User:Mcapdevila/Nibbler

A nibbler is a tool used in stamping and shear processes for sheet metal cutting and molding. Unlike the conventional system, this tool is characterized by following a line of cutting and free forming in an independent process. This is achieved by the periodic movement up and down of a punch that is open on one side and advances at the same time as biting, which is why they are called screw removers. The tool head rotates and can move in all directions allowing complex shapes to be cut. [3]

Apart from manual, manually operated or electrically operated nibblers, there are also CNC-controlled machine tools, usually combined with punching machines. While the two cutting edges of manual handscrews are usually next to each other like scissors and are connected to each other by a common axis of rotation, a hand-remover machine usually performs the same movement as a punch. The difference is that when biting, the snowplow performs many successive steps one after another, while feeding the sheet slowly in front of the tool in order to produce a longer cut. [4]

Advantages and disadvantages
Punch from an electrically operated manual nibbler

Just like in an ordinary punch, the tool of a nibbler consists of a punch and a die. This allows you to cut sections of sheet metal without distortion. However, residue occurs during biting, as part of the sheet metal is pierced.

In the cutting of sections of complex shape, round punches allow tight curves, resulting in crescent-shaped residues. The shape and width of the cutting track depend on the dimensions of the punch.

When making internal trims with manual nibblers, a pilot hole is required to initiate the cutting edge. Wavy or trapezoidal sheets can also be cut, in particular with manual slip removers and, unlike a cut made with scissors in which the cutting track is distorted, the one made with a nibbler is free of distortions, since it has a counterpunch that prevents it. [5]

Unlike water jet and laser cutting, forming processing steps can be carried out with the same processing machine that also uses the nibbler. In many cases, not only sheet metal cuts have to be made, but also sections are deformed in order to introduce ventilation elements, step holes, etc. Modern screw machines, with a rotating shaft tool holder, can even make threads, in which the thread is created not by cutting the material, but by displacing it. Compared to cut nuts, threads made in this way can be subjected to higher loads, and chips are not produced during their manufacture that can prevent further processing. [6]

Standard tools
Hand tools are called nibblers. The standard equipment of a machine tool stir includes seals with the most important simple geometric shapes, such as p. B. circle, square, rectangle or oval. Arc-shaped punches are also used to cut larger openings, which can produce, for example, a circular cut, joining several strokes. [7]

Recurring sheet metal cuts frequently used, such as computer housing openings for D-Sub connectors and the like, are usually made with chassis punches made for each specific application.

Special tools
0:50A machine tool drills holes of different shapes in a metal sheet with a rotating (multi-tool) tool head. Another rotating tool head is located below the sheet, since a fixed counterpoint is required during drilling to prevent deformation of the sheet.

In production (large) series, such as control cabinets, special tools are also often used, which can cut complete contours with a few tool strokes. A special type of tool is the so-called multi-tool. which has several perforation tools connected to a head and can be used by turning the support plate. [8]

Machines
Modern CNC-controlled handscrew or punch machines are characterized by high productivity with lower unit costs (compared to laser cutting machines). However, arbitrary contours cannot be cut. [9]

Combined machines
In order to combine the advantages of nibblers with laser cutting machines, there are different manufacturers that offer combined machines allowing both forming operations of any contour. with the punching head like laser cutting. [10] Another type of nibbler combines these features with guillotine shear technology in order to optimally execute the long, straight cuts that often need to be made. [11]