Deep hole processing has been widely used in the die and mould industry, which solves the problems of fine and long holes that can not be solved by ordinary drilling machine in die and mould processing. The processing cost of the die is effectively reduced. Undertake the most precise deep hole processing, aperture 3-35 length can achieve 2600. The water, oil, gas, single oblique, double oblique, upsetting and pinhole in the die are solved to the greatest extent.
Overview of Deep Hole Processing Tolerance - Deep Hole Processing Manufacturers come to tell you:
First: The Meaning of Basic Terms of Tolerance
1) Basic size; the given size at design time is called basic size. Basic dimensions
2) Actual dimension: The dimension obtained by measuring after parts are processed is called actual dimension.
3) Limit size: The two limit values of the actual size allowed to change are called limit size. It is determined by basic size. The larger of the two limit values is called the near-large limit size Dmax (or dmax); the smaller is called the limit size Dmin (or dmin). Dimensional deviation; The algebraic difference of a certain size minus its basic size is called dimensional deviation, or deviation for short. Actual deviation = actual size - Basic Size
The algebraic difference between the near large limit size and its basic size is called the upper deviation; the near small limit size is called the lower deviation; the upper deviation and the lower deviation are collectively called the limit deviation. According to the standard, the upper deviation code of the hole is ES, the upper deviation code of the shaft is es, the lower deviation code of the hole is EI, the lower deviation code of the shaft is ei, and the deep hole processing rule is as follows:
ES = Near Large Limit Size of Hole - Basic Size of Hole
CS = Near Large Limit Size of Axis - Basic Size of Axis
EI = Near Small Limit Size of Holes - Basic Size of Holes
EI = Near Small Limit Size of Axis - Axis Basic Size
The deviation can be positive, negative or zero.
5) Dimension tolerance, the allowable variation of size is called dimension tolerance, abbreviated as tolerance. Tolerance is equal to the algebraic difference between near large limit size and near small limit size, or the algebraic difference between upper deviation and lower deviation.
6) Zero line: It shows the relationship between ultimate dimension, dimension deviation and dimension tolerance of holes and axes with basic dimensions opposite and matching each other. For convenience, in practice, only the enlarged tolerance zones of holes and axes are usually drawn, which are called tolerance and matching diagrams, abbreviated as tolerance zones diagrams, as shown in Pavilion l-b. In the tolerance zone diagram, a reference line to determine the deviation, i.e. zero deviation line, is zero-tapping line, which usually represents the basic size. The positive deviation is above the zero line. The negative deviation is below the zero line.
7) Dimensional tolerance zone: An area defined by two straight lines representing the upper and lower deviations in the tolerance zone diagram. In Fig. 6-36b, the area defined by ES and E lines is the dimension tolerance zone of holes; the area defined by CS and EI lines is the dimension tolerance zone of axes, and the hole tolerance zone is generally represented by oblique lines; and the axle tolerance zone is generally represented by dots.
Two Basic Elements for Determining Tolerances
Tolerance zone is determined by standard tolerance and basic deviation, standard tolerance determines the size of tolerance zone, and basic deviation determines the location of tolerance zone relative to change.
1) Standard tolerance: Standard tolerance is defined by everybody's standard and is used to determine any tolerance of the size of the tolerance zone. Tolerance grade determines the accuracy of size. The standard divides tolerance into 20 grades, which are expressed by IT01, IT0, IT1-IT18 respectively. It is called standard tolerance, and IT (International Tolerance) represents standard tolerance. When the basic size is fixed, the higher the tolerance grade, the smaller the standard tolerance value, the higher the accuracy of the size. Holes and shafts of the same basic size and tolerance grade have the same standard tolerance. In order to use conveniently, the standard divides the basic dimension range (< 500) into 13 dimension segments, and stipulates the tolerance values according to different tolerance grades corresponding to each dimension segment, and lists them in the form of tables.
2) Basic deviation; the standard arrangement is used to determine the upper or lower deviation of the tolerance zone relative to the zero line position; generally the deviation near the zero line is the base water deviation. When the tolerance zone is above the zero line, the basic deviation is the lower deviation; when the tolerance zone is below the change, the basic deviation is the upper deviation, as shown in Figure 2.
Everyone has standardized and serialized the basic deviations, stipulating 28 basic deviations of holes and axes, respectively, in Latin characters, arranged in sequence, capital letters for holes, and lowercase letters for axes.
Only one end of the basic deviation of each tolerance zone is closed, and the position of the other end depends on the value of standard tolerance.
In the basic deviation series of holes, the basic deviation from A to H is the lower deviation EI, from J to ZC is the upper deviation ES, and the upper and lower deviations of JS are +/-IT/2, respectively.
In the basic deviation series of axes, the basic deviation from a to h is the upper deviation es, the basic deviation from J to ZC is the lower deviation ei, and the upper and lower deviations of is are +/-IT/2, respectively.
According to international standards, the following is the standard tolerance table with basic size of 0-500 mm and accuracy of 4-18 grades.
