of the special fixture.
Application of super-long hole combination fixture
The length of the main beam of the rapier loom is 2330~2730mm. It is processed by Toshiba processing center. The length and width of the working table of this machine tool are 2200×1800mm. The longest main beam extends 1390mm beyond the machine table. In order to complete the task of processing the main beam of the new rapier loom, we have cooperated with technicians. 8 pieces of 1000×1000mm hole system foundation board are adopted. On the table top of the machine tool, an inverted stepped assembly structure extends to both sides of the machine table. Assembled into a 2800mm super long table. In order to prevent the base plate of the hole system from bending and deforming under stress, several positioning pins with a diameter of 16mm are inserted into the positioning holes on several base plates. Effectively enhance the rigidity of the assembly table. On the hole system foundation plate, two more 180×120×60mm groove system foundation boards are assembled. According to different main beam lengths, two trough foundation plates can be moved to adjust and assemble the position for supporting and clamping the main beam, and it is possible to process main beams of several lengths. The application of this combination fixture solves the processing of ultra-long parts and lays the foundation for the accumulation of experience in processing such parts in the future.
Application of Combined Fixture for Hole System of Middle Wall Panel
The middle wall panel is the main part of the spinning frame, which belongs to the frame thin plate part, which is easily deformed during processing. We use a 1000×1000×50mm hole system foundation plate, as well as compression pliers and supporting parts. A set of fixtures for rough and fine milling of the large surface of the wall panel are formed. In addition, a 1000×1000×50mm hole-based foundation plate was used to assemble a set of fixtures with a supporting block designed and manufactured by myself, which was used for rough and fine milling the other side of the middle wall panel, which solved the processing of the middle wall panel. Not only achieved satisfactory results, but also reduced the workload of designing and manufacturing special fixtures.
Application of Combined Fixture for Hole System of Complex Parts
The rapier loom cam box and square box are more complicated parts. According to the characteristics of the parts, we use the base plate, square box and other hole system modular fixture components, specially select and prepare some accessories to form a set of fixtures, and the use effect is very satisfactory.
Super processing
The size of the steel frame of the brushing machine is 1600×1500mm in length and height, which has exceeded the size of the double-sided base angle iron of length and height of 1400×1095mm. In order to solve the processing problem of the steel frame of the brushing machine, we boldly innovated, on the double-sided basic angle iron with length × height of 1400 × 1095mm. Four 850×850×50mm hole-based foundation plates are respectively fixed on the four corners of the double-sided foundation angle iron to assemble a super large butterfly base. On this butterfly base body, the positioning and clamping of the steel frame of the bristle machine can be processed by using the combined fixture elements of the hole system.
Application of Hole Combination Fixture in Blade Machining
Because of the high-precision positioning accuracy and high-precision characteristics of the hole series modular fixture components, the use of the hole series modular fixture to assemble the precision parts fixture of the aircraft engine is more suitable for solving the problem of the guide blade observation hole processing. The hole series modular fixture is selected to solve the processing problems of precision parts, which not only guarantees the accuracy of the parts, but also ensures the manufacturing cycle and reduces the manufacturing cost.
Fixture requirements
The axis of the machined hole is perpendicular to the bottom plane of the fixture, the blade angular positioning is accurate, and the fixture repeat positioning accuracy is good.
Positioning analysis
The blades are positioned based on the plane datum C and the plane datum D, limiting 3 degrees of freedom; 2 short cylindrical pins are used for secondary positioning, limiting 2 degrees of freedom, and determining the position of the center of the circle; 1 short cylindrical pin is used for angular positioning of the blade , Tangent to the short slope, restricting the blade to rotate along the X axis
Fixture adjustment
(1) Outer circle positioning adjustment Since 2 points can determine the center position of the arc, two pins with a diameter of 12mm are used to locate the outer circle datum A—RXX of the blade. Calculate the center position of the 2 pins in the computer. Use the drill template and eccentric pin to adjust the position according to the data;
(2) Angular positioning adjust the angular positioning position of the blade;
(3) Adjustment of the step difference of the reference plane;
(4) Adjustment of drilling template;
(5) For clamping, use two sets of pressure plates to respectively press the end faces of the upper and lower edge plates of the blade, and use the tightening bolts to tighten the arc of the lower edge plate of the blade to prevent displacement of the blade during drilling.
