The performance of a product removal machine is not determined solely by the speed and precision of the arm. The performance of the "chuck" that directly holds the molded product also greatly affects productivity, quality, and stable operation of the equipment. If the selection or design of the chuck is not appropriate, it can lead to problems such as products falling, deformation, or misalignment.
In this article,This article explains the role, types, and importance of chucks in retrieval machines, and also introduces the features of chucks from Sailor Pen's Robotics Equipment Division.
▼Key points of this article
- The chuck of an extraction machine is an arm-end mechanism (EOAT) that grips the product while it is being extracted from the mold and transported to a predetermined position.
- The role of a chuck is not just "gripping," but also four other functions: "product removal confirmation (product detection)," "precise positioning," and "internal chuck processing and pitch change."
- The main types are suction cup chucks, blower chucks, mechanical chucks, and composite types, and the appropriate type is selected according to the product shape and transport conditions.
- "Product detection," which detects any remaining product inside the mold, is a crucial function directly related to mold protection.
- Sailor Pen's Robotics Division, with its design philosophy of "reliable handling that does not rely on gravity" and over half a century of experience, can handle multiple item picking and highly difficult retrieval tasks.
What is a chuck in an extraction machine?
In a product extraction machine, the chuck is the arm-end mechanism that grips the product while the machine extracts it from the mold and moves it to a predetermined position..
In the robotics industry, the entire mechanism at the end of an arm is called an "end effector," and the mechanism responsible for gripping is called a "hand." However, at Sailor Pen's Robotics Equipment Division, these gripping mechanisms are collectively referred to as a "chuck (End Of Arm Tool: EOAT)."
First, let me explain the basic function of a zipper.
Basic role of a zipper
The primary role of a chuck in a product dispenser is to grip the product, but that's not all. It primarily performs the following four functions:
- Gripping the molded product
- Product removal confirmation
- Precise positioning
- Machining and pitch changes are performed inside the chuck.
Gripping the molded product
The basic role of a chuck is to securely hold molded parts or runners from inside the molding machine to outside the machine.Therefore, products immediately after injection molding are soft and easily deformed due to the high temperature, so it is necessary to hold them at the appropriate point with a gripping force that matches the shape and material of the workpiece.
Furthermore, since the arm moves at high speed from inside the mold to the conveyor outside the molding machine or to the next processing equipment while still gripping the product, it needs to have enough gripping force to prevent the product from falling due to the force of acceleration and deceleration of the arm.
Product removal confirmation
Chucks are usually equipped with sensors to check whether they have properly gripped the product.
If gripping fails and the product remains inside the mold, the molding machine can be stopped by a sensor signal. This prevents the problem of the mold being damaged if the mold closes with the product still inside.
Precise positioning
When inserting parts into a mold or transferring them to a secondary processing device, positioning pins or a "compliance module (*)" can be installed inside the chuck to achieve precise alignment.
*When positioning pins are installed, the entire chuck needs to move in accordance with the pins to absorb any misalignment at the moment of insertion or part transfer. This mechanism is called a compliance module.
Machining inside the chuck, product pitch change
By incorporating a drive mechanism such as a cylinder within the chuck, it is possible to change the product pitch and arrangement before handing it over to the next process. Furthermore, it is possible to install nippers for runner cutting or incorporate inspection functions.
Main types of chucks for extractors
There are several types of chucks used in extraction machines, depending on the workpiece shape and transport conditions. There are mainly four types, each suited to different applications.
- Suction cup zipper
- Blower chuck
- Mechanical chuck
- Composite type chuck
Selecting a chuck suitable for the product enables stable transport.
*Modification of the extraction machine itself may be required to use a different type of chuck.
Suction cup zipper
A suction cup chuck is a type of chuck that uses a vacuum pad (suction cup) to hold molded products in place.This is how it works. A vacuum generator (ejector) installed in the main body of the device sucks the air out of the suction cup, creating a negative pressure (vacuum) state. The product is then attracted and gripped by the pressure difference with atmospheric pressure. A vacuum generator and its piping are required, but they are usually standard equipment on the extraction machine.
When manufacturing a suction cup chuck, first determine the type, position, and number of suction cups, then use a frame (such as a screw rail) to arrange the suction cup units and connect the piping. Manufacturing is relatively easy compared to other types.
However, to use the suction type, the product must have a smooth surface that the suction cup can adhere to. Products with a textured surface or those that do not have a sufficient surface for adhesion may not have sufficient suction power.
Blower chuck
A blower chuck is a type of suction type.Yes, it uses a large blower motor to suck up the entire product in a way similar to a vacuum cleaner.
This method is used for products that are too small to be held by suction cups, or for products that do not have a flat surface. A thick air pipe needs to be installed on the extraction unit itself.
A blower chuck has a suction opening that is recessed to match the shape of the product, and unlike a suction cup, it is okay if some air leaks between the product and the chuck.
Mechanical chuck
A mechanical chuck is a system that uses an air cylinder to drive the jaws or clamping mechanism, physically gripping and holding the molded product.It is used for heavy molded products that are difficult to hold using vacuum suction alone, as well as for workpieces with complex shapes.
While the mechanical clamping mechanism provides high gripping force, it may leave scratches or indentations on the product surface.
Composite type chuck
A combination of suction cup suction, a blower chuck, and a mechanical chuck within a single chuck.By utilizing the unique features of each method, stable retrieval is achieved.
For example, one use case involves holding the product body with a suction cup while gripping the runner of the submarine gate with a mechanical chuck. Another configuration involves using a blower chuck to hold the product while the runner portion is held in place by a suction cup.
Product detection in a checker
One of the important roles of a chuck is to ensure that the product has been completely removed from the mold, that is, to confirm that no product remains inside the mold. There are several methods for this product detection.
In the case of a suction cup zipper
In the case of suction cup chucks, a method is used in which a pressure sensor is attached to the piping and the pressure is monitored. If the suction cup is properly attached, the vacuum level will increase, and conversely, if the product is dropped and the suction cup is released to the atmosphere, the vacuum level will not increase, so the pressure difference is used for detection.
In the case of a blower chuck
In the case of a blower chuck, detection is possible if there is a sufficient pressure difference between when the product is being held and when it is not (when even one of many products falls). If the pressure difference is not large enough, a laser light sensor may be used.
In the case of a mechanical chuck
In the case of mechanical chucks, one method is to detect whether the product has been properly gripped by using a sensor attached to the cylinder to determine the position of the chuck jaws. Another method involves attaching suction cups to the jaws of the mechanical chuck to detect the product, and detecting it based on the pressure difference described above.
Thus, when designing a chuck, how the product is detected is just as important as how it is gripped.
Features of the Chuck from Sailor Pen's Robotics Division
Chuck performance is a crucial factor affecting the overall efficiency of the molding line. Sailor Pen's Robotics Equipment Division develops unique chucks that can accommodate diverse molding conditions and workpiece shapes. Here, we introduce Sailor's unique features and capabilities.
Sailor's unique zipper design
At Sailor Pen's Robotics Equipment Division, we design chucks optimized for specific workpiece shapes and molding conditions. In particular,The design philosophy employs a focus on securely holding products and ensuring stable transport.Its distinguishing feature is this point.
In the design of equipment for Sailor Pen's robotics division, basicallyAdopting a policy that does not utilize gravityIn other words, instead of using drops or slips to move the product, the arm and chuck are transported to the destination, placed in the designated position, and then released. By reducing the time the product moves through the air without a guide and minimizing reliance on friction for transport, instability is reduced, resulting in stable transport.
Based on a similar design philosophy, the chuck shape and gripping method have also been enhanced to ensure reliable gripping and detection of products. Combined with the high rigidity and vibration damping performance of the extraction machine body, it can handle high-speed extraction and multi-cavity molds with more than 100 cavities.
In addition, Leveraging our experience in manufacturing automated equipment and designing and producing custom chucks for over half a century, we propose optimal chuck designs that can handle even the most challenging retrieval tasks.
Parts and item development including customer-made zippers.
We also stock parts for customers to manufacture their own chucks. In particular, rail-type chucks are highly versatile, and we offer sets tailored to different mold gate types and orientations, making them easy to try out.
Chucks for pin gate and hot runner molds
Because it doesn't require gripping the runner, it has a simple structure. There are several types depending on the chuck rotation method and whether or not it is eccentric.
80 type chuck unit
The 80-type chuck unit isA general-purpose chuck unit compatible with Type D horizontal control (chuck horizontal control), suitable for pin gate and hot runner molds.Because it does not require gripping the runner, it has a relatively simple structure, which allows for stable product holding and reliable transport.
83 type chuck unit
The 83-type chuck unit isGeneral-purpose chuck unit compatible with Type A horizontal control (chuck horizontal control) in the case of no eccentricity..
Chucks for molds such as tunnel gates and side gates
To allow for simultaneous removal of the runners, it incorporates a mechanical chuck-type runner chuck.
81 type chuck unit
The 81-type chuck unit isA general-purpose chuck unit for tunnel gate and side gate molds, compatible with Type D horizontal control (chuck horizontal rotation control unit).It has a built-in mechanical chuck for removing the runner together with the product, allowing you to hold the product and runner at the same time.
*Supports stable removal in tunnel gate and side gate molds.
82 type chuck unit
The 82-type chuck unit isEccentricityNone,Type A horizontal control (chuck horizontal control) compatible general-purpose chuck unitIt is compatible with tunnel gate molds and other types of molds, and is equipped with a mechanical chuck for gripping sprues.
84 type chuck unit
The 84-type chuck unit isCompatible with Type A horizontal control (chuck horizontal control),Tunnel gates, etc.Eccentricity for moldsYesGeneral-purpose chuck unitThis allows for position adjustment according to mold and product conditions due to the eccentric design.
The best type to choose depends on your specific usage conditions, including the size of your molding machine, extraction machine, and mold. Please feel free to contact us for advice.
Summary
In a mold removal machine, the chuck not only grips the molded product but also plays a crucial role in ensuring that the product has been securely removed, thus protecting the mold. There are various types of chucks, such as suction cup chucks, blower chucks, and mechanical chucks, each with its own characteristics and suitable applications.
Selecting the right chuck leads to stable production and high-precision conveying. Sailor Pen's Robotics Equipment Division prioritizes high reliability in chuck design and offers a wide range of parts to meet the needs of diverse molding environments. We propose the optimal chuck for your application and molding conditions.
If you have any questions regarding chuck selection or design, please feel free to contact Sailor Pen's Robotics Division.We offer a wide range of general-purpose chuck units to suit various mold and gate shapes, from pin gates and hot runners to tunnel and side gates. We also design and manufacture custom chucks to accommodate multi-cavity molds with over 100 cavities and highly complex removal processes.
Based on our experience in developing automated equipment for over half a century, we will propose the optimal chuck for your molding process. Please feel free to contact us.
