Cutting

The cutting is a manufactoring process of parts. It is a kind of Cisaillage on a closed contour. A difference is made on the terms:

  • cutting, in order to obtain a circumference defined according to a precise form and dimensions.
  • punching, in order to perforate a part (example a perforation).
The punch punches the plate (Tôle, Papier, paperboard, foam…), and it is a cut out part which is obtained.

Cutting (traditional)

The traditional cutting of a thin material (paperboard, plastic, sheet) is done using scissors, shears or nibbling machines possibly. The defect inherent in this type of cutting is that it moves away the two cut out parts gradually thus involving local deformations. The more sinuous the layout is, plus these deformations will be importantes.
A cutting without deformation will be obtained by the equivalent of punching for example with a fine blade scalpel (cutter) for the paperboard and the plastic.

In current language, a cutting indicates a model out of paperboard to be cut out and assemble.

Industrial cutting

the tool of cutting (compound of a sharp steel blade of approximately 23 mm in height and 1 to 2 mm thickness fixed in a plywood of approximately 18 mm) of the shape of the desired end product is posed in a press.

For fine materials (a few millimetres) and the small ones and average series is used a press called " platinize portefeuille" : the fixed marble receives the tool, the mobile marble receives the sheet to be cut out and the unit is closed again with the manner of a wallet.

Always for fine materials but in great series a turntable rotary printing-press is used. The sheets are pulled by rollers under the tool.

For thicker materials requiring stronger pressures, the tools (with higher blades, 50 to 100 mm) are assembled on hydraulic presses.

In France, it is in the area of Besancon, the capital of microtechnic and the clock industry, that the cradle of cutting is, with companies like Bourgeois Cutting, Augé Cutting and the Groupe Simonin.

Fine cutting

Operation which consists in cutting out parts in rather thick sheet. The part obtained by this process with the characteristic to have the cut out edge perfectly perpendicular to the face, and of very good geometrical and dimensional qualities. The tools necessary for this cutting are of particular design compared to the tools of cutting usual because the sheet is maintained in the phase cuts out by snap rings of reserve.

Vocabulary

  • Punching: waste is called punching, they are holes of small diameter.
  • Cutting: the product obtained is a blank (often recovered for an operation of stamping or folding).
  • Crevage : it is a partial cutting.
  • Notching: it is a cutting leading to a contour.
  • Nibbling: it is punching partial by progressive displacement of the part or the punch.
  • Levelling: it is cutting in recovery (in order to obtain a precision of dimensions and surface quality).
  • Routing: completion of a contour already outlined, modified during a deformation.
  • Not: One calls “not” the length whose the band between two blows of press advances.

Setting in band

The study of the setting in band consists in seeking the provision of the parts in a sheet band while trying to produce a minimum of waste.

Setting in simple band

In the general case the parts are laid out after.

The distance between two parts and the width of the edges of band are equal to the thickness of cut out metal.

variation = thickness of sheet cut out.

Nevertheless, in the case of metal cutting low thickness, it is careful to preserve a certain behavior at waste. The width of this last is of 2 mm at least.

Sometimes logic will make choose a lower or higher width according to the type of part studied.

See too

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