At the urging of customers, Müller looked at addressing the primary issues with existing Takeout robots for thin wall containers. The existing “state of the art” systems were fairly primitive. Not many technological improvements in years. The key areas where molders found issues with the existing Takeout robots were the following:
- High Volume Vacuum to try to suck containers from mold cores.
- Receivers to capture containers.
- Changing from container to container is time consuming and challenging.
- All cavities do not always eject at the same time.
- Large Footprint, bulky size.
No Receivers
The Müller Takeout robots do not use receivers for removing the finished containers. Receivers inherently have many shortcomings. They can be torn off of the takeout arm. They need to be specific to a containers diameter and height. They are used to try to suck the parts off of the mold cores. The parts don't always come out evenly and do not always sit completely in the receivers.
Without receivers the arm thickness is reduced. This allows the arm to enter the mold area prior to the clamp being fully open. The robot arms are therefore fully in the mold, and in position for removing the ejected containers, at the same time the mold comes to full open. With the receiver method the arms cannot enter until the mold is open enough to give full clearance to the receivers. For taller containers this can add critical tenths of a second to the intrusion time.
The Müller Takeout robots use suction cups to remove the containers from the cores. This eliminates the potential of ripping off receivers. This makes the takeout arm thin and allows the robot to get into the mold and in position to remove the finished containers. All prior to the clamp coming to the full open position.
Dynamic movement
By having no receivers, the Müller takeout arms can start to enter the mold as soon as the mold starts opening. A programmed dynamic entry moves the takeout arm, following with the moving mold. When the clamp comes to the full open position and the ejection signal is given, the Müller arm is already in position to retrieve the molded parts. Dynamic entry allows for a much smoother movement of the arm. This eliminates having extreme accelerations and sudden stopping. These types of sudden and high speed movements cause unnecessary wear and tear on the robot and increase maintenance costs and reduce the life of the robot dramatically. With dynamic entry, Müller is able to still have minimal intrusion times while causing minimal shock to the mechanics of the robot. On the takeout movement the Müller robot does not need to wait for a vacuum signal. By not using receivers the takeout arm can immediately start to move out of the mold, eliminating tenths of seconds of delay time, waiting for all of vacuum signals. The molding machine can get the signal to close as the arm is almost completely out of the mold.
Strip Stroke
With large cavitation mold with a single face or in a stack arrangement, with time, all of the cavities do not eject simultaneously. Individual cavities could stick, poppets get worn out, air valves start to wear. Air distribution may not be completely equal across the whole mold. The Müller Takeout robot incorporates a Strip Stroke. The robot arm moves towards the cores and picks up the finished containers. We do not need to wait for all of the cavities to eject. We do not need to wait for the containers to be completely blown/sucked into the receivers. This is a Takeout Robot not a vacuum cleaner. Müller robots go in and “take-out” the finished container.
Improved efficiency
When receivers are used, high volume vacuum needs to be generated in order to remove the containers off of the mold cores. This method of part removal required substantial air flow to generate the vacuum for part removal. Many current takeout robot suppliers using receivers require high volume air motors to generate the vacuum. High volume vacuum motors are typically used for lifting applications and for cleaning carpets. For removing light, plastic containers, they are not the optimal solution. These motors generate heat, which is pumped into the production floor. They create high volumes of vacuum, but only for the purpose of capturing a relatively small bottom surface of a container. The remaining vacuum simply goes into the atmosphere. Is that efficiency? The Müller Takeout robot does not have any high volume vacuum generators. With the use of focused, suction cups for removal of the containers, only a vacuum pump is required. Today’s vacuum pumps are highly efficient. Offering efficiencies up to four time higher than high volume vacuum generators. Müller is continuing development work on further reducing the air consumption with higher volume, higher efficiency valves and tubing located closer to where it is needed.
Quick changeout time
Müller has developed a technology for making changeovers from mold to mold very quick and easy. Whether the mold change includes a cavitation change and/or a pitch change, Müller has a solution. Müller offers three options of changeovers. A manual changeover which takes approximately 20 minutes for a stack mold. A hybrid method that includes both manual and motor driven changeover. The hybrid method required approximately 10 minutes for changeover. The third method is completely automatic, all done through the robot’s HMI. The fully automatic method takes less than 5 minutes for a complete change on a stack mold. No tools required for the changeover! No storing of EOAT. Eliminates damage caused by moving EOAT’s in and out.
Accumulation time up to 1 hour
All Müller Takeout robots include a stacker. The stacking can be designed to maximize the accumulation times up to 1 hour. An accumulation time of one hours allows for large potential reductions in packing labor. One packer can handle multiple molding machines. The cost savings for the reduced labor can have tremendous impact on the bottom line.
Background information
Founded in 1959, the H. Müller-Fabrique de Moules SA company of Conthey, Switzerland, supplies top quality molds and robots for thin-wall packaging and In-Mold Labeling applications. MÜLLER IML has been developing systems
for use in the plastics packaging industry world-wide since 1993. MÜLLER uses its longstanding know-how and high standard of quality to assist companies in the food, non-food and medical technology sectors with the development of new packaging for their products. The services provided by MÜLLER range from the development of innovative products to the construction of high-capacity production lines and customer support along the entire supply chain. MÜLLER delivers optimum results from a single source with proverbial Swiss precision.