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Dimensional tolerances according to ISO 3302-1

Cutting standards

Cutting standards in industry are a key factor in the performance of semi-finished products, parts and finished products. We invite you to visit the guide in which we describe the most common standards.

 

Non-contact cutting methods

 

Non-contact cutting methods involve cutting the material without its direct contact with the abrasive. The most popular methods of non-contact cutting include:

 

Water cutting

Cutting with water (WaterJet) is a cold cut, without thermal deformation, and allows you to cut virtually all soft materials (rubber, cardboard, glass) and hard (stone). This method is used for precise cutting using a high-pressure jet of water. WaterJet enables dust-free cutting of large thicknesses, and also prevents problems related to thermal expansion of materials. It is a universal solution that allows you to cut all materials.

 

Plasma cutting

Plasma cutting is classified as thermal cutting. It is used to cut metals (aluminum, black steel, stainless steel, copper, cast iron) with a plasma arc. Various types of cutting can be performed with the plasma torch (basic, template, multiple sheets simultaneously, mechanized, gouging, bevelling). Plasma cutting is characterized by high cutting speed and the ability to cut thin materials without burning the edges. Plasma cutting technology is not used to machine titanium.

 

Laser cut

Laser cutting is classified as thermal cutting and enables a wide range of cutting various materials (wood, plastic, paper, various types of steel). It depends on the laser source used (gas lasers, solid-state lasers, semiconductor lasers). Laser cutting is characterized by high precision and cutting speed, as well as a narrow cutting gap and a minimum heat-affected zone. The laser cutting technology allows you to cut materials such as: non-ferrous metals and their alloys, black steel, alloy steels, wood, PVC, plexiglass. Laser cutting is not used to process materials with a high light reflectance.

 

What is workshop tolerance?

 

The shop tolerance determines the level of precision to be applied during production. The operator decides the level of deviation from the original specifications giving a controlled and allowed margin of error. Tolerance is the allowable variation for a given size to get the proper function. It is an essential aspect of product design.

 

Cutting standards

 

Machine operators most often apply standard tolerances when the customer does not specify tolerance levels. The scope of standard machining tolerances is determined by standardization bodies, which include, among others:

  • International Organization for Standardization (ISO)
  • American Society of Mechanical Engineers (ASME)
  • American National Standards Institute (ANSI)

 

ISO 2768 standard

 

ISO 2768 was created by the International Organization for Standardization (ISO) and aims to simplify drawing specifications for mechanical tolerances. It mainly deals with parts produced by machining or material removal. Specifies the extent to which variation is accepted between nominal dimensions and other dimension values that qualify as a fit. It consists of two parts: ISO 2768-1 and ISO 2768-2. All tolerance limits are given in millimeters. These parts define mechanical levels of precision to simplify engineering drawings.

 

ISO 2768-1 aims to simplify drawing markings and defines general tolerances in 4 tolerance classes:

  • f – petite
  • m – average
  • c – thick
  • v – very thick

 

The above standard applies to angular dimensions (e.g. 90 ° right angles) and linear dimensions (external and internal dimensions, step sizes, diameters, radii, distances, external radii and chamfer heights for broken edges) without individual tolerance markings.

 

ISO 2768-2 is used to simplify the drawing and defines general tolerances in 3 tolerance classes (H, K, L). The tolerances refer to geometric flatness and straightness, cylindricity and circularity.

 

Taking into account the ISO 2768 specification in the production process ensures proper control of every element of geometry and part size.

 

ISO 9013 standard

 

The ISO 9013 cutting standard defines the quality of materials suitable for thermal cutting:

  • laser cutting from 0.5 to 32 mm
  • plasma cutting from 0.5 to 150 mm
  • oxy-fuel flame cutting from 3 to 300 mm

 

This standard contains geometric product specifications and quality tolerances. The dimensions of the cut are specified in millimeters. The above standard allows you to define how to measure the quality of the cut with the division into the thickness of the processed material. The product geometry specifications apply if the reference to this document is given in the drawings or in the relevant documents, e.g. delivery conditions.

 

ISO 286 standard

 

ISO 286 defines the specifications for the basics of tolerances, deviations and fits.

 

ISO 286-1 is the product geometric tolerance (GPS) standard. The standard is used for linear dimensions of elements of the following types:

  • cylinder
  • two parallel opposite surfaces

 

ISO 268-1 defines the basic concepts and related terminology for a coding system. Provides a standardized selection of tolerance classes for general purposes from a variety of possibilities. Additionally, it defines basic fit terminology between two size characteristics without orientation and location constraints, and explains the principles of “base hole” and “base shaft”.

 

ISO 1829 standard

 

This standard was withdrawn in 2010. is intended to guide the user towards the preferred tolerance zones for shafts and holes to be used as a fit. It gave the possibility of a very elaborate selection of various symbols for the tolerance zones. It included upper and lower deviations for holes (internal features) and shafts (external features). She made recommendations for the product.

 

Standard EN 20286

 

EN 20286-2 defines the deviations for commonly used tolerance classes, calculated from the information given in ISO 286-1. It includes values for the upper and lower deviations, as shown in the figure. It summarizes the numerical values for the basic sizes from 3 mm to 3150 mm inclusive.

 

JIS B 0401 standard

 

JIS (Japanese Industrial Standards) are Japanese industrial standards. The JIS B 0401 standard defines the geometrical specifications of the product. Specifies standard tolerance classes and limit deviations for holes and shafts.

 

ANSI B4.1 and ANSI B4.2

 

This standard is produced by the American National Standards Institute (ANSI). ANSI B4.1 specifies the preferred tolerances for boundaries and fits for unthreaded cylindrical features by and defines specific sizes, fits, tolerances, and allowances to be used where applicable.

 

ANSI B4.1 is divided into classes in three general groups depending on the field and type of application. Standard fits are marked with symbols. Symbols are not intended to show manufacturing details in drawings, only sizes should be specified in detail drawings. This standard does not cover location tolerances.

 

The specification can be defined in the metric or inch system. The inch decimal system is based on the ANSI B4.1 standard, while the ANSI B4.2 metric system is based on the ISO millimeter system.

 

The ANSI B4.2 standard describes the limits and fits system in the ISO system for mating parts. It specifies, among others: preferred basic sizes and tolerance zones as well as limitations and fit for sizes up to and including 500 mm.

 

As you can see, the presented classification is extensive and is crucial for the execution of individual elements.

We invite you to buy our rubber products, including those with water cutting services, rubber washers and other flat rubber gaskets.

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