GB2200865A

GB2200865A - Multiple block mold

Info

Publication number: GB2200865A
Application number: GB08703202A
Authority: GB
Inventors: Chun Pak Lau
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-02-12
Filing date: 1987-02-12
Publication date: 1988-08-17
Anticipated expiration: 2007-02-12
Also published as: GB8703202D0; GB2200865B

Abstract

A multiple block mold 10 whose mold parts are adapted to be combined and stacked up selectively comprises a plurality of cavity block units 12, each comprising a plurality of sub-blocks 20, 22, 24, 26 defining a mold cavity 16 having the shape of an item to be formed; a central sprue block unit 14 having passages for directing the flow of molding material from an inlet of a central sprue 44 to the mold cavities of adjacent cavity block units 12; a plurality of intermediate runner block units 50, each defining at least one passage for directing flow of molding material between cavity block units; and means for urging the cavity block units, the central sprues block units and the intermediate block units into a fluid-tight engagement. The mould 10 can be extended in the horizontal and vertical directions by the addition of extra block units 12, 14, 50. <IMAGE>

Description

MULTIPLE BLOCK MOLD The present invention relates generally to molds and in particular to multiple block molds of multi-cavity for the making of relatively small items such as plastic bases of integrated circuits. The invention seeks to provide a multiple block mold having its mold parts generally provided in block form and adapted to be combined and stacked up selectively forming instant channels or passages for directing the flow of fluent molding material which is to be formed and cured in the mold.

Molds are known in prior arts. Traditional mold system applies single layer block mold of hard metal in chase form.

One of the disadvantages of this traditional mold is its complexity in structure and its high cost in manufacture. Yet another disadvantage is its low productivity. Aperture plate molding is another type of molding system. This molding system makes use of single plate mold which is made of metal with a lesser degree of hardness. This kind of mold is easier to produce and less expensive as compared with the above traditional one. However, -mold of this type has some defects. The life span is relatively short due to the hardness of the metal chosen. Furthermore, the precision of the items produced are low.

The prior arts mentioned above also share some common defects. The productivity is, to a certain extent, limited by restrictions imposed upon individual molding machine.

Cleansing of the mold is not made easy to perform. The molding systems are thus basically of manual operation.

Complete automation is not common to the traditional molding systems.

The object of the present invention is to produce a new type of mold and method to eliminate the defects existing in the prior arts.

According to the present invention there is provided a multiple block mold having its mold parts adapted to be combined and overlapped selectively comprising, a plurality of cavity block units, each comprising a plurality of subblocks defining at least one mold cavity each having the shape of an item to be formed; at least one central sprue block unit, each of the central sprue block units being corresponded to and positioned in alignment with at least one of the cavity block units defining channels or passages for directing the flow of fluent molding material from an inlet of a vertically extending central sprue to inlets of the at least one mold cavity of each of the corresponding cavity block units; a plurality of intermediate runner block units, each being disposed between and positioned in alignment with two horizontally disposed cavity block units and defining at least one passage or channel for directing the flow of fluent molding material outwardly from an inner cavity block unit to a corresponding outer cavity block unit; each of the cavity block units, each of the central sprue block units and each of the intermediate runner block units are respectively adapted to be stacked over one another forming vertically expandable columns of blocks which are adapted to be abutted against each other and expandable in the horizontal direction; means for urging the cavity block units, the central sprue block units and the intermediate block units into +luid-tight pinching engagement; and guiding means being provided on each block unit for guiding the movement thereof between a closed or "locked" position and an open or "unlocked" position of the mold; whereby the block units, upon mold closure, are urged upon each others forming instant barriers and channels therein for directing the flow of fluent molding material which is being formed and cured in the mold.

The mold parts can be readily extensible either horizontally or vertically. This renders the system to be more flexible. A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 shows a fragmentary vertical sectional view, with portions broken away, showing a preferred embodiment of a multiple block mold assembly embodying the present invention; Figure 2 shows a horizontal sectional view,with portions broken away, illustrating the multi-cavi-ty structure of the mold assembly of the invention.

Figure 3 is a fragmentary vertical sectional view similar to that of Figure 1, showing an expanded version of the multiple block mold; and Figure 4 is a fragmentary horizontal sectional view similar to that of Figure 2, showing an expanded version of the multiple block mold of the present invention.

This invention utilizes certain principles and/or concepts as set forth in the claims appended to this specification. Those skilled in the arts will realize that these principles and/or concepts are capable of being utilized in a variety of embodiments which may differ from the present embodiment given for illustrative purposes herein. For this reason, this invention is not to be construed as being limited solely to the illustrative embodiment, but should only be construed in view of the claims.

Referring now to Figure 1, a multiple block mold is designated generally by reference numeral 10. The multiple block mold 10 comprises a plurality of cavity block units 12, central sprue block assembly 14 and a plurality of intermediate runner block units 16.

These block units 12, 14 and 16 are adapted to be combined and stacked up selectively thereby building up a multiple block mold 10 according to the present invention.

Each cavity block unit 12 consists of four individual blocks, namely, an upper or top cover block 20, an upper or top cavity block 22, a lower or bottom cavity block 24 and a lower or bottom cover block 26. Top cover block 20 and top cavity block 22 together form a mold top half whereas bottom cover block 26 and bottom cavity block 24 together form a mold bottom half. Being in the shape of a solid rectangular block, top and bottom cover blocks 20 and 26 constitute the top and bottom parts of cavity block unit 12 respectively with the cavity blocks 22, 24 being sandwiched therebetween.

Provided on each of the top and bottom cavity blocks 22, 24 and disposed substantially at the center thereof is at least one cavity, generally designated 18, having the shape of an item to be formed.

It can be seen in Figure 1 that at least a portion of the lower surface of the top cover block 20 and at least a portion of the upper surface of the bottom cover block 26 are exposed to and forming an upper and a lower surface of the mold cavity 18 respectively.

It can also be seen that top and bottom cover block 20 and 26, both having exactly the same horizontal sectional dimension as the top and bottom cavity block 22 and 24, are in the form of a plain solid rectangular block. Each of the blocks 20, 22, 24 and 26 has substantially flat surfaces so that oppositely facing surfaces of adjacent blocks a:e adapted to be abutted against each other without leaving any undesired gap therebetween when the blocks are in their closed or "locked" position.

Central sprue block assembly 14 as shown in the preferred embodiment in Figure 1 consists of three central sprue block units, namely, an upper central sprue block unit 30, a middle central sprue block unit 32 and a lower central sprue block unit 34.

It will be appreciated that the central sprue block units 30, 32 and 34 bear the same sectional dimensions. The only difference is the construction of the sprue means being disposed within the central sprue block units 14. The central sprue block units 30, 32, 34 and their associated sprue means will now be described in more detail.

The upper central sprue block unit 30 consists of four overlaying blocks 36, 38, 40 and 42, with a portion thereof including vertically extending surfaces defining part of the shape of a central sprue 44 which extends downwardly from an inlet 46 of the central sprue 44, and with a portion thereof including surfaces defining at least a section of the channels or passages 48 extending from the central sprue 44 to the inlets of the mold cavities 18 of the corresponding adjacent cavity block units 12'.

The middle central sprue block unit 32 also consists of four overlaying blocks, with a portion thereof including vertically extending surfaces defining part of the shape of central sprue 44 which extends downwardly and continuously from the section of the central sprue 44 of the upper central sprue block unit 30, and with a portion thereof including surfaces defining at least a section of the channels or passages 48 extending from the central sprue 44 to the inlets of the mold cavities 18 of the corresponding adjacent cavity block units 12".

Similarly, the lower central sprue block unit 34 consists of four overlaying blocks, with a portion thereof including surfaces defining at least a section of the passages or channels 48 extending from the central sprue 44 to the inlets of the mold cavities 18 of the corresponding adjacent cavity block unit 12'''.

plurality of intermediate runner block units 16 are disposed between two horizontally positioned cavity block units 12. Each of the intermediate runner block units 16 consists of an upper or top intermediate runner block 50 and a lower or bottom- intermediate runner block 52.

Top intermediate runner block 50 is a plain solid rectangular block with a portion of the bottom surface thereof defining part of the surfaces of the channels 54 extending from an inner cavity block unit 12 to a corresponding outer cavity block unit 12.

Bottom intermediate runner block 52 consists of recesses or grooves 56 (Figure 2) defining another part of the surfaces of channels extending from an inner cavity block unit 12 to a corresponding outer cavity block unit 12.

Figure 2 its a horizontal sectional view taken generally as indicated along line x-x of Figure 1, showing a sectional plan view of a preferred embodiment of the mold assembly according to the present invention.

It is accordingly seen that two mold cavities 18 are disposed in each cavity block unit 12 and are in fluent communication with mold cavities 18 of horizontal adjacent cavity block unit 12.

Cavity block units 12, as can be seen from Figure 1, are symmetrically arranged with respect to the central sprue 44. This is to facilitate an even distribution of fluent molding material to the cavity block units 12 positioned on both sides of the mold 10.

Although it has been shown and described in the present embodiment that only two columns of cavity block units 12 are placed on both side of the mold 10, it is contemplated that additional columns of cavity block units 12 can be interposed therebetween on both sides respectively. This would render the mold apparatus 10 to be extensible in the longitudinal direction. Also, it has been shown and described that two mold cavities 18 are provided on each of the cavity block unit 12. It is appreciated that, in practice, more mold cavities 18 can be used. This renders the mold apparatus 10 to be extensible in the latitudinal direction.

Figure 3 depicts a fragmentary vertical sectional view of an expanded version of multiple block mold 10 hereinbefore described. The new version of mold 10 is generally indicated by 10'. It can be seen that mold 10' has been structurally expanded in the vertical direction.

Five rows of block units are employed. This vertical expansion is achieved by introducing and interposing additional rows 58 and 60 to rows 62, 64 and 66.

Figure 4 htBws a fragmentary horizontal sectional view similar to that of Figure 2, showing the expanded version of multiple block mold 10 being expanded in the horizontal direction. It will be seen that mold 10' can be structurally expanded in both the longitudinal and latitudinal directions.

According to this expanded embodiment, three columns of cavity block units 68, 70 and 72 are employed, each cavity block unit having four mold cavities 74 disposed therein.

Two colums of intermediate runner block units 76, 78 are positioned between columns 68 and 70, 70 and 72 respectively.

Numeral 80 designates one of the central sprue block units of the central sprue block assembly 82 used in cooperation with corresponding cavity block unit 84 of cavity block column 68. Passages or channels 86, partially shown in Figure 3, are used for communication between a central sprue 88 and mold cavities 74 of cavity block unit 84.

Expansion of the mold system of the present invention either vertically or horizontally would bring to an increase of the productivity without investment on extra pieces of machines or on extra labour and time.

An essential feature of the present invention lies in the flexibility of the arraangement of the mold parts.

Opposite surfaces of adjacent blocks of the same dimension are adapted to be abutted against each other forming instant pasaages or channels for directing the flow of fluent molding material which is being formed and cured in the mold. Preferably, the blocks are clamped together and urged into a +luid-tight relation by the application of conventional box-form fixer or conventional hydraulic fixer (not shown) in a manner known to those skilled in the art.

This would allow the mold to be held in a closed or "locked" position when fluent molding material is forced into the mold cavity.

It can be seen that each top and bottom cover block 20, 26, each top and bottom cavity block 22, 24, each central sprue sub-block 36, 38, 40, 42 and each upper and lower intermediate runner block 50, 52 are of simple structure mostly with flat surfaces. Cleansing of the mold 10 and 10' is considerably easy and automation of the molding system according to the present invention is, therefore, made feasible. Furthermore, the manufacture of blocks 20, 22, 24, 26, 36, 38, 40, 42, 50 and 52 will be very. easy and the cost of manufacture is low. It is also understood that the size of each block is small so that each block can be made relatively rigid in comparison with those of the prior art.

This leads to a prolongation of the life span of the blocks.

Pin and bush means, designated by numerals 90 and 92 respectively, are provided on each cavity block unit 12 for guaranteeing a secure engagement thereof within the mold and for guiding movement thereof in a vertical direction between an "unlocked" position and a "locked" position of the mold.

Means (not shown) are connected to the fixer means for controlling the motion thereof so as to facilitate automation of the molding machine.

It will thus be seen that the present invention provides novel multiple block mold assembly and system having a number of advantages and characteristics, including those herein specifically pointed out and others which are inherent in the invention

Claims

CLAIMS 1. A multiple block mold having its mold parts adapted to be combined and overlapped freely and selectively comprising: a. a plurality of cavity block units, each comprising a plurality of sub-blocks and defining at least one mold cavity each having the shape of an item to be formed; b. at least one central sprue block unit, each of said central sprue block units being corresponded to and positioned in horizontal alignment with at least one of said cavity block units and defining channels or passages for directing the flow of fluent molding material from an inlet of a vertically extending central sprue to inlets of said at least one mold cavity of each of said corresponding cavity block units;; c. a plurality of intermediate runner block units, each being disposed between and positioned in alignment with two horizontally disposed cavity block units and defining at least one passage or channel for directing the flow of fluent molding material outwardly from an inner cavity block unit to a corresponding outer cavity block unit; d. each of said cavity block units, each of said central sprue block units and each of said intermediate runner block units are respectively adapted to be stacked over one another forming vertically expandable columns of blocks which are adapted to be abutted against each other and expandable. in the horizontal direction e. means for urging said cavity block units, said central sprue block units and said intermediate block units into +luid-tight pinching engagement;; f. whereby said block units, having, upon mold closure, an overall shape of a block, are provided therein with instant barriers and channels for directing the flow of fluent molding material which is being formed and cured in the mold; g. guiding means being provided on each cavity block unit for guiding the movement thereof between a mold closing position and a mold opening position.
2. A multiple block mold as claimed -in Claim 1 wherein said central sprue block units are disposed in the middle of the mold,whereas said cavity block units and said intermediate runner block units are disposed symmetrically relative to said central sprue units.
3. A multiple block mold as claimed in Claim 1 or Claim 2, wherein each of said central sprue block units consists of four overlaying sub-blocks, each being arranged in horizontal alignment with a sub-block of each of . said at least one corresponding cavity block unit, and each having portions thereof including surfaces defining part of the shape of said central sprue extending from an inlet of said central sprue, and/or defining a section of the passages which extend from said central sprue to the inlets of said at least one mold cavity of each of said corresponding cavity block units.
4. A multiple block mold as claimed in Claim 2 or Claim 3 wherein, said sub-blocks of each of said cavity block units are formed of an upper and a lower cover block means including surfaces thereof defining respectively an upper and a lower surface of said -at least one mold cavity of said cavity block unit, and an upper and a lower cavity block means being sandwiched between said upper and lower cover block means, each being provided thereon with at least one cavity including surfaces defining other surface of said at least one mold cavity of said cavity block unit.
5. A multiple block mold as claimed in Claim 4, wherein each of said intermediate runner block units consists of an upper intermediate runner block and a lower intermediate runner block, said upper intermediate runner block has a lower surface thereof defining an upper surface of said at least one passage or channel extending from one end of said intermediate runner block unit to the other end thereof, and said lower intermediate runner block has at the upper surface thereof provided with at least one groove with surfaces thereof defining other surfaces of said at least one passage or channel extending from one end of said intermediate runner block unit to the other end thereof.
6. A multiple block mold as claimed in any one of the preceding claims, wherein said means is á box-+orm fixer.
7. A multiple block mold as claimed in any one of the preceding claims, wherein said means is a hydraulic fixer.
8. A multiple block mold as claimed in any one of the preceding claims, wherein said guiding means are in the form of pins and bushes.
9. A multiple block mold substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.