Дизайн в сочетании регулируемый торцевых фрез с CBN для высокоскоростной обработки измеренных пазы

Design of combined adjustable face mills with СBN for high-speed processing of measured grooves.

When processing some types of directing, adjusting grooves under radio equipment and other products there is a need for the big nomenclature of the tool as grooves differ geometrical parameters and a profile form. Therefore they can't be processed the standard tool for one pass. The sketch of section of a groove of a standard detail "plate" with an inclination in 10 ° is submitted in fig. 1

Fig. 1 Sketch of a detail "plate".

One of the directions, substantially milling of such details raising efficiency of process of processing, application of combined mills equipped with cutting elements from STM with adjustment on diameter of a mill (Patent No. 88594) is. The three-dimensional model of a similar design is presented in fig. 2 In fig. 3 the scheme of knot of turn of a cutting element with СBN for ensuring adjustment of geometrical parameters after control is submitted. At turn of the adjusting screw 3 on a corner μ the intermediate plug will turn on a corner θ. As the rotary knife is established eccentricly in the intermediate plug, it will make turn on a corner ε. The cutting plate will adopt the provision at which corners of cutting of a cutting element will accept values excellent from initial that will lead to emergence of negative back corners.

 

 

Fig. 3 Scheme of knot of turn of a cutting element with СBN.

For installation of positive back corners it is necessary to turn cutting insert together with the clown on a corner θ. On the basis of the scheme presented in fig. 4 the formula for corner definition θ is received θ.

 

 

 

 

 

As an example in fig. 5 it is dismissed changes of back corners at control of a mill for processing of grooves by the sizes 66 and 68 of mm

 

Fig. 5 Scheme of Change of Back Corners at control of a mill for processing of a groove of other size (the provision of a knife 1 on the provision of a knife 2).

Apparently from the scheme 5, the size of a back corner of a mill changed with 15⁰ to-9⁰. At turn of the clown on a corner θ = 34,17 ° the back corner accepts a reference value (Fig. 6). Processing of details is carried out from aluminum at cutting speeds to 2000m/min. When processing at such speed dynamic balancing of the tool is necessary. For dynamic balancing, apply special balancing cars by which determine centrifugal force, size of eccentricity and freight weight for the counterbalancing couple of moments. The balancing Best Balance 4000 car which allows to carry out dynamic balancing of a various class of accuracy of G according to GOST ISO 1940-1-2007 was applied to balancing of a face adjustable mill. Depending on the chosen parameters of balancing the system will specify the mass of a balancing element and a corner of its installation. The set parameters and results of measurements are brought to the monitor (Fig. 9а) also remain in memory that does work with data of the most convenient.

а	б

Fig. 7 Window of a Conclusion of Results of Measurements.

The producer of polycrystalline CD10 diamond the Sandvik Coromant company recommends to conduct processing of aluminum alloys at speeds about 2000 m/min that with a diameter of mill of 66 mm, corresponds to rotation frequency 9651ob/min. In the course of balancing of an experimental mill by balancing Best Balance 4000 car, the class of accuracy of balancing of G6.3, according to GOST ISO 1940-1-2007 that allows to conduct processing with a frequency of rotation of the tool to 11000 rpm (Fig. 7b) was reached. Experiment was made on the multi-purpose MAZAK Variaxis 630-5X machine. Preparation of a prismatic form from D16 brand aluminum was as an example used. For control of parallelism the contact Renishaw OMP6 sensor was used. For control of parallelism of the plane of a detail with the table plane, the probe concerns a detail in three points through which the system of ChPU of the machine builds the plane, and compares its situation with the reference. During measurement it was revealed that the plane of a detail crosses the plane of a table of the machine at an angle 0.02 °. Such size of a deviation from parallelism is little significant and won't have essential impact on results of experiment. Measurement showed that after control diameter of cutting part of a mill makes 66.06 mm that corresponds to width of a processed measured groove of mm (table 1).

Table 1. Results of measurement of width of the processed measured grooves
Name	Groove width , мм
	section I	section II	section III
	66.03	66.01	66.02
	68.12	68.15	68.11

For understanding of limit values of speed of cutting at which the processed measured groove meets drawing requirements, processing of a measured groove of mm was carried out at various values of speed of cutting. It is necessary to consider that eventually operation of the tool there is a change of geometrical parameters of a cutting edge and therefore intensity of emergence of an average deviation can increase with increase in time (fig. 8)

Table 2. Comparison of results of measurement of width of the processed measured groove to value of speed of cutting.
Speed of cutting, m/min.	Average deviation of width of a groove, mkm
	At static balancing	At dynamic balancing on the class G6.3
100	20	10
200	10	10
300	20	20
400	30	20
500	70	40
600	210	50
800	350	70
1000	580	80
1200	-	90
1500	-	130
1800	-	260
2000	-	350

 

 

 

Where λ_c (v) and λ_д (v) - intensity of emergence of an average deviation at static and dynamic balancing, f_c(v) and f_д(v) - distribution density at static and dynamic balancing; F_c(v) and F_д(v) - function of distribution of a deviation at static and dynamic balancing.

Conclusions:

1 . The received formula for corner definition θ characterizes interrelation of design data of adjusting knot with angles of rotation of its separate elements at control for a certain size of a groove.

2 . Being guided by results of experiment, the tool of the similar sizes and a design, balanced by a static method at parallel stands, it isn't recommended to use over 2400 rpm with a frequency of rotation of a spindle. and a dynamic method on a class of accuracy of balancing of G6.3 with a frequency of rotation of a spindle over 8500 rpm

Bibliography:

1 . The patent for useful model No. 88594 "The national team an end face - a trailer mill with cutting elements from nonostrukturirovanny superfirm materials"

2 . Grechishnikov V.A. Grigoriev S. N., Kirsanov S. V., Skinners of D.V., Kokarev V. I. Skhirtladze A.G. Metal-cutting tool. Textbook. M. :ITs MGTU "Stankin", "Janus-to", 2005, 586с.

3 . Chulin I.V. Features of design of shaped mills for processing of surfaces with rectilinear образующими.//the Monthly scientific technical journal "STIN". -2011- . No. 12. Page 13-16

4 . Isayev A.V. Design of combined shaped mills with the round replaceable many-sided plates located on screw поверхности.//the Messenger of MGTU Stankin. 2011 . No. 1. Page 61-66

6 . Volosova M. A. Grigoriev S. N. Cutting plates from ceramics: influence of abrasive processing and coverings on their operational показатели.//the Messenger of MGTU "Stankin". The scientific reviewed magazine. M: MGTU "Stankin", No. 2(14), 2011, S. 68-74