What Are The Design Principles Of Jig And Fixture? -->

What Are The Design Principles Of Jig And Fixture?


Designing of the simple and economical jig and fixture is based on some fundamental principles. A designer should be properly understood this principle before starting the actual design. The principle consideration in designing of jig and fixture is listed below.

Read: What Is The Difference between Jig and Fixture?
Objectives of Tool Design and Duties of Tool Design Engineer

Component and production requirements

Carefully Studying of the component will help to increase overall productivity of the plant. It ensures the proper sequence of manufacturing. In order to increase the production, the one machine setting should be allowed to perform maximum number of operations. The actual production requirements help to decide the mode of tooling arrangement (manual, automatic or semi-automatic).

Machine, tool, accessories and standard parts

One should be considered the actual capacity of machine used in manufacturing. Tool and accessories selected so that to increase the use of standard parts. Special tool and accessories use only when the standard part is unsuitable for the work.


A component should be properly clamped during the work. The purpose of clamping is to hold work piece securely on jigs and fixture against forces during the cutting action. At the same time it should not deform the work material. It is advisable that to provide the clamping directly above the supporting points of work. Using other location may cause the vibration of the work, it results in distortion of position in the machining process. The clamping and adjustment should be provided on the side of fixture that nearest to the operator. By doing so loading and unloading become easy and quick.

Locating point and support

The locating device is designed so that each workpiece loaded on the machine must occupy the same position as the previous one. Locator ensures the workpiece movement is fully constrained. The location should ensure the equal distribution of force acting on them during the various machining operations. The material used for them should be hard and wear resistant. The designer should consider making the locating points visible to worker from his working position. The removable locating point is also desirable.

Read: Locating Of Workpiece In Tool Engineering. Basic Rules For Location


Enough clearance should be provided between component and jig and fixture; it also considers the variable size of work. There should also be clearance for the operator. Handling clearance provided for the handling of the workpiece. There should be adequate clearance for the removal of swarf from the work region.

Design for safety and easy handling

Safety is important, jig and fixture are designed to assure full safety for the operator as well as operation. A jig and fixture must be safe to use. Avoid the sharp corners on the jig and fixture. There should be no (or minimize it) outward projection of screws and bolts.

It should ensure easy and rapid that loading and unloading of the tool. Overall the equipment should be light and easy to handle. If it is heavy, provide lifting point on them.

Other General consideration

  • Reduction of idling time
  • There should be an arrangement for coolant/cutting oil supply to the cutting edges.
  • They must be fool proof: make it is impossible to insert component into equipment in wrong way.
  • Provide ejecting devices: they are useful to eject heavy work pieces when a work is done.
  • The design should be simple and economical

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