Design outline of tooling, fixture and inspection tool

Design purpose

The purpose of tooling, fixture and checking fixture is to improve the efficiency of batch production of mechanical products and ensure the quality stability of mechanical products, so as to achieve the purpose of reducing the production cost of products. Therefore, the design and manufacture of tooling, fixture and inspection fixture should be subject to this purpose unconditionally.

Design considerations

Tooling, fixture, inspection tools are generally single piece, set production, but the use time is generally long, mold tooling mainly consider service life, maintenance conditions, etc. Fixture tooling is mainly considered to be convenient, safe, efficient and reliable. Inspection tools mainly consider the use of convenient, reliable, convenient maintenance and so on.

In view of the above reasons, the design cost of tooling, fixture and checking fixture should give way to safety, efficiency, reliability, service life, convenience and other factors.

Material selection criteria

Mature standard parts (such as guide post, guide sleeve, fastener, spring, hardware, air cylinder, hydraulic cylinder, standard mold base, quick chuck, etc.) shall be used as far as possible in the design.

For the design of main parts, it is necessary to carefully design the matching and hardness selection of metal materials and types of heat treatment (such as quenching and tempering, high frequency, carburizing and quenching, nitriding and quenching), especially consider the prevention of deformation of parts after heat treatment, and consider hardness matching and necessary lubrication measures for parts with mutual friction.

The thickness and type of coating (galvanizing, nickel plating, bright chromium plating, anodizing, hard anodizing, conductive anodizing, hard chromium plating, bluing, etc.) shall be carefully designed for surface treatment according to the function of parts.

Basic points of design of tooling, fixture and checking tool

1. Clamping method of mechanical parts

A direct alignment clamp

Low efficiency, high alignment accuracy; suitable for single small batch and simple shape workpiece.

In the figure below, the four jaw chuck itself is a kind of fixture, just a general fixture.

B marking and aligning clamping

It is suitable for small batch and complex shape castings.

2. Three principles of clamping parts after positioning in fixture

a. The principle of parts not moving after positioning in fixture

The direction of the clamping force should be selected to point to the positioning datum (the first datum), and the size of the clamping force should be enough to balance the influence of other forces, so that the parts will not move in the machining process.

b. The principle of non deformation of parts after positioning in fixture