Challenge

Advanced Sheet Metal Design Using NX Cad Challenge_7_ Metal bracket-II

MMayank Tiwari16 Jul 2023

ADVANCED SHEET METAL DESIGN USING NX CAD

CHALLENGE - 7 , METAL BRACKET - 2

OBJECTIVE - TO DESIGN A BRACKET USING NX CAD & UNDERSTANDING SHEET METAL APPLICATIONS & ITS IMPORTANCE AS PER INDUSTRY STANDARDS.

INTRODUCTION - BRACKETS ARE INTERMEDIATE COMPONENTS THAT ATTACTH ONE OBJECT TO ANOTHER OR A FIXTURE WHICH OVERHANGS FROM A WALL TO CARRY A WEIGHT,OR ALIGN PARTS WITHIN AN ENCLOSURE OR FORTIFY A PART BY SUPPLYING EXTRA STRUCTURAL SUPPORT. DEPENDING ON ITS TYPE , A BRACKET IS EITHER MOUNTED WITH HARDWARE OR WELDED INSIDE A SHEET METAL PART.

APPLICATION OF METAL BRACKETS - 1. BRACKET FOR SPLIT AIR CONDITIONERS

2. LED TELEVISION MOUNT BRACKET

3. CABLE CRIMP SLEEVE BRACKETS IN AUTOMOBILES.

4. HINGE BRACKETS FOR DOORS

SHEET METAL DEFINITION -

SHEET METAL IS ANY METAL THAT HAS A THICKNESS IN BERWEEN 0.5 mm & 6 mm. ANY METAL PIECE THICKER THAN 6 mm ARE CONSIDERED AS STRUCTURAL METALS ( FOR EG - STRUCTURAL STEEL) & ANY METAL PIECE HAVING THICKNESS LOWER THAN 0.2 mm IS CALLED METAL FOIL ( FOR EG ALUMINIUM FOIL). SHEET METAL IS ONE OF THE FUNDAMENTAL FORMS USED IN METALWORKING,& IT CAN BE CUT & BENT INTO A VARIETY OF SHAPES.IT IS FOUND IN VARIOUS INDUSTRIAL APPLICATIONS RANGING FROM SMALL & LIGHT FIXTURE TO AN AUTOMOTIVE BODY PART. SHEET METAL APPLICATIONS HAVE A WIDE RANGE DUE TO ITS PROPERTIES LIKE - HIGH STRENGTH LOW WEIGHT & CORROSION RESISTANCE. GENERAL SHEET METAL MATERIALS ARE STEEL, ALUMINIUM , BRASS , TITANIUM. THERE ARE TWO WAYS OF PRODUCING SHEET METAL - HOT ROLLING & COLD ROLLING. FOR PRECISE APPLICATIONS , COLD ROLLED SHEETS ARE PREFERRED AS MANUFACTURERS HAVE MORE CONTROL OVER THE FINAL DIMENSIONS. THIS IS BECAUSE IN HOT ROLLED SHEETS , AFTER COOLING ,THE STEEL SHRINKS SLIGHTLY & THE SHAPE MIGHT CHANGE A LITTLE.

FOLLOWING ARE SOME SHEET METAL FORMING PROCESS -

1. SHEET METAL BENDING

2. SHEET METAL CURLING

3. SHEET METAL DECAMBERING

4. SHEET METAL EXPANDING

5. DEEP DRAWING

6. HYDROFORMING

7. INCREMENT SHEET METAL

8. IRONING

9. PRESS BRAKE FORMING

10. PUNCHING

11. ROLLING

12. WHEELING

SHEET METAL TERMINOLOGIES -

1. BEND RADIUS - WHEN A SHEET METAL IS BENT IT DOES NOT EXACTLY FORM 90 DEG AT THE CORNER. THE CORNER IS CURVED FORMING A TANGENCY BETWEEN THE WEB & THE LEG FORMING A G1 CONTINUITY. THE INSIDE RADIUS OF THIS CURVED CORNER IS CALEED BEND RADIUS.

2. K-FACTOR - WHEN A MATERIAL IS BENT THE INNER PORTION UNDERGOES COMPRESSION & THE OUTER PORTION UNDERGOES TENSION . THIS CHANGES THE LENGTH OF BOTH OUTER & INNER SURFACES. THERE IS A NEUTRAL PLANE BETWEEN BOTH THESE PLANES WHERE CHANGE IN LENGTH IS ZERO. THIS IS WHERE TRANSITION FROM COMPRESSION TO TENSION TAKES PLACE.

* THE RATIO OF NEUTRAL LINE DISTANCE TO THE MATERIAL THICKNESS IS CALLED K-FACTOR.

* VALUE OF K-FACTOR DEPENDS ON - MATERIAL THICKNESS, MATERIAL PROPERTIES & BEND RADIUS.

3. BEND ALLOWANCE & BEND DEDUCTION - THESE TWO ARE THE METHODA TO DETERMINE THE FLAT LENGTH OF SHEET METAL STOCK TO GIVE THE DESIRED DIMENSION OF THE BENT PART. OTHER METHODS INCLUDE BEND TABLES, K-FACTOR & BEND CALCULATIONS.

BY DEFINITION , THE BEND ALLOWANCE IS THE ARC LENGTH OF THE BEND AS MEASURED ALONG THE NEUTRAL AXIS OF THE MATERIAL. BY DEFINITION, THE BEND DEDUCTION IS THE DIFFERENCE BETWEEN THE BEND ALLOWANCE & TWICE THE OUTSIDE SETBACK.