Technological support to improve the quality of a core dril on the basis of a combined finishing treatment.

The purpose of this master's theme is to improve the quality and durability of a core drill on the basis of a combined finishing treatment.

Core drill is a multiblade tool for intermediate or final processing of pre-manufactured holes. 3D model of core drill with cylindrical shank of high-speed steel (GOST 12489-71) is shown in Figure 1 [1].

Figure 1. 3D model of the core drill [3]

Standard technological process of manufacturing core drill is shown in Table 1 below [2]

Number operations	Name of operation	Description of the operation on Equipment.
005	Forest harvesting	Grinding HSS on eccentric press
010	broaching	Pulling the ends of high speed steel on long semi-automatic machine
015	Centering	Centering on two sides by centering machine
020	Turning	Grinding on the outside diameter on semi-automatic lathe
025	Grinding	Grinding on semi-automatic grinding machine
030	Milling	Milling helical grooves on the semi-automatic milling machine
035	heat treatment	hardening or quenching
040	Waterjet cleaning
045	Polishing	Polishing helical grooves on a special polishing head
050	grinding	Grinding on the outside diameter at the circular grinding
055	Sharpening	Sharpening on semi-automatic

 

To improve the technological characteristics and quality of core drill, a more streamlined process will be added to the existing process in Table 1, which will consist of the following steps:

1. Pneumofluids oriented processing,

2. Ultrasonic cleaning,

3. Vacuum ion-plasma spraying.

In the first stage, efficeint technological process is accomplished by direct pneumatic jet spraying of cutting edge of the core drill. This type of process is used to ensure efficient processing of complex profile design of miniature and large-sized products, which the conventional methods cannot be processed or it requires large effort. Figure 2a shows the device for Pneumatic jet spraying of cutting edge of the core drill.

Pneumatic jet spraying of cutting edge of the core drilll provides solution to two problems:

1. Running surface-plastic deformation of cutting edges (main, auxiliary and transverse edges), front and rear surfaces of the tool and their hardening. Here, we also have cutting edge training to further the work tool.

2. It produces rounding of the cutting edges of the tool (for high-speed steel to a value - r = 10 ... 15 microns, for a solid alloy to a value of r = 15 ... 30 mm). Rounding edges is a necessary operation process for further removing microchipping cutting wedge and formation of small thick stress, and it is also used in some cases to remove burrs formed during the back surface of the backing instruments. Figure 2b shows the manufacturing material for Pneumatic jet spraying process- silicon carbide black F100.

Figure 2a. The device for Pneumatic jet spraying of the core drill cutting edge.

Figure 2b. Silicon carbide black - F100.

 

In the second stage, an efficient technological operation process is executed to prepare the core drill for spray coating. At this stage, the following steps are taken: degreasing tool using ultrasound, washing tools, drying tool. In addition, chemical cleaning and waterjet cleaning can also be performd. To do this, a special environment applied and modes of processing is used.

Ultrasonic cleaning - it is method of cleaning the surface of an object using an high frequency sound waves (ultrasonic vibrator) to agitate in an aqueous or organic compound. The ultrasound is not effective without the cleaning solvent. The use of ultrasound is usually a faster cleaning process and enhances its quality. In addition, it is possible in many cases to replace the flammable and toxic solvents to safer detergents without loss of quality cleaning. This operation is carried out on ultrasonic machine for the integrated ultrasonic treatment of the axial cutting tools, which is shown in Figure 3.

Figure 3. Installation for integrated ultrasonic treatment of axial cutting tools

As the source of vibration applied, setting of ultrasound var 3-4 and magnetostrictive transducers ICP 2.5 - 18, mounted on special baths. Degreasing was carried out by immersing the instruments in the solution at a temperature of 50-60 °C. Solution: trisodium phosphate - 30-40 g/l, soda ash Tech 20-30 g/l, surface active agent RP-7 or OP-10 - 3.5 g/. In addition, petrol be used into the boot (BR-1) GOST 443-76, followed by rinsing in ethyl alcohol fractionation. Time degreasing 3-7 min.

In the third stage management process operations are performed causing the vacuum ion-plasma coatings. At this stage, provided the following operations:

- Nitriding tool in a glow discharge (excerpt - about 30 minutes, air-nitrided dressed up to 135 ... 665 Pa, the operating voltage - 350 ... 550 V).

- Ion bombardment and heating of the tool 5 ... 10 minutes.

- Metallization of the functional elements of the tool 3 ... 5 min.

- Application of multilayer composite coating of titanium nitride (15-20 layers).

- Cooling the tool. [6]

Figure 4 – animation of ion-plasma spraying process

(Animation format: Animated GIF, volume - 147 kB, consists of 23 frames, 3 repetitions)

Vacuum ion-plasma spraying is designed for applying protective and decorative coatings of different composition on metal products, products from some types of plastics and glass, hard coatings for machine parts and mechanisms, as well as the machining tool.
Figure 5 shows a general view of the apparatus 6.6 HHB for vacuum ion-plasma spray coatings on the axial edge tools. This setting allows you to implement a full range of all operations of the third phase for an efficient finishing treatment process of the core drill.

Figure 5. The general view of the 6.6 HHB Machine for vacuum ion-plasma spray coatings on edge tools

When all the stages 3 stages are completed, the new core drill will be madeto test functionally-oriented coverage and comparison of its technological characteristics with a standard core drill. 3D model of the functional-coatedcore drilll shown figure 6.

Figure 6. 3D model of the functional-coated core drill

Note: At the time that i wrote this abstract of my master degree project theme, the work is not complete. Full text of work and materials can be obtained from the Project Supervisor after the completion date which is 31.12.2010.

 

References

1. Directory toolmaker, Ed. IA Ordinartseva. L.: Mashinostroenie, 1987. - 846 pp.


2. Manufacturing cutting tools / AI Snow leopards, AV Ivanov, KI Pantry and others - M.: Mashinostroenie, 1979. - 136 pp.


3. Technology of production of cutting tools / MM Paley - M.: Mashgiz, 1963. - 483 pp.


4. Wear-resistant coating for high-speed tools / JN Grandchildren, AA Markov, LV Lavrov, NY Berdyshev. - K.: Tehnika, 1992. - 143 pp.


5. VD Evdokimov, Klimenko, LP, Evdokimova AN The technology of hardening of engineering materials: textbook, reference book / Edited by Prof. VD Evdokimova. - Odessa Nikolaev: Izd NGGU them. Peter Graves, 2005. - 352.


6. Mikhailov AN, Mikhailov V., Mikhailova, EA Methods and basic principles of synthesis of functionally-oriented vacuum ion-plasma coatings engineering products. Strengthening technology and coatings. - M. Mashinostroenie. № 7. 2005. C. 3 - 9.


7. Methods of finding new technical solutions, Ed. AI Polovinkina. - Yoshkar-Ola: Mar. book. Publishing House, 1976. - 192 pp.