Method of producing resin mold

Details Method of producing resin mold Method of producing resin mold

2002-08-22

2004-07-20

Kuhns, Allan R. (Department: 1732)

Plastic and nonmetallic article shaping or treating: processes

With step of making mold or mold shaping, per se

Utilizing surface to be reproduced as an impression pattern

C264S225000, C264S278000, C264S317000

Reexamination Certificate

active

06764630

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a method of producing a resin mold which is one kind of easy-to-use mold.
BACKGROUND ART
As molds used for molding resins, there have been generally used metal molds, and in some cases, for example, for trial production or small-quantity production, there have been used resin molds of a type in which a plane facing to a cavity is made from a resin.
For example, a method of producing a resin mold has been described in Japanese Patent Laid-open No. 2001-105438 entitled “Method of Producing Resin Mold”. FIGS. 7, 9 and 10 in this document are recited in the following figures.
FIGS.
16
(
a
) to
16
(
c
) are views showing a related art resin mold and a production method thereof described in the above document, wherein FIGS.
16
(
a
),
16
(
b
) and
16
(
c
) are recited from
FIGS. 10
,
7
, and
9
of the above document, respectively. It is to be noted that in FIGS.
16
(
a
) to
16
(
c
), all of parts are denoted by new reference numerals.
FIG.
16
(
a
) is a sectional view of a finished resin mold. A resin mold
100
is composed of a front side mold part
101
and a back side mold part
102
. The front side mold part
101
includes a reinforcing member
103
to which a resin layer
104
is provided, and the back side mold part
102
includes a reinforcing member
105
to which a resin layer
106
is provided. A cavity
107
is formed between the resin layers
104
and
106
. Accordingly, the resin mold
100
is a mold of a type in which a plane facing to a cavity is made from a resin. A method of producing such a resin mold
100
will be described with reference to FIGS.
16
(
b
) and
16
(
c
).
In the step shown in FIG.
16
(
b
), a master model
110
including clamping lug portions
111
and
112
is clamped between the reinforcing members
103
and
105
, and resins
115
and
116
are injected in mold surface forming spaces
113
and
114
, respectively.
In the step shown in FIG.
16
(
c
), after the resins
115
and
116
are cured to form the resin layers
104
and
106
, the reinforcing members
103
and
105
are separated from each other, to remove the master model
110
. By assembling the reinforcing members
103
and
105
in the state that the master model
110
has been removed, the resin mold
100
shown in FIG.
16
(
a
) is obtained.
Referring to FIG.
16
(
c
), as the master model
110
, there has been generally used a rapid prototyping model produced by a rapid prototyping process advantageous in easy production. The rapid prototyping model, however, is poor in rigidity, to be thus easily deflected.
As described above, the resins
115
and
116
are injected in the mold surface forming spaces
113
and
114
, respectively, in the step shown in FIG.
16
(
b
). In this step, a deviation of injection timing or the like inevitably occurs, to deflect the master model
110
rightwardly or leftwardly. To prevent such deflection of the master model
110
, supporting members
117
and
118
are inserted as shown in the figure; however, portions, apart from these supporting members
117
and
118
, of the master model
110
are defected. If the master model
110
is deflected, the shape of the cavity
107
shown in FIG.
16
(
a
) becomes inaccurate, with a result that the finishing accuracy of a molded product is degraded.
An object of the present invention is to provide a method of producing a resin mold, which is capable of preventing a master model from being deflected.
DISCLOSURE OF THE INVENTION
To achieve the above object, according to an invention described in claim 1, there is provided a method of producing a resin mold, characterized by including the steps of preparing a master model having a shape corresponding to a product shape and including a clamping lug portion at a periphery of the master model, and a first back surface reinforcing member and a second back surface reinforcing member; clamping the master model between the first and second back surface reinforcing members in a state that a first resin filling space is kept between the master model except the clamping lug portion and the first back surface reinforcing member and a second resin filling space is kept between the master model except the clamping lug portion and the second back surface reinforcing member; filling the first resin filling space with a temporary filler, the temporary filler being adapted to be easily injected in or discharged out of the first resin filling space; filling the second resin filling space with a resin as a material of the resin mold, and curing the resin; discharging the temporary filler from the first resin filling space; filling the first resin filling space with a resin as a material of the resin mold, and curing the resin; and removing the master model.
The back surface of the master model is supported by the temporary filler having been injected to fill the first resin filling space. In such a state, a resin as a material of the resin mold is injected to fill the second resin filling space. Subsequently, in the state that the back surface of the master model is supported by the resin having been injected to fill the second resin filling space, a resin as a material of the resin mold is injected to fill the first resin filling space. In this way, at the time of filling the space with a resin as a material of the resin mold, since the back surface of the master model is supported by the temporary filler or the resin as a material of the resin mold having been injected to fill the opposed space, the master model is prevented from being deflected. As a result, it is possible to obtain a cavity with a high accuracy, and hence to obtain a molded product having a desirable shape.


REFERENCES:
patent: 4946637 (1990-08-01), Masciarelli, Jr.
patent: 5028291 (1991-07-01), Delgrange et al.
patent: 5039468 (1991-08-01), Sellers
patent: 6224816 (2001-05-01), Hull et al.
patent: 6375880 (2002-04-01), Cooper et al.
patent: 6497834 (2002-12-01), Vargo et al.
patent: 2001-105438 (2001-04-01), None

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