Push boring to transform the machine tool that pull boring

Summary: To process long and thin pipe, transform the machine tool that push boring into the machine tool that pull boring, the refrigeration that solved boring cutter successfully and the problem such as the lubricant, stiffness that stops staff of bits and platoon bits, boring and treatment precision. What petro-chemical factory uses is high temperature resistant centrifugal casting becomes the semifinished product that splitting decomposition provides, material is Cr25Ni35Nb character, length is more than 4m, external diameter is 56mm. The surface outside requirement pipe is not machined and inside the surface must be machined, the internal diameter after treatment is Ø43 ± 0.

1mm, ra3 of exterior surface roughness.

2µm. Be more than the pipe of 50mm to internal diameter, it is the treatment that push boring normally. The advantage of this method is: The structure is simple, makings and treatment go to the lavatory on. But when pipe internal diameter is less than 50mm, boring lever is long and thin, if use the means that push boring, it is bits difficulty, easy that because boring staff is too thin rigid inadequacy can produce oscillatory, platoon precision of short, treatment is hard to assure life of dozen of knife, cutting tool, pipe wall is large all do not penetrate even tube wall. Accordingly, when processing long and thin pipe, answer to change the treatment that push boring to pull boring treatment. The will primary machine tool that push boring transforms the machine tool that pull boring, main shaft rotate speed uses transducer to have stepless speed regulation, machine tool slideway and precision satisfy boring to machine a requirement. Graph 1 to transform the sketch map of the machine tool that pull boring after. Push boring to change the specific process that helps boring to be as follows: 1.

Cooling glue is in charge of 2.

Casing 3.

Bring guide-post bushing 4.

Workpiece 5.

The center is worn 6.

Boring lever bearing 7.

Bracket pursues the refrigeration of the refrigeration of boring cutter of sketch map of the 1 machine tool that pull boring and lubricant boring cutter and the assurance that lubricating is cutting tool service life. The structure is here medium, we cool the high pressure in primary machine tool the inclined hole that the system passes arbor to go up, undertake cool and lubricating to ministry of cutting tool blade, still use high-pressured liquid to develop the scrap of cutting tool head at the same time, this is one of crucial technologies that help boring. The reaming knife in pulling boring and float reamer are the main component that assures to machine quality, reaming hilt semifinished product machines basic measure, take the amount of bore with a reamer with have certain, undertake by float reamer dimension is amended, reduce exterior surface roughness to be worth, achieve blueprint requirement. Graph 2 to help boring structure the job pursues. Platoon bits is in charge of boring to slightness, platoon bits already difficult important. If cut bits cannot smoothly eduction, can lower cutting tool life greatly, make machine exterior quality aggravation, block discharges bits passageway, cause cannot machine. Because pipe internal diameter is small, the space that discharge bits is very limited, accordingly, we design boring staff the configuration that takes helix chamfer (graph 2) . Such, assured the stiffness of boring lever already, assured to have again enough the big channel that discharge bits. In be being machined actually, in helix groovy helix is driven and high pressure erodes oilily below double action, scrap is successful the ground by eduction. Of helix chamfer come back to the direction of rotation with pipe contrary. 1.

Bring guide-post bushing 2.

Nut 3.

Gland 4.

Float bearing 5.

Arbor 6.

Float reamer 7.

Reaming knife 8.

Impaction nut 9.

Workpiece 10.

The lever that pull boring pursues what the 2 structures that pull boring are versed in constructive boring cutter breaks bits Cr25Ni35Nb material is agglutinant big, use boring of common cutting tool, because platoon bits space is little,meet, scrap is too long cannot eduction. Accordingly, must use the boring tool that takes bits chamfer (graph 2) . The guiding of boring lever is covered and float bearing introduces smoothly to assure boring cutter inside the canal, must add in the front of feed bring guide-post bushing, the internal diameter that brings guide-post bushing and the diameter that machine a requirement are consistent. To increase the stiffness of boring lever, assure to machine precision, bearing of a float was added in the knife head back end of boring lever, the material of float bearing is soft qualitative bakelite character, the workpiece precision after treatment assures with respect to the precision that relies on float bearing. When because soft qualitative bakelite wears away when out of tolerance, must change. Effective treatment effect is very good after will pushing boring to change to pull boring, the error of aperture of long and thin canal that treatment gives is not more than ± 0.

1mm, ra3 of exterior surface roughness.

2µm, achieve the technical requirement of a regulation. CNC Milling