JPH02268938A - Method and device for casting - Google Patents

Abstract

PURPOSE: To easily manufacture a casting mold by forming a solid block from a forming material, hardening the block, removing a material from the block and forming a cavity for forming. CONSTITUTION: The solid block 2 and a core 15 composed of forming sand are formed with a forming machine 1 and hardened. A hole is formed on the block 2 with a CNC multiaxis machining centers 12, 13. The block 2, core 15 and the necessary insert are assembled with a CNC assembling robot 17 to form a finish mold 18. In this process, a pouring sprue 19 is disposed and a cut-off device 21 is arranged in a gantry mold CNC robot 20, and then, the casting mold having good efficiency in small scaled batch production form can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to the production of cast products made of metals and other materials, and in particular to the production of collabsible molds for such cast products and the production of cast products from the collabible molds. This invention relates to a casting device.

(Prior Art and Problems to be Solved by the Invention) Currently, casting products are basically manufactured using collapsible sand molds.
The cavities are manufactured by injecting molten material into cavities in the mold, which are formed by ramming sand around a rigid pattern.
ml, and the pattern is then removed from the mold.

However, forming the patterns requires skilled techniques and therefore the patterns are expensive to manufacture. Furthermore, you will need a place to store the patterns, and
It takes time and effort to store and retrieve. Such problems can be caused by undercuts and other re-entrant features.
This becomes noticeable when manufacturing complex castings with ant 5 hape). This is because the pattern must be complex in order to be able to be removed from the mold. As a result, it becomes difficult to efficiently manufacture cast products using a small-scale batch method.

A good casting cannot be made without a good mold, and a mold is only as good as its ability to produce a dimensionally accurate pattern free of imperfections or defects. “The term molding process is
Used to refer to the materials used and the method of making the mold. "casting plant"
The term "l" refers to the equipment that carries out the molding process as well as the method of introducing metal into the cavity of the mold and all the steps carried out in making the casting.

The known forming process has several characteristics: (1) the use of a pattern [or core box], (2) several types of agglomerated mixtures consisting of granular refractories and paing, (3) (4) curing the agglomerate or forming a bond of the agglomerate while in contact with the pattern; (5) removing the pattern from the cured agglomerate mold; and (6) They share the following characteristics: assembling the mold and core piece to form a completed mold, and injecting metal into the mold.

The casting mold manufacturing method of the present invention, the casting device of the present invention, and the cast product obtained by the method or device of the present invention include:
Features 1.3.4 and 5 above can be omitted.

According to the casting method of the present invention, a mold can be made without using a rigid pattern, so problems related to the use of patterns can be solved. It is relatively easy to form the concave corner shape in the block, and of course the cast product can be easily removed because the mold is collabable.

The primary purpose of the pattern is for use in molding. However, in order to successfully produce a casting and to make it suitable for further processing, the pattern needs to perform other functions than just forming the mold cavity. It may be said that

In order to successfully produce a casting, it is generally necessary to fit into the pattern a system of channels and feed reservoirs (gates and risers) for introducing metal into the cavities of the mold.

The present invention has been made to solve the above-mentioned problems of the prior art.

(Means for Solving the Problems) Therefore, according to the - aspect of the present invention, there are a step of making a solid block made of a molding material, a step of hardening the block, and a step of removing the material from the block and molding it. A method of manufacturing a casting mold is provided, which includes the step of forming at least a part of a cavity for a casting mold.

The material of the block is preferably removed by machining. A number of separate blocks containing material to be removed from a portion of the mold cavity were formed with zero machining through each block that were held together to form a complete mold cavity. Each short mold with each cavity is grouped together on a conveyor system and has the same length as the entire length of the short multiple molds grouped together and is formed into a group of block molds. A casting is formed having an overall shape defined by the cavity.

According to another aspect of the invention, the casting is formed from a group of mold blocks in which the molding cavities of the group vary from block to block to form the desired shape of the complete cavity. The blocks have various overall dimensions so as to reduce the amount of machining to form the cavities and to reduce the amount of mold material that must be removed after solidification of the casting. It has become.

A cavity with an approximate profile is formed in the block during the formation of a solid block before material is further removed from said block to form a molding cavity of the correct shape, thereby reducing the amount of material to be removed. You can also try to reduce the amount.

The gating system preferably comprises channels and risers for introducing molten metal into a forming cavity formed in the block by removing material from the block. After solidification, the channels and risers can be cut away from the desired casting, along with the surrounding mold material, while the block remains on the conveyor.

According to another preferred aspect of the invention, a casting apparatus is provided. This casting equipment consists of compressed forming sand (m
Olding 5andl block and aeration passage (aera
perforation machine for forming the tion passage (
A drilling machine, a multi-axis pre-machine system that removes material from the block to form a cavity for molten metal, and a series of block molds guided through a molten metal delivery system to supply molten metal to the forming cavity. conveyor means for removing solidified metal that is surplus to the desired casting when the metal-filled block is placed on said conveyor system;
and sha-ker means for removing remaining portions of block material from the finished casting.

Control means are preferably provided for positioning the machining system on one of a number of axes and for moving the tool the required amount into the block.

In accordance with yet another aspect of the invention, a casting apparatus is provided for forming a solid block of molding material having an approximately preformed molding cavity.

This casting apparatus consists of a molding material-containing molding box with opposing sides formed by an open-work frame with a large number of through-holes, a ram passing through the through-holes, and a predetermined sequence of multi-axis robotic means for positioning a ram over a number of predetermined apertures in said sequence and pushing the ram by a required amount through said sequence of predetermined apertures to approximate the molding cavity of the desired profile. It includes drive and control means for contouring and machining means for removing molding material to form a molding cavity of the exact contour required.

EXAMPLE The apparatus shown in Figures 1 to 5 is suitable for making collabible casting molds and metal castings from such molds and is equipped with one or more computers so that the operation can be fully automated. (not shown). This equipment creates a mold from a molding material in the form of sand mixed with an alkaline phenolic resin binder that is cured by gas.

The device comprises a molding machine 1 for forming and curing solid blocks 2 of molding sand. As shown in more detail in FIGS. 2 to 5, the molding machine 1 is equipped with a rectangular vibrating mold 3, and one side 4 of the mold 3 is
It is rotatably attached via one edge 5. An ejector piston 6 is also attached to the mold 3, and a hopper 7 connected to a scale (not shown) is located in the retracted position (FIG. 3) and in the working position above the mold 3 (second position). The hopper is arranged to be movable between the mold 3 and the mold 3 at the working position.
It is now possible to put it into the Hydraulic ram (
A hydraulic ram 8 is also movable between a retracted position (Fig. 2) and a working position (Fig. 3), and this ram 8 moves the mixture contained in the mold 3 into the working position. Compress at . The ram 8 also includes a vibrator 9 connected to a gas source (not shown) and an opening 10 through which gas can flow into the mixture.

In FIG. 1, a three-axis CNC drilling machine is illustrated at 11. The drilling machine can have a single drill or a multi-spindle head and is adapted to form holes in the block 2 to allow aeration. Two CNC multi-axis machining centers 12.13 are provided which are adapted to machine the block 2 to form the cavity 14, the centers having the shape to be cast and having a runner ( runner), riser and feed,
Core print and line-up location (line-up 1o
cationl or to form the core 15. A sprayer 16 is arranged to spray mold coating onto the block and core.

A CNC assembly robot 17 is provided to assemble the block 2 and the core 15 together with other inserts (not shown) such as runners and riser sleeves, heating sleeves, strainers and chills.
A completed mold 18 is now formed. An injection ladle (not shown) is also provided for injecting the required amount of molten metal into each mold 18, for which purpose an injection funnel 19 positioned in the X-Y direction is provided. fluctuations in ladle extrusion trajectory and runner cut in the mold.
1n-feed) is compensated for. gantry-molded
) The CN C robot 20 operates a cutting device 21 to cut off excess portions from the cooled casting.
5and 5hake-of
f) with a conveyor (not shown). The device also collects excess sand and connects it to a sand regeneration and recirculation circuit (
A take-off device (not shown) is provided for returning the container to the container (not shown).

In operation, the apparatus of this embodiment is controlled entirely by a computer programmed with respect to a given casting, in this case element 22 of FIG. 6, which operates the entire mechanical section.

The first step in the operation is to form a solid block 2 of hardened molding sand by feeding a predetermined weight of the sand resin mixture from the hopper 7 to the mold 3 (FIG. 2).

The mold 3 vibrates the mixture, the hopper 7 retracts and the ram 8 moves to its working position (FIG. 3) to compress the sand mixture. Gas is then supplied to the block 2 to harden it. Next, the block 2 is removed from the mold 3 by rotating open the side 4 of the block and sufficiently pushing out the block 2 with the ejector piston 6 (FIG. 4).

The piston 6 and mold side 4 are replaced and prepared for the next cycle.

Block 2, CNC drilling machine 1 for aeration
1 and then to CNC machining center 12.13. The processing machine 12.13 transforms the block 2 into a core 15 or mold 18 by forming a cavity 14 of the shape to be cast, optionally including a gate system with runners, risers and feeds.
Machined into the appropriate shape. The element is placed at the mold parting line (
If a parting 1ine) is required, this is formed by the side of the block and the remainder of the mold is formed by the adjacent side of the next block. The two machining centers are shown performing the slowest operations on the line.

The block 2 and core 15 are transferred to the sprayer 16 to be coated with mold coating and then transferred to the assembly robot 17. The robot 17 assembles the blocks and cores in the proper sequence and orientation to complete the mold 18, including inserts such as launch and live sleeves and chills as required. The injection ladle injects a precise amount of metal into the mold 18, guided by two sides and packed into a precision channel that indexes the mold to the injection machine that inserts the funnel 19. , the mold is then transferred to a cooling system to solidify the casting, and then transferred to a robot 20 to cut off the liner and riser. This operation is performed with the casting still in the mold 18, which acts as a clamp and positioning device to resist the cutting forces. The mold 18 and casting are then transferred to a sand dump conveyor.

The apparatus of the present invention can be used to implement a novel method of forming collabible molds that do not require the use of rigid patterns and can be formed into complex shapes with relative ease.

Therefore, the range of selection regarding the arrangement of the mold parting line is further increased, and it is possible to obtain a cast product with improved layer quality. This is illustrated in FIG. Figure 7 shows
A cross-section of a disk element 23 with various undercuts, which heretofore required complex and rigid patterns, can be easily produced by the method of the present invention using parting lines 24 is shown.

An example of a casting made in accordance with the present invention will be described in more detail with respect to FIG. 8A. Mold sand block 31
A through hole 32 is formed in and then a hole 33 is provided. The tool, that is, the boring bar 38, is passed along the axis to the required distance toward the hole 33, moved radially outward, and rotated to cut a full 34 mm. Further movement forms cavities 35, 36, 37, etc. Molten metal is fed into the mold from the right end of the hole 32, and excess solidified metal is cut off along with the surrounding mold sand. The remaining sand is broken down to give the casting the desired shape.

Complex castings can be made from two half-patterns without using wooden patterns held together with bins. The splits and tapers needed to pull the pattern out of the sand are not present in the casting; these tapers in pattern casting must be removed by machining and, if left behind, the molded part will no longer be required. It will make it even heavier. Reentrant shape, i.e. flange 34.35
．． 36 and 37 do not pose any problems, patterned sand castings required separate patterns and molds held together, but this meant that the parting lines required extra casting. Fettling becomes a problem.

The method and apparatus of the present invention are particularly advantageous in making crankshafts, engine shilling blocks, and many other complex shaped castings from cast iron or aluminum or other metals.

The apparatus of the invention also includes a runner,
A novel method of making castings from collapsible molds can be implemented by cutting off risers and other excess parts. This allows the entire casting process to be automated. Furthermore, the invention provides the advantage that by combining the two methods, castings can be produced automatically and economically using a computer. The central computer keeps parameters related to several castings in order so that changes can be easily made. Also.

The shape of a given cavity or core can be easily varied, which is particularly advantageous in speeding up the development of new castings.

Furthermore, according to the apparatus of the present invention, a suitable mold 18
By overlapping the elements, elements of various lengths can be manufactured, as indicated by reference numeral 25 in FIG.

Although other types of forming sands may of course be used, the selection of the sand is primarily a consideration of the material and shape of the casting and the length of the casting cycle.

The illustrated C,NG drilling and machining center is of a three-axis configuration, but more multi-axis versions with variable tilt spindles can also be used. Additionally, CNC rotating centers may be better suited for making certain shapes. These devices will naturally differ from those used for metals because of the different properties of the blocks. These devices produce 1500c per minute
Since it is necessary to remove the sand with a minimum speed of c, a larger axial travel speed (axis tra-v
else rate)'. This is compensated for by the lower cutting forces that occur, and the positioning accuracy is of the order of +/-0.05 mm versus +/-0.01 mm for metal cutting devices.

Forming machine 1 and CNC machining center 11.12 and 1
3 can be used not only to form molds, but also to form conventional patterns from block 2.

Such a pattern is of course not used in the rest of the system, but is pulled out of the device and covered with a heated plastic film which is sprayed or suctioned onto the sand pattern. This film protects the sand pattern and also acts as a female profile. The pattern can be used to create a mold by any known technique using patterns. The ability to form patterns from reusable materials in this manner allows patterns to be manufactured and modified easily and inexpensively. Furthermore, since the data for creating the pattern is naturally stored in the computer, there is no need to store the physical pattern.

Excess sand may have to be machined away from the block to form the desired cavity. If the apparatus of the invention is often to be used for applications of this kind, the preform approximate cavity forming apparatus shown in FIGS. 9 and 10 can be used instead of the block forming stations of FIGS. 2.3, 4 and 5. (Pre-far
med approxy-mate avity m
Olding device will be used. By creating similar cavities, the machining can be programmed to minimize the amount of sand that must be removed. One or more of these platens replace the sides of the block machine shown at station 1 in FIG. This device is
Actuation is achieved by disposing a series of rods R in a grid and a programmable actuator A to push each rod a specific distance as required, thereby creating the exact shape required. A three-dimensional profile (profile) can be obtained which approximates the shape of the sand. The shaping of the sand can be carried out using one or more of these plates forming the sides of the block-forming machine. In practice, In most cases what is needed is two opposing 2
There are two sides. If the depth of the cavity varies widely enough to interfere with compaction of the sand, only one such plate may be used; in most cases this is sufficient and makes good use of the sand. can do. When one molded plate-like body is used, the plate-like body ejection mechanism, which becomes complicated when two or more plate-like bodies are used, can be simplified.

The operation of a typical molded plate will now be described; however, since such plates can be used in a variety of electrical, magnetic, hydraulic, or pneumatic grips and actuation devices, the following description is not merely This is an example.

Such a device, as shown, comprises a grid consisting of flat locators L1 and slotted locators L2. These are fixed to the U-shaped clamp F by flexible fasteners (metal or rubber). The clamp arrangement further includes a crossbar B. Bar B
and clamp F are dual-pressure type (dual-pressure type)
rel hydraulic cylinder C+hydraulic cylinder C is physically held. The entire clamp arrangement holds the rod R to the grid. When the rod is waiting to be set to the programmed length by actuator A, the entire structure is clamped with a low clamping pressure. In this state, the rods are only moved axially within the grid under the force of the actuator. The actuator itself can be programmed in the X and Y directions to cover all rods in the grid, and in the Z direction to set the axial position of each rod. When the rod is set to the specified length, the hydraulic pressure switches to a high clamping force, and the plate is held in this state (sand block).
used for molding. The various parting lines of the plate are sealed to prevent sand and hardener from entering or exiting.

The selection of rod dimensions depends primarily on how well the device will be used.

By incorporating such improvements into the line, the entire mold can be machined in one pass since the machining simply finishes the cavities that have already been partially formed. Therefore, the required profile is created by varying the setting of the rods. As you can see, machining to the desired contour simply means:
Finish to the required degree of curvature of the desired shape, e.g. remove the square edge left by the rod < fblend o
ff). The output of the molding line is essentially independent of the volume of the cavity to be created in the sand.

- At the end of the molding cycle of the batch casting, the plate is removed, the low ramp force is switched on and all the rods are pushed back by a flat surface flush with the plate and the next element is Reset to perform molding.

(Effects) The method and casting apparatus for making a casting mold according to the present invention have a number of advantages over casting systems that use patterns. Changing from one casting operation to another can be done without delaying or stopping the line, but in traditional casting, new and different patterns are easily available from the pattern storage. In the present invention, changing the casting operation requires reprogramming the multi-axis machining equipment or selecting from memory of the program. It just becomes. The mold and core can be manufactured without the need for hardware or consumable patterns, i.e. wax and polystyrene molds in the form of patterns or core boxes. Tools and tool paths
This can be done by appropriately combining the following.

A large number of different castings can be made in one mold or six (traditionally, by flooravoiding) without the problem of inserting a "loose" pattern to completely occupy the mold. It is now possible to easily produce long elements with different lengths, which were previously produced only by the conventional method.

Additionally, the present invention allows new prototype castings to be created quickly compared to conventional pattern casting techniques that require the production of patterns. In this case, adjustments can be easily made in the line without having to stop the line during pattern changes or playback.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing the layout of an apparatus for carrying out the casting mold manufacturing method and casting product manufacturing method according to the present invention, FIGS. 2 and 3 are cross-sectional views, and FIGS. FIG. 6 is a side view of an element manufactured by the apparatus of FIG. 1, FIGS. 7.8 and 8A are explanatory views showing examples of elements that can be cast, Chapter 9i5
Figures 1 and 10 are perspective and front views showing approximate cavity forming boxes to reduce the amount of machining. DESCRIPTION OF SYMBOLS 1...Molding machine, 2...Block, 3...Vibrating mold, 4...Side part, 5...Edge part, 6...Protruding piston, 7...Hopper, 8...・Ram, 9...pipe, lO...opening, 11...triaxial CNC drilling machine, 1
2.13... Machining center, 14... Cavity, 15... Core, 16... Sprayer, 17... Assembly robot, 18... Mold, 19... Funnel, 2
0... CNC robot, 21... Cutting device, 22.
...Element, 31...Block, 32.Through hole, 33.
... Hole, 34... Groove, 35.36.37... Cavity, 38... Tool, A... Actuator, B...
...Crossbar, C,,C,...Hydraulic cylinder, F.
・U-shaped clamp, Ll, Lx...locator. Figure 2 Figure 3

Claims (12)

[Claims] (1) forming a solid block from the molding material;
A method of manufacturing a casting mold comprising the steps of: hardening a block; and forming at least a portion of a molding cavity by removing material from the block. 2. The method of claim 1, wherein the material of the block is removed by machining. (3) A plurality of separate blocks containing material to be removed to form portions of the mold cavity are held together to form a complete mold cavity. Method described. (4) the material to be removed by forming a cavity in the block with an approximate profile in the step of forming the solid block, and further removing material from the block to form a molding cavity with an accurate shape; 4. A method according to any one of claims 1 to 3, characterized in that the amount of . (5) Any one of claims 1 to 4, characterized in that the gate system comprising a channel and a riser and for introducing molten metal into the molding cavity is formed by removing material from the block. Method described. (6) The channels and risers are located away from the parting line between adjacent molding cavities while the casting is still on the conveyor system and in a manner that reduces subsequent strip cleaning of the casting. 6. A method according to claim 5, characterized in that the blocks are machined to facilitate subsequent removal from the casting of material solidified in the channels and risers. (7) Using short molds with cavities penetrated by machining and grouping block molds together, having lengths equal to the short multiple molds grouped together and groups of block molds; 1. A method for manufacturing a cast product, comprising forming a product having a shape defined by a cavity formed in the mold. (8) The molding cavity in each block varies from block to block to form a complete cavity of the desired shape, and the blocks are removed after solidification of the casting, reducing the amount of machining to form the cavity. 8. A method according to claim 7, characterized in that the method has different overall dimensions so as to reduce the amount of molding material to be produced. (9) forming a solid block from the molding material;
hardening the block, removing material from the block to form a forming cavity and channels and risers for introducing molten metal into the cavity, and forming the channels and risers from the desired casting around the surroundings after solidification. A casting method that includes a step of cutting off the material. (10) a molding machine for forming and curing blocks of molding sand; a punching machine for forming aeration passages in the compressed blocks of molding sand; and removing material from the blocks to form cavities for molten metal. a multi-axis machining system; a conveyor means for guiding the rows of block molds through a molten metal supply system to supply molten metal to the molding cavity; and when the blocks filled with metal are placed on said conveyor system. So, and
A casting apparatus comprising cutting means for removing solidified metal superfluous to the desired casting and shaker means for removing remaining block material from the finished casting before removal from the conveyor belt. 11. The apparatus of claim 10, further comprising control means for positioning the machining system on one of a number of axes and moving the tool the required amount into the block. (12) A casting apparatus for forming a solid block made of a molding material and having a preformed approximate molding cavity, comprising opposing sides formed by an open work frame with a number of through holes. a molding box containing molding material, a ram passing through the through hole, multi-axis robotic means for positioning the ram over a number of predetermined apertures in a predetermined sequence; drive and control means for shaping the molding material into a contour approximating the desired contour of the molding cavity by pushing the molding material by an amount of , and machining means for removing the molding material to form the molding cavity of the desired precise contour. A casting device comprising: