Handling parts in white rooms

GHS Automation AG is a Swiss company specializing in the automation of processes and Spain represented by Alboex. In this article we echo of an application in the molding by injection of a piece for the field of medicine, where the role of automation is very relevant.

Fig. 1 Setting up the computer with description of the different seasons

This fully automated plant, which advises this article serves to manufacture rings of subject of membranes for medical uses. Parts are produced, reviewed and are packed in accordance with strict conditions of white room. A multifunctional robot and gripper system are the two most important elements.

Manufacturing in clean rooms poses a fundamental challenge: when the pieces that will occur are made of plastic and are intended for medical uses, the requirements are much stricter. An example is the fully automated production as described below, which carried out a threefold process: manufacturing of rings of subject of membranes by moulding by injection, quality control and packaging.

The company originator and promoter of the project has been Gemü GmbH (Rotkreuz, Switzerland), while that the production team has been designed and manufactured by GUS Automation AG (formerly Geiger Handling Systems GmbH, see the info box), which has also been the general contractor. This company is specialized in the design of fully automated machines for the production of plastic parts; GUS Automation AG develops projects of very different classes based on their own systems and components, which include: machines for cutting burrs, linear robots, and external supply 6 axis industrial robots. Depending on how they are integrated molding machines by injection or thermoforming and according to the provision of peripheral equipment (material flow), these machines can be operated without interruption. The design of the machine was made difficult by the fact that the rings of subject of membranes should occur, retire and packed in Cleanroom conditions.

To ensure that all stages of the process - from production and manipulation to the exit of the products already packaged - could be carried out in accordance with the conditions, have been arranged two clean rooms. First of all, the area where is located the machine Demag Ergotech 80/420, provided by the client, which had to be adapted in accordance with the requirements of class 6 of the standard ISO 14644-1. This area is also used for the manipulation of parts and packaging. On the other hand, created a cleanroom class 7 for the following tasks: loading of empty metallic containers in the deposit, storage of membrane rings already packed in metallic packaging and storage of spare parts.

The plant is equipped with drawers carriers serving as a means of interconnection between the white room of class 6 (machine of molding injection and manipulation of the robot) and the white room of class 7. Thanks to this element, it is not necessary that no one within the clean rooms during production. The production line is so automated that it is only necessary that among staff for scheduled maintenance operations or if there is a bug.

The main element of the unit of production of rings of subject of membranes is the industrial 6 axis robot, which handles all operations, from the handling, distribution and packaging until the transfer of parts to the appropriate boxes. In order to maintain the conditions of white room, was chosen a Stäubli RX130 robot, which is equipped with a multifunctional grip designed and manufactured by GHS Automation System. The rest of the components of the production line are:

• Machine of molding injection Demag Ergotech 80/420, white room version;

• Machine of molding by injection of a single cavity, which can be adjusted to create three different types of rings;

• Support base for the placement of the sliding deposit (for empty metal containers), drawer carrier for the storage of the already packed rings and receiver holder for storage of the leftover elements;

• Station for the filling of containers; and

• Station for closure (soldier) of the packaging.

Fig. 2. The station 1 serves to separate the metallic packaging and supply

The multifunctional robot and gripper system carried out the most important functions of the plant. The manipulation and the material flow starting in station 1: a unit of hoisting of electric drive separates and takes the metallic packaging of the deposit. The containers are loaded into the deposit in the antechamber (Cleanroom class 7), which then it is transferred to one room white class 6 through a sliding module.

From here, through the grip the robot vacuum device, the package is transferred to station 2 provision of packaging, where it stands and immobilize via suction cups. To open the container, the robot runs grip device by vacuum: from above, a hopper is inserted into the open bag (season 4). At the same time, through the system of grip, the robot takes a complete ring, along with its trough (season 5) of the injection mould. The robot expels the trough a container located under the mold and passes through the upper part of the hopper with membrane clamping ring.

Once introduced the piece molded metal container, through the grip by vacuum device package is transported to the station soldier (season 5), where the containers are sealed on an ongoing basis. Then the robot carries the container sealed until the storage of finished parts (season 6) receiver and deposits it according to a pattern of provision in pallets.

• The length of the cycle

• The time of injection

• The measurement time

• Elespacio of food

• Mass pad

• The temperature of the mold or

• The specific pressure of injection

They exceed the limits of tolerance, the injection molding machine or the own mold send a signal to the robot at the beginning of the cycle. In these cases, immediately after removing the piece, the robot moves to the drawer of pieces of waste (season 7) and there lays the faulty part. Both finished parts drawer and drawer of pieces of waste can be transported manually; to this end, the modules are displaced persons from the white room class 6 to the sector of cleanroom class 7, you can access authorized personnel and download deposits.

Fig. 3. The robot Stäubli RX 130 has been equipped with the multifunctional grip of GSH Automation system

Fig. 4 Internal station 4: the products are introduced in metal containers through a hopper

Fig. 5 Station of soldier for the continuous closure of the full container (season 6)

The automation of this plant for production of rings of subject of membranes in Cleanroom conditions has led to the creation of a highly efficient system of production, review and packaging, capable of carrying out production processes entirely autonomously in a period of 80 minutes. The cycle lasts 40 seconds per piece (material: PVDF) and the time of intervention to remove the pieces and remove the troughs is just 3.5 seconds. Thus, despite using a complex multifunctional grip system, the robot is capable of withdrawing the pieces and remove the troughs at high speeds, thus providing more time for the rest of the tasks.

Due to the weight of the grip system, dynamic movement and various stations to which it should arrive, separated by the corresponding distance, they chose a large robot that could perform all these tasks in a reproducible way. On the other hand, thanks to the high level of functional integration, the production line has been automated with a relatively low number of components. This in turn ensures a high level of availability and stability of process.