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GB2031767A - Method and apparatus for the compacting of foundry moulding sand - Google Patents

Method and apparatus for the compacting of foundry moulding sand Download PDF

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Publication number
GB2031767A
GB2031767A GB7931283A GB7931283A GB2031767A GB 2031767 A GB2031767 A GB 2031767A GB 7931283 A GB7931283 A GB 7931283A GB 7931283 A GB7931283 A GB 7931283A GB 2031767 A GB2031767 A GB 2031767A
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GB
United Kingdom
Prior art keywords
moulding
sand
pressing
press
moulding box
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB7931283A
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GB2031767B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arenco BMD Maschinenfabrik GmbH
Original Assignee
Arenco BMD Maschinenfabrik GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Arenco BMD Maschinenfabrik GmbH filed Critical Arenco BMD Maschinenfabrik GmbH
Publication of GB2031767A publication Critical patent/GB2031767A/en
Application granted granted Critical
Publication of GB2031767B publication Critical patent/GB2031767B/en
Expired legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22CFOUNDRY MOULDING
    • B22C15/00Moulding machines characterised by the compacting mechanism; Accessories therefor
    • B22C15/28Compacting by different means acting simultaneously or successively, e.g. preliminary blowing and finally pressing
    • B22C15/30Compacting by different means acting simultaneously or successively, e.g. preliminary blowing and finally pressing by both pressing and jarring devices
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22CFOUNDRY MOULDING
    • B22C15/00Moulding machines characterised by the compacting mechanism; Accessories therefor
    • B22C15/02Compacting by pressing devices only
    • B22C15/08Compacting by pressing devices only involving pneumatic or hydraulic mechanisms

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Devices For Molds (AREA)

Abstract

In a method of compacting foundry moulding sand in moulding boxes, wherein a volume of moulding sand is relatively large in relation to the cavity volume of the moulding box, the sand is compacted first of all from below and then from above in the moulding box; the quantity of excess moulding sand is so dimensioned that, after the pressing from below is concluded, moulding sand still projects above the moulding box. Apparatus for carrying out the said method includes a pattern plate 5 forced upwardly into a moulding box 7, a filling frame 8 and a press plate 9 which enters the frame during final compaction. The sand may be subjected to oscillation at least during its upward pressing. <IMAGE>

Description

SPECIFICATION Method and apparatus for the compacting of foundry moulding sand The invention relates to a method for the compressing or compacting of foundry moulding sand in moulding boxes and also to an apparatus for carrying out the method.
A large number of methods are known for compacting foundry moulding sand. Naturally, all of them aim at compacting the moulding sand in the best possible way so as to obtain a perfect casting when the mould is subsequently filled with the casting substance. The problems in compacting consist on the one hand in the relatively large voids volume of the moulding sand in a relatively loose bed, and on the other hand in the poor sliding properties of the sand particles.
In the known vacuum pressing process the moulding sand is subjected during pressing to a negative pressure intended to ensure that the air contained in the moulding sand bed escapes rapidly and completely. This process gives satisfactory results only with moulding sand free of binding agents.
Methods are also known wherein a mechanical jarring, jolting or shaking movement is introduced into the moulding sand additionally to the pressing. This is effected by preshaking the moulding sand before the pressing, although shaking can still also be carried out during the pressing operation. The shaking movement is produced by impact of the press table on an anvil, whereby a very sharp impact deceleration occurs-as much as 200 g or even more. The frequency amounts to about 10 Hz. This method does in fact achieve a very good packing effect, but it involves the production of considerable noise.
Therefore it is scarcely possible, at the present day, to meet environmental considerations.
Furthermore, so-called shooting methods are known, wherein the moulding sand is shot suddenly into the moulding box under positive pressure, in order to obtain good pre-compacting, more especially in the region of the pattern. Then a pressing operation is also carried out. These shooting methods have in fact been found valuable in practice, but they bring problems when complicated patterns have to be dealt with. It has already been attempted to provide a remedy in that connection by arranging that the upper press plate against which the mould is moved by means of the press table is constructed as a profiled plate, the profile being adapted to the pattern contour. It is also known to use so-called multi-ram press head, in other words using a plurality of rams instead of the press plate.In both cases an aim is to produce the most uniform possible compacting over the entire depth of the moulding sand in dependence on the pattern contour. To some extent, indeed, it is ensured that the moulding sand penetrates even into small and complicated spaces, but on the whole the degree of compaction is unsatisfactory.
The shaking-pressing method has been found to be the most versatile, with a satisfactory degree of compacting and with any pattern form. But up to the present time it has not been possible, despite many efforts, to find a satisfactory solution to the noise nuisance.
An object of the invention is to provide a method and an apparatus which allow cleancontour forming of even complicated patterns and involve the production of only a small amount of noise.
According to a first basic aspect of the invention there is provided a method for the compacting of foundry moulding sand in moulding boxes, excess sand being pressed into the moulding box from above, in which method, before the pressing from above is carried out, the moulding sand in the moulding box is pre-compacted from below, the quantity of excess sand being so dimensioned that, after the pressing from below has been concluded, moulding sand still projects above the moulding box.
A method is in fact known wherein moulding sand is compacted from below instead of from above. But in that case the excess moulding sand, which is situated in a filling frame arranged below the moulding box, must be very carefully dosaged since the press plate is flush with the upper edge of the moulding box. The quantity of excess moulding sand must be so dimensioned that after the pressing the plane of division of the mould finishes flush with the lower edge of the moulding box. With too small a quantity of excess moulding sand the mould will be too soft; with too large a quantity it will be over-compacted.
The method proposed by the present invention comprises substantially a combination of known methods of pressing from above and below. The advantage is achieved in the first instance that during pressing from below the moulding sand is pre-compacted in the region of the pattern, thus ensuring that it will be possible to mould with sharp outlines in that region. During subsequent pressing from above the final compacting of the moulding sand above the pattern takes place, so that after both pressing operations the mould has a good and homogeneous degree of compaction.With the method proposed by the present invention, despite the pressing from below it is surprisingly possible to obviate the disadvantage of under-pressing or over-pressing existing with the known pressing methods, since the excess sand for pressing from below does not have to be precisely dosaged and instead it has simply to be ensured that sufficient surplus sand is still present for the second method stage, that is pressing from above. Then when pressing from above it is no longer vital whether after the pressing there is still some moulding sand projecting or whether the moulding sand surface is below the upper edge of the moulding box.
According to a preferred further development of this method, the moulding sand is subjected to harmonic or superimposed oscillation at least during the pressing carried out from below. In other words a mechanical movement is introduced into the moulding sand which-in contrast to the known jolting or shaking methodsdoes not achieve compacting by a very considerable impact deceleration but promotes the sliding of the sand particles on one another and on the adjoining moulding box and pattern surface, with the result that the escape of the pore air from the packed sand is promoted as compacting progresses, settling of the moulding sand in the moulding box is promoted, and not least the pressing force necessary is reduced.This oscillatory movement is transmitted to the moulding sand at least during the pressing from below, so that the sliding of the sand particles takes place under the continuously increasing pressing pressure.
Practical tests have shown that an oscillation of about 50-100Hz is particularly advantageous for the compacting of moulding sand.
In contrast to the known shaking methods with their sharp mass deceleration the amount of noise produced with a harmonic or superimposed oscillation system is much less and more acceptable. In addition it is substantially simpler to damp the radiated sound.
Oscillation can be produced with conventional means or can be transmitted by way of the means, conveniently hydraulic, producing the pressing pressure.
To carry out the method the invention employs apparatus having the known features of a press table, a pattern plate connected thereto, a moulding box, a filling frame receiving the excess sand, and a press plate which is situated thereabove and against which the mould is moved by means of the press table.
Apparatus of this kind are known in many constructional forms for pure pressing methods of compacting and for pressing-shaking methods. The excess sand is displaced out of the filling frame into the moulding box from above.
According to a second aspect of the invention, in such apparatus the clear cross-section of the moulding box is slightly larger than the outline of the pattern plate, and the moulding box and filling frame bear by way of hydraulic pistons on the one hand on the pattern plate and on the other hand on the press plate, the hydraulic pistons being so acted upon or controlled that when pressing from below the lower pistons enter their associated cylinders, with the upper pistons stationary, then upper and lower pistons are moved upwards cynchronously until the lower edge of the moulding box is again flush with the upper side of the pattern plate, and finally, during pressing from above, the upper pistons enter their associated cylinders whilst the lower pistons are stopped.
The first component feature of this apparat' us proposed by the present invention ensures that the pattern plate can enter the moulding box when pressing from below, i.e. presses the moulding sand upwards against the press plate, during which process the moulding sand in the region of the pattern is compacted. During this phase of the operation, the moulding box and filling frame remain in their initial position because of their support through the agency of the sydraulic pistons, according to the second component feature.
In the subsequent joint movement of the hydraulic pistons in an upward direction, filling frame and moulding box are taken along also i.e. moved upwards. They are displaced relatively to the moulding sand until the lower edge of the moulding box is situated in the plane of division of the pattern, in other words is flush with the top side of the pattern plate.
Then compressing from above is carried out, the press table pushing the moulding sand further against the press plate, so that further excess sand is displaced from the filling frame into the moulding box and compacted. The hydraulic cylinders are so controlled that the moulding box and the filling frame follow the movement of the pattern plate, in other words the lower edge of the moulding box remains in the plane of division of the pattern.
In a preferred form of embodiment of the apparatus described oscillation generators are provided at the pattern plate, the press table, the press plate or the moulding box, which are excited at least during the pressing carried out from below. These oscillation generators can be situated, for example, in a suitable chamber in the pattern plate or the press table. They are advantageously so designed that the oscillation still has am amplitude between 0.4 and 1 mm at a frequency of about 50-100 Hz is spite of the occurrance of the pressing pressure. Through the pressing pressure which occurs, the press table can follow the further packing of the moulding sand into the moulding box which is achieved with the oscillation, i.e. the oscillation movement occurs during the pressure increase to the preset pressing pressure. With such oscil- lations, accelerations or decelerations of about 5 to 20 g occur, whose effects on the production of sound can be controlled without difficulty.
in another form of embodiment of the apparatus wherein the press piston is operated hydraulically, the invention proposes that a hydraulic pulse generator is arranged in the hydraulic circuit of the press piston, so that the oscillation is transmitted through the hydraulic column.
The invention will be described hereinafter with the help of phase illustrations and constructional forms shown in the drawings, wherein: Figure 1 shows a diagrammatic longitudinal section through the machine parts important to the invention, in the region of the moulding box; Figure 2 shows four phase illustrations (a), (b), (c), and (d) showing the way the method proceeds; Figure 3 shows a view similar to Fig. 2 of a constructional form with oscillation generation, and Figure 4 shows a view similar to Fig. 3 of another constructional form with oscillation generation.
Since a substantially conventional pressmoulding machine can be used for carrying out the method proposed by the present invention, the drawings show only those machine parts which are significant for the invention. The machine frame, the sand feed arrangement and the moulding box conveying apparatus, in particular, have been omitted.
Reference will first be made to Fig. 1.
The moulding machine comprises, in the conventional way, a press piston 1 which is guided in a stationary press cylinder 2 and is operated generally with compressed air. The press piston 1 carries a press table 3 on which a pattern plate support 4 is secured.
Secured in turn on the pattern plate support 4 is the pattern plate 5 with the pattern 6, which is surrounded by a moulding box 7.
Between the moulding box 7 and a press plate 8 a filling frame 8 is arranged. The moulding sand is introduced into the moulding box by way of a feed arrangement not shown, with the press plate 9 swung out for example, until the moulding sand finishes substantially flush with the upper edge of the filling frame 8.
As Fig. 1 shows, the internal clear width of the moulding box 7 is somewhat larger than the outline of the pattern plate 5. Thus the moulding box cannot bear on the pattern plate. On the contrary, lower hydraulic pistons 10 and upper hydraulic pistons 11 serve as supports for the moulding box 7 and the filling frame 8 respectively. The lower hydraulic pistons 10 run in cylinders 1 2 on the pattern plate support and engage on the underside of the moulding box 7 by means of their piston rods 1 3. The upper hydraulic pistons 11 run in cylinders 14 of the press plate 9 and engage by means of their piston rods 1 5 on the upper side of the filling frame 8.
The phase illustrations shown in Fig. 2 illustrate the pattern of operation in the compacting of moulding sand. The view in Fig.
2(a) shows the initial position corresponding to the position shown in Fig. 1. Moulding box 7 and filling frame 8 are filled up to the top edge thereof with moulding sand, and the press plate 9 is brought into position. First (Fig. 2b) preliminary pressing occurs, i.e.
pressing from below. Because of the press stroke of the table 3, pattern plate support 4 with pattern plate 5 enter the moulding box 7 from below, with the pattern 6. The pressing pressure is accepted by the press plate 9 which is stationary in this phase. In this prepressing the moulding sand is packed more particularly in the region near the contour of the pattern 6 which is designated at 1 6. The lower and upper hydraulic pistons 10, 11 are locked with one another during the preliminary pressing, so that they maintain their original position, but the lower pistons 10 enter their cylinders 1 2 because of the movement of the pattern plate support 4.In this phase of course the moulding sand is also pre-compacted in the region 1 7 below the press plate 9, this plate acting as an abutment for the pressing pressure.
In the subsequent phase shown in Fig. 2(c) moulding box 7 and filling frame 8 are raised by synchronous operating movement of the lower and upper pistons 10, 11, until the lower edge of the moulding box 7 is flush with the top side of the pattern plate 5.
In the concluding phase shown in Fig. 2(d) the lower and upper pistons 10, 11 are so controlled that they follow synchronously the further pressing movement of the pattern plate support 4, and thus the flush situation between the lower edge of the moulding box 7 and the upper side of the pattern plate 5 is maintained. Further compacting occurs, the final compacting of the moulding sand in the moulding box 7.
The height of the filling frame 8 or the filling height of the moulding sand respectively is so dimensioned in the starting position shown in Fig. (2a), as far as possible, that after the final compacting as shown in Fig.
(2d) the moulding sand finishes approximately flush with the upper edge of the moulding box 7. A small protrusion of moulding sand is not harmful, and can be scraped off if necessary.
Fig. 3 shows a first constructional form whereby the moulding sand is subjected to harmonic or superimposed oscillation during pressing from below. In this constructional example the pattern plate support 4 has within it a chamber 1 8 above the press table 3. Secured on the press table are conventional contra-rotating unbalance-type oscillation generators 1 9 from which oscillations are transmitted via the press table 3, the pattern plate support 4 and the pattern plate 5 into the moulding sand. In this axample of embodiment the press piston 2 must be mounted on a damping spring, which is shown schemati- cally at 20. This may be-it should be pointed out expressly- a mechanical spring or equally well a pneumatic spring.
In the constructional from shown in Fig. 4 the pattern plate 5 is not secured on the pattern plate support 4 but bears by means of damping springs 21 on the same or on the press table 3. In this case the oscillation generators 22 are arranged on the underside of the pattern plate 5 and thus cause the latter to oscillate, the oscillation being then transmitted from the pattern plate into the moulding sand. In this constructional example the pressing pressure of the press piston 2 or press table 3, during preliminary pressing, is transmitted in the first instance through the springs 21 to the pattern plate 5. In the final compacting shown in Fig. 2(d) the pattern plate support 4 abuts by means of abutment portions 23 against the underside of the pattern plate 5, so that the pressing pressure in transmitted directly to the pattern plate.
Instead of the illustrated constructional examples, the oscillation generators may of course also be arranged on the moulding box 7 or on the press plate 9. It is also possible to operate the press piston 2 hydraulically and to make the hydraulic fluid oscillate by means of a conventional pulse generator. In this case the oscillations are transmitted direct to the moulding sand via press table, pattern plate support and pattern plate.

Claims (9)

1. A method for the compacting of foundry moulding sand in moulding boxes, excess sand being pressed into the moulding box from above, in which method, before the pressing from above is carried out, the moulding sand in the moulding box is pre-compacted from below, the quantity of excess sand being so dimensioned that, after the pressing from below has been concluded, moulding sand still projects above the moulding box.
2. A method according to claim 1, in which the moulding sand is subjected to harmonic or superimposed oscillation, at least during the pressing from below.
3. A method according to claim 2, in which the moulding sand is subjected to oscillation of at least 50 Hz.
4. A method according to any one of claims 1 to 3, in which the oscillation is transmitted by way of a hydraulic means.
5. A methos according to claim 4, in which the oscillation is introduced through the agency of the hydraulic means producing the pressing pressure.
6. Apparatus for carrying out a method according to claim 1, with a press table, a pattern plate connected thereto, a moulding box with a filling frame which receives the excess sand, and a press plate which is situated thereabove and against which the mould is moved by means of the press table, in which apparatus the internal clear cross-section of the moulding box is slightly larger than the outline of the pattern plate, and the moulding box and filling frame bear by way of hydraulic pistons on the one hand on the pattern plate or pattern plate support and on the other hand on the press plate, the hydraulic pistons being so acted upon or controlled that when pressing is carried out from below the lower pistons enter the cylinders associated with said pistons whilst the upper pistons are blocked, and then upper and lower pistons are moved synchronously upwards until the moulding box has its lower edge flush again with the upper edge of the pattern plate, and finally during pressing from above the upper pistons enter the cylinders associated with then whilst the lower pistons are blocked.
7. Apparatus according to claim 6 for carrying out a method according to claim 2, or 3, in which apparatus, at the pattern plate, the press table, the moulding box or the press plate, there are arranged oscillation generators which are actuated at least during the pressing carried out from below.
8. Apparatus according to claim 6 with a hydraulically operated press piston for carrying out a method according to claim 4 or 5, in which apparatus a hydraulic pulse generator is arranged in the hydraulic circuit of the press piston.
9. A method for the compacting of foundry moulding sand substantially as herein described with reference to the accompanying drawings.
1 0. Apparatus for the compacting of foundry moulding sand substantially as herein described with reference to the accompanying drawings.
GB7931283A 1978-10-06 1979-09-10 Method and apparatus for the compacting of foundry moulding sand Expired GB2031767B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19782843598 DE2843598A1 (en) 1978-10-06 1978-10-06 METHOD AND DEVICE FOR COMPRESSING FOUNDRY SAND

Publications (2)

Publication Number Publication Date
GB2031767A true GB2031767A (en) 1980-04-30
GB2031767B GB2031767B (en) 1983-06-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB7931283A Expired GB2031767B (en) 1978-10-06 1979-09-10 Method and apparatus for the compacting of foundry moulding sand

Country Status (6)

Country Link
JP (1) JPS5554242A (en)
CH (1) CH642289A5 (en)
DE (1) DE2843598A1 (en)
FR (1) FR2437896A1 (en)
GB (1) GB2031767B (en)
IT (1) IT1164509B (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2134426A (en) * 1983-02-02 1984-08-15 Gen Kinematics Corp A vibratory ram compaction mold forming machine for a foundry
DE4425334A1 (en) * 1993-07-20 1995-01-26 Dansk Ind Syndikat Method and apparatus for the production of moulds or parts thereof by compaction of particulate material
EP1222979A4 (en) * 2000-04-13 2004-11-24 Sintokogio Ltd Compressing method for casting sand and device therefor
EP1208928A4 (en) * 2000-04-21 2005-08-17 Sintokogio Ltd Die molding machine and pattern carrier
CN100544856C (en) * 2000-04-13 2009-09-30 新东工业株式会社 The compression method of molding sand
CN109175266A (en) * 2018-10-09 2019-01-11 禹州市毛吕铸造有限公司 A kind of sand casting compaction apparatus
EP3539686A1 (en) * 2018-03-15 2019-09-18 Künkel Wagner Germany GmbH Moulding machine with a bolster arrangement and method for producing a mould

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0285821A3 (en) * 1987-04-08 1988-11-30 BMD Badische Maschinenfabrik Durlach GmbH Process and device for compacting moulding materials for foundry moulds
JP5451157B2 (en) * 2009-04-13 2014-03-26 メタルエンジニアリング株式会社 Mold making method
JP5596986B2 (en) * 2010-01-20 2014-10-01 メタルエンジニアリング株式会社 Mold making method and apparatus

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR460355A (en) * 1913-07-09 1913-11-29 Johann Fuelscher Molding machine for foundries
FR577575A (en) * 1924-02-22 1924-09-08 Machine for making sand molds using a lower extension and double clamping
BE364471A (en) * 1929-10-10
US2209792A (en) * 1938-02-14 1940-07-30 S P O Inc Molding machine
FR1482416A (en) * 1966-06-03 1967-05-26 Zd Za Elektromotori Molding method and device for the production of foundry molds
FR2024651A5 (en) * 1969-09-29 1970-08-28 Inst T Casting-moulds

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2134426A (en) * 1983-02-02 1984-08-15 Gen Kinematics Corp A vibratory ram compaction mold forming machine for a foundry
DE4425334A1 (en) * 1993-07-20 1995-01-26 Dansk Ind Syndikat Method and apparatus for the production of moulds or parts thereof by compaction of particulate material
EP1222979A4 (en) * 2000-04-13 2004-11-24 Sintokogio Ltd Compressing method for casting sand and device therefor
CN100544856C (en) * 2000-04-13 2009-09-30 新东工业株式会社 The compression method of molding sand
EP1208928A4 (en) * 2000-04-21 2005-08-17 Sintokogio Ltd Die molding machine and pattern carrier
US7237593B2 (en) 2000-04-21 2007-07-03 Sintokogio, Ltd. Molding machine and a pattern carrier used therefor
KR100838875B1 (en) * 2000-04-21 2008-06-16 신토고교 가부시키가이샤 Mold Molding Machine and Pattern Carrier
EP3539686A1 (en) * 2018-03-15 2019-09-18 Künkel Wagner Germany GmbH Moulding machine with a bolster arrangement and method for producing a mould
EP3539686B1 (en) 2018-03-15 2022-01-26 Künkel Wagner Germany GmbH Moulding machine with a bolster arrangement and method for producing a mould
CN109175266A (en) * 2018-10-09 2019-01-11 禹州市毛吕铸造有限公司 A kind of sand casting compaction apparatus

Also Published As

Publication number Publication date
JPS5554242A (en) 1980-04-21
CH642289A5 (en) 1984-04-13
FR2437896B1 (en) 1983-11-25
DE2843598A1 (en) 1980-04-17
IT7925604A0 (en) 1979-09-11
GB2031767B (en) 1983-06-15
FR2437896A1 (en) 1980-04-30
IT1164509B (en) 1987-04-15

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