EP0802839B1 - Process for introducing cores into a casting mould - Google Patents

Abstract

PCT No. PCT/EP96/02943 Sec. 371 Date Jun. 25, 1997 Sec. 102(e) Date Jun. 25, 1997 PCT Filed Jul. 4, 1996 PCT Pub. No. WO97/16271 PCT Pub. Date May 9, 1997A process for inserting cores into a casting mold includes inserting a plurality of individual cores into a template; forming a core group by joining together the plurality of individual cores within the template using a bracing and securing device which is detachable; dipping the core group into a founder's black bath to provide a coated core group; drying the coated core group; inserting the core group after drying into the casting mold; and removing the bracing and securing device. The process advantageously additionally includes providing a plurality of core groups that form a core assembly for a casting mold; forming a core set by joining together the plurality of core groups using a bracing and securing device; dipping the core set into a founder's black bath to provide a coated core set; drying the coated core set; inserting the core set after drying into the casting mold; and removing the bracing and securing device. The plurality of cores have respective contact surfaces that touch each other, and the process advantageously includes providing an adhesive on at least some of the contact surfaces prior to inserting the plurality of cores into the template.

Description

The invention relates to a method for introducing cores in a mold.

In foundry technology, especially in gray cast iron technology, It was previously common for at least two molded boxes formed mold for the production of thin-walled castings, for example engine blocks, in one of the mold boxes insert the appropriate cores by hand. Especially with the Manufacture of engine blocks from gray cast iron are increasing Dimensions regarding the complexity of the engine block, weight savings, Dimensional accuracy and surface quality made higher demands. This makes it necessary to Core manufacturing area as filigree as possible and also in your Geometry to produce very complex cores that the following mechanical processing of the engine blocks to a minimum to reduce. Here it turned out that it was useful is to design the engine block to be manufactured in such a way that so far in a subsequent mechanical processing drilled holes, breakthroughs or the like be cast in from the start. This requires that mutually adjacent cores corresponding approaches have these breakthroughs in the mold "keep clear". It has been found, however, that due to unavoidable wear and tear unavoidable dimensional deviations especially in this one Area of contact of neighboring cores on the ones to be manufactured Breakthrough burrs occur after the casting is formed have to be reworked.

US-A-4,273,182 describes a process for forming a core package described, in which the individual core parts without use corresponding gauges by means of interlocking interlocking Core parts put together to form a core package will. The core package is then strapped using a strapping machine put a plastic strap, its superimposed Ends are inextricably linked. The core package fixed in this way is then placed in the mold inserted. When pouring the plastic tape evaporates under the heat of the molten metal.

From EP-A-0 209 809 a method is known in which the individual core parts are placed in a joining device, the assigned areas of the individual cores with a Glue are coated and then the individual Cores pressed into a core package and over the glue firmly connected to each other to form a core package. That so The core package formed can then be immersed in a size bath and then placed in the mold.

The invention is based on the object of a method to create a simplification to introduce the Cores in such a mold and expensive Avoids post-processing.

According to the invention, this object is achieved by that the individual cores are placed in a setting gauge, that the contiguous, forming a core group Cores in the setting gauge using clamping and holding devices be connected to each other that the connected Core group dipped in a size bath and dried and that the dried core group in the mold used and then the tension is released. With this The method is used to advantage that at least some, provide cores forming a core group with core brands are that can be designed so that they are on the one hand touch each other and on the other hand also the protrude from the actual forming core surface and corresponding Form contact surfaces so that the cores through here a corresponding, for example frame-shaped clamping means braced against each other over their contact surfaces and can be fixed against each other and thus as one Unit can be handled. It is useful if the contacting contact surfaces of the cores in front of the Insert so-called green glue into the setting gauge to improve cohesion. Becomes this core group according to the inventive method dipped in a sizing bath and the sizing after dried, then the unavoidable relatively thin gaps in the area of the contact surfaces adjacent single cores filled in by the size, so that the formation of burrs is avoided becomes. The core group is then created with the help of the clamping and Holding means transported further and into the prepared Casting mold, for example a lower case, used, so that after releasing the tension the top box is put on and performed the casting process in the usual way can be.

The method according to the invention allows, depending on the design of the casting to be made, a single one core group composed of several individual cores or also one out of several, a core assembly for a casting mold forming core group as a core sentence about the clamping and To connect holding means with each other and in tension Condition of the individual treatment steps until insertion to perform in the mold. That is the possibility given even very complex core groups in this way to handle. It is also possible for individual core parts Approaches to be provided, which were previously individually in a mold were inserted in the manufacture of the cores with to connect the associated core, for example to glue via an adhesive connection, so that this on complicated in its structure, from two or more Share composed single core nevertheless in the Core group is included, provided with the size coating and then into the mold can be inserted. The additional required so far Inlay work that always leads to the formation of burrs in the Transition area between the single core and the associated one Basic core is avoided, because by the Sizing the entire core group the approach between the core approach and the associated basic core a ridge formation avoids.

The method according to the invention is based on a flow diagram explained in more detail below.

As can be seen from the drawing, there are four core forming stations four single, for the production of a casting required cores formed and solidified in the usual way.

The individual cores 1, 2, 3 and 4 are then in the process step I inserted into a setting gauge 5, through which the mutual assignment of cores 1, 2, 3 and 4 fixed is. The cores 1, 2, 3 and 4 are on their outside facing side in the usual way with core marks 6, which are now designed to be outward-looking Have contact surface, which in turn is expedient is designed so that adjacent contact surfaces 7 aligned.

Those forming a core group, inserted into the setting gauge 5 Single cores 1, 2, 3 and 4 are now with one for example, frame-shaped clamping and holding means 8 firmly clamped together, the against each other directed approaches 9 on the individual cores 1, 2, 3 and 4, depending on the design of the casting to be produced either for making breakthroughs in corresponding Wall parts of the casting serve or they in turn are formed as core brands, firmly together be pressed. The cores can face each other Contact surfaces 9.1 with a so-called green adhesive be provided so that in this area by gluing the fixation is increased. With appropriate Design of the individual cores 1, 2, 3 and 4 is thus given the opportunity to clamp the individual cores over the To combine holding means 8 into a manageable unit 10, like this for the subsequent process step II is shown. The tensioning of the tensioning and Holding means 8 can now with the appropriate design through the medium itself or through a comprehensive one and exciting manipulator 8.1.

The core group combined into a unit 10 can now in a process step III via the manipulator 8.1, the clamping and holding means 8 on the gripping cam 8.2 recorded, transported and in a size bath 11 to be dipped. Here, the clamping and holding means 8 can also be turned by the manipulator 8.1, so that excess size drips off after diving can. Since the frame-shaped clamping and Holding means 8 the cores summarized as a core group 1, 2, 3 and 4 holds only in the area of the core brands later when pouring the the appropriate areas of the Casting molding surfaces of the core group completely coated with sizing, with the column in particular between the individual adjacent cores 1, 2, 3 and 4 are closed by the size and thus the formation of cast burrs is avoided.

In the subsequent process step IV must nummore the unit 10 is fed to a drying device 16 in which the size coat is dried, for example by a combined microwave and Air drying process.

To guide the unit through the dryer, is manipulator 8.1 in a movable furnace support 12 filed. The furnace support 12 has two opposite Pages cheeks 13 on with their inward clamping surfaces 14 opening upwards are inclined towards each other. On the clamping and holding device 8 are on both sides of the gripping cam 8.2 this outstanding clamping cams 15 arranged with one of the Provide clamping surface 14 correspondingly inclined counter surface are so that when the unit 10 is placed in the furnace support 12 the clamping and holding means 8 between the side cheeks 13 is firmly clamped. Then the manipulator 8.1 be solved and the entire arrangement in the drying facility 16 can be retracted.

After drying is complete, the unit 10 summarized core group from the furnace support 12 of the Manipulator 8.1 highlighted and now in the next step V in the lower box 17 or an assembly gauge a prepared mold. Only now the frame-shaped clamping and holding means 8 from the core group solved and removed. Then in the following Process step VI of the upper box 18 on the lower box 17 placed and firmly connected to it, so that subsequently the casting process can take place.

From the above description of the procedure for a schematic embodiment with one four individual cores composed core group can be seen that even very complex castings according to the invention Procedures can be created. It is quite so possible, several, one core for one mold forming core groups, from the design of the casting should not be connected to one another corresponding design of the clamping and holding means to combine as a complete core sentence and in the subsequent treatment, d. H. covering with a size and then drying until Place in the mold to hold together.

It is readily apparent that by summarizing from individual cores to core groups and / or that Grouping of core groups into complete core sentences, the effort for transport and the individual work steps Dip, dry and insert the cores into the Mold to be minimized. So much for the individual cores have associated approaches to creating breakthroughs are provided in the finished casting, by the Finishing of the complete core group or the Core sentence are closed, the following are reduced Cleaning work, especially deburring on the finished Casting considerably. The further advantage of the invention Procedure is that by insertion a complete core group and / or a complete Core set in the mold improves dimensional accuracy and so that the committee is minimized.

Another advantage of the method according to the invention is in that the cycle times when casting the finished molds can be increased since those for inserting cores required time is significantly reduced.

Another advantage of the method according to the invention is also in that greater flexibility with regard to given on customer requirements or further developments is. Here it is only necessary when designing of the cores to ensure that neighboring ones Cores, even if there are no approaches between them Formation of breakthroughs and then anyway must have core brands so that the core brands that are required anyway are directly related to each other touch so that tensioning with the appropriate design the core brands on the outside over a preferably frame-shaped clamping and holding means is possible.

The method according to the invention also allows, however a common clamping and holding device two or more related core groups to a complete Summarize core sentence without the individual core groups even through an appropriate arrangement of approaches are to be brought into contact with each other. The invention The procedure is therefore also possible if individual core groups with regard to their core brands none have a common clamping plane. Here it is possible in a main frame the individual core groups with separate Clamping and holding devices together and for the subsequent process steps up to Insert into the mold to handle.

Claims (3)

1. A method for introducing cores into a casting mould, characterised in that the individual cores (1, 2, 3, 4) are introduced into a template (5), that the cores (1, 2, 3, 4) which adjoin one another and form a core group are joined together in the template (5) by means of a bracing and holding means (8), that the interconnected core group is dipped into a founder's black bath (11) and dried, and that the dried core group is inserted into the casting mould (17, 18) and then the bracing means is released.
2. A method according to Claim 1, characterised in that a plurality of core groups which form core inserts for a casting mould are joined together as a core set by means of a bracing and holding means (8), are treated and are inserted into the casting mould.
3. A method according to Claim 1 or 2, characterised in that the contact surfaces (9.1) of the cores (1, 2, 3, 4) which contact one another are provided with an adhesive before insertion into the template (5).

Images