Design a drill jig for drilling on cylindrical surface – Mechanical Project

Abstract :

The aim of the project is to design a jig for drilling machine to perform drilling operation accurately for cylindrical work pieces. While making holes on the cylindrical work pieces lot of problems encountered such as inaccuracy, misalignment, etc. These problems cause rejection of finished jobs, productivity losses, more time consumption, etc. In this project an attempt has made to design a drill jig and use the same during drilling the holes on cylindrical work pieces, which eliminates the problems faced during conventional drilling. This procedure helps in increasing the production rate, accuracy, perfect alignment, reducing operators fatigue etc. In this procedure a drill jig will guide the drill bit to the correct position on the work piece. The drill jig has been designed carefully by considering the design principle and design procedure. Number of features has been studied and the suitable one has been selected. With implementation of CAD and Pro/E, the modelling of each component of a jig is designed.

DRILL JIG :

A drill jig is used whenever it is necessary to drill holes to exact location in many identical parts Drill jigs are used to save layout time , avoid incorrectly located holes and produce holes accurately and economically.

DEFINITION OF JIG:

A jig may be defined as a device, which holds and locates a work piece, guides and controls one or more cutting tools. The holding of work and guiding of tool are such that they are located in true positions relative to each other.

OBJECTIVES :

Each part is quickly and accurately aligned. To drill three successive holes

SELECTION OF CLAMPING:

Grub screws are used for clamping . These are used to fix the work piece rigidly with the jig. Grub screws of pitch 1 mm and major diameter of 6 mm is selected. It is available in steel.

SELECTION OF JIG BODY:

Length of the work piece = 88 mm Outer diameter of work piece = 32 j6 mm Length of the jig body = 90 mm Inner diameter of jig body = 32 j6 mm Outer diameter of jig body = 40 mm Thickness of the collar = 5 mm Outer diameter of collar = 48 mm Jig body is made up of alloy steel En 24 of hardness 56 to 60 HRC.

Assembled jig : Assembled jig

design of jig for cylindrical surface mechanical project

ADVANTAGES :

It eliminates the marking out measuring and other setting methods before machining
It enables identical parts which are interchangeable, this facilitates the assembly operation
It increases the machining accuracy because the work piece is automatically located and the tool in guided without making manual adjustment

DISADVANTAGES :

It requires surface plate for aligning the workpiece with the jig and for clamping.
Requires magnetic V-block for locating the jig rigidly

CONCLUSION

The newly designed drill jig helps to simplify the operation and reduces the risk of the operator during loading and unloading. Therefore even unskilled workers can operate the machine to produce accurate holes on the work piece. The replacement of skilled worker also proves cost effective. It drills the holes on the components with accurate alignment and hence loss of rejections will be minimized. It also protects the work piece surface free from scratches, damages, etc. formed by the chips generated during machining.