Page 25 - UniorTools-Eng

Manufacturing procedure for a

combination wrench at Unior

1. Cutting: Cutting material is the "rst operation in the technological procedure of
wrench manufacturing. Optimum design of a cut provides optimal use of material.

2. Forging: Forging technology at Unior ensures excellent strength characteristics

of wrenches. Notably, it maintains appropriate "ber orientation in a forged part,
leaving it uninterrupted and the same as in a rolled blank. That characteristic of
forged parts is vital for achieving the characteristics of products exposed to heavy
dynamic loads, such as Unior wrenches.

3. Trimming: Super&uous material around a forged part is removed using a special-
purpose trimming tool; material is trimmed to the desired shape, always making the
weight of trimmings as low as possible.

4. Perforation: Following the forging and trimming phases, perforations are made
in the workpiece by punching or cutting. This procedure can be carried out either
on hot or cold workpieces.

5. Burring and grinding: Wrenches are contour-ground on grinding machines,
thus making surfaces smooth on the edges of a wrench. After that, edges on forged
parts are made smooth in special machines using mechanical and chemical means.

6. Machine marking and bending: Each wrench is impressed with an appropriate
marking providing information about the source of a wrench, dimensions and
material used. The ring of the wrench is accordingly o!set in line with the standard.

7. Broaching: In broaching, suitable gaps are made on special-purpose tools;
material is broached with linear motion of a tool incorporating a large number of
cutting blades.

8. Tempering: Tempering by heating and cooling is designed to improve the grain

&ow of the steel and thereby increase the toughness of the wrench at the desired
points; this heat treatment process grants the Unior wrenches a long lifespan and
resistance to high loads and pressure.

9. Sanding: Various abrasive substances are blasted onto the surface of the
wrenches by means of compressed air. The abrasives burr the surface, while at
the same time imparting to it a certain asperity, important for the subsequent
application of a suitable galvanic (protective) coating.

10. Chrome plating and polishing: Wrenches are coated with a thin, but solid
layer of chromium oxide to protect them from corrosion and other external
in&uence. Chromium coating gives a wrench a professional appearance and

warrants a long service life.

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