DE102016221674B4 - Control for a device for the production of die-cast parts - Google Patents

Abstract

Control for a device (10) for producing die-cast parts from a die-casting mold (12) and a suction device provided for the controlled evacuation of a mold cavity, the device being connected to a central controller (1), characterized in that the controller is a control unit ( 1), in which a module (1a, 1b ...) is connected to the device for producing die-cast parts and further modules are connected to at least one hydraulic and pneumatic unit (3, 3 ', ..) for controlling valves, The control unit (1) contains components for controlling valves in the casting tool for the use of vacuum-assisted die casting, the type of the valves, i.e. mechanical, hydraulic, pneumatic, being interchangeable, and the at least one module for the hydraulic unit (3) being parallel with it the at least one module for the pneumatic unit (3) can be operated.

Description

The present invention relates to a control for a device for producing die-cast parts with a die and a suction device provided for the controlled evacuation of a mold cavity, which consists of a vacuum unit and a suction line connecting the vacuum unit and the die.

State of the art

A device for the production of die-cast parts is from the DE 30 02 886 C2 known. In this as well as in other known die casting machines with suction devices for venting the molds, the last mold filling with liquid metal takes place in cooperation with the evacuation of the mold within a few milliseconds. The aim is to achieve the highest possible vacuum in the mold cavity of the casting mold in order to achieve the highest possible quality of the casting.

The EP 0 600 324 A1 describes a method for producing a vacuum in a vacuum die casting machine, in which the vacuum to be applied to the die can be subjected to regulation during the casting process. The pressure curve of the vacuum applied via a vacuum valve is regulated by means of a switching valve so that the pressure in the mold cavity, in the casting chamber and in the suction pipe is regulated according to a certain adjustable function per unit of time. The negative pressure is measured by a vacuum probe, which measures the pressure in a vacuum connection line.

From the EP0819487B1 a device for producing die-cast parts is known which has two valves arranged in a suction line. The two valves connected in parallel establish or interrupt the connection between a vacuum tank and a die. By closing the two valves, a so-called reference space is created in the suction line. This reference space shows the state that prevailed when the last evacuation process of the die was completed. This makes it possible in a simple manner to determine a wide variety of parameters which are decisive for the quality of the die casting, in particular the residual moisture content in the system, and to control the device accordingly.

From the DE 4 313 800 A1 a method for controlling a die casting device with controlled evacuation is known. This control is central, but has no modules that are intended for different tasks.

From the DE 20 2004 017 551 U1 a control system for hydraulic and pneumatic components is known.

The WO 91/17 010 A1 shows a valve mechanism, depending on the application, a valve is installed that works either hydraulically or pneumatically. The control is only designed for the current valve.

EP 1 516 687 A1 such as US 2006/0 042 773 A1 use different valve types as an alternative to each other.

All known die casting processes require control for the individual processes. Not only the movable tool has to be checked, but also the valves and slides, as well as the introduction of the casting material, require control.

It is an object of the present invention to provide an improved control which is capable of flexibly fulfilling all the tasks of a vacuum-assisted casting process.

The object is achieved with a controller for a device for producing diecast parts from a die and a suction device provided for the controlled evacuation of a mold cavity, the device being connected to a central controller, the controller having a control unit in which at least one module are connected to the device for the production of die-cast parts and further modules with at least one hydraulic and / or pneumatic unit for the control of valves.

The control is particularly flexible and can be adapted to the needs of different systems.

It is advantageous that the at least one module for the hydraulic unit can be operated in parallel with the at least one module for the pneumatic unit. This allows the control system to be used in mixed systems in which different hydraulic or pneumatic components are used.

The control unit has components for controlling valves in the casting tool for the use of vacuum-assisted die casting, the type of the valves, that is to say mechanically, hydraulically and pneumatically, being interchangeable. This allows mixed operation of the device with different modules.

It is advantageous if the components for controlling valves consist of software components.

The control unit has inputs for all measurement data collected on the device.

Figure list

Further details, features and advantages of the invention result from the following description of an exemplary embodiment shown in the drawing.

• 1 eine dreidimensionale Darstellung der Vorrichtung,
• 2 eine schematische Darstellung der erfindungsgemäßen Vorrichtung zur Herstellung von Druckgussteilen in Seitenansicht;
• 3 eine schematische Darstellung der erfindungsgemäßen Vorrichtung zur Herstellung von Druckgussteilen in Aufsicht,
• 4 einen Schnitt durch ein Filtermodul,
• 5 eine schematische Darstellung eines Filters,
• 6 einen Schnitt durch einen Filtereinsatz,
• 7 ein Schema einer Steuereinheit.

In it show:

• 1 a three-dimensional representation of the device,
• 2nd a schematic representation of the device according to the invention for the production of die-cast parts in side view;
• 3rd 1 shows a schematic representation of the device according to the invention for the production of die-cast parts in supervision,
• 4th a section through a filter module,
• 5 a schematic representation of a filter,
• 6 a section through a filter insert,
• 7 a schematic of a control unit.

One in the 1 schematically illustrated device 10th for the production of die-cast parts essentially comprises a die-casting mold 12 and a suction device 16 . The die casting mold 12 in this example consists of a movable mold half 14 and a fixed mold half 15 . The suction device 16 consists in particular of a suction line 20th and an associated vacuum pump 18th . On that of the vacuum pump 18th opposite end of the suction line is this with the movable mold half 14 and / or with the fixed mold half 15 the die casting mold 12 connected. In the exemplary embodiment there are 2 suction lines 20th with the vacuum pump 18th connected. The suction lines each end on the mold halves 14 and 15 .

Between the die 12 , or between the mold halves and the vacuum pump 18th are filter modules 2nd arranged in the suction line. The form vacuum valve is in 1 not shown, it is located in the die near the connection of the suction line 20th . The filters are arranged in the suction line and divide the suction line 20th in a first section, the line 20a and a second section, the suction line 20b . A control unit 3rd , which in this example is connected to the form vacuum valve via hydraulic connections, is attached to the die casting machine. One control 1 is only indicated by a screen.

The device is in 2nd as a side view and in 3rd shown as a top view, with the vacuum form valve 21st is shown.
The suction line 20th contains the following components: cables 20a from the form vacuum valve 21st to the main valve, a filter module 2nd and a suction line 20b between filter module 2nd and vacuum pump 18th .
The suction line or the section of the line 20a starts close to or in the form vacuum valve 21st .
The suction line consists of a special heat-resistant vacuum hose and sits next to the filter module 2nd , through the filter module 2nd via a vacuum hose to a hand valve, which is not shown, and the die casting machine. From there, the line leads into a vacuum line system and ends at the vacuum pump station.

The filter module 2nd is designed as a compact component and has different tasks.
The filter module is in 4th shown enlarged.

The filter module has a connection on the inlet and outlet side, which is connected by screw connections 100 can be connected with 1 or 2 inch connectors. The compact filter module is over these screw connections 2nd connectable with the tubing of the vacuum system.
Via a reducing double nipple 101 is a filter housing 102 tied up. There are knurled screws on the filter housing 103 to recognize the filter housing coming from a floor 102a and a lid 102b exists, connect.
A pressure sensor is connected to the filter 104 that's about a reduction 105 connected.
A pressure gauge is located downstream 106 appropriate. About clamps 107 and screw connections there is a 2/2-way valve 108, i.e. a valve with two controlled connections and two switching positions in the filter module. This valve serves as the main valve.
in the 2nd / 2nd The directional control valve accommodates the residual moisture measurement, which projects into a reference room as in the prior art.
The reference space shows the environmental parameters of the state that prevailed when the die casting process was completed and the evacuation of the die 12 was completed.
All sensors, the pressure sensors and the residual moisture sensors are directly or indirectly with the control unit 1 connected. The valves are also with this control unit 1 connected, the control unit controlling the entire casting process with all components in accordance with the determined measured values.

The filter used in the filter module itself consists of a filter housing 102 that from a floor 102a and a lid 102b consists. The two components are with the thumbscrews 103 connected so that the housing components can be separated in a simple manner. To the housing parts 102a and 102b there is an O-ring to seal 205 on a flat peripheral surface of the housing parts, which have a groove for guiding the O-ring, three knurled screws, which are attached equidistant to each other. Of course, the person skilled in the art can also use any other number of knurled screws. The use of the knurled screws greatly simplifies the maintenance of the filter, since the filter can be opened by a person without the use of a tool.

If the two components, as in 5 shown, separated, you can see a filter insert inside 200 . The filter insert is as in 6 shown in section from a metal cylinder by two perforated disks 201 is completed. Between the two perforated disks 201 are a fine filter 203 and a coarse filter 204 appropriate. A safety ring is used to fix the fine filter and the coarse filter in the metal cylinder.
The coarse filter consists of steel filter wool and can be cleaned by tapping the dirt out of the casting process.
The fine filter is cleaned with benzene or a suitable cleaning agent. It is important that the rough side of the filter with the steel wool filter points in the direction of the form vacuum valve and the fine filter points in the direction of the solenoid valve. The change intervals of the filter insert depend on the extent of the dirt particles deposited during a production shift. With heavy use, hourly filter insert changes are quite manageable.
The filter combination of a coarse filter and a fine filter reduces the entry of dirt from the casting process towards the sensors to a minimum.

The filter housing 102 is equipped with a pressure gauge which shows the actual value of the vacuum during the emptying phase, the final value represents the vacuum level in the cavity.

The filter housing 102 has an integrated 1/2-inch opening for connecting the sensor 104 for measuring and recording the pressure.
The analog output signal from the sensor is sent to the control unit 1 transfer.
The filter module with solenoid valve and other components works much more wear-free than without a filter, as they can be replaced and / or cleaned in a simple manner.

The machine according to the invention for the production of die-cast parts also requires at least one form-fitting valve for the suction device near the casting mold.
In die casting machines with suction devices for venting the molds, the last mold filling with liquid metal takes place in cooperation with the evacuation of the mold within a few milliseconds. In order to achieve the highest possible vacuum, it is therefore expedient to close the suction channel which is used for evacuation and is connected to the mold as late as possible, ie shortly before the liquid metal can inject into the suction system. Suitable valves are used, for example, as hydraulic valves in the DE3002886 A1 described.

There are alternative valve shapes, such as pneumatic valves or washboard valves, that are used to quickly reduce the pressure in the mold.
Pneumatic valves have system-related problems. Compared to hydraulic drives, the pneumatic forces and moments are significantly lower and pneumatic cylinder movements are always point-to-point. The end position is defined by a fixed stop. As a result, pneumatic valves must be installed very close to the mold, which increases the wear on these components.

Washboard valves are referred to as an "open ventilation system": The ventilation performance of the valve is mainly determined by the gap size between the valve halves and the valve width. These valves are often used in combination with a displacement or time-controlled valve.

The type of valve, as a form vacuum valve, does not limit the performance of the device according to the invention. It is rather the case that different valve types can be used. In addition, a die casting machine does not necessarily have to be equipped with one valve type, but combinations of different valve types are also permitted.

• P = Betriebsdruck der Druckgussmaschine (min 120-160 Bar);
• T = Tankrohr (0 Bar);
• A = Zylinder ausrücken = offenes Ventil (mit 120-160 Bar);
• B = Zylinder einrücken = geschlossenes Ventil. (mit einem Speicherdruck von ca. 95-100 Bar)

The device according to the invention has a control unit 1 which processes all measured values of the device and with which all hydraulic, pneumatic systems are controlled.
A hydraulic control unit 3rd controls the pressure cylinder of a hydraulic valve from the insertion of the valve actuation insert to the opening and closing of the molded valve using control bolts.
This exemplary hydraulic control unit 3rd is on a distributor plate 4th screwed on. The following connections are located on the distributor plate:

• P = operating pressure of the die casting machine (min 120-160 bar);
• T = tank pipe (0 bar);
• A = disengage cylinder = open valve (with 120-160 bar);
• B = engage cylinder = closed valve. (with a storage pressure of approx. 95-100 bar)

A control valve Y1 , a directional spool valve Y2 with a cartridge check valve in the P-tube from Y2, a directional spool valve Y3 , a pressure reducing valve (≈ 95 - 100 bar), a diaphragm accumulator (Po- = 60 bar nitrogen) and a cartridge check valve in the P-tube of the base plate are in one control unit 3rd integrated in a single housing.
The integrated directional spool valve Y3 serves as a safety valve for automatically releasing the accumulator pressure when the system is switched off. The diaphragm accumulator is designed for a constant pressure to move the hydraulic cylinder and thus the slide-in unit to open / close the vacuum valve.

The device for the production of die-cast parts also has a modular control. Control means all components and software that are accommodated in a compact control cabinet, which is then connected to the overall system.
The control essentially consists of a control unit 1 and has inputs for the acquisition of all measurement data collected on the device and control outputs for suction paths and subunits such as the hydraulic control 3rd and the pneumatic control 3 ' . The control system is designed so that it is compatible with different components and valve shapes. The controller can control different types of valves in parallel, such as a hydraulic and a pneumatic valve. Replacing a valve type with another type is simple in this way, since only the associated control module is activated and adapted.
With the control system according to the invention, several mold evacuation lines and rapid vacuum lines can be controlled.
The control is implemented in a control cabinet with PLC control. The control enables a reliable query based on the piston position of the molded valve in order to detect the closed state of the valve.
The breech position can, however, also be adjustable and variable without measurement of the position by measuring in the weft movement and is thus controlled by the control system via predefined time sequences.

In 7 the control is shown schematically. The actual software is modular as software components 1a , 1b , 1c , 1d , 1e shown. The software is suitable for operating individual modules together, while unwanted modules remain inactive.

The software modules 1a ... 1e control two control units in this example via data connections 3rd and 3 ' on. These are either control units for valves of the same or different types. So the control unit 3rd a control unit for hydraulic molded vacuum valves, the control unit 3` in contrast, a control unit for pneumatic valves. The control also optionally controls the vacuum units and the actual die casting machine.

• a) Evakuierung einer Druckgießform,
• b) Füllen der Druckgießform mit Gießmaterial,
• c) Entnehmen des Druckgussteiles,
• e) Messungen von Umgebungsparameter im Filtermodul und
• f) entsprechend dem Ergebnis dieser Messungen eine Vorrichtung zur Herstellung von Druckgussteilen gesteuert.

The process for the production of die-cast parts is characterized by the following process steps:

• a) evacuation of a die,
• b) filling the die with casting material,
• c) removing the die-cast part,
• e) measurements of environmental parameters in the filter module and
• f) controlled a device for producing die-cast parts according to the result of these measurements.

This ensures that the method can be controlled in accordance with the actual environmental parameters in the die and can be standardized to corresponding optimized environmental parameters. It is thus possible to set the casting process so that the measured residual moisture reaches a typical minimum depending on the die casting mold and part and the process changes to a stable state.

Reference symbol list

1

Control unit

1a, 1b, 1c, 1d, 1e

Control modules

2nd

Filter module

3rd

Control module

4th

Distribution plate

10th

contraption

12

Die casting mold

16

Suction device

14

Movable mold half

15

Fixed mold half

18th

Vacuum pump

20th

Suction line

20a

management

20b

Suction line

21st

Form vacuum valve

100

Screw connection

101

Reducing double nipple

102

Filter housing

102 a, b

Bottom and lid

103

Thumbscrew

104

Pressure sensor

105

reduction

106

manometer

107

clamp

108

2/2 way valve

200

Filter insert

202

Perforated discs

203

Fine filter

204

Coarse filter

205

O-ring

Claims (3)

Control for a device (10) for producing die-cast parts from a die-casting mold (12) and a suction device provided for the controlled evacuation of a mold cavity, the device being connected to a central controller (1), characterized in that the controller is a control unit ( 1), in which a module (1a, 1b ...) is connected to the device for producing die-cast parts and further modules are connected to at least one hydraulic and pneumatic unit (3, 3 ', ..) for controlling valves, The control unit (1) contains components for controlling valves in the casting tool for the use of vacuum-assisted die casting, the type of the valves, i.e. mechanical, hydraulic, pneumatic, being interchangeable, and the at least one module for the hydraulic unit (3) being parallel with it the at least one module for the pneumatic unit (3) can be operated. Control after Claim 1 , characterized in that the components for controlling valves consist of software components. Control after Claim 1 or 2nd , characterized in that the control unit (1) contains inputs for all measurement data collected on the device.

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