Plastic tandem extrusion sizer mold

Details Plastic tandem extrusion sizer mold Plastic tandem extrusion sizer mold

2001-05-08

2004-03-09

Davis, Robert (Department: 1722)

Plastic article or earthenware shaping or treating: apparatus

Including means advancing continuous length work through...

C425S186000, C425S195000, C425S326100, C425S384000, C425S388000

Reexamination Certificate

active

06702560

ABSTRACT:

FIELD OF INVENTION
The present invention relates to forming device for the manufacture of a profile, especially to a plastic tandem extrusion sizer mold and the manufacture method thereof, by which the quality of profile extruded is ensured, and its design and manufacture period is shortened effectively and steadily.
BACKGROUND OF INVENTION
Traditionally, the well-known extrusion sizer mold, illustrated in
FIG. 1
as a sectional view of a sizer mold for subsection extrusion, is made up of one to six single sizers installed with isometric distance on a base formed by sole plate seat
1
and sole plate
2
. The mold cavity
13
is surrounded by upper plate
10
, side baffle
9
, side baffle
8
, side baffle
6
and lower plate
4
. The upper cover constituted by upper plate
10
and upper cover plate can be moved upward around the axis of hinge
18
and opened: handle
12
is the handle for operation. The whole cavity is of the open type. The parting face is parallel to the extrusion direction, and the selection of the parting face depends on the complexity of the cavity.
Conventionally the cavity is divided into several opened parts formed by plate at transition points, a female die cavity which is not easy to machine, and nook points, in order to dig, mill and grind every part easily. A line cutting electric spark process is often taken to machining those which are more complicated in shape, and are very difficult to machine, for example the side baffle
8
, and then all parts are assembled together to form a mold cavity. Gas slot
14
is machined at the inner face of the cavity channel, and a gas path system is formed by gas slot
14
, gas hole
15
, gas chamber
16
and gas extraction nozzle
17
. Gas slot
14
is communicated with gas hole
15
, and then communicated with gas chamber
16
, and gas nozzle
17
and gas chamber
16
are communicated with each other. The run-through cross section between the gas hole
15
and gas slot
14
is too small, that is, the effective cross section for gas extraction is too small, and this inevitable defect results in that the vacuum of the cavity is not easy to establish, and it goes against the sizing of the profile.
Around the cavity a water hole
20
is formed. The water hole
20
keeps a certain distance from the gas slot
14
to prevent water leakage brought on by the connection between them. Not only this, but also the arrangement and connection of the water hole
20
is complicated. As the water hole goes through the parting face of the plate, the O-shape gasket
7
is used to seal the clearance between them, and the technological hole should be plugged up by aluminum plug
5
as the water hole goes through the side baffle
6
. All of water holes are holes whose depth is more than 20 times its diameter, and machined along the length direction of each sizer, so the water holes need to be far more from the gas slots (that is, from the cavity) to insure that water leakage will not occur, but this causes the disadvantage of bad cooling of the production in the cavity.
For the sake of full cooling and sizing of the production in the cavity, a conventional sizer mold is made up of several sections of sizers installed axially with isometric distance on a sole plate. Generally the section number is one to six; the least number is one. The length of each section is about 200 mm to 600 mm. The disadvantage of this kind of mold installed by parts is that the geometry center of its cavity is not easy to keep in a same line, that is, it is difficult to ensure the coaxiality of sections.
To sum up, this kind of cavity opened type sizer mold is complicated in configuration, its manufacture requiring several machines such as bull planer, omnipotence miller, grinder, line cutting electric spark process, omnipotence tool miller and omnipotence tool grinder etc., and through several complicated working procedures, so the accumulative error is difficult to avoid and cavity dimension precision is not easy to ensure, and especially the rectification of special parts of the cavity could not be met. For different productions, the parting face is different, and the connection between the sizer and gas and water also is different, so that the exterior connection is difficult to standardize, and the positions and numbers of the gas nozzle
17
and the water nozzle
19
are different in case of different parting face and different section assembly. Once the profile is plugged up, only manual dismantling can be done, the resultant disadvantage being manpower consumption, damage to the installation precision, and unavoidable replacement error. On account of the development of the extrusion mold, most corporations domestic and foreign carry out this conventional method, the only different is that each corporation has its own manufacture experiments.
SUMMARY OF THE INVENTION
The object underlying the invention is to overcome the disadvantage of the above conventional extrusion sizer mold, and to provide a new plastic tandem extrusion sizer mold. The sizer mold of the present invention gets over the limitations of cavity parting, machining deep holes, cutting gas slots, trivial design and bad precision, and the product manufactured by this sizer mold have simple and novelty construction, and steady performance, and can be manufactured rapidly.
An other object of the present invention is to provide a method for manufacturing the above plastic tandem extrusion sizer mold. The manufacture method of the present invention is based on the standardization manufacture for the machining process of the central parts constituting the plastic tandem extrusion sizer mold. Semi-finished parts are made ready in advance, so the period for production design is shortened, and manufacturing technological is simplified, manufacturing efficiency improved, precision machining highly concentrated, and performance of the production steadied.
The objects are accomplished by a sizer mold according to the present invention and by a method for manufacturing the above sizer mold. The plastic tandem extrusion sizer mold of the present invention contains plates, cavity, water holes, gas holes and gas slots, and is characterized in an inlet plate, middle plates and an outlet plate are connected with each other in series by columniform pin, and then side baffles are added to fix them up on a base with the aid of bolts. A close cavity is formed in the center of the inlet plate, the middle plates and the outlet plate, there are no joints around the cavity, and the cavity has no parting sections. There are water holes and gas holes at the circumference of the cavity, and a rubber sealing gasket, which connects water holes and separates gas slots, is placed between the corresponding water holes of two plates. The cavity, gas slots, gas holes and gas nozzles communicate with each other, a water nozzle installed at the inlet plates is communicated with water hole, and a gas nozzle is installed on the middle plate selected.
The inlet plate, several middle plates and the outlet plate of the same thickness are placed upright and arranged in series longitudinally.
A concave stand is milled at one end face of the inlet plate and the middle plate. At the four corners of the concave stand, the gas holes are drilled. The gas slots are formed by the combination of plates and concave stand in turn, and the gas slots are connected with each other in series via the gas holes at the four corners. Gas is taken out in subsection from the gas nozzles on the middle plate selected and gas holes connected, and each gas slot contributes itself to the parallel connection between sections.
No gas holes are formed at the inlet plate and the last middle plate. The cavity at the outlet plate is a rectangle cavity for covering the cavity at the middle plate.
An annular water trough surrounds the cavity at the inlet end of the inlet plate. At the outlet end, water-through hole is drilled in the annular water trough surrounding the cavity. The water-through holes are of the same dimension and distribute uniformly, and the wa

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