DE1508691A1 - Process for the production of casting molds by pressing - Google Patents

Description

Process for the production of cast barrels by eating

The invention relates to processes but the production of Molds by pressing.

There is a method for producing casting molds duroh pressing of the molding sand, in which a! Form plate with recess is used, which is arranged over the molding box filled with molding sand opposite the model 00 sitting on the model plate, that the recess during the pressing process with molding sand is filled (see VG Kadnlkow ⁿ Masohinenformerei ⁿ , Verlag lenisdat I960). During the pressing process, the mold plate is pressed into the molding sand on the side opposite the valve joint of the mold.

It is a disadvantage of the known method that it involves friction of the molding sand grains against each other and on the model and format walls, the mold under the mold plate is more compact than on the model plate side. But Ss is »um high quality · casting molds In order to preserve it, it is necessary that the dit Diohte is reversed distributed (i.e. that the molding sand compacts more strongly on the model side is). This disadvantage in the distribution of the molding sand density is particularly noticeable when there are living spaces in the models or between the models and molding box walls

909844/0830

Height compared to its cross-section is great 1st · The mold plate must, in these palls, a sufficiently compacted surface of the form (on the model plate side), old great force in the Form are pressed into it. As a result of this, the molding sand is not only shifted in the direction of movement of the molding plate, but it also "flows" to the sides. In addition, the large feeding pressure through which the molding sand in the narrow spaces is to be compressed, too much compression of the mixture in other zones where it is not mentioned. The taller the shape is

that's how harder it is to close the molding sand in tight spaces compress and the required density distribution on the mold surface and to achieve in Ti facility. For the reasons mentioned, the production of molds duroh Sruok on the mold plate, which is on the side opposite the molded part joint, only used with a limited range of simple penalties.

Attempts have been made to eliminate the disadvantages mentioned * duroh that When pressing the molding sand, the press pressure was exerted on the model plate. But since you are doing this on the opposite of the molding joint Side used a flat plate, was used when forming- »· high models of molding sand also compacted unevenly.

Eb is the aim of the present invention, the mentioned Vaoh parts to eliminate.

The object of the invention is to provide a method for the production of casting molds using presses that are required one compaction of the molding sand guaranteed and that allows » Molds for a wide range of castings, especially for to make high models.

909844/0830

According to the invention give up is achieved in _t that the molding box "is filled in under the Forntellfuso arranged pattern plate with molding sand, while the Foraplatte dee immobile with respect to the molding box on the surface of sand is attached, wherein the mold plate cavity-free τοη sand remains, and the molding sand after duroh the pattern plate is pressed together so that the recess of the mold plate is filled with sand.

The method according to the invention for the production of casting molds is Duroh drawings explained in more detail!

Ea shows

Fig. 1 shows the device for the production of molds before the beginning of the pressing process

Fig. 2 shows the same device after completion of the Preßvc. ^; -, The following symbols are used

h - model height ι

S - height of the vertical molding sand column in front of the Proeeonj Y - size of the recess in the mold plate | H - molding box height j A. - Height of the "usataliohen molding sandschioht, which during pressing

is compressed ι

Z - height of the vertical molding sand column after pressing) I - the weighting factor that determines the degree of compaction of the molding sand

indicates. It is expressed by the ratio -y-. In practice, the value of K varies between 0.3 and 0.6.

The affiliation of the abbreviation to a specific vertical Section is indicated by the dossen index. For example, the index 0 (zero) indicates that the abbreviation applies to the section 0-0,

BAD ORiGfNAL

'0 9 8 4' «/ Q 8 3 0

because the model plate is guided outside the model. The Indey ⁿ i ⁿ veiat out that the abbreviation for one of the vertical sections 1-1, 2-2 true ... "dl · duroh different sections of the Modellee are guided.

According to the invention, molds are produced in the following manner.

The model 1 is attached to the model plate 2 "which can be pushed into the Durohzugrahmen 3 with the help of the piston 4 · Si" Model plate 2 is lowered deeper than the parting line of the form, ie deeper than the upper level of the DurohEugsrahmene 7 "and swar around the Value A ₀ ■ Z _Q * Z _Q m Z _Q · H. The molding box 5 is placed on the frame 3 and the resulting space is filled with molding sand Vis on the upper edge of the molding box. You yarn Yorriohtung is pressed against the mold plate 6, which is attached to the cross member 7 of the 7ormmasohine. .

For pressing, the piston 4 with the plate 2 and dta model 1 in the fig. 2 visible position raised. Here, part of the mixture is pressed into the recess in the mold plate 6. The resulting sand protrusion can then be cut off.

The required hardness of various surface sections of the casting mold that come into contact with the metal is achieved by the corresponding compression of the forrasand columns S ₀ , S ^, Sg ···. Depending on the particularities of the mold, the same or different diameters of these columns may be required. Corresponding Verte E are chosen for this purpose.

The compression of the column S _Q Uder of the model plate depends on how deep the latter was lowered under the mold part joint during the filling of the molding box * with molding sand, ie the compression depends on the Vert A ₀ , which is determined according to the above procedure.

9098U / Oi30 c

• · · ο

The compression of the molded sandottulen above the model with the height S ₁ , in the given case S ₁ , S ₂ , is determined by the corresponding size I _{1 of} the molded plate recess, in the given case T ₁ , Y ₂ *. The size of the mold plate recess is calculated using the following formula!

* <> - h - η + -JEi H ₁ (D

1 K 1 K *

Xm special case in which even compression of all 'Formean columns required I & t, i.e. at KaLa Kvldem, takes! Formula (1) the following form anι

Since Z <: 1, the fraction in formula (2) always becomes significant ! your all one and consequently the greetings of the clay plate recess lower than the model height. For example, at 1-0.7

γ. & x2L ·. h »o, 41 h _±

¹ 1 + 0.7 ^{A X}

ORIGINAL BATH 909844/0830

Claims (1)

Claim Process but production of molds by pressing the molding sand in which a shaped plate with a recess is used, which over the « molding box filled with molding sand opposite the one on the model plate seated model is arranged so that the recess is filled with molding sand during the pressing process; is marked, daduroh, that the molding box is filled with molding sand with the model plate arranged under the molding joint, before the molding plate unbeve% ioh with respect to the molding box on the surface of the sand, the molding plate recess remaining free of sand and danao the molding sand is pressed through the model plate so that the cavity of the mold plate is filled with sand. _BATH • 00844/0130